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gecko-dev/layout/base/nsLayoutUtils.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsLayoutUtils_h__
#define nsLayoutUtils_h__
#include "LayoutConstants.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/Maybe.h"
#include "mozilla/TypedEnumBits.h"
#include "nsBoundingMetrics.h"
#include "nsChangeHint.h"
#include "nsFrameList.h"
#include "mozilla/layout/FrameChildList.h"
#include "nsThreadUtils.h"
#include "nsIPrincipal.h"
#include "FrameMetrics.h"
#include "nsIWidget.h"
#include "nsCSSPropertyID.h"
#include "nsStyleCoord.h"
#include "nsStyleConsts.h"
#include "nsGkAtoms.h"
#include "imgIContainer.h"
#include "mozilla/gfx/2D.h"
#include "Units.h"
#include "mozilla/ToString.h"
#include "mozilla/ReflowOutput.h"
#include "ImageContainer.h"
#include "gfx2DGlue.h"
#include "nsStyleConsts.h"
#include "SVGImageContext.h"
#include <limits>
#include <algorithm>
#include "gfxPoint.h"
#include "nsClassHashtable.h"
class gfxContext;
class nsPresContext;
class nsIContent;
class nsAtom;
class nsIScrollableFrame;
class nsRegion;
class nsDisplayListBuilder;
enum class nsDisplayListBuilderMode : uint8_t;
class nsDisplayItem;
class nsFontMetrics;
class nsFontFaceList;
class nsIImageLoadingContent;
class nsBlockFrame;
class nsContainerFrame;
class nsView;
class nsIFrame;
class nsStyleCoord;
class nsStyleCorners;
class nsPIDOMWindowOuter;
class imgIRequest;
class nsIDocument;
struct nsStyleFont;
struct nsOverflowAreas;
namespace mozilla {
class ComputedStyle;
enum class CSSPseudoElementType : uint8_t;
class EventListenerManager;
enum class LayoutFrameType : uint8_t;
struct IntrinsicSize;
struct ContainerLayerParameters;
class WritingMode;
class DisplayItemClip;
class EffectSet;
struct ActiveScrolledRoot;
enum class StyleImageOrientation : uint8_t;
namespace dom {
class CanvasRenderingContext2D;
class DOMRectList;
class Element;
class Event;
class HTMLImageElement;
class HTMLCanvasElement;
class HTMLVideoElement;
class InspectorFontFace;
class OffscreenCanvas;
class Selection;
} // namespace dom
namespace gfx {
struct RectCornerRadii;
enum class ShapedTextFlags : uint16_t;
} // namespace gfx
namespace layers {
class Image;
class StackingContextHelper;
class Layer;
} // namespace layers
} // namespace mozilla
namespace mozilla {
struct DisplayPortPropertyData {
DisplayPortPropertyData(const nsRect& aRect, uint32_t aPriority)
: mRect(aRect)
, mPriority(aPriority)
{}
nsRect mRect;
uint32_t mPriority;
};
struct DisplayPortMarginsPropertyData {
DisplayPortMarginsPropertyData(const ScreenMargin& aMargins,
uint32_t aPriority)
: mMargins(aMargins)
, mPriority(aPriority)
{}
ScreenMargin mMargins;
uint32_t mPriority;
};
struct MotionPathData {
gfx::Point mTranslate;
float mRotate;
};
} // namespace mozilla
// For GetDisplayPort
enum class RelativeTo {
ScrollPort,
ScrollFrame
};
// Flags to customize the behavior of nsLayoutUtils::DrawString.
enum class DrawStringFlags {
eDefault = 0x0,
eForceHorizontal = 0x1 // Forces the text to be drawn horizontally.
};
MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(DrawStringFlags)
enum class ReparentingDirection {
Backwards,
Forwards,
Variable // Could be either of the above; take most pessimistic action.
};
/**
* nsLayoutUtils is a namespace class used for various helper
* functions that are useful in multiple places in layout. The goal
* is not to define multiple copies of the same static helper.
*/
class nsLayoutUtils
{
typedef mozilla::ComputedStyle ComputedStyle;
typedef mozilla::dom::DOMRectList DOMRectList;
typedef mozilla::layers::Layer Layer;
typedef mozilla::layers::StackingContextHelper StackingContextHelper;
typedef mozilla::ContainerLayerParameters ContainerLayerParameters;
typedef mozilla::IntrinsicSize IntrinsicSize;
typedef mozilla::gfx::SourceSurface SourceSurface;
typedef mozilla::gfx::Color Color;
typedef mozilla::gfx::DrawTarget DrawTarget;
typedef mozilla::gfx::ExtendMode ExtendMode;
typedef mozilla::gfx::SamplingFilter SamplingFilter;
typedef mozilla::gfx::Float Float;
typedef mozilla::gfx::Point Point;
typedef mozilla::gfx::Rect Rect;
typedef mozilla::gfx::RectDouble RectDouble;
typedef mozilla::gfx::Size Size;
typedef mozilla::gfx::Matrix4x4 Matrix4x4;
typedef mozilla::gfx::Matrix4x4Flagged Matrix4x4Flagged;
typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
typedef mozilla::gfx::StrokeOptions StrokeOptions;
typedef mozilla::image::ImgDrawResult ImgDrawResult;
public:
typedef mozilla::layers::FrameMetrics FrameMetrics;
typedef mozilla::layers::ScrollMetadata ScrollMetadata;
typedef FrameMetrics::ViewID ViewID;
typedef mozilla::CSSPoint CSSPoint;
typedef mozilla::CSSSize CSSSize;
typedef mozilla::CSSIntSize CSSIntSize;
typedef mozilla::CSSRect CSSRect;
typedef mozilla::ScreenMargin ScreenMargin;
typedef mozilla::LayoutDeviceIntSize LayoutDeviceIntSize;
typedef mozilla::LayoutDeviceRect LayoutDeviceRect;
typedef mozilla::StyleGeometryBox StyleGeometryBox;
typedef mozilla::SVGImageContext SVGImageContext;
typedef mozilla::LogicalSize LogicalSize;
/**
* Finds previously assigned ViewID for the given content element, if any.
* Returns whether a ViewID was previously assigned.
*/
static bool FindIDFor(const nsIContent* aContent, ViewID* aOutViewId);
/**
* Finds previously assigned or generates a unique ViewID for the given
* content element.
*/
static ViewID FindOrCreateIDFor(nsIContent* aContent);
/**
* Find content for given ID.
*/
static nsIContent* FindContentFor(ViewID aId);
/**
* Find the scrollable frame for a given ID.
*/
static nsIScrollableFrame* FindScrollableFrameFor(ViewID aId);
/**
* Find the ID for a given scrollable frame.
*/
static ViewID FindIDForScrollableFrame(nsIScrollableFrame* aScrollable);
/**
* Get display port for the given element, relative to the specified entity,
* defaulting to the scrollport.
*/
static bool GetDisplayPort(nsIContent* aContent, nsRect *aResult,
RelativeTo aRelativeTo = RelativeTo::ScrollPort);
/**
* Check whether the given element has a displayport.
*/
static bool HasDisplayPort(nsIContent* aContent);
/**
* Check whether the given frame has a displayport. It returns false
* for scrolled frames and true for the corresponding scroll frame.
* Optionally pass the child, and it only returns true if the child is the
* scrolled frame for the displayport.
*/
static bool FrameHasDisplayPort(nsIFrame* aFrame, const nsIFrame* aScrolledFrame = nullptr);
/**
* Check if the given element has a margins based displayport but is missing a
* displayport base rect that it needs to properly compute a displayport rect.
*/
static bool IsMissingDisplayPortBaseRect(nsIContent* aContent);
/**
* Go through the IPC Channel and update displayport margins for content
* elements based on UpdateFrame messages. The messages are left in the
* queue and will be fully processed when dequeued. The aim is to paint
* the most up-to-date displayport without waiting for these message to
* go through the message queue.
*/
static void UpdateDisplayPortMarginsFromPendingMessages();
/**
* @return the display port for the given element which should be used for
* visibility testing purposes.
*
* If low-precision buffers are enabled, this is the critical display port;
* otherwise, it's the same display port returned by GetDisplayPort().
*/
static bool GetDisplayPortForVisibilityTesting(
nsIContent* aContent,
nsRect* aResult,
RelativeTo aRelativeTo = RelativeTo::ScrollPort);
enum class RepaintMode : uint8_t {
Repaint,
DoNotRepaint
};
/**
* Invalidate for displayport change.
*/
static void InvalidateForDisplayPortChange(nsIContent* aContent,
bool aHadDisplayPort,
const nsRect& aOldDisplayPort,
const nsRect& aNewDisplayPort,
RepaintMode aRepaintMode = RepaintMode::Repaint);
/**
* Set the display port margins for a content element to be used with a
* display port base (see SetDisplayPortBase()).
* See also nsIDOMWindowUtils.setDisplayPortMargins.
* @param aContent the content element for which to set the margins
* @param aPresShell the pres shell for the document containing the element
* @param aMargins the margins to set
* @param aAlignmentX, alignmentY the amount of pixels to which to align the
* displayport built by combining the base
* rect with the margins, in either direction
* @param aPriority a priority value to determine which margins take effect
* when multiple callers specify margins
* @param aRepaintMode whether to schedule a paint after setting the margins
* @return true if the new margins were applied.
*/
static bool SetDisplayPortMargins(nsIContent* aContent,
nsIPresShell* aPresShell,
const ScreenMargin& aMargins,
uint32_t aPriority = 0,
RepaintMode aRepaintMode = RepaintMode::Repaint);
/**
* Set the display port base rect for given element to be used with display
* port margins.
* SetDisplayPortBaseIfNotSet is like SetDisplayPortBase except it only sets
* the display port base to aBase if no display port base is currently set.
*/
static void SetDisplayPortBase(nsIContent* aContent, const nsRect& aBase);
static void SetDisplayPortBaseIfNotSet(nsIContent* aContent, const nsRect& aBase);
/**
* Get the critical display port for the given element.
*/
static bool GetCriticalDisplayPort(nsIContent* aContent, nsRect* aResult);
/**
* Check whether the given element has a critical display port.
*/
static bool HasCriticalDisplayPort(nsIContent* aContent);
/**
* If low-precision painting is turned on, delegates to GetCriticalDisplayPort.
* Otherwise, delegates to GetDisplayPort.
*/
static bool GetHighResolutionDisplayPort(nsIContent* aContent, nsRect* aResult);
/**
* Remove the displayport for the given element.
*/
static void RemoveDisplayPort(nsIContent* aContent);
/**
* Use heuristics to figure out the child list that
* aChildFrame is currently in.
*/
static mozilla::layout::FrameChildListID GetChildListNameFor(nsIFrame* aChildFrame);
/**
* Returns the ::before pseudo-element for aContent, if any.
*/
static mozilla::dom::Element* GetBeforePseudo(const nsIContent* aContent);
/**
* Returns the frame corresponding to the ::before pseudo-element for
* aContent, if any.
*/
static nsIFrame* GetBeforeFrame(const nsIContent* aContent);
/**
* Returns the ::after pseudo-element for aContent, if any.
*/
static mozilla::dom::Element* GetAfterPseudo(const nsIContent* aContent);
/**
* Returns the frame corresponding to the ::after pseudo-element for aContent,
* if any.
*/
static nsIFrame* GetAfterFrame(const nsIContent* aContent);
/**
* Given a frame, search up the frame tree until we find an
* ancestor that (or the frame itself) is of type aFrameType, if any.
*
* @param aFrame the frame to start at
* @param aFrameType the frame type to look for
* @param aStopAt a frame to stop at after we checked it
* @return a frame of the given type or nullptr if no
* such ancestor exists
*/
static nsIFrame* GetClosestFrameOfType(nsIFrame* aFrame,
mozilla::LayoutFrameType aFrameType,
nsIFrame* aStopAt = nullptr);
/**
* Given a frame, search up the frame tree until we find an
* ancestor that (or the frame itself) is a "Page" frame, if any.
*
* @param aFrame the frame to start at
* @return a frame of type mozilla::LayoutFrameType::Page or nullptr if no
* such ancestor exists
*/
static nsIFrame* GetPageFrame(nsIFrame* aFrame);
/**
* Given a frame which is the primary frame for an element,
* return the frame that has the non-pseudoelement ComputedStyle for
* the content.
* This is aPrimaryFrame itself except for tableWrapper frames.
*
* Given a non-null input, this will return null if and only if its
* argument is a table wrapper frame that is mid-destruction (and its
* table frame has been destroyed).
*/
static nsIFrame* GetStyleFrame(nsIFrame* aPrimaryFrame);
/**
* Given a content node,
* return the frame that has the non-pseudoelement ComputedStyle for
* the content. May return null.
* This is aContent->GetPrimaryFrame() except for tableWrapper frames.
*/
static nsIFrame* GetStyleFrame(const nsIContent* aContent);
/**
* Gets the real primary frame associated with the content object.
*
* In the case of absolutely positioned elements and floated elements,
* the real primary frame is the frame that is out of the flow and not the
* placeholder frame.
*/
static nsIFrame* GetRealPrimaryFrameFor(const nsIContent* aContent);
#ifdef DEBUG
// TODO: remove, see bug 598468.
static bool gPreventAssertInCompareTreePosition;
#endif // DEBUG
/**
* CompareTreePosition determines whether aContent1 comes before or
* after aContent2 in a preorder traversal of the content tree.
*
* @param aCommonAncestor either null, or a common ancestor of
* aContent1 and aContent2. Actually this is
* only a hint; if it's not an ancestor of
* aContent1 or aContent2, this function will
* still work, but it will be slower than
* normal.
* @return < 0 if aContent1 is before aContent2
* > 0 if aContent1 is after aContent2,
* 0 otherwise (meaning they're the same, or they're in
* different documents)
*/
static int32_t CompareTreePosition(nsIContent* aContent1,
nsIContent* aContent2,
const nsIContent* aCommonAncestor = nullptr)
{
return DoCompareTreePosition(aContent1, aContent2, -1, 1, aCommonAncestor);
}
/*
* More generic version of |CompareTreePosition|. |aIf1Ancestor|
* gives the value to return when 1 is an ancestor of 2, and likewise
* for |aIf2Ancestor|. Passing (-1, 1) gives preorder traversal
* order, and (1, -1) gives postorder traversal order.
*/
static int32_t DoCompareTreePosition(nsIContent* aContent1,
nsIContent* aContent2,
int32_t aIf1Ancestor,
int32_t aIf2Ancestor,
const nsIContent* aCommonAncestor = nullptr);
/**
* CompareTreePosition determines whether aFrame1 comes before or
* after aFrame2 in a preorder traversal of the frame tree, where out
* of flow frames are treated as children of their placeholders. This is
* basically the same ordering as DoCompareTreePosition(nsIContent*) except
* that it handles anonymous content properly and there are subtleties with
* continuations.
*
* @param aCommonAncestor either null, or a common ancestor of
* aContent1 and aContent2. Actually this is
* only a hint; if it's not an ancestor of
* aContent1 or aContent2, this function will
* still work, but it will be slower than
* normal.
* @return < 0 if aContent1 is before aContent2
* > 0 if aContent1 is after aContent2,
* 0 otherwise (meaning they're the same, or they're in
* different frame trees)
*/
static int32_t CompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
nsIFrame* aCommonAncestor = nullptr)
{
return DoCompareTreePosition(aFrame1, aFrame2, -1, 1, aCommonAncestor);
}
static int32_t CompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
nsTArray<nsIFrame*>& aFrame2Ancestors,
nsIFrame* aCommonAncestor = nullptr)
{
return DoCompareTreePosition(aFrame1, aFrame2, aFrame2Ancestors,
-1, 1, aCommonAncestor);
}
/*
* More generic version of |CompareTreePosition|. |aIf1Ancestor|
* gives the value to return when 1 is an ancestor of 2, and likewise
* for |aIf2Ancestor|. Passing (-1, 1) gives preorder traversal
* order, and (1, -1) gives postorder traversal order.
*/
static int32_t DoCompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
int32_t aIf1Ancestor,
int32_t aIf2Ancestor,
nsIFrame* aCommonAncestor = nullptr);
static nsIFrame* FillAncestors(nsIFrame* aFrame,
nsIFrame* aStopAtAncestor,
nsTArray<nsIFrame*>* aAncestors);
static int32_t DoCompareTreePosition(nsIFrame* aFrame1,
nsIFrame* aFrame2,
nsTArray<nsIFrame*>& aFrame2Ancestors,
int32_t aIf1Ancestor,
int32_t aIf2Ancestor,
nsIFrame* aCommonAncestor);
/**
* LastContinuationWithChild gets the last continuation in aFrame's chain
* that has a child, or the first continuation if the frame has no children.
*/
static nsContainerFrame* LastContinuationWithChild(nsContainerFrame* aFrame);
/**
* GetLastSibling simply finds the last sibling of aFrame, or returns nullptr if
* aFrame is null.
*/
static nsIFrame* GetLastSibling(nsIFrame* aFrame);
/**
* FindSiblingViewFor locates the child of aParentView that aFrame's
* view should be inserted 'above' (i.e., before in sibling view
* order). This is the first child view of aParentView whose
* corresponding content is before aFrame's content (view siblings
* are in reverse content order).
*/
static nsView* FindSiblingViewFor(nsView* aParentView, nsIFrame* aFrame);
/**
* Get the parent of aFrame. If aFrame is the root frame for a document,
* and the document has a parent document in the same view hierarchy, then
* we try to return the subdocumentframe in the parent document.
* @param aExtraOffset [in/out] if non-null, then as we cross documents
* an extra offset may be required and it will be added to aCrossDocOffset.
* Be careful dealing with this extra offset as it is in app units of the
* parent document, which may have a different app units per dev pixel ratio
* than the child document.
*/
static nsIFrame* GetCrossDocParentFrame(const nsIFrame* aFrame,
nsPoint* aCrossDocOffset = nullptr);
/**
* IsProperAncestorFrame checks whether aAncestorFrame is an ancestor
* of aFrame and not equal to aFrame.
* @param aCommonAncestor nullptr, or a common ancestor of aFrame and
* aAncestorFrame. If non-null, this can bound the search and speed up
* the function
*/
static bool IsProperAncestorFrame(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
nsIFrame* aCommonAncestor = nullptr);
/**
* Like IsProperAncestorFrame, but looks across document boundaries.
*
* Just like IsAncestorFrameCrossDoc, except that it returns false when
* aFrame == aAncestorFrame.
*/
static bool IsProperAncestorFrameCrossDoc(nsIFrame* aAncestorFrame, nsIFrame* aFrame,
nsIFrame* aCommonAncestor = nullptr);
/**
* IsAncestorFrameCrossDoc checks whether aAncestorFrame is an ancestor
* of aFrame or equal to aFrame, looking across document boundaries.
* @param aCommonAncestor nullptr, or a common ancestor of aFrame and
* aAncestorFrame. If non-null, this can bound the search and speed up
* the function.
*
* Just like IsProperAncestorFrameCrossDoc, except that it returns true when
* aFrame == aAncestorFrame.
*/
static bool IsAncestorFrameCrossDoc(const nsIFrame* aAncestorFrame, const nsIFrame* aFrame,
const nsIFrame* aCommonAncestor = nullptr);
/**
* Sets the fixed-pos metadata properties on aLayer.
* aAnchorRect is the basic anchor rectangle. If aFixedPosFrame is not a viewport
* frame, then we pick a corner of aAnchorRect to as the anchor point for the
* fixed-pos layer (i.e. the point to remain stable during zooming), based
* on which of the fixed-pos frame's CSS absolute positioning offset
* properties (top, left, right, bottom) are auto. aAnchorRect is in the
* coordinate space of aLayer's container layer (i.e. relative to the reference
* frame of the display item which is building aLayer's container layer).
*/
static void SetFixedPositionLayerData(Layer* aLayer, const nsIFrame* aViewportFrame,
const nsRect& aAnchorRect,
const nsIFrame* aFixedPosFrame,
nsPresContext* aPresContext,
const ContainerLayerParameters& aContainerParameters);
/**
* Get the scroll id for the root scrollframe of the presshell of the given
* prescontext. Returns NULL_SCROLL_ID if it couldn't be found.
*/
static FrameMetrics::ViewID ScrollIdForRootScrollFrame(nsPresContext* aPresContext);
/**
* Return true if aPresContext's viewport has a displayport.
*/
static bool ViewportHasDisplayPort(nsPresContext* aPresContext);
/**
* Return true if aFrame is a fixed-pos frame and is a child of a viewport
* which has a displayport. These frames get special treatment from the compositor.
* aDisplayPort, if non-null, is set to the display port rectangle (relative to
* the viewport).
*/
static bool IsFixedPosFrameInDisplayPort(const nsIFrame* aFrame);
/**
* GetScrollableFrameFor returns the scrollable frame for a scrolled frame
*/
static nsIScrollableFrame* GetScrollableFrameFor(const nsIFrame *aScrolledFrame);
/**
* GetNearestScrollableFrameForDirection locates the first ancestor of
* aFrame (or aFrame itself) that is scrollable with overflow:scroll or
* overflow:auto in the given direction and where either the scrollbar for
* that direction is visible or the frame can be scrolled by some
* positive amount in that direction.
* The search extends across document boundaries.
*
* @param aFrame the frame to start with
* @param aDirection Whether it's for horizontal or vertical scrolling.
* @return the nearest scrollable frame or nullptr if not found
*/
enum Direction { eHorizontal, eVertical };
static nsIScrollableFrame* GetNearestScrollableFrameForDirection(nsIFrame* aFrame,
Direction aDirection);
enum {
/**
* If the SCROLLABLE_SAME_DOC flag is set, then we only walk the frame tree
* up to the root frame in the current document.
*/
SCROLLABLE_SAME_DOC = 0x01,
/**
* If the SCROLLABLE_INCLUDE_HIDDEN flag is set then we allow
* overflow:hidden scrollframes to be returned as scrollable frames.
*/
SCROLLABLE_INCLUDE_HIDDEN = 0x02,
/**
* If the SCROLLABLE_ONLY_ASYNC_SCROLLABLE flag is set, then we only
* want to match scrollable frames for which WantAsyncScroll() returns
* true.
*/
SCROLLABLE_ONLY_ASYNC_SCROLLABLE = 0x04,
/**
* If the SCROLLABLE_ALWAYS_MATCH_ROOT flag is set, then we will always
* return the root scrollable frame for the root document (in the current
* process) if we encounter it, whether or not it is async scrollable or
* overflow: hidden.
*/
SCROLLABLE_ALWAYS_MATCH_ROOT = 0x08,
/**
* If the SCROLLABLE_FIXEDPOS_FINDS_ROOT flag is set, then for fixed-pos
* frames that are in the root document (in the current process) return the
* root scrollable frame for that document.
*/
SCROLLABLE_FIXEDPOS_FINDS_ROOT = 0x10
};
/**
* GetNearestScrollableFrame locates the first ancestor of aFrame
* (or aFrame itself) that is scrollable with overflow:scroll or
* overflow:auto in some direction.
*
* @param aFrame the frame to start with
* @param aFlags if SCROLLABLE_SAME_DOC is set, do not search across
* document boundaries. If SCROLLABLE_INCLUDE_HIDDEN is set, include
* frames scrollable with overflow:hidden.
* @return the nearest scrollable frame or nullptr if not found
*/
static nsIScrollableFrame* GetNearestScrollableFrame(nsIFrame* aFrame,
uint32_t aFlags = 0);
/**
* GetScrolledRect returns the range of allowable scroll offsets
* for aScrolledFrame, assuming the scrollable overflow area is
* aScrolledFrameOverflowArea and the scrollport size is aScrollPortSize.
* aDirection is either NS_STYLE_DIRECTION_LTR or NS_STYLE_DIRECTION_RTL.
*/
static nsRect GetScrolledRect(nsIFrame* aScrolledFrame,
const nsRect& aScrolledFrameOverflowArea,
const nsSize& aScrollPortSize,
uint8_t aDirection);
/**
* HasPseudoStyle returns true if aContent (whose primary style
* context is aComputedStyle) has the aPseudoElement pseudo-style
* attached to it; returns false otherwise.
*
* @param aContent the content node we're looking at
* @param aComputedStyle aContent's ComputedStyle
* @param aPseudoElement the id of the pseudo style we care about
* @param aPresContext the presentation context
* @return whether aContent has aPseudoElement style attached to it
*/
static bool HasPseudoStyle(nsIContent* aContent,
ComputedStyle* aComputedStyle,
mozilla::CSSPseudoElementType aPseudoElement,
nsPresContext* aPresContext);
/**
* If this frame is a placeholder for a float, then return the float,
* otherwise return nullptr. aPlaceholder must be a placeholder frame.
*/
static nsIFrame* GetFloatFromPlaceholder(nsIFrame* aPlaceholder);
// Combine aNewBreakType with aOrigBreakType, but limit the break types
// to StyleClear::Left, Right, Both.
static mozilla::StyleClear CombineBreakType(mozilla::StyleClear aOrigBreakType,
mozilla::StyleClear aNewBreakType);
/**
* Get the coordinates of a given DOM mouse event, relative to a given
* frame. Works only for DOM events generated by WidgetGUIEvents.
* @param aDOMEvent the event
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetDOMEventCoordinatesRelativeTo(mozilla::dom::Event* aDOMEvent,
nsIFrame* aFrame);
/**
* Get the coordinates of a given native mouse event, relative to a given
* frame.
* @param aEvent the event
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetEventCoordinatesRelativeTo(
const mozilla::WidgetEvent* aEvent,
nsIFrame* aFrame);
/**
* Get the coordinates of a given point relative to an event and a
* given frame.
* @param aEvent the event
* @param aPoint the point to get the coordinates relative to
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetEventCoordinatesRelativeTo(
const mozilla::WidgetEvent* aEvent,
const mozilla::LayoutDeviceIntPoint& aPoint,
nsIFrame* aFrame);
/**
* Get the coordinates of a given point relative to a widget and a
* given frame.
* @param aWidget the event src widget
* @param aPoint the point to get the coordinates relative to
* @param aFrame the frame to make coordinates relative to
* @return the point, or (NS_UNCONSTRAINEDSIZE, NS_UNCONSTRAINEDSIZE) if
* for some reason the coordinates for the mouse are not known (e.g.,
* the event is not a GUI event).
*/
static nsPoint GetEventCoordinatesRelativeTo(nsIWidget* aWidget,
const mozilla::LayoutDeviceIntPoint& aPoint,
nsIFrame* aFrame);
/**
* Get the popup frame of a given native mouse event.
* @param aPresContext only check popups within aPresContext or a descendant
* @param aEvent the event.
* @return Null, if there is no popup frame at the point, otherwise,
* returns top-most popup frame at the point.
*/
static nsIFrame* GetPopupFrameForEventCoordinates(
nsPresContext* aPresContext,
const mozilla::WidgetEvent* aEvent);
/**
* Get container and offset if aEvent collapses Selection.
* @param aPresShell The PresShell handling aEvent.
* @param aEvent The event having coordinates where you want to
* collapse Selection.
* @param aContainer Returns the container node at the point.
* Set nullptr if you don't need this.
* @param aOffset Returns offset in the container node at the point.
* Set nullptr if you don't need this.
*/
MOZ_CAN_RUN_SCRIPT
static void GetContainerAndOffsetAtEvent(nsIPresShell* aPresShell,
const mozilla::WidgetEvent* aEvent,
nsIContent** aContainer,
int32_t* aOffset);
/**
* Translate from widget coordinates to the view's coordinates
* @param aPresContext the PresContext for the view
* @param aWidget the widget
* @param aPt the point relative to the widget
* @param aView view to which returned coordinates are relative
* @return the point in the view's coordinates
*/
static nsPoint TranslateWidgetToView(nsPresContext* aPresContext,
nsIWidget* aWidget,
const mozilla::LayoutDeviceIntPoint& aPt,
nsView* aView);
/**
* Translate from view coordinates to the widget's coordinates.
* @param aPresContext the PresContext for the view
* @param aView the view
* @param aPt the point relative to the view
* @param aWidget the widget to which returned coordinates are relative
* @return the point in the view's coordinates
*/
static mozilla::LayoutDeviceIntPoint
TranslateViewToWidget(nsPresContext* aPresContext,
nsView* aView, nsPoint aPt,
nsIWidget* aWidget);
static mozilla::LayoutDeviceIntPoint
WidgetToWidgetOffset(nsIWidget* aFromWidget, nsIWidget* aToWidget);
enum FrameForPointFlags {
/**
* When set, paint suppression is ignored, so we'll return non-root page
* elements even if paint suppression is stopping them from painting.
*/
IGNORE_PAINT_SUPPRESSION = 0x01,
/**
* When set, clipping due to the root scroll frame (and any other viewport-
* related clipping) is ignored.
*/
IGNORE_ROOT_SCROLL_FRAME = 0x02,
/**
* When set, return only content in the same document as aFrame.
*/
IGNORE_CROSS_DOC = 0x04,
/**
* When set, return only content that is actually visible.
*/
ONLY_VISIBLE = 0x08
};
/**
* Given aFrame, the root frame of a stacking context, find its descendant
* frame under the point aPt that receives a mouse event at that location,
* or nullptr if there is no such frame.
* @param aPt the point, relative to the frame origin
* @param aFlags some combination of FrameForPointFlags
*/
static nsIFrame* GetFrameForPoint(nsIFrame* aFrame, nsPoint aPt,
uint32_t aFlags = 0);
/**
* Given aFrame, the root frame of a stacking context, find all descendant
* frames under the area of a rectangle that receives a mouse event,
* or nullptr if there is no such frame.
* @param aRect the rect, relative to the frame origin
* @param aOutFrames an array to add all the frames found
* @param aFlags some combination of FrameForPointFlags
*/
static nsresult GetFramesForArea(nsIFrame* aFrame, const nsRect& aRect,
nsTArray<nsIFrame*> &aOutFrames,
uint32_t aFlags = 0);
/**
* Transform aRect relative to aFrame up to the coordinate system of
* aAncestor. Computes the bounding-box of the true quadrilateral.
* Pass non-null aPreservesAxisAlignedRectangles and it will be set to true if
* we only need to use a 2d transform that PreservesAxisAlignedRectangles().
*
* |aMatrixCache| allows for optimizations in recomputing the same matrix over
* and over. The argument can be one of the following values:
* nullptr (the default) - No optimization; the transform matrix is computed on
* every call to this function.
* non-null pointer to an empty Maybe<Matrix4x4> - Upon return, the Maybe is
* filled with the transform matrix that was computed. This can then be passed
* in to subsequent calls with the same source and destination frames to avoid
* recomputing the matrix.
* non-null pointer to a non-empty Matrix4x4 - The provided matrix will be used
* as the transform matrix and applied to the rect.
*/
static nsRect TransformFrameRectToAncestor(const nsIFrame* aFrame,
const nsRect& aRect,
const nsIFrame* aAncestor,
bool* aPreservesAxisAlignedRectangles = nullptr,
mozilla::Maybe<Matrix4x4Flagged>* aMatrixCache = nullptr,
bool aStopAtStackingContextAndDisplayPortAndOOFFrame = false,
nsIFrame** aOutAncestor = nullptr);
/**
* Gets the transform for aFrame relative to aAncestor. Pass null for
* aAncestor to go up to the root frame. aInCSSUnits set to true will
* return CSS units, set to false (the default) will return App units.
*/
static Matrix4x4Flagged GetTransformToAncestor(const nsIFrame *aFrame,
const nsIFrame *aAncestor,
uint32_t aFlags = 0,
nsIFrame** aOutAncestor = nullptr);
/**
* Gets the scale factors of the transform for aFrame relative to the root
* frame if this transform is 2D, or the identity scale factors otherwise.
*/
static gfxSize GetTransformToAncestorScale(nsIFrame* aFrame);
/**
* Gets the scale factors of the transform for aFrame relative to the root
* frame if this transform is 2D, or the identity scale factors otherwise.
* If some frame on the path from aFrame to the display root frame may have an
* animated scale, returns the identity scale factors.
*/
static gfxSize GetTransformToAncestorScaleExcludingAnimated(nsIFrame* aFrame);
/**
* Find the nearest common ancestor frame for aFrame1 and aFrame2. The
* ancestor frame could be cross-doc.
*/
static nsIFrame* FindNearestCommonAncestorFrame(nsIFrame* aFrame1,
nsIFrame* aFrame2);
/**
* Transforms a list of CSSPoints from aFromFrame to aToFrame, taking into
* account all relevant transformations on the frames up to (but excluding)
* their nearest common ancestor.
* If we encounter a transform that we need to invert but which is
* non-invertible, we return NONINVERTIBLE_TRANSFORM. If the frames have
* no common ancestor, we return NO_COMMON_ANCESTOR.
* If this returns TRANSFORM_SUCCEEDED, the points in aPoints are transformed
* in-place, otherwise they are untouched.
*/
enum TransformResult {
TRANSFORM_SUCCEEDED,
NO_COMMON_ANCESTOR,
NONINVERTIBLE_TRANSFORM
};
static TransformResult TransformPoints(nsIFrame* aFromFrame, nsIFrame* aToFrame,
uint32_t aPointCount, CSSPoint* aPoints);
/**
* Same as above function, but transform points in app units and
* handle 1 point per call.
*/
static TransformResult TransformPoint(nsIFrame* aFromFrame, nsIFrame* aToFrame,
nsPoint& aPoint);
/**
* Transforms a rect from aFromFrame to aToFrame. In app units.
* Returns the bounds of the actual rect if the transform requires rotation
* or anything complex like that.
*/
static TransformResult TransformRect(nsIFrame* aFromFrame, nsIFrame* aToFrame,
nsRect& aRect);
/**
* Converts app units to pixels (with optional snapping) and appends as a
* translation to aTransform.
*/
static void PostTranslate(Matrix4x4& aTransform, const nsPoint& aOrigin, float aAppUnitsPerPixel, bool aRounded);
/**
* Get the border-box of aElement's primary frame, transformed it to be
* relative to aFrame.
*/
static nsRect GetRectRelativeToFrame(mozilla::dom::Element* aElement,
nsIFrame* aFrame);
/**
* Returns true if aRect with border inflation of size aInflateSize contains
* aPoint.
*/
static bool ContainsPoint(const nsRect& aRect, const nsPoint& aPoint,
nscoord aInflateSize);
/**
* Clamp aRect relative to aFrame to the scroll frames boundary searching from
* aFrame.
*/
static nsRect ClampRectToScrollFrames(nsIFrame* aFrame,
const nsRect& aRect);
/**
* Return true if a "layer transform" could be computed for aFrame,
* and optionally return the computed transform. The returned
* transform is what would be set on the layer currently if a layers
* transaction were opened at the time this helper is called.
*/
static bool GetLayerTransformForFrame(nsIFrame* aFrame,
Matrix4x4Flagged* aTransform);
/**
* Given a point in the global coordinate space, returns that point expressed
* in the coordinate system of aFrame. This effectively inverts all
* transforms between this point and the root frame.
*
* @param aFrame The frame that acts as the coordinate space container.
* @param aPoint The point, in the global space, to get in the frame-local space.
* @return aPoint, expressed in aFrame's canonical coordinate space.
*/
static nsPoint TransformRootPointToFrame(nsIFrame* aFrame,
const nsPoint &aPoint)
{
return TransformAncestorPointToFrame(aFrame, aPoint, nullptr);
}
/**
* Transform aPoint relative to aAncestor down to the coordinate system of
* aFrame.
*/
static nsPoint TransformAncestorPointToFrame(nsIFrame* aFrame,
const nsPoint& aPoint,
nsIFrame* aAncestor);
/**
* Helper function that, given a rectangle and a matrix, returns the smallest
* rectangle containing the image of the source rectangle.
*
* @param aBounds The rectangle to transform.
* @param aMatrix The matrix to transform it with.
* @param aFactor The number of app units per graphics unit.
* @return The smallest rect that contains the image of aBounds.
*/
static nsRect MatrixTransformRect(const nsRect &aBounds,
const Matrix4x4 &aMatrix, float aFactor);
static nsRect MatrixTransformRect(const nsRect &aBounds,
const Matrix4x4Flagged &aMatrix, float aFactor);
/**
* Helper function that, given a point and a matrix, returns the image
* of that point under the matrix transform.
*
* @param aPoint The point to transform.
* @param aMatrix The matrix to transform it with.
* @param aFactor The number of app units per graphics unit.
* @return The image of the point under the transform.
*/
static nsPoint MatrixTransformPoint(const nsPoint &aPoint,
const Matrix4x4 &aMatrix, float aFactor);
/**
* Given a graphics rectangle in graphics space, return a rectangle in
* app space that contains the graphics rectangle, rounding out as necessary.
*
* @param aRect The graphics rect to round outward.
* @param aFactor The number of app units per graphics unit.
* @return The smallest rectangle in app space that contains aRect.
*/
static nsRect RoundGfxRectToAppRect(const Rect &aRect, float aFactor);
/**
* Given a graphics rectangle in graphics space, return a rectangle in
* app space that contains the graphics rectangle, rounding out as necessary.
*
* @param aRect The graphics rect to round outward.
* @param aFactor The number of app units per graphics unit.
* @return The smallest rectangle in app space that contains aRect.
*/
static nsRect RoundGfxRectToAppRect(const gfxRect &aRect, float aFactor);
/**
* Returns a subrectangle of aContainedRect that is entirely inside the rounded
* rect. Complex cases are handled conservatively by returning a smaller
* rect than necessary.
*/
static nsRegion RoundedRectIntersectRect(const nsRect& aRoundedRect,
const nscoord aRadii[8],
const nsRect& aContainedRect);
static nsIntRegion RoundedRectIntersectIntRect(const nsIntRect& aRoundedRect,
const RectCornerRadii& aCornerRadii,
const nsIntRect& aContainedRect);
/**
* Return whether any part of aTestRect is inside of the rounded
* rectangle formed by aBounds and aRadii (which are indexed by the
* enum HalfCorner constants in gfx/2d/Types.h). This is precise.
*/
static bool RoundedRectIntersectsRect(const nsRect& aRoundedRect,
const nscoord aRadii[8],
const nsRect& aTestRect);
static bool MaybeCreateDisplayPortInFirstScrollFrameEncountered(
nsIFrame* aFrame, nsDisplayListBuilder& aBuilder);
enum class PaintFrameFlags : uint32_t {
PAINT_IN_TRANSFORM = 0x01,
PAINT_SYNC_DECODE_IMAGES = 0x02,
PAINT_WIDGET_LAYERS = 0x04,
PAINT_IGNORE_SUPPRESSION = 0x08,
PAINT_DOCUMENT_RELATIVE = 0x10,
PAINT_HIDE_CARET = 0x20,
PAINT_TO_WINDOW = 0x40,
PAINT_EXISTING_TRANSACTION = 0x80,
PAINT_NO_COMPOSITE = 0x100,
PAINT_COMPRESSED = 0x200
};
/**
* Given aFrame, the root frame of a stacking context, paint it and its
* descendants to aRenderingContext.
* @param aRenderingContext a rendering context translated so that (0,0)
* is the origin of aFrame; for best results, (0,0) should transform
* to pixel-aligned coordinates. This can be null, in which case
* aFrame must be a "display root" (root frame for a root document,
* or the root of a popup) with an associated widget and we draw using
* the layer manager for the frame's widget.
* @param aDirtyRegion the region that must be painted, in the coordinates
* of aFrame.
* @param aBackstop paint the dirty area with this color before drawing
* the actual content; pass NS_RGBA(0,0,0,0) to draw no background.
* @param aBuilderMode Passed through to the display-list builder.
* @param aFlags if PAINT_IN_TRANSFORM is set, then we assume
* this is inside a transform or SVG foreignObject. If
* PAINT_SYNC_DECODE_IMAGES is set, we force synchronous decode on all
* images. If PAINT_WIDGET_LAYERS is set, aFrame must be a display root,
* and we will use the frame's widget's layer manager to paint
* even if aRenderingContext is non-null. This is useful if you want
* to force rendering to use the widget's layer manager for testing
* or speed. PAINT_WIDGET_LAYERS must be set if aRenderingContext is null.
* If PAINT_DOCUMENT_RELATIVE is used, the visible region is interpreted
* as being relative to the document (normally it's relative to the CSS
* viewport) and the document is painted as if no scrolling has occured.
* Only considered if nsIPresShell::IgnoringViewportScrolling is true.
* PAINT_TO_WINDOW sets painting to window to true on the display list
* builder even if we can't tell that we are painting to the window.
* If PAINT_EXISTING_TRANSACTION is set, then BeginTransaction() has already
* been called on aFrame's widget's layer manager and should not be
* called again.
* If PAINT_COMPRESSED is set, the FrameLayerBuilder should be set to
* compressed mode to avoid short cut optimizations.
*
* So there are three possible behaviours:
* 1) PAINT_WIDGET_LAYERS is set and aRenderingContext is null; we paint
* by calling BeginTransaction on the widget's layer manager.
* 2) PAINT_WIDGET_LAYERS is set and aRenderingContext is non-null; we
* paint by calling BeginTransactionWithTarget on the widget's layer
* manager.
* 3) PAINT_WIDGET_LAYERS is not set and aRenderingContext is non-null;
* we paint by construct a BasicLayerManager and calling
* BeginTransactionWithTarget on it. This is desirable if we're doing
* something like drawWindow in a mode where what gets rendered doesn't
* necessarily correspond to what's visible in the window; we don't
* want to mess up the widget's layer tree.
*/
static nsresult PaintFrame(gfxContext* aRenderingContext, nsIFrame* aFrame,
const nsRegion& aDirtyRegion, nscolor aBackstop,
nsDisplayListBuilderMode aBuilderMode,
PaintFrameFlags aFlags = PaintFrameFlags(0));
/**
* Uses a binary search for find where the cursor falls in the line of text
* It also keeps track of the part of the string that has already been
* measured so it doesn't have to keep measuring the same text over and over.
*
* @param "aBaseWidth" contains the width in twips of the portion
* of the text that has already been measured, and aBaseInx contains
* the index of the text that has already been measured.
*
* @param aTextWidth returns (in twips) the length of the text that falls
* before the cursor aIndex contains the index of the text where the cursor
* falls.
*/
static bool
BinarySearchForPosition(DrawTarget* aDrawTarget,
nsFontMetrics& aFontMetrics,
const char16_t* aText,
int32_t aBaseWidth,
int32_t aBaseInx,
int32_t aStartInx,
int32_t aEndInx,
int32_t aCursorPos,
int32_t& aIndex,
int32_t& aTextWidth);
class BoxCallback {
public:
BoxCallback() : mIncludeCaptionBoxForTable(true) {}
virtual void AddBox(nsIFrame* aFrame) = 0;
bool mIncludeCaptionBoxForTable;
};
/**
* Collect all CSS boxes associated with aFrame and its
* continuations, "drilling down" through table wrapper frames and
* some anonymous blocks since they're not real CSS boxes.
* If aFrame is null, no boxes are returned.
* SVG frames return a single box, themselves.
*/
static void GetAllInFlowBoxes(nsIFrame* aFrame, BoxCallback* aCallback);
/**
* Like GetAllInFlowBoxes, but doesn't include continuations.
*/
static void AddBoxesForFrame(nsIFrame* aFrame, BoxCallback* aCallback);
/**
* Find the first frame descendant of aFrame (including aFrame) which is
* not an anonymous frame that getBoxQuads/getClientRects should ignore.
*/
static nsIFrame* GetFirstNonAnonymousFrame(nsIFrame* aFrame);
class RectCallback {
public:
virtual void AddRect(const nsRect& aRect) = 0;
};
struct RectAccumulator : public RectCallback {
nsRect mResultRect;
nsRect mFirstRect;
bool mSeenFirstRect;
RectAccumulator();
virtual void AddRect(const nsRect& aRect) override;
};
struct RectListBuilder : public RectCallback {
DOMRectList* mRectList;
explicit RectListBuilder(DOMRectList* aList);
virtual void AddRect(const nsRect& aRect) override;
};
static nsIFrame* GetContainingBlockForClientRect(nsIFrame* aFrame);
enum {
RECTS_ACCOUNT_FOR_TRANSFORMS = 0x01,
// Two bits for specifying which box type to use.
// With neither bit set (default), use the border box.
RECTS_USE_CONTENT_BOX = 0x02,
RECTS_USE_PADDING_BOX = 0x04,
RECTS_USE_MARGIN_BOX = 0x06, // both bits set
RECTS_WHICH_BOX_MASK = 0x06 // bitmask for these two bits
};
/**
* Collect all CSS boxes (content, padding, border, or margin) associated
* with aFrame and its continuations, "drilling down" through table wrapper
* frames and some anonymous blocks since they're not real CSS boxes.
* The boxes are positioned relative to aRelativeTo (taking scrolling
* into account) and passed to the callback in frame-tree order.
* If aFrame is null, no boxes are returned.
* For SVG frames, returns one rectangle, the bounding box.
* If aFlags includes RECTS_ACCOUNT_FOR_TRANSFORMS, then when converting
* the boxes into aRelativeTo coordinates, transforms (including CSS
* and SVG transforms) are taken into account.
* If aFlags includes one of RECTS_USE_CONTENT_BOX, RECTS_USE_PADDING_BOX,
* or RECTS_USE_MARGIN_BOX, the corresponding type of box is used.
* Otherwise (by default), the border box is used.
*/
static void GetAllInFlowRects(nsIFrame* aFrame, const nsIFrame* aRelativeTo,
RectCallback* aCallback, uint32_t aFlags = 0);
static void GetAllInFlowRectsAndTexts(nsIFrame* aFrame,
const nsIFrame* aRelativeTo,
RectCallback* aCallback,
mozilla::dom::Sequence<nsString>* aTextList,
uint32_t aFlags = 0);
/**
* Computes the union of all rects returned by GetAllInFlowRects. If
* the union is empty, returns the first rect.
* If aFlags includes RECTS_ACCOUNT_FOR_TRANSFORMS, then when converting
* the boxes into aRelativeTo coordinates, transforms (including CSS
* and SVG transforms) are taken into account.
* If aFlags includes one of RECTS_USE_CONTENT_BOX, RECTS_USE_PADDING_BOX,
* or RECTS_USE_MARGIN_BOX, the corresponding type of box is used.
* Otherwise (by default), the border box is used.
*/
static nsRect GetAllInFlowRectsUnion(nsIFrame* aFrame, const nsIFrame* aRelativeTo,
uint32_t aFlags = 0);
enum {
EXCLUDE_BLUR_SHADOWS = 0x01
};
/**
* Takes a text-shadow array from the style properties of a given nsIFrame and
* computes the union of those shadows along with the given initial rect.
* If there are no shadows, the initial rect is returned.
*/
static nsRect GetTextShadowRectsUnion(const nsRect& aTextAndDecorationsRect,
nsIFrame* aFrame,
uint32_t aFlags = 0);
/**
* Computes the destination rect that a given replaced element should render
* into, based on its CSS 'object-fit' and 'object-position' properties.
*
* @param aConstraintRect The constraint rect that we have at our disposal,
* which would e.g. be exactly filled by the image
* if we had "object-fit: fill".
* @param aIntrinsicSize The replaced content's intrinsic size, as reported
* by nsIFrame::GetIntrinsicSize().
* @param aIntrinsicRatio The replaced content's intrinsic ratio, as reported
* by nsIFrame::GetIntrinsicRatio().
* @param aStylePos The nsStylePosition struct that contains the 'object-fit'
* and 'object-position' values that we should rely on.
* (This should usually be the nsStylePosition for the
* replaced element in question, but not always. For
* example, a <video>'s poster-image has a dedicated
* anonymous element & child-frame, but we should still use
* the <video>'s 'object-fit' and 'object-position' values.)
* @param aAnchorPoint [out] A point that should be pixel-aligned by functions
* like nsLayoutUtils::DrawImage. See documentation
* in nsCSSRendering.h for ComputeObjectAnchorPoint.
* @return The nsRect into which we should render the replaced content (using
* the same coordinate space as the passed-in aConstraintRect).
*/
static nsRect ComputeObjectDestRect(const nsRect& aConstraintRect,
const IntrinsicSize& aIntrinsicSize,
const nsSize& aIntrinsicRatio,
const nsStylePosition* aStylePos,
nsPoint* aAnchorPoint = nullptr);
/**
* Get the font metrics corresponding to the frame's style data.
* @param aFrame the frame
* @param aSizeInflation number to multiply font size by
*/
static already_AddRefed<nsFontMetrics> GetFontMetricsForFrame(
const nsIFrame* aFrame, float aSizeInflation);
static already_AddRefed<nsFontMetrics>
GetInflatedFontMetricsForFrame(const nsIFrame* aFrame)
{
return GetFontMetricsForFrame(aFrame, FontSizeInflationFor(aFrame));
}
/**
* Get the font metrics corresponding to the given style data.
* @param aComputedStyle the style data
* @param aSizeInflation number to multiply font size by
*/
static already_AddRefed<nsFontMetrics> GetFontMetricsForComputedStyle(
ComputedStyle* aComputedStyle,
nsPresContext* aPresContext,
float aSizeInflation = 1.0f,
uint8_t aVariantWidth = NS_FONT_VARIANT_WIDTH_NORMAL);
/**
* Get the font metrics of emphasis marks corresponding to the given
* style data. The result is same as GetFontMetricsForComputedStyle
* except that the font size is scaled down to 50%.
* @param aComputedStyle the style data
* @param aInflation number to multiple font size by
*/
static already_AddRefed<nsFontMetrics> GetFontMetricsOfEmphasisMarks(
ComputedStyle* aComputedStyle,
nsPresContext* aPresContext,
float aInflation)
{
return GetFontMetricsForComputedStyle(aComputedStyle,
aPresContext,
aInflation * 0.5f);
}
/**
* Find the immediate child of aParent whose frame subtree contains
* aDescendantFrame. Returns null if aDescendantFrame is not a descendant
* of aParent.
*/
static nsIFrame* FindChildContainingDescendant(nsIFrame* aParent, nsIFrame* aDescendantFrame);
/**
* Find the nearest ancestor that's a block
*/
static nsBlockFrame* FindNearestBlockAncestor(nsIFrame* aFrame);
/**
* Find the nearest ancestor that's not for generated content. Will return
* aFrame if aFrame is not for generated content.
*/
static nsIFrame* GetNonGeneratedAncestor(nsIFrame* aFrame);
/**
* Cast aFrame to an nsBlockFrame* or return null if it's not
* an nsBlockFrame.
*/
static nsBlockFrame* GetAsBlock(nsIFrame* aFrame);
/*
* Whether the frame is an nsBlockFrame which is not a wrapper block.
*/
static bool IsNonWrapperBlock(nsIFrame* aFrame);
/**
* If aFrame is an out of flow frame, return its placeholder, otherwise
* return its parent.
*/
static nsIFrame* GetParentOrPlaceholderFor(nsIFrame* aFrame);
/**
* If aFrame is an out of flow frame, return its placeholder, otherwise
* return its (possibly cross-doc) parent.
*/
static nsIFrame* GetParentOrPlaceholderForCrossDoc(nsIFrame* aFrame);
/**
* Get a frame's next-in-flow, or, if it doesn't have one, its
* block-in-inline-split sibling.
*/
static nsIFrame*
GetNextContinuationOrIBSplitSibling(nsIFrame *aFrame);
/**
* Get the first frame in the continuation-plus-ib-split-sibling chain
* containing aFrame.
*/
static nsIFrame*
FirstContinuationOrIBSplitSibling(const nsIFrame *aFrame);
/**
* Get the last frame in the continuation-plus-ib-split-sibling chain
* containing aFrame.
*/
static nsIFrame*
LastContinuationOrIBSplitSibling(const nsIFrame *aFrame);
/**
* Is FirstContinuationOrIBSplitSibling(aFrame) going to return
* aFrame?
*/
static bool
IsFirstContinuationOrIBSplitSibling(nsIFrame *aFrame);
/**
* Check whether aFrame is a part of the scrollbar or scrollcorner of
* the root content.
* @param aFrame the checking frame.
* @return true if the frame is a part of the scrollbar or scrollcorner of
* the root content.
*/
static bool IsViewportScrollbarFrame(nsIFrame* aFrame);
/**
* Get the contribution of aFrame to its containing block's intrinsic
* size for the given physical axis. This considers the child's intrinsic
* width, its 'width', 'min-width', and 'max-width' properties (or 'height'
* variations if that's what matches aAxis) and its padding, border and margin
* in the corresponding dimension.
* @param aPercentageBasis an optional percentage basis (in aFrame's WM).
* If the basis is indefinite in a given axis, pass a size with
* NS_UNCONSTRAINEDSIZE in that component.
* If you pass Nothing() a percentage basis will be calculated from aFrame's
* ancestors' computed size in the relevant axis, if needed.
* @param aMarginBoxMinSizeClamp make the result fit within this margin-box
* size by reducing the *content size* (flooring at zero). This is used for:
* https://drafts.csswg.org/css-grid/#min-size-auto
*/
enum class IntrinsicISizeType { MIN_ISIZE, PREF_ISIZE };
static const auto MIN_ISIZE = IntrinsicISizeType::MIN_ISIZE;
static const auto PREF_ISIZE = IntrinsicISizeType::PREF_ISIZE;
enum {
IGNORE_PADDING = 0x01,
BAIL_IF_REFLOW_NEEDED = 0x02, // returns NS_INTRINSIC_WIDTH_UNKNOWN if so
MIN_INTRINSIC_ISIZE = 0x04, // use min-width/height instead of width/height
};
static nscoord
IntrinsicForAxis(mozilla::PhysicalAxis aAxis,
gfxContext* aRenderingContext,
nsIFrame* aFrame,
IntrinsicISizeType aType,
const mozilla::Maybe<LogicalSize>& aPercentageBasis = mozilla::Nothing(),
uint32_t aFlags = 0,
nscoord aMarginBoxMinSizeClamp = NS_MAXSIZE);
/**
* Calls IntrinsicForAxis with aFrame's parent's inline physical axis.
*/
static nscoord IntrinsicForContainer(gfxContext* aRenderingContext,
nsIFrame* aFrame,
IntrinsicISizeType aType,
uint32_t aFlags = 0);
/**
* Get the definite size contribution of aFrame for the given physical axis.
* This considers the child's 'min-width' property (or 'min-height' if the
* given axis is vertical), and its padding, border, and margin in the
* corresponding dimension. If the 'min-' property is 'auto' (and 'overflow'
* is 'visible') and the corresponding 'width'/'height' is definite it returns
* the "specified size" for:
* https://drafts.csswg.org/css-grid/#min-size-auto
* Note that the "transferred size" is not handled here; use IntrinsicForAxis.
* Note that any percentage in 'width'/'height' makes it count as indefinite.
* If the 'min-' property is 'auto' and 'overflow' is not 'visible', then it
* calculates the result as if the 'min-' computed value is zero.
* Otherwise, return NS_UNCONSTRAINEDSIZE.
*
* @param aPercentageBasis the percentage basis (in aFrame's WM).
* Pass NS_UNCONSTRAINEDSIZE if the basis is indefinite in either/both axes.
* @note this behavior is specific to Grid/Flexbox (currently) so aFrame
* should be a grid/flex item.
*/
static nscoord
MinSizeContributionForAxis(mozilla::PhysicalAxis aAxis,
gfxContext* aRC,
nsIFrame* aFrame,
IntrinsicISizeType aType,
const LogicalSize& aPercentageBasis,
uint32_t aFlags = 0);
/*
* Convert nsStyleCoord to nscoord when percentages depend on the
* containing block size.
* @param aPercentBasis The width or height of the containing block
* (whichever the client wants to use for resolving percentages).
*/
static nscoord ComputeCBDependentValue(nscoord aPercentBasis,
const nsStyleCoord& aCoord);
static nscoord ComputeBSizeDependentValue(
nscoord aContainingBlockBSize,
const nsStyleCoord& aCoord);
static nscoord ComputeBSizeValue(nscoord aContainingBlockBSize,
nscoord aContentEdgeToBoxSizingBoxEdge,
const nsStyleCoord& aCoord)
{
MOZ_ASSERT(aContainingBlockBSize != nscoord_MAX || !aCoord.HasPercent(),
"caller must deal with %% of unconstrained block-size");
MOZ_ASSERT(aCoord.IsCoordPercentCalcUnit());
nscoord result = aCoord.ComputeCoordPercentCalc(aContainingBlockBSize);
// Clamp calc(), and the subtraction for box-sizing.
return std::max(0, result - aContentEdgeToBoxSizingBoxEdge);
}
// XXX to be removed
static bool IsAutoHeight(const nsStyleCoord &aCoord, nscoord aCBHeight)
{
return IsAutoBSize(aCoord, aCBHeight);
}
static bool IsAutoBSize(const nsStyleCoord &aCoord, nscoord aCBBSize)
{
nsStyleUnit unit = aCoord.GetUnit();
return unit == eStyleUnit_Auto || // only for 'height'
unit == eStyleUnit_None || // only for 'max-height'
// The enumerated values were originally aimed at inline-size
// (or width, as it was before logicalization). For now, let them
// return true here, so that we don't call ComputeBSizeValue with
// value types that it doesn't understand. (See bug 1113216.)
//
// FIXME (bug 567039, bug 527285)
// This isn't correct for the 'fill' value or for the 'min-*' or
// 'max-*' properties, which need to be handled differently by
// the callers of IsAutoBSize().
unit == eStyleUnit_Enumerated ||
(aCBBSize == nscoord_MAX && aCoord.HasPercent());
}
static bool IsPaddingZero(const nsStyleCoord &aCoord)
{
return (aCoord.GetUnit() == eStyleUnit_Coord &&
aCoord.GetCoordValue() == 0) ||
(aCoord.GetUnit() == eStyleUnit_Percent &&
aCoord.GetPercentValue() == 0.0f) ||
(aCoord.IsCalcUnit() &&
// clamp negative calc() to 0
aCoord.ComputeCoordPercentCalc(nscoord_MAX) <= 0 &&
aCoord.ComputeCoordPercentCalc(0) <= 0);
}
static bool IsMarginZero(const nsStyleCoord &aCoord)
{
return (aCoord.GetUnit() == eStyleUnit_Coord &&
aCoord.GetCoordValue() == 0) ||
(aCoord.GetUnit() == eStyleUnit_Percent &&
aCoord.GetPercentValue() == 0.0f) ||
(aCoord.IsCalcUnit() &&
aCoord.ComputeCoordPercentCalc(nscoord_MAX) == 0 &&
aCoord.ComputeCoordPercentCalc(0) == 0);
}
static void MarkDescendantsDirty(nsIFrame *aSubtreeRoot);
static void MarkIntrinsicISizesDirtyIfDependentOnBSize(nsIFrame* aFrame);
/*
* Calculate the used values for 'width' and 'height' when width
* and height are 'auto'. The tentWidth and tentHeight arguments should be
* the result of applying the rules for computing intrinsic sizes and ratios.
* as specified by CSS 2.1 sections 10.3.2 and 10.6.2
*/
static nsSize ComputeAutoSizeWithIntrinsicDimensions(nscoord minWidth, nscoord minHeight,
nscoord maxWidth, nscoord maxHeight,
nscoord tentWidth, nscoord tentHeight);
// Implement nsIFrame::GetPrefISize in terms of nsIFrame::AddInlinePrefISize
static nscoord PrefISizeFromInline(nsIFrame* aFrame,
gfxContext* aRenderingContext);
// Implement nsIFrame::GetMinISize in terms of nsIFrame::AddInlineMinISize
static nscoord MinISizeFromInline(nsIFrame* aFrame,
gfxContext* aRenderingContext);
// Get a suitable foreground color for painting aColor for aFrame.
static nscolor DarkenColorIfNeeded(nsIFrame* aFrame, nscolor aColor);
// Get a suitable foreground color for painting aField for aFrame.
// Type of aFrame is made a template parameter because nsIFrame is not
// a complete type in the header. Type-safety is not harmed given that
// DarkenColorIfNeeded requires an nsIFrame pointer.
template<typename Frame, typename T, typename S>
static nscolor GetColor(Frame* aFrame, T S::* aField) {
nscolor color = aFrame->GetVisitedDependentColor(aField);
return DarkenColorIfNeeded(aFrame, color);
}
// Get a baseline y position in app units that is snapped to device pixels.
static gfxFloat GetSnappedBaselineY(nsIFrame* aFrame, gfxContext* aContext,
nscoord aY, nscoord aAscent);
// Ditto for an x position (for vertical text). Note that for vertical-rl
// writing mode, the ascent value should be negated by the caller.
static gfxFloat GetSnappedBaselineX(nsIFrame* aFrame, gfxContext* aContext,
nscoord aX, nscoord aAscent);
static nscoord AppUnitWidthOfString(char16_t aC,
nsFontMetrics& aFontMetrics,
DrawTarget* aDrawTarget) {
return AppUnitWidthOfString(&aC, 1, aFontMetrics, aDrawTarget);
}
static nscoord AppUnitWidthOfString(const nsString& aString,
nsFontMetrics& aFontMetrics,
DrawTarget* aDrawTarget) {
return nsLayoutUtils::AppUnitWidthOfString(aString.get(), aString.Length(),
aFontMetrics, aDrawTarget);
}
static nscoord AppUnitWidthOfString(const char16_t *aString,
uint32_t aLength,
nsFontMetrics& aFontMetrics,
DrawTarget* aDrawTarget);
static nscoord AppUnitWidthOfStringBidi(const nsString& aString,
const nsIFrame* aFrame,
nsFontMetrics& aFontMetrics,
gfxContext& aContext) {
return nsLayoutUtils::AppUnitWidthOfStringBidi(aString.get(),
aString.Length(), aFrame,
aFontMetrics, aContext);
}
static nscoord AppUnitWidthOfStringBidi(const char16_t* aString,
uint32_t aLength,
const nsIFrame* aFrame,
nsFontMetrics& aFontMetrics,
gfxContext& aContext);
static bool StringWidthIsGreaterThan(const nsString& aString,
nsFontMetrics& aFontMetrics,
DrawTarget* aDrawTarget,
nscoord aWidth);
static nsBoundingMetrics AppUnitBoundsOfString(const char16_t* aString,
uint32_t aLength,
nsFontMetrics& aFontMetrics,
DrawTarget* aDrawTarget);
static void DrawString(const nsIFrame* aFrame,
nsFontMetrics& aFontMetrics,
gfxContext* aContext,
const char16_t* aString,
int32_t aLength,
nsPoint aPoint,
ComputedStyle* aComputedStyle = nullptr,
DrawStringFlags aFlags = DrawStringFlags::eDefault);
static nsPoint GetBackgroundFirstTilePos(const nsPoint& aDest,
const nsPoint& aFill,
const nsSize& aRepeatSize);
/**
* Supports only LTR or RTL. Bidi (mixed direction) is not supported.
*/
static void DrawUniDirString(const char16_t* aString,
uint32_t aLength,
const nsPoint& aPoint,
nsFontMetrics& aFontMetrics,
gfxContext& aContext);
/**
* Helper function for drawing text-shadow. The callback's job
* is to draw whatever needs to be blurred onto the given context.
*/
typedef void (* TextShadowCallback)(gfxContext* aCtx,
nsPoint aShadowOffset,
const nscolor& aShadowColor,
void* aData);
static void PaintTextShadow(const nsIFrame* aFrame,
gfxContext* aContext,
const nsRect& aTextRect,
const nsRect& aDirtyRect,
const nscolor& aForegroundColor,
TextShadowCallback aCallback,
void* aCallbackData);
/**
* Gets the baseline to vertically center text from a font within a
* line of specified height.
* aIsInverted: true if the text is inverted relative to the block
* direction, so that the block-dir "ascent" corresponds to font
* descent. (Applies to sideways text in vertical-lr mode.)
*
* Returns the baseline position relative to the top of the line.
*/
static nscoord GetCenteredFontBaseline(nsFontMetrics* aFontMetrics,
nscoord aLineHeight,
bool aIsInverted);
/**
* Derive a baseline of |aFrame| (measured from its top border edge)
* from its first in-flow line box (not descending into anything with
* 'overflow' not 'visible', potentially including aFrame itself).
*
* Returns true if a baseline was found (and fills in aResult).
* Otherwise returns false.
*/
static bool GetFirstLineBaseline(mozilla::WritingMode aWritingMode,
const nsIFrame* aFrame, nscoord* aResult);
/**
* Just like GetFirstLineBaseline, except also returns the top and
* bottom of the line with the baseline.
*
* Returns true if a line was found (and fills in aResult).
* Otherwise returns false.
*/
struct LinePosition {
nscoord mBStart, mBaseline, mBEnd;
LinePosition operator+(nscoord aOffset) const {
LinePosition result;
result.mBStart = mBStart + aOffset;
result.mBaseline = mBaseline + aOffset;
result.mBEnd = mBEnd + aOffset;
return result;
}
};
static bool GetFirstLinePosition(mozilla::WritingMode aWritingMode,
const nsIFrame* aFrame,
LinePosition* aResult);
/**
* Derive a baseline of |aFrame| (measured from its top border edge)
* from its last in-flow line box (not descending into anything with
* 'overflow' not 'visible', potentially including aFrame itself).
*
* Returns true if a baseline was found (and fills in aResult).
* Otherwise returns false.
*/
static bool GetLastLineBaseline(mozilla::WritingMode aWritingMode,
const nsIFrame* aFrame, nscoord* aResult);
/**
* Returns a block-dir coordinate relative to this frame's origin that
* represents the logical block-end of the frame or its visible content,
* whichever is further from the origin.
* Relative positioning is ignored and margins and glyph bounds are not
* considered.
* This value will be >= mRect.BSize() and <= overflowRect.BEnd() unless
* relative positioning is applied.
*/
static nscoord CalculateContentBEnd(mozilla::WritingMode aWritingMode,
nsIFrame* aFrame);
/**
* Gets the closest frame (the frame passed in or one of its parents) that
* qualifies as a "layer"; used in DOM0 methods that depends upon that
* definition. This is the nearest frame that is either positioned or scrolled
* (the child of a scroll frame).
*/
static nsIFrame* GetClosestLayer(nsIFrame* aFrame);
/**
* Gets the graphics sampling filter for the frame
*/
static SamplingFilter GetSamplingFilterForFrame(nsIFrame* aFrame);
static inline void InitDashPattern(StrokeOptions& aStrokeOptions,
uint8_t aBorderStyle) {
if (aBorderStyle == NS_STYLE_BORDER_STYLE_DOTTED) {
static Float dot[] = { 1.f, 1.f };
aStrokeOptions.mDashLength = MOZ_ARRAY_LENGTH(dot);
aStrokeOptions.mDashPattern = dot;
} else if (aBorderStyle == NS_STYLE_BORDER_STYLE_DASHED) {
static Float dash[] = { 5.f, 5.f };
aStrokeOptions.mDashLength = MOZ_ARRAY_LENGTH(dash);
aStrokeOptions.mDashPattern = dash;
} else {
aStrokeOptions.mDashLength = 0;
aStrokeOptions.mDashPattern = nullptr;
}
}
/**
* Convert an nsRect to a gfxRect.
*/
static gfxRect RectToGfxRect(const nsRect& aRect,
int32_t aAppUnitsPerDevPixel);
static gfxPoint PointToGfxPoint(const nsPoint& aPoint,
int32_t aAppUnitsPerPixel) {
return gfxPoint(gfxFloat(aPoint.x) / aAppUnitsPerPixel,
gfxFloat(aPoint.y) / aAppUnitsPerPixel);
}
/* N.B. The only difference between variants of the Draw*Image
* functions below is the type of the aImage argument.
*/
/**
* Draw a background image. The image's dimensions are as specified in aDest;
* the image itself is not consulted to determine a size.
* See https://wiki.mozilla.org/Gecko:Image_Snapping_and_Rendering
* @param aContext The context to draw to, already set up with an
* appropriate scale and transform for drawing in
* app units.
* @param aForFrame The nsIFrame that we're drawing this image for.
* @param aImage The image.
* @param aImageSize The unscaled size of the image being drawn.
* (This might be the image's size if no scaling
* occurs, or it might be the image's size if
* the image is a vector image being rendered at
* that size.)
* @param aDest The position and scaled area where one copy of
* the image should be drawn. This area represents
* the image itself in its correct position as defined
* with the background-position css property.
* @param aFill The area to be filled with copies of the image.
* @param aRepeatSize The distance between the positions of two subsequent
* repeats of the image. Sizes larger than aDest.Size()
* create gaps between the images.
* @param aAnchor A point in aFill which we will ensure is
* pixel-aligned in the output.
* @param aDirty Pixels outside this area may be skipped.
* @param aImageFlags Image flags of the imgIContainer::FLAG_* variety.
* @param aExtendMode How to extend the image over the dest rect.
*/
static ImgDrawResult DrawBackgroundImage(gfxContext& aContext,
nsIFrame* aForFrame,
nsPresContext* aPresContext,
imgIContainer* aImage,
const CSSIntSize& aImageSize,
SamplingFilter aSamplingFilter,
const nsRect& aDest,
const nsRect& aFill,
const nsSize& aRepeatSize,
const nsPoint& aAnchor,
const nsRect& aDirty,
uint32_t aImageFlags,
ExtendMode aExtendMode,
float aOpacity);
/**
* Draw an image.
* See https://wiki.mozilla.org/Gecko:Image_Snapping_and_Rendering
* @param aRenderingContext Where to draw the image, set up with an
* appropriate scale and transform for drawing in
* app units.
* @param aComputedStyle The ComputedStyle of the nsIFrame (or
* pseudo-element) for which this image is being
* drawn.
* @param aImage The image.
* @param aDest Where one copy of the image should mapped to.
* @param aFill The area to be filled with copies of the
* image.
* @param aAnchor A point in aFill which we will ensure is
* pixel-aligned in the output.
* @param aDirty Pixels outside this area may be skipped.
* @param aImageFlags Image flags of the imgIContainer::FLAG_* variety
*/
static ImgDrawResult DrawImage(gfxContext& aContext,
ComputedStyle* aComputedStyle,
nsPresContext* aPresContext,
imgIContainer* aImage,
const SamplingFilter aSamplingFilter,
const nsRect& aDest,
const nsRect& aFill,
const nsPoint& aAnchor,
const nsRect& aDirty,
uint32_t aImageFlags,
float aOpacity = 1.0);
/**
* Draw a whole image without scaling or tiling.
*
* @param aRenderingContext Where to draw the image, set up with an
* appropriate scale and transform for drawing in
* app units.
* @param aImage The image.
* @param aDest The top-left where the image should be drawn.
* @param aDirty If non-null, then pixels outside this area may
* be skipped.
* @param aSVGContext Optionally provides an SVGImageContext.
* Callers should pass an SVGImageContext with at
* least the viewport size set if aImage may be of
* type imgIContainer::TYPE_VECTOR, or pass
* Nothing() if it is of type
* imgIContainer::TYPE_RASTER (to save cycles
* constructing an SVGImageContext, since this
* argument will be ignored for raster images).
* @param aImageFlags Image flags of the imgIContainer::FLAG_* variety
* @param aSourceArea If non-null, this area is extracted from
* the image and drawn at aDest. It's
* in appunits. For best results it should
* be aligned with image pixels.
*/
static ImgDrawResult DrawSingleUnscaledImage(gfxContext& aContext,
nsPresContext* aPresContext,
imgIContainer* aImage,
const SamplingFilter aSamplingFilter,
const nsPoint& aDest,
const nsRect* aDirty,
const mozilla::Maybe<SVGImageContext>& aSVGContext,
uint32_t aImageFlags,
const nsRect* aSourceArea = nullptr);
/**
* Draw a whole image without tiling.
*
* @param aRenderingContext Where to draw the image, set up with an
* appropriate scale and transform for drawing in
* app units.
* @param aImage The image.
* @param aDest The area that the image should fill.
* @param aDirty Pixels outside this area may be skipped.
* @param aSVGContext Optionally provides an SVGImageContext.
* Callers should pass an SVGImageContext with at
* least the viewport size set if aImage may be of
* type imgIContainer::TYPE_VECTOR, or pass
* Nothing() if it is of type
* imgIContainer::TYPE_RASTER (to save cycles
* constructing an SVGImageContext, since this
* argument will be ignored for raster images).
* @param aImageFlags Image flags of the imgIContainer::FLAG_*
* variety.
* @param aAnchor If non-null, a point which we will ensure
* is pixel-aligned in the output.
* @param aSourceArea If non-null, this area is extracted from
* the image and drawn in aDest. It's
* in appunits. For best results it should
* be aligned with image pixels.
*/
static ImgDrawResult DrawSingleImage(gfxContext& aContext,
nsPresContext* aPresContext,
imgIContainer* aImage,
const SamplingFilter aSamplingFilter,
const nsRect& aDest,
const nsRect& aDirty,
const mozilla::Maybe<SVGImageContext>& aSVGContext,
uint32_t aImageFlags,
const nsPoint* aAnchorPoint = nullptr,
const nsRect* aSourceArea = nullptr);
/**
* Given an imgIContainer, this method attempts to obtain an intrinsic
* px-valued height & width for it. If the imgIContainer has a non-pixel
* value for either height or width, this method tries to generate a pixel
* value for that dimension using the intrinsic ratio (if available). The
* intrinsic ratio will be assigned to aIntrinsicRatio; if there's no
* intrinsic ratio then (0, 0) will be assigned.
*
* This method will always set aGotWidth and aGotHeight to indicate whether
* we were able to successfully obtain (or compute) a value for each
* dimension.
*
* NOTE: This method is similar to ComputeSizeWithIntrinsicDimensions. The
* difference is that this one is simpler and is suited to places where we
* have less information about the frame tree.
*/
static void ComputeSizeForDrawing(imgIContainer* aImage,
CSSIntSize& aImageSize,
nsSize& aIntrinsicRatio,
bool& aGotWidth,
bool& aGotHeight);
/**
* Given an imgIContainer, this method attempts to obtain an intrinsic
* px-valued height & width for it. If the imgIContainer has a non-pixel
* value for either height or width, this method tries to generate a pixel
* value for that dimension using the intrinsic ratio (if available). If,
* after trying all these methods, no value is available for one or both
* dimensions, the corresponding dimension of aFallbackSize is used instead.
*/
static CSSIntSize
ComputeSizeForDrawingWithFallback(imgIContainer* aImage,
const nsSize& aFallbackSize);
/**
* Given the image container, frame, and dest rect, determine the best fitting
* size to decode the image at, and calculate any necessary SVG parameters.
*/
static mozilla::gfx::IntSize
ComputeImageContainerDrawingParameters(imgIContainer* aImage,
nsIFrame* aForFrame,
const LayoutDeviceRect& aDestRect,
const StackingContextHelper& aSc,
uint32_t aFlags,
mozilla::Maybe<SVGImageContext>& aSVGContext);
/**
* Given a source area of an image (in appunits) and a destination area
* that we want to map that source area too, computes the area that
* would be covered by the whole image. This is useful for passing to
* the aDest parameter of DrawImage, when we want to draw a subimage
* of an overall image.
*/
static nsRect GetWholeImageDestination(const nsSize& aWholeImageSize,
const nsRect& aImageSourceArea,
const nsRect& aDestArea);
/**
* Given an image container and an orientation, returns an image container
* that contains the same image, reoriented appropriately. May return the
* original image container if no changes are needed.
*
* @param aContainer The image container to apply the orientation to.
* @param aOrientation The desired orientation.
*/
static already_AddRefed<imgIContainer>
OrientImage(imgIContainer* aContainer,
const mozilla::StyleImageOrientation& aOrientation);
/**
* Determine if any corner radius is of nonzero size
* @param aCorners the |nsStyleCorners| object to check
* @return true unless all the coordinates are 0%, 0 or null.
*
* A corner radius with one dimension zero and one nonzero is
* treated as a nonzero-radius corner, even though it will end up
* being rendered like a zero-radius corner. This is because such
* corners are not expected to appear outside of test cases, and it's
* simpler to implement the test this way.
*/
static bool HasNonZeroCorner(const nsStyleCorners& aCorners);
/**
* Determine if there is any corner radius on corners adjacent to the
* given side.
*/
static bool HasNonZeroCornerOnSide(const nsStyleCorners& aCorners,
mozilla::Side aSide);
/**
* Determine if a widget is likely to require transparency or translucency.
* @param aBackgroundFrame The frame that the background is set on. For
* <window>s, this will be the canvas frame.
* @param aCSSRootFrame The frame that holds CSS properties affecting
* the widget's transparency. For menupopups,
* aBackgroundFrame and aCSSRootFrame will be the
* same.
* @return a value suitable for passing to SetWindowTranslucency.
*/
static nsTransparencyMode GetFrameTransparency(nsIFrame* aBackgroundFrame,
nsIFrame* aCSSRootFrame);
/**
* A frame is a popup if it has its own floating window. Menus, panels
* and combobox dropdowns are popups.
*/
static bool IsPopup(const nsIFrame* aFrame);
/**
* Find the nearest "display root". This is the nearest enclosing
* popup frame or the root prescontext's root frame.
*/
static nsIFrame* GetDisplayRootFrame(nsIFrame* aFrame);
/**
* Get the reference frame that would be used when constructing a
* display item for this frame. Rather than using their own frame
* as a reference frame.)
*
* This duplicates some of the logic of GetDisplayRootFrame above and
* of nsDisplayListBuilder::FindReferenceFrameFor.
*
* If you have an nsDisplayListBuilder, you should get the reference
* frame from it instead of calling this.
*/
static nsIFrame* GetReferenceFrame(nsIFrame* aFrame);
/**
* Get textrun construction flags determined by a given style; in particular
* some combination of:
* -- TEXT_DISABLE_OPTIONAL_LIGATURES if letter-spacing is in use
* -- TEXT_OPTIMIZE_SPEED if the text-rendering CSS property and font size
* and prefs indicate we should be optimizing for speed over quality
*/
static mozilla::gfx::ShapedTextFlags
GetTextRunFlagsForStyle(ComputedStyle* aComputedStyle,
nsPresContext* aPresContext,
const nsStyleFont* aStyleFont,
const nsStyleText* aStyleText,
nscoord aLetterSpacing);
/**
* Get orientation flags for textrun construction.
*/
static mozilla::gfx::ShapedTextFlags
GetTextRunOrientFlagsForStyle(ComputedStyle* aComputedStyle);
/**
* Takes two rectangles whose origins must be the same, and computes
* the difference between their union and their intersection as two
* rectangles. (This difference is a superset of the difference
* between the two rectangles.)
*/
static void GetRectDifferenceStrips(const nsRect& aR1, const nsRect& aR2,
nsRect* aHStrip, nsRect* aVStrip);
/**
* Get a device context that can be used to get up-to-date device
* dimensions for the given window. For some reason, this is more
* complicated than it ought to be in multi-monitor situations.
*/
static nsDeviceContext*
GetDeviceContextForScreenInfo(nsPIDOMWindowOuter* aWindow);
/**
* Some frames with 'position: fixed' (nsStyleDisplay::mPosition ==
* NS_STYLE_POSITION_FIXED) are not really fixed positioned, since
* they're inside an element with -moz-transform. This function says
* whether such an element is a real fixed-pos element.
*/
static bool IsReallyFixedPos(const nsIFrame* aFrame);
/**
* This function says whether `aFrame` would really be a fixed positioned
* frame if the frame was created with NS_STYLE_POSITION_FIXED.
*
* It is effectively the same as IsReallyFixedPos, but without asserting the
* position value. Use it only when you know what you're doing, like when
* tearing down the frame tree (where styles may have changed due to
* ::first-line reparenting and rule changes at the same time).
*/
static bool MayBeReallyFixedPos(const nsIFrame* aFrame);
/**
* Obtain a SourceSurface from the given DOM element, if possible.
* This obtains the most natural surface from the element; that
* is, the one that can be obtained with the fewest conversions.
*
* The flags below can modify the behaviour of this function. The
* result is returned as a SurfaceFromElementResult struct, also
* defined below.
*
* Currently, this will do:
* - HTML Canvas elements: will return the underlying canvas surface
* - HTML Video elements: will return the current video frame
* - Image elements: will return the image
*
* The above results are modified by the below flags (copying,
* forcing image surface, etc.).
*/
enum {
/* When creating a new surface, create an image surface */
SFE_WANT_IMAGE_SURFACE = 1 << 0,
/* Whether to extract the first frame (as opposed to the
current frame) in the case that the element is an image. */
SFE_WANT_FIRST_FRAME_IF_IMAGE = 1 << 1,
/* Whether we should skip colorspace/gamma conversion */
SFE_NO_COLORSPACE_CONVERSION = 1 << 2,
/* Specifies that the caller wants either OPAQUE or NON_PREMULT mAlphaType,
if this is can be done efficiently. */
SFE_PREFER_NO_PREMULTIPLY_ALPHA = 1 << 3,
/* Whether we should skip getting a surface for vector images and
return a DirectDrawInfo containing an imgIContainer instead. */
SFE_NO_RASTERIZING_VECTORS = 1 << 4,
/* If image type is vector, the return surface size will same as
element size, not image's intrinsic size. */
SFE_USE_ELEMENT_SIZE_IF_VECTOR = 1 << 5
};
struct DirectDrawInfo {
/* imgIContainer to directly draw to a context */
nsCOMPtr<imgIContainer> mImgContainer;
/* which frame to draw */
uint32_t mWhichFrame;
/* imgIContainer flags to use when drawing */
uint32_t mDrawingFlags;
};
struct SurfaceFromElementResult {
friend class mozilla::dom::CanvasRenderingContext2D;
friend class nsLayoutUtils;
/* If SFEResult contains a valid surface, it either mLayersImage or mSourceSurface
* will be non-null, and GetSourceSurface() will not be null.
*
* For valid surfaces, mSourceSurface may be null if mLayersImage is non-null, but
* GetSourceSurface() will create mSourceSurface from mLayersImage when called.
*/
/* Video elements (at least) often are already decoded as layers::Images. */
RefPtr<mozilla::layers::Image> mLayersImage;
protected:
/* GetSourceSurface() fills this and returns its non-null value if this SFEResult
* was successful. */
RefPtr<mozilla::gfx::SourceSurface> mSourceSurface;
public:
/* Contains info for drawing when there is no mSourceSurface. */
DirectDrawInfo mDrawInfo;
/* The size of the surface */
mozilla::gfx::IntSize mSize;
/* The principal associated with the element whose surface was returned.
If there is a surface, this will never be null. */
nsCOMPtr<nsIPrincipal> mPrincipal;
/* The image request, if the element is an nsIImageLoadingContent */
nsCOMPtr<imgIRequest> mImageRequest;
/* Whether the element was "write only", that is, the bits should not be exposed to content */
bool mIsWriteOnly;
/* Whether the element was still loading. Some consumers need to handle
this case specially. */
bool mIsStillLoading;
/* Whether the element has a valid size. */
bool mHasSize;
/* Whether the element used CORS when loading. */
bool mCORSUsed;
gfxAlphaType mAlphaType;
// Methods:
SurfaceFromElementResult();
// Gets mSourceSurface, or makes a SourceSurface from mLayersImage.
const RefPtr<mozilla::gfx::SourceSurface>& GetSourceSurface();
};
// This function can be called on any thread.
static SurfaceFromElementResult
SurfaceFromOffscreenCanvas(mozilla::dom::OffscreenCanvas *aOffscreenCanvas,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
static SurfaceFromElementResult
SurfaceFromOffscreenCanvas(mozilla::dom::OffscreenCanvas *aOffscreenCanvas,
uint32_t aSurfaceFlags = 0) {
RefPtr<DrawTarget> target = nullptr;
return SurfaceFromOffscreenCanvas(aOffscreenCanvas, aSurfaceFlags, target);
}
static SurfaceFromElementResult SurfaceFromElement(mozilla::dom::Element *aElement,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
static SurfaceFromElementResult SurfaceFromElement(mozilla::dom::Element *aElement,
uint32_t aSurfaceFlags = 0) {
RefPtr<DrawTarget> target = nullptr;
return SurfaceFromElement(aElement, aSurfaceFlags, target);
}
// There are a bunch of callers of SurfaceFromElement. Just mark it as
MOZ_CAN_RUN_SCRIPT_BOUNDARY
static SurfaceFromElementResult SurfaceFromElement(nsIImageLoadingContent *aElement,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
// Need an HTMLImageElement overload, because otherwise the
// nsIImageLoadingContent and mozilla::dom::Element overloads are ambiguous
// for HTMLImageElement.
static SurfaceFromElementResult SurfaceFromElement(mozilla::dom::HTMLImageElement *aElement,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
static SurfaceFromElementResult SurfaceFromElement(mozilla::dom::HTMLCanvasElement *aElement,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
static SurfaceFromElementResult SurfaceFromElement(mozilla::dom::HTMLVideoElement *aElement,
uint32_t aSurfaceFlags,
RefPtr<DrawTarget>& aTarget);
/**
* When the document is editable by contenteditable attribute of its root
* content or body content.
*
* Be aware, this returns nullptr if it's in designMode.
*
* For example:
*
* <html contenteditable="true"><body></body></html>
* returns the <html>.
*
* <html><body contenteditable="true"></body></html>
* <body contenteditable="true"></body>
* With these cases, this returns the <body>.
* NOTE: The latter case isn't created normally, however, it can be
* created by script with XHTML.
*
* <body><p contenteditable="true"></p></body>
* returns nullptr because <body> isn't editable.
*/
static mozilla::dom::Element*
GetEditableRootContentByContentEditable(nsIDocument* aDocument);
static void AddExtraBackgroundItems(nsDisplayListBuilder& aBuilder,
nsDisplayList& aList,
nsIFrame* aFrame,
const nsRect& aCanvasArea,
const nsRegion& aVisibleRegion,
nscolor aBackstop);
/**
* Returns true if the passed in prescontext needs the dark grey background
* that goes behind the page of a print preview presentation.
*/
static bool NeedsPrintPreviewBackground(nsPresContext* aPresContext);
/**
* Types used by the helpers for InspectorUtils.getUsedFontFaces.
* The API returns an array (UsedFontFaceList) that owns the
* InspectorFontFace instances, but during range traversal we also
* want to maintain a mapping from gfxFontEntry to InspectorFontFace
* records, so use a temporary hashtable for that.
*/
typedef nsTArray<nsAutoPtr<mozilla::dom::InspectorFontFace>> UsedFontFaceList;
typedef nsDataHashtable<nsPtrHashKey<gfxFontEntry>,
mozilla::dom::InspectorFontFace*> UsedFontFaceTable;
/**
* Adds all font faces used in the frame tree starting from aFrame
* to the list aFontFaceList.
* aMaxRanges: maximum number of text ranges to record for each face.
*/
static nsresult GetFontFacesForFrames(nsIFrame* aFrame,
UsedFontFaceList& aResult,
UsedFontFaceTable& aFontFaces,
uint32_t aMaxRanges,
bool aSkipCollapsedWhitespace);
/**
* Adds all font faces used within the specified range of text in aFrame,
* and optionally its continuations, to the list in aFontFaceList.
* Pass 0 and INT32_MAX for aStartOffset and aEndOffset to specify the
* entire text is to be considered.
* aMaxRanges: maximum number of text ranges to record for each face.
*/
static void GetFontFacesForText(nsIFrame* aFrame,
int32_t aStartOffset,
int32_t aEndOffset,
bool aFollowContinuations,
UsedFontFaceList& aResult,
UsedFontFaceTable& aFontFaces,
uint32_t aMaxRanges,
bool aSkipCollapsedWhitespace);
/**
* Walks the frame tree starting at aFrame looking for textRuns.
* If |clear| is true, just clears the TEXT_RUN_MEMORY_ACCOUNTED flag
* on each textRun found (and |aMallocSizeOf| is not used).
* If |clear| is false, adds the storage used for each textRun to the
* total, and sets the TEXT_RUN_MEMORY_ACCOUNTED flag to avoid double-
* accounting. (Runs with this flag already set will be skipped.)
* Expected usage pattern is therefore to call twice:
* (void)SizeOfTextRunsForFrames(rootFrame, nullptr, true);
* total = SizeOfTextRunsForFrames(rootFrame, mallocSizeOf, false);
*/
static size_t SizeOfTextRunsForFrames(nsIFrame* aFrame,
mozilla::MallocSizeOf aMallocSizeOf,
bool clear);
/**
* Returns true if the frame has any current CSS transitions.
* A current transition is any transition that has not yet finished playing
* including paused transitions.
*/
static bool HasCurrentTransitions(const nsIFrame* aFrame);
/**
* Returns true if |aFrame| has an animation of |aProperty| regardless of
* whether the property is overridden by !important rule.
*/
static bool HasAnimationOfProperty(const nsIFrame* aFrame,
nsCSSPropertyID aProperty);
/**
* Returns true if |aEffectSet| has an animation of |aProperty| regardless of
* whether the property is overridden by !important rule.
*/
static bool HasAnimationOfProperty(mozilla::EffectSet* aEffectSet,
nsCSSPropertyID aProperty);
/**
* Returns true if |aFrame| has an animation of |aProperty| which is
* not overridden by !important rules.
*/
static bool HasEffectiveAnimation(const nsIFrame* aFrame,
nsCSSPropertyID aProperty);
/**
* Checks if off-main-thread animations are enabled.
*/
static bool AreAsyncAnimationsEnabled();
/**
* Checks if we should warn about animations that can't be async
*/
static bool IsAnimationLoggingEnabled();
/**
* Checks if retained display lists are enabled.
*/
static bool AreRetainedDisplayListsEnabled();
static bool DisplayRootHasRetainedDisplayListBuilder(nsIFrame* aFrame);
/**
* Find a suitable scale for a element (aFrame's content) over the course of any
* animations and transitions of the CSS transform property on the
* element that run on the compositor thread.
* It will check the maximum and minimum scale during the animations and
* transitions and return a suitable value for performance and quality.
* Will return scale(1,1) if there are no such animations.
* Always returns a positive value.
* @param aVisibleSize is the size of the area we want to paint
* @param aDisplaySize is the size of the display area of the pres context
*/
static Size ComputeSuitableScaleForAnimation(const nsIFrame* aFrame,
const nsSize& aVisibleSize,
const nsSize& aDisplaySize);
/**
* Checks whether we want to use the GPU to scale images when
* possible.
*/
static bool GPUImageScalingEnabled();
/**
* Checks whether we want to layerize animated images whenever possible.
*/
static bool AnimatedImageLayersEnabled();
/**
* Checks whether support for inter-character ruby is enabled.
*/
static bool IsInterCharacterRubyEnabled();
/**
* Checks whether content-select is enabled.
*/
static bool IsContentSelectEnabled();
static bool InterruptibleReflowEnabled()
{
return sInterruptibleReflowEnabled;
}
/**
* Unions the overflow areas of the children of aFrame with aOverflowAreas.
* aSkipChildLists specifies any child lists that should be skipped.
* kSelectPopupList and kPopupList are always skipped.
*/
static void UnionChildOverflow(nsIFrame* aFrame,
nsOverflowAreas& aOverflowAreas,
mozilla::layout::FrameChildListIDs aSkipChildLists =
mozilla::layout::FrameChildListIDs());
/**
* Return the font size inflation *ratio* for a given frame. This is
* the factor by which font sizes should be inflated; it is never
* smaller than 1.
*/
static float FontSizeInflationFor(const nsIFrame *aFrame);
/**
* Perform the first half of the computation of FontSizeInflationFor
* (see above).
* This includes determining whether inflation should be performed
* within this container and returning 0 if it should not be.
*
* The result is guaranteed not to vary between line participants
* (inlines, text frames) within a line.
*
* The result should not be used directly since font sizes slightly
* above the minimum should always be adjusted as done by
* FontSizeInflationInner.
*/
static nscoord InflationMinFontSizeFor(const nsIFrame *aFrame);
/**
* Perform the second half of the computation done by
* FontSizeInflationFor (see above).
*
* aMinFontSize must be the result of one of the
* InflationMinFontSizeFor methods above.
*/
static float FontSizeInflationInner(const nsIFrame *aFrame,
nscoord aMinFontSize);
static bool FontSizeInflationEnabled(nsPresContext *aPresContext);
/**
* See comment above "font.size.inflation.maxRatio" in
* modules/libpref/src/init/all.js .
*/
static uint32_t FontSizeInflationMaxRatio() {
return sFontSizeInflationMaxRatio;
}
/**
* See comment above "font.size.inflation.emPerLine" in
* modules/libpref/src/init/all.js .
*/
static uint32_t FontSizeInflationEmPerLine() {
return sFontSizeInflationEmPerLine;
}
/**
* See comment above "font.size.inflation.minTwips" in
* modules/libpref/src/init/all.js .
*/
static uint32_t FontSizeInflationMinTwips() {
return sFontSizeInflationMinTwips;
}
/**
* See comment above "font.size.inflation.lineThreshold" in
* modules/libpref/src/init/all.js .
*/
static uint32_t FontSizeInflationLineThreshold() {
return sFontSizeInflationLineThreshold;
}
static bool FontSizeInflationForceEnabled() {
return sFontSizeInflationForceEnabled;
}
static bool FontSizeInflationDisabledInMasterProcess() {
return sFontSizeInflationDisabledInMasterProcess;
}
/**
* See comment above "font.size.systemFontScale" in
* modules/libpref/init/all.js.
*/
static float SystemFontScale() {
return sSystemFontScale / 100.0f;
}
static float MaxZoom() {
return sZoomMaxPercent / 100.0f;
}
static float MinZoom() {
return sZoomMinPercent / 100.0f;
}
static bool SVGTransformBoxEnabled() {
return sSVGTransformBoxEnabled;
}
static uint32_t IdlePeriodDeadlineLimit() {
return sIdlePeriodDeadlineLimit;
}
static uint32_t QuiescentFramesBeforeIdlePeriod() {
return sQuiescentFramesBeforeIdlePeriod;
}
/**
* See comment above "font.size.inflation.mappingIntercept" in
* modules/libpref/src/init/all.js .
*/
static int32_t FontSizeInflationMappingIntercept() {
return sFontSizeInflationMappingIntercept;
}
/**
* Returns true if the nglayout.debug.invalidation pref is set to true.
* Note that sInvalidationDebuggingIsEnabled is declared outside this function to
* allow it to be accessed an manipulated from breakpoint conditions.
*/
static bool InvalidationDebuggingIsEnabled() {
return sInvalidationDebuggingIsEnabled || getenv("MOZ_DUMP_INVALIDATION") != 0;
}
static void Initialize();
static void Shutdown();
/**
* Register an imgIRequest object with a refresh driver.
*
* @param aPresContext The nsPresContext whose refresh driver we want to
* register with.
* @param aRequest A pointer to the imgIRequest object which the client wants
* to register with the refresh driver.
* @param aRequestRegistered A pointer to a boolean value which indicates
* whether the given image request is registered. If
* *aRequestRegistered is true, then this request will not be
* registered again. If the request is registered by this function,
* then *aRequestRegistered will be set to true upon the completion of
* this function.
*
*/
static void RegisterImageRequest(nsPresContext* aPresContext,
imgIRequest* aRequest,
bool* aRequestRegistered);
/**
* Register an imgIRequest object with a refresh driver, but only if the
* request is for an image that is animated.
*
* @param aPresContext The nsPresContext whose refresh driver we want to
* register with.
* @param aRequest A pointer to the imgIRequest object which the client wants
* to register with the refresh driver.
* @param aRequestRegistered A pointer to a boolean value which indicates
* whether the given image request is registered. If
* *aRequestRegistered is true, then this request will not be
* registered again. If the request is registered by this function,
* then *aRequestRegistered will be set to true upon the completion of
* this function.
*
*/
static void RegisterImageRequestIfAnimated(nsPresContext* aPresContext,
imgIRequest* aRequest,
bool* aRequestRegistered);
/**
* Deregister an imgIRequest object from a refresh driver.
*
* @param aPresContext The nsPresContext whose refresh driver we want to
* deregister from.
* @param aRequest A pointer to the imgIRequest object with which the client
* previously registered and now wants to deregister from the refresh
* driver.
* @param aRequestRegistered A pointer to a boolean value which indicates
* whether the given image request is registered. If
* *aRequestRegistered is false, then this request will not be
* deregistered. If the request is deregistered by this function,
* then *aRequestRegistered will be set to false upon the completion of
* this function.
*/
static void DeregisterImageRequest(nsPresContext* aPresContext,
imgIRequest* aRequest,
bool* aRequestRegistered);
/**
* Shim to nsCSSFrameConstructor::PostRestyleEvent. Exists so that we
* can avoid including nsCSSFrameConstructor.h and all its dependencies
* in content files.
*/
static void PostRestyleEvent(mozilla::dom::Element* aElement,
nsRestyleHint aRestyleHint,
nsChangeHint aMinChangeHint);
/**
* Updates a pair of x and y distances if a given point is closer to a given
* rectangle than the original distance values. If aPoint is closer to
* aRect than aClosestXDistance and aClosestYDistance indicate, then those
* two variables are updated with the distance between aPoint and aRect,
* and true is returned. If aPoint is not closer, then aClosestXDistance
* and aClosestYDistance are left unchanged, and false is returned.
*
* Distances are measured in the two dimensions separately; a closer x
* distance beats a closer y distance.
*/
template<typename PointType, typename RectType, typename CoordType>
static bool PointIsCloserToRect(PointType aPoint, const RectType& aRect,
CoordType& aClosestXDistance,
CoordType& aClosestYDistance);
/**
* Computes the box shadow rect for the frame, or returns an empty rect if
* there are no shadows.
*
* @param aFrame Frame to compute shadows for.
* @param aFrameSize Size of aFrame (in case it hasn't been set yet).
*/
static nsRect GetBoxShadowRectForFrame(nsIFrame* aFrame, const nsSize& aFrameSize);
#ifdef DEBUG
/**
* Assert that there are no duplicate continuations of the same frame
* within aFrameList. Optimize the tests by assuming that all frames
* in aFrameList have parent aContainer.
*/
static void
AssertNoDuplicateContinuations(nsIFrame* aContainer,
const nsFrameList& aFrameList);
/**
* Assert that the frame tree rooted at |aSubtreeRoot| is empty, i.e.,
* that it contains no first-in-flows.
*/
static void
AssertTreeOnlyEmptyNextInFlows(nsIFrame *aSubtreeRoot);
#endif
/**
* Helper method to get touch action behaviour from the frame
*/
static uint32_t
GetTouchActionFromFrame(nsIFrame* aFrame);
/**
* Helper method to transform |aBounds| from aFrame to aAncestorFrame,
* and combine it with |aPreciseTargetDest| if it is axis-aligned, or
* combine it with |aImpreciseTargetDest| if not. The transformed rect is
* clipped to |aClip|; if |aClip| has rounded corners, that also causes
* the imprecise target to be used.
*/
static void
TransformToAncestorAndCombineRegions(
const nsRegion& aRegion,
nsIFrame* aFrame,
const nsIFrame* aAncestorFrame,
nsRegion* aPreciseTargetDest,
nsRegion* aImpreciseTargetDest,
mozilla::Maybe<Matrix4x4Flagged>* aMatrixCache,
const mozilla::DisplayItemClip* aClip);
/**
* Populate aOutSize with the size of the content viewer corresponding
* to the given prescontext. Return true if the size was set, false
* otherwise.
*/
static bool
GetContentViewerSize(nsPresContext* aPresContext,
LayoutDeviceIntSize& aOutSize);
/**
* Calculate the compostion size for a frame. See FrameMetrics.h for
* defintion of composition size (or bounds).
* Note that for the root content document's root scroll frame (RCD-RSF),
* the returned size does not change as the document's resolution changes,
* but for all other frames it does. This means that callers that pass in
* a frame that may or may not be the RCD-RSF (which is most callers),
* are likely to need special-case handling of the RCD-RSF.
*/
static nsSize
CalculateCompositionSizeForFrame(nsIFrame* aFrame, bool aSubtractScrollbars = true);
/**
* Calculate the composition size for the root scroll frame of the root
* content document.
* @param aFrame A frame in the root content document (or a descendant of it).
* @param aIsRootContentDocRootScrollFrame Whether aFrame is already the root
* scroll frame of the root content document. In this case we just
* use aFrame's own composition size.
* @param aMetrics A partially populated FrameMetrics for aFrame. Must have at
* least mCompositionBounds, mCumulativeResolution, and
* mDevPixelsPerCSSPixel set.
*/
static CSSSize
CalculateRootCompositionSize(nsIFrame* aFrame,
bool aIsRootContentDocRootScrollFrame,
const FrameMetrics& aMetrics);
/**
* Calculate the scrollable rect for a frame. See FrameMetrics.h for
* defintion of scrollable rect. aScrollableFrame is the scroll frame to calculate
* the scrollable rect for. If it's null then we calculate the scrollable rect
* as the rect of the root frame.
*/
static nsRect
CalculateScrollableRectForFrame(nsIScrollableFrame* aScrollableFrame, nsIFrame* aRootFrame);
/**
* Calculate the expanded scrollable rect for a frame. See FrameMetrics.h for
* defintion of expanded scrollable rect.
*/
static nsRect
CalculateExpandedScrollableRect(nsIFrame* aFrame);
/**
* Returns true if the widget owning the given frame uses asynchronous
* scrolling.
*/
static bool UsesAsyncScrolling(nsIFrame* aFrame);
/**
* Returns true if the widget owning the given frame has builtin APZ support
* enabled.
*/
static bool AsyncPanZoomEnabled(nsIFrame* aFrame);
/**
* Returns the current APZ Resolution Scale. When Java Pan/Zoom is
* enabled in Fennec it will always return 1.0.
*/
static float GetCurrentAPZResolutionScale(nsIPresShell* aShell);
/**
* Returns true if we need to disable async scrolling for this particular
* element. Note that this does a partial disabling - the displayport still
* exists but uses a very small margin, and the compositor doesn't apply the
* async transform. However, the content may still be layerized.
*/
static bool ShouldDisableApzForElement(nsIContent* aContent);
/**
* Log a key/value pair for APZ testing during a paint.
* @param aManager The data will be written to the APZTestData associated
* with this layer manager.
* @param aScrollId Identifies the scroll frame to which the data pertains.
* @param aKey The key under which to log the data.
* @param aValue The value of the data to be logged.
*/
static void LogTestDataForPaint(mozilla::layers::LayerManager* aManager,
ViewID aScrollId,
const std::string& aKey,
const std::string& aValue) {
DoLogTestDataForPaint(aManager, aScrollId, aKey, aValue);
}
/**
* A convenience overload of LogTestDataForPaint() that accepts any type
* as the value, and passes it through mozilla::ToString() to obtain a string
* value. The type passed must support streaming to an std::ostream.
*/
template <typename Value>
static void LogTestDataForPaint(mozilla::layers::LayerManager* aManager,
ViewID aScrollId,
const std::string& aKey,
const Value& aValue) {
DoLogTestDataForPaint(aManager, aScrollId, aKey,
mozilla::ToString(aValue));
}
/**
* Calculate a basic FrameMetrics with enough fields set to perform some
* layout calculations. The fields set are dev-to-css ratio, pres shell
* resolution, cumulative resolution, zoom, composition size, root
* composition size, scroll offset and scrollable rect.
*
* Note that for the RCD-RSF, the scroll offset returned is the layout
* viewport offset; if you need the visual viewport offset, that needs to
* be queried independently via nsIPresShell::GetVisualViewportOffset().
*
* By contrast, ComputeFrameMetrics() computes all the fields, but requires
* extra inputs and can only be called during frame layer building.
*/
static FrameMetrics CalculateBasicFrameMetrics(nsIScrollableFrame* aScrollFrame);
/**
* Calculate a default set of displayport margins for the given scrollframe
* and set them on the scrollframe's content element. The margins are set with
* the default priority, which may clobber previously set margins. The repaint
* mode provided is passed through to the call to SetDisplayPortMargins.
* The |aScrollFrame| parameter must be non-null and queryable to an nsIFrame.
* @return true iff the call to SetDisplayPortMargins returned true.
*/
static bool CalculateAndSetDisplayPortMargins(nsIScrollableFrame* aScrollFrame,
RepaintMode aRepaintMode);
/**
* If |aScrollFrame| WantsAsyncScroll() and we don't have a scrollable
* displayport yet (as tracked by |aBuilder|), calculate and set a
* displayport.
*
* If this is called during display list building pass DoNotRepaint in
* aRepaintMode.
*
* Returns true if there is a displayport on an async scrollable scrollframe
* after this call, either because one was just added or it already existed.
*/
static bool MaybeCreateDisplayPort(nsDisplayListBuilder& aBuilder,
nsIFrame* aScrollFrame,
RepaintMode aRepaintMode);
static nsIScrollableFrame* GetAsyncScrollableAncestorFrame(nsIFrame* aTarget);
/**
* Sets a zero margin display port on all proper ancestors of aFrame that
* are async scrollable.
*/
static void SetZeroMarginDisplayPortOnAsyncScrollableAncestors(nsIFrame* aFrame,
RepaintMode aRepaintMode);
/**
* Finds the closest ancestor async scrollable frame from aFrame that has a
* displayport and attempts to trigger the displayport expiry on that
* ancestor.
*/
static void ExpireDisplayPortOnAsyncScrollableAncestor(nsIFrame* aFrame);
static bool IsOutlineStyleAutoEnabled();
static void SetBSizeFromFontMetrics(const nsIFrame* aFrame,
mozilla::ReflowOutput& aMetrics,
const mozilla::LogicalMargin& aFramePadding,
mozilla::WritingMode aLineWM,
mozilla::WritingMode aFrameWM);
static bool HasDocumentLevelListenersForApzAwareEvents(nsIPresShell* aShell);
/**
* Set the viewport size for the purpose of clamping the scroll position
* for the root scroll frame of this document
* (see nsIDOMWindowUtils.setVisualViewportSize).
*/
static void SetVisualViewportSize(nsIPresShell* aPresShell,
CSSSize aSize);
/**
* Returns true if the given scroll origin is "higher priority" than APZ.
* In general any content programmatic scrolls (e.g. scrollTo calls) are
* higher priority, and take precedence over APZ scrolling. This function
* returns true for those, and returns false for other origins like APZ
* itself, or scroll position updates from the history restore code.
*/
static bool CanScrollOriginClobberApz(nsAtom* aScrollOrigin);
static ScrollMetadata ComputeScrollMetadata(nsIFrame* aForFrame,
nsIFrame* aScrollFrame,
nsIContent* aContent,
const nsIFrame* aReferenceFrame,
mozilla::layers::LayerManager* aLayerManager,
ViewID aScrollParentId,
const nsRect& aViewport,
const mozilla::Maybe<nsRect>& aClipRect,
bool aIsRoot,
const ContainerLayerParameters& aContainerParameters);
/**
* Returns the metadata to put onto the root layer of a layer tree, if one is
* needed. The last argument is a callback function to check if the caller
* already has a metadata for a given scroll id.
*/
static mozilla::Maybe<ScrollMetadata> GetRootMetadata(nsDisplayListBuilder* aBuilder,
mozilla::layers::LayerManager* aLayerManager,
const ContainerLayerParameters& aContainerParameters,
const std::function<bool(ViewID& aScrollId)>& aCallback);
/**
* If the given scroll frame needs an area excluded from its composition
* bounds due to scrollbars, return that area, otherwise return an empty
* margin.
* There is no need to exclude scrollbars in the following cases:
* - If the scroll frame is not the RCD-RSF; in that case, the composition
* bounds is calculated based on the scroll port which already excludes
* the scrollbar area.
* - If the scrollbars are overlay, since then they are drawn on top of the
* scrollable content.
*/
static nsMargin ScrollbarAreaToExcludeFromCompositionBoundsFor(nsIFrame* aScrollFrame);
/**
* Looks in the layer subtree rooted at aLayer for a metrics with scroll id
* aScrollId. Returns true if such is found.
*/
static bool ContainsMetricsWithId(const Layer* aLayer, const ViewID& aScrollId);
static bool ShouldUseNoScriptSheet(nsIDocument* aDocument);
static bool ShouldUseNoFramesSheet(nsIDocument* aDocument);
/**
* Get the text content inside the frame. This methods traverse the
* frame tree and collect the content from text frames. Note that this
* method is similiar to nsContentUtils::GetNodeTextContent, but it at
* least differs from that method in the following things:
* 1. it skips text content inside nodes like style, script, textarea
* which don't generate an in-tree text frame for the text;
* 2. it skips elements with display property set to none;
* 3. it skips out-of-flow elements;
* 4. it includes content inside pseudo elements;
* 5. it may include part of text content of a node if a text frame
* inside is split to different continuations.
*/
static void GetFrameTextContent(nsIFrame* aFrame, nsAString& aResult);
/**
* Same as GetFrameTextContent but appends the result rather than sets it.
*/
static void AppendFrameTextContent(nsIFrame* aFrame, nsAString& aResult);
/**
* Takes a selection, and returns selection's bounding rect which is relative
* to its root frame.
*
* @param aSel Selection to check
*/
static nsRect GetSelectionBoundingRect(mozilla::dom::Selection* aSel);
/**
* Calculate the bounding rect of |aContent|, relative to the origin
* of the scrolled content of |aRootScrollFrame|.
* Where the element is contained inside a scrollable subframe, the
* bounding rect is clipped to the bounds of the subframe.
*/
static CSSRect GetBoundingContentRect(const nsIContent* aContent,
const nsIScrollableFrame* aRootScrollFrame);
/**
* Returns the first ancestor who is a float containing block.
*/
static nsBlockFrame* GetFloatContainingBlock(nsIFrame* aFrame);
/**
* Walks up the frame tree from |aForFrame| up to |aTopFrame|, or to the
* root of the frame tree if |aTopFrame| is nullptr, and returns true if
* a transformed frame is encountered.
*/
static bool IsTransformed(nsIFrame* aForFrame, nsIFrame* aTopFrame = nullptr);
/**
* Walk up from aFrame to the cross-doc root, accumulating all the APZ callback
* transforms on the content elements encountered along the way. Return the
* accumulated value.
* XXX: Note that this does not take into account CSS transforms, nor
* differences in structure between the frame tree and the layer tree (which
* is probably what we *want* to be computing).
*/
static CSSPoint GetCumulativeApzCallbackTransform(nsIFrame* aFrame);
/**
* Compute a rect to pre-render in cases where we want to render more of
* something than what is visible (usually to support async transformation).
* @param aDirtyRect the area that's visible
* @param aOverflow the total size of the thing we're rendering
* @param aPrerenderSize how large of an area we're willing to render
* @return A rectangle that includes |aDirtyRect|, is clamped to |aOverflow|,
* and is no larger than |aPrerenderSize| (unless |aPrerenderSize|
* is smaller than |aDirtyRect|, in which case the returned rect
* will still include |aDirtyRect| and thus be larger than
* |aPrerenderSize|).
*/
static nsRect ComputePartialPrerenderArea(const nsRect& aDirtyRect,
const nsRect& aOverflow,
const nsSize& aPrerenderSize);
/*
* Checks whether a node is an invisible break.
* If not, returns the first frame on the next line if such a next line exists.
*
* @return true if the node is an invisible break.
* aNextLineFrame is returned null in this case.
* false if the node causes a visible break or if the node is no break.
*
* @param aNextLineFrame assigned to first frame on the next line if such a
* next line exists, null otherwise.
*/
static bool IsInvisibleBreak(nsINode* aNode, nsIFrame** aNextLineFrame = nullptr);
static nsRect ComputeGeometryBox(nsIFrame* aFrame,
StyleGeometryBox aGeometryBox);
static nsPoint ComputeOffsetToUserSpace(nsDisplayListBuilder* aBuilder,
nsIFrame* aFrame);
// Return the default value to be used for -moz-control-character-visibility,
// from preferences.
static uint8_t ControlCharVisibilityDefault();
enum class FlushUserFontSet {
Yes,
No,
};
static already_AddRefed<nsFontMetrics> GetMetricsFor(nsPresContext* aPresContext,
bool aIsVertical,
const nsStyleFont* aStyleFont,
nscoord aFontSize,
bool aUseUserFontSet,
FlushUserFontSet aFlushUserFontSet);
/**
* Appropriately add the correct font if we are using DocumentFonts or
* overriding for XUL
*/
static void FixupNoneGeneric(nsFont* aFont,
const nsPresContext* aPresContext,
uint8_t aGenericFontID,
const nsFont* aDefaultVariableFont);
/**
* For an nsStyleFont with mSize set, apply minimum font size constraints
* from preferences, as well as -moz-min-font-size-ratio.
*/
static void ApplyMinFontSize(nsStyleFont* aFont,
const nsPresContext* aPresContext,
nscoord aMinFontSize);
static void ComputeSystemFont(nsFont* aSystemFont,
mozilla::LookAndFeel::FontID aFontID,
const nsPresContext* aPresContext,
const nsFont* aDefaultVariableFont);
static void ComputeFontFeatures(const nsCSSValuePairList* aFeaturesList,
nsTArray<gfxFontFeature>& aFeatureSettings);
static void ComputeFontVariations(const nsCSSValuePairList* aVariationsList,
nsTArray<gfxFontVariation>& aVariationSettings);
static uint32_t ParseFontLanguageOverride(const nsAString& aLangTag);
/**
* Returns true if there are any preferences or overrides that indicate a
* need to create a MobileViewportManager.
*/
static bool ShouldHandleMetaViewport(nsIDocument* aDocument);
/**
* Resolve a CSS <length-percentage> value to a definite size.
*/
template<bool clampNegativeResultToZero>
static nscoord ResolveToLength(const nsStyleCoord& aCoord,
nscoord aPercentageBasis)
{
NS_WARNING_ASSERTION(aPercentageBasis >= nscoord(0), "nscoord overflow?");
switch (aCoord.GetUnit()) {
case eStyleUnit_Coord:
MOZ_ASSERT(!clampNegativeResultToZero || aCoord.GetCoordValue() >= 0,
"This value should have been rejected by the style system");
return aCoord.GetCoordValue();
case eStyleUnit_Percent:
if (aPercentageBasis == NS_UNCONSTRAINEDSIZE) {
return nscoord(0);
}
MOZ_ASSERT(!clampNegativeResultToZero || aCoord.GetPercentValue() >= 0,
"This value should have been rejected by the style system");
return NSToCoordFloorClamped(aPercentageBasis *
aCoord.GetPercentValue());
case eStyleUnit_Calc: {
nsStyleCoord::Calc* calc = aCoord.GetCalcValue();
nscoord result;
if (aPercentageBasis == NS_UNCONSTRAINEDSIZE) {
result = calc->mLength;
} else {
result = calc->mLength +
NSToCoordFloorClamped(aPercentageBasis * calc->mPercent);
}
if (clampNegativeResultToZero && result < 0) {
return nscoord(0);
}
return result;
}
default:
MOZ_ASSERT_UNREACHABLE("Unexpected unit!");
return nscoord(0);
}
}
/**
* Resolve a column-gap/row-gap to a definite size.
* @note This method resolves 'normal' to zero.
* Callers who want different behavior should handle 'normal' on their own.
*/
static nscoord ResolveGapToLength(const nsStyleCoord& aGap,
nscoord aPercentageBasis)
{
if (aGap.GetUnit() == eStyleUnit_Normal) {
return nscoord(0);
}
return ResolveToLength<true>(aGap, aPercentageBasis);
}
/**
* Get the computed style from which the scrollbar style should be
* used for the given scrollbar part frame.
*/
static ComputedStyle* StyleForScrollbar(nsIFrame* aScrollbarPart);
/**
* Generate the motion path transform result.
**/
static mozilla::Maybe<mozilla::MotionPathData>
ResolveMotionPath(const nsIFrame* aFrame);
private:
static uint32_t sFontSizeInflationEmPerLine;
static uint32_t sFontSizeInflationMinTwips;
static uint32_t sFontSizeInflationLineThreshold;
static int32_t sFontSizeInflationMappingIntercept;
static uint32_t sFontSizeInflationMaxRatio;
static bool sFontSizeInflationForceEnabled;
static bool sFontSizeInflationDisabledInMasterProcess;
static uint32_t sSystemFontScale;
static uint32_t sZoomMaxPercent;
static uint32_t sZoomMinPercent;
static bool sInvalidationDebuggingIsEnabled;
static bool sInterruptibleReflowEnabled;
static bool sSVGTransformBoxEnabled;
static uint32_t sIdlePeriodDeadlineLimit;
static uint32_t sQuiescentFramesBeforeIdlePeriod;
/**
* Helper function for LogTestDataForPaint().
*/
static void DoLogTestDataForPaint(mozilla::layers::LayerManager* aManager,
ViewID aScrollId,
const std::string& aKey,
const std::string& aValue);
static bool IsAPZTestLoggingEnabled();
};
MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(nsLayoutUtils::PaintFrameFlags)
template<typename PointType, typename RectType, typename CoordType>
/* static */ bool
nsLayoutUtils::PointIsCloserToRect(PointType aPoint, const RectType& aRect,
CoordType& aClosestXDistance,
CoordType& aClosestYDistance)
{
CoordType fromLeft = aPoint.x - aRect.x;
CoordType fromRight = aPoint.x - aRect.XMost();
CoordType xDistance;
if (fromLeft >= 0 && fromRight <= 0) {
xDistance = 0;
} else {
xDistance = std::min(abs(fromLeft), abs(fromRight));
}
if (xDistance <= aClosestXDistance) {
if (xDistance < aClosestXDistance) {
aClosestYDistance = std::numeric_limits<CoordType>::max();
}
CoordType fromTop = aPoint.y - aRect.y;
CoordType fromBottom = aPoint.y - aRect.YMost();
CoordType yDistance;
if (fromTop >= 0 && fromBottom <= 0) {
yDistance = 0;
} else {
yDistance = std::min(abs(fromTop), abs(fromBottom));
}
if (yDistance < aClosestYDistance) {
aClosestXDistance = xDistance;
aClosestYDistance = yDistance;
return true;
}
}
return false;
}
namespace mozilla {
/**
* Converts an nsPoint in app units to a Moz2D Point in pixels (whether those
* are device pixels or CSS px depends on what the caller chooses to pass as
* aAppUnitsPerPixel).
*/
inline gfx::Point NSPointToPoint(const nsPoint& aPoint,
int32_t aAppUnitsPerPixel) {
return gfx::Point(gfx::Float(aPoint.x) / aAppUnitsPerPixel,
gfx::Float(aPoint.y) / aAppUnitsPerPixel);
}
/**
* Converts an nsRect in app units to a Moz2D Rect in pixels (whether those
* are device pixels or CSS px depends on what the caller chooses to pass as
* aAppUnitsPerPixel).
*/
gfx::Rect NSRectToRect(const nsRect& aRect, double aAppUnitsPerPixel);
/**
* Converts an nsRect in app units to a Moz2D Rect in pixels (whether those
* are device pixels or CSS px depends on what the caller chooses to pass as
* aAppUnitsPerPixel).
*
* The passed DrawTarget is used to additionally snap the returned Rect to
* device pixels, if appropriate (as decided and carried out by Moz2D's
* MaybeSnapToDevicePixels helper, which this function calls to do any
* snapping).
*/
gfx::Rect NSRectToSnappedRect(const nsRect& aRect, double aAppUnitsPerPixel,
const gfx::DrawTarget& aSnapDT);
/**
* Converts, where possible, an nsRect in app units to a Moz2D Rect in pixels
* (whether those are device pixels or CSS px depends on what the caller
* chooses to pass as aAppUnitsPerPixel).
*
* If snapping results in a rectangle with zero width or height, the affected
* coordinates are left unsnapped
*/
gfx::Rect NSRectToNonEmptySnappedRect(const nsRect& aRect, double aAppUnitsPerPixel,
const gfx::DrawTarget& aSnapDT);
void StrokeLineWithSnapping(const nsPoint& aP1, const nsPoint& aP2,
int32_t aAppUnitsPerDevPixel,
gfx::DrawTarget& aDrawTarget,
const gfx::Pattern& aPattern,
const gfx::StrokeOptions& aStrokeOptions = gfx::StrokeOptions(),
const gfx::DrawOptions& aDrawOptions = gfx::DrawOptions());
namespace layout {
/**
* An RAII class which will, for the duration of its lifetime,
* **if** the frame given is a container for font size inflation,
* set the current inflation container on the pres context to null
* (and then, in its destructor, restore the old value).
*/
class AutoMaybeDisableFontInflation {
public:
explicit AutoMaybeDisableFontInflation(nsIFrame *aFrame);
~AutoMaybeDisableFontInflation();
private:
nsPresContext *mPresContext;
bool mOldValue;
};
void MaybeSetupTransactionIdAllocator(layers::LayerManager* aManager,
nsPresContext* aPresContext);
} // namespace layout
} // namespace mozilla
class nsSetAttrRunnable : public mozilla::Runnable
{
public:
nsSetAttrRunnable(mozilla::dom::Element* aElement, nsAtom* aAttrName,
const nsAString& aValue);
nsSetAttrRunnable(mozilla::dom::Element* aElement, nsAtom* aAttrName,
int32_t aValue);
NS_DECL_NSIRUNNABLE
RefPtr<Element> mElement;
RefPtr<nsAtom> mAttrName;
nsAutoString mValue;
};
class nsUnsetAttrRunnable : public mozilla::Runnable
{
public:
nsUnsetAttrRunnable(mozilla::dom::Element* aElement, nsAtom* aAttrName);
NS_DECL_NSIRUNNABLE
RefPtr<Element> mElement;
RefPtr<nsAtom> mAttrName;
};
// This class allows you to easily set any pointer variable and ensure it's
// set to nullptr when leaving its scope.
template<typename T>
class MOZ_RAII SetAndNullOnExit
{
public:
SetAndNullOnExit(T* &aVariable, T* aValue) {
aVariable = aValue;
mVariable = &aVariable;
}
~SetAndNullOnExit() {
*mVariable = nullptr;
}
private:
T** mVariable;
};
#endif // nsLayoutUtils_h__
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