gecko-dev/layout/base/nsCSSRendering.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
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*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
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*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
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* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* utility functions for drawing borders and backgrounds */
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#ifndef nsCSSRendering_h___
#define nsCSSRendering_h___
#include "nsStyleConsts.h"
#include "gfxBlur.h"
#include "gfxContext.h"
#include "gfxImageSurface.h"
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struct nsPoint;
class nsStyleContext;
class nsPresContext;
class nsRenderingContext;
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struct nsCSSRendering {
/**
* Initialize any static variables used by nsCSSRendering.
*/
static void Init();
/**
* Clean up any static variables used by nsCSSRendering.
*/
static void Shutdown();
static void PaintBoxShadowInner(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aFrameArea,
const nsRect& aDirtyRect);
static void PaintBoxShadowOuter(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aFrameArea,
const nsRect& aDirtyRect);
static void ComputePixelRadii(const nscoord *aAppUnitsRadii,
nscoord aAppUnitsPerPixel,
gfxCornerSizes *oBorderRadii);
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/**
* Render the border for an element using css rendering rules
* for borders. aSkipSides is a bitmask of the sides to skip
* when rendering. If 0 then no sides are skipped.
*/
static void PaintBorder(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
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nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
nsStyleContext* aStyleContext,
PRIntn aSkipSides = 0);
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/**
* Like PaintBorder, but taking an nsStyleBorder argument instead of
* getting it from aStyleContext.
*/
static void PaintBorderWithStyleBorder(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
const nsStyleBorder& aBorderStyle,
nsStyleContext* aStyleContext,
PRIntn aSkipSides = 0);
/**
* Render the outline for an element using css rendering rules
* for borders. aSkipSides is a bitmask of the sides to skip
* when rendering. If 0 then no sides are skipped.
*/
static void PaintOutline(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
nsStyleContext* aStyleContext);
/**
* Render keyboard focus on an element.
* |aFocusRect| is the outer rectangle of the focused element.
* Uses a fixed style equivalent to "1px dotted |aColor|".
* Not used for controls, because the native theme may differ.
*/
static void PaintFocus(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
const nsRect& aFocusRect,
nscolor aColor);
/**
* Render a gradient for an element.
*/
static void PaintGradient(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsStyleGradient* aGradient,
const nsRect& aDirtyRect,
const nsRect& aOneCellArea,
const nsRect& aFillArea);
/**
* Find the frame whose background style should be used to draw the
* canvas background. aForFrame must be the frame for the root element
* whose background style should be used. This function will return
* aForFrame unless the <body> background should be propagated, in
* which case we return the frame associated with the <body>'s background.
*/
static nsIFrame* FindBackgroundStyleFrame(nsIFrame* aForFrame);
/**
* @return true if |aFrame| is a canvas frame, in the CSS sense.
*/
static bool IsCanvasFrame(nsIFrame* aFrame);
/**
* Fill in an aBackgroundSC to be used to paint the background
* for an element. This applies the rules for propagating
* backgrounds between BODY, the root element, and the canvas.
* @return true if there is some meaningful background.
*/
static bool FindBackground(nsPresContext* aPresContext,
nsIFrame* aForFrame,
nsStyleContext** aBackgroundSC);
/**
* As FindBackground, but the passed-in frame is known to be a root frame
* (returned from nsCSSFrameConstructor::GetRootElementStyleFrame())
* and there is always some meaningful background returned.
*/
static nsStyleContext* FindRootFrameBackground(nsIFrame* aForFrame);
/**
* Returns background style information for the canvas.
*
* @param aForFrame
* the frame used to represent the canvas, in the CSS sense (i.e.
* nsCSSRendering::IsCanvasFrame(aForFrame) must be true)
* @param aRootElementFrame
* the frame representing the root element of the document
* @param aBackground
* contains background style information for the canvas on return
*/
static nsStyleContext*
FindCanvasBackground(nsIFrame* aForFrame, nsIFrame* aRootElementFrame)
{
NS_ABORT_IF_FALSE(IsCanvasFrame(aForFrame), "not a canvas frame");
if (aRootElementFrame)
return FindRootFrameBackground(aRootElementFrame);
// This should always give transparent, so we'll fill it in with the
// default color if needed. This seems to happen a bit while a page is
// being loaded.
return aForFrame->GetStyleContext();
}
/**
* Find a frame which draws a non-transparent background,
* for various table-related and HR-related backwards-compatibility hacks.
* This function will also stop if it finds themed frame which might draw
* background.
*
* Be very hesitant if you're considering calling this function -- it's
* usually not what you want.
*/
static nsIFrame*
FindNonTransparentBackgroundFrame(nsIFrame* aFrame,
bool aStartAtParent = false);
/**
* Determine the background color to draw taking into account print settings.
*/
static nscolor
DetermineBackgroundColor(nsPresContext* aPresContext,
nsStyleContext* aStyleContext,
nsIFrame* aFrame);
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/**
* Render the background for an element using css rendering rules
* for backgrounds.
*/
enum {
/**
* When this flag is passed, the element's nsDisplayBorder will be
* painted immediately on top of this background.
*/
PAINTBG_WILL_PAINT_BORDER = 0x01,
/**
* When this flag is passed, images are synchronously decoded.
*/
PAINTBG_SYNC_DECODE_IMAGES = 0x02,
/**
* When this flag is passed, painting will go to the screen so we can
* take advantage of the fact that it will be clipped to the viewport.
*/
PAINTBG_TO_WINDOW = 0x04
};
static void PaintBackground(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
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nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
PRUint32 aFlags,
nsRect* aBGClipRect = nsnull);
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/**
* Same as |PaintBackground|, except using the provided style structs.
* This short-circuits the code that ensures that the root element's
* background is drawn on the canvas.
*/
static void PaintBackgroundWithSC(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
nsStyleContext *aStyleContext,
const nsStyleBorder& aBorder,
PRUint32 aFlags,
nsRect* aBGClipRect = nsnull);
/**
* Returns the rectangle covered by the given background layer image, taking
* into account background positioning, sizing, and repetition, but not
* clipping.
*/
static nsRect GetBackgroundLayerRect(nsPresContext* aPresContext,
nsIFrame* aForFrame,
const nsRect& aBorderArea,
const nsStyleBackground& aBackground,
const nsStyleBackground::Layer& aLayer);
/**
* Called by the presShell when painting is finished, so we can clear our
* inline background data cache.
*/
static void DidPaint();
// Draw a border segment in the table collapsing border model without
// beveling corners
static void DrawTableBorderSegment(nsRenderingContext& aContext,
PRUint8 aBorderStyle,
nscolor aBorderColor,
const nsStyleBackground* aBGColor,
const nsRect& aBorderRect,
PRInt32 aAppUnitsPerCSSPixel,
PRUint8 aStartBevelSide = 0,
nscoord aStartBevelOffset = 0,
PRUint8 aEndBevelSide = 0,
nscoord aEndBevelOffset = 0);
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/**
* Function for painting the decoration lines for the text.
* NOTE: aPt, aLineSize, aAscent and aOffset are non-rounded device pixels,
* not app units.
* input:
* @param aGfxContext
* @param aDirtyRect no need to paint outside this rect
* @param aColor the color of the decoration line
* @param aPt the top/left edge of the text
* @param aLineSize the width and the height of the decoration
* line
* @param aAscent the ascent of the text
* @param aOffset the offset of the decoration line from
* the baseline of the text (if the value is
* positive, the line is lifted up)
* @param aDecoration which line will be painted. The value can be
* NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_OVERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_LINE_THROUGH.
* @param aStyle the style of the decoration line such as
* NS_STYLE_TEXT_DECORATION_STYLE_*.
* @param aDescentLimit If aDescentLimit is zero or larger and the
* underline overflows from the descent space,
* the underline should be lifted up as far as
* possible. Note that this does not mean the
* underline never overflows from this
* limitation. Because if the underline is
* positioned to the baseline or upper, it causes
* unreadability. Note that if this is zero
* or larger, the underline rect may be shrunken
* if it's possible. Therefore, this value is
* used for strikeout line and overline too.
*/
static void PaintDecorationLine(gfxContext* aGfxContext,
const gfxRect& aDirtyRect,
const nscolor aColor,
const gfxPoint& aPt,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const PRUint8 aDecoration,
const PRUint8 aStyle,
const gfxFloat aDescentLimit = -1.0);
/**
* Function for getting the decoration line rect for the text.
* NOTE: aLineSize, aAscent and aOffset are non-rounded device pixels,
* not app units.
* input:
* @param aPresContext
* @param aLineSize the width and the height of the decoration
* line
* @param aAscent the ascent of the text
* @param aOffset the offset of the decoration line from
* the baseline of the text (if the value is
* positive, the line is lifted up)
* @param aDecoration which line will be painted. The value can be
* NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_OVERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_LINE_THROUGH.
* @param aStyle the style of the decoration line such as
* NS_STYLE_TEXT_DECORATION_STYLE_*.
* @param aDescentLimit If aDescentLimit is zero or larger and the
* underline overflows from the descent space,
* the underline should be lifted up as far as
* possible. Note that this does not mean the
* underline never overflows from this
* limitation. Because if the underline is
* positioned to the baseline or upper, it causes
* unreadability. Note that if this is zero
* or larger, the underline rect may be shrunken
* if it's possible. Therefore, this value is
* used for strikeout line and overline too.
* output:
* @return the decoration line rect for the input,
* the each values are app units.
*/
static nsRect GetTextDecorationRect(nsPresContext* aPresContext,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const PRUint8 aDecoration,
const PRUint8 aStyle,
const gfxFloat aDescentLimit = -1.0);
protected:
static gfxRect GetTextDecorationRectInternal(const gfxPoint& aPt,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const PRUint8 aDecoration,
const PRUint8 aStyle,
const gfxFloat aDscentLimit);
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};
/*
* nsContextBoxBlur
* Creates an 8-bit alpha channel context for callers to draw in, blurs the
* contents of that context and applies it as a 1-color mask on a
* different existing context. Uses gfxAlphaBoxBlur as its back end.
*
* You must call Init() first to create a suitable temporary surface to draw
* on. You must then draw any desired content onto the given context, then
* call DoPaint() to apply the blurred content as a single-color mask. You
* can only call Init() once, so objects cannot be reused.
*
* This is very useful for creating drop shadows or silhouettes.
*/
class nsContextBoxBlur {
public:
enum {
FORCE_MASK = 0x01
};
/**
* Prepares a gfxContext to draw on. Do not call this twice; if you want
* to get the gfxContext again use GetContext().
*
* @param aRect The coordinates of the surface to create.
* All coordinates must be in app units.
* This must not include the blur radius, pass
* it as the second parameter and everything
* is taken care of.
*
* @param aBlurRadius The blur radius in app units.
*
* @param aAppUnitsPerDevPixel The number of app units in a device pixel,
* for conversion. Most of the time you'll
* pass this from the current PresContext if
* available.
*
* @param aDestinationCtx The graphics context to apply the blurred
* mask to when you call DoPaint(). Make sure
* it is not destroyed before you call
* DoPaint(). To set the color of the
* resulting blurred graphic mask, you must
* set the color on this context before
* calling Init().
*
* @param aDirtyRect The absolute dirty rect in app units. Used to
* optimize the temporary surface size and speed up blur.
*
* @param aSkipRect An area in device pixels (NOT app units!) to avoid
* blurring over, to prevent unnecessary work.
*
* @param aFlags FORCE_MASK to ensure that the content drawn to the
* returned gfxContext is used as a mask, and not
* drawn directly to aDestinationCtx.
*
* @return A blank 8-bit alpha-channel-only graphics context to
* draw on, or null on error. Must not be freed. The
* context has a device offset applied to it given by
* aRect. This means you can use coordinates as if it
* were at the desired position at aRect and you don't
* need to worry about translating any coordinates to
* draw on this temporary surface.
*
* If aBlurRadius is 0, the returned context is aDestinationCtx and
* DoPaint() does nothing, because no blurring is required. Therefore, you
* should prepare the destination context as if you were going to draw
* directly on it instead of any temporary surface created in this class.
*/
gfxContext* Init(const nsRect& aRect, nscoord aSpreadRadius,
nscoord aBlurRadius,
PRInt32 aAppUnitsPerDevPixel, gfxContext* aDestinationCtx,
const nsRect& aDirtyRect, const gfxRect* aSkipRect,
PRUint32 aFlags = 0);
/**
* Does the actual blurring/spreading. Users of this object *must*
* have called Init() first, then have drawn whatever they want to be
* blurred onto the internal gfxContext before calling this.
*/
void DoEffects();
/**
* Does the actual blurring and mask applying. Users of this object *must*
* have called Init() first, then have drawn whatever they want to be
* blurred onto the internal gfxContext before calling this.
*/
void DoPaint();
/**
* Gets the internal gfxContext at any time. Must not be freed. Avoid
* calling this before calling Init() since the context would not be
* constructed at that point.
*/
gfxContext* GetContext();
Change the blur radius for -moz-box-shadow and text-shadow to match what is specified in css3-background, and the blur radius for canvas to follow what is specified in HTML5. (Bug 590039) r=roc a2.0=blocking2.0:beta6 This fixes the multiplication by 1.5 in gfxAlphaBoxBlur::CalculateBlurRadius (originally added in changeset ce9f05b57b95 for bug 467518) to work correctly. It was previously a multiplication by 1 due to integer division. CalculateBlurRadius previously multiplied by 1.880; it now multiplies by 2.820. This changes canvas shadow handling to multiply shadowBlur by 2 before taking its square root, as described in the spec. This means that canvas shadow blurs 8px or smaller are 1.5 times larger than they were previously (due to the CalculateBlurRadius change), and canvas shadow blurs larger than 8px are 2.121 times larger than they were previously (due to the CalculateBlurRadius change *and* the additional factor of sqrt(2)). This changes text-shadow and -moz-box-shadow handling to use CalculateBlurRadius on half of the value given instead of passing the value through directly. This means that text-shadow and box-shadow blurs are multiplied by 1.410 relative to their old sizes. It also means that we round rather than floor, so that the effect that used to be drawn by a blur in the range 1px to 1.99px is now drawn by a blur anywhere in the range 0.36px to 1.05px, the effect that used to be drawn by a blur in the range 2px to 2.99px is now drawn by a blur anywhere in the range 1.06px to 1.77px, what used to be a drawn by a blur in the range 3px to 3.99px is now drawn by a blur anywhere in the range 1.78px to 2.47px, etc.
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/**
* Get the margin associated with the given blur radius, i.e., the
* additional area that might be painted as a result of it. (The
* margin for a spread radius is itself, on all sides.)
*/
static nsMargin GetBlurRadiusMargin(nscoord aBlurRadius,
PRInt32 aAppUnitsPerDevPixel);
protected:
gfxAlphaBoxBlur blur;
nsRefPtr<gfxContext> mContext;
gfxContext* mDestinationCtx;
};
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#endif /* nsCSSRendering_h___ */