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gecko-dev/dom/canvas/CanvasRenderingContext2D.h

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/* 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 CanvasRenderingContext2D_h
#define CanvasRenderingContext2D_h
#include "mozilla/Attributes.h"
#include <vector>
#include "nsIDOMCanvasRenderingContext2D.h"
#include "nsICanvasRenderingContextInternal.h"
#include "mozilla/RefPtr.h"
#include "nsColor.h"
#include "mozilla/dom/HTMLCanvasElement.h"
#include "mozilla/dom/HTMLVideoElement.h"
#include "gfxTextRun.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/CanvasGradient.h"
#include "mozilla/dom/CanvasRenderingContext2DBinding.h"
#include "mozilla/dom/CanvasPattern.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/UniquePtr.h"
#include "gfx2DGlue.h"
#include "imgIEncoder.h"
#include "nsLayoutUtils.h"
#include "mozilla/EnumeratedArray.h"
#include "FilterSupport.h"
#include "nsSVGEffects.h"
#include "Layers.h"
class nsGlobalWindow;
class nsXULElement;
namespace mozilla {
namespace gl {
class SourceSurface;
} // namespace gl
namespace dom {
class HTMLImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap;
typedef HTMLImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap CanvasImageSource;
class ImageData;
class StringOrCanvasGradientOrCanvasPattern;
class OwningStringOrCanvasGradientOrCanvasPattern;
class TextMetrics;
class CanvasFilterChainObserver;
class CanvasPath;
extern const mozilla::gfx::Float SIGMA_MAX;
template<typename T> class Optional;
struct CanvasBidiProcessor;
class CanvasRenderingContext2DUserData;
class CanvasDrawObserver;
/**
** CanvasRenderingContext2D
**/
class CanvasRenderingContext2D final :
public nsICanvasRenderingContextInternal,
public nsWrapperCache
{
virtual ~CanvasRenderingContext2D();
public:
CanvasRenderingContext2D();
virtual JSObject* WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;
HTMLCanvasElement* GetCanvas() const
{
// corresponds to changes to the old bindings made in bug 745025
return mCanvasElement->GetOriginalCanvas();
}
void Save();
void Restore();
void Scale(double x, double y, mozilla::ErrorResult& error);
void Rotate(double angle, mozilla::ErrorResult& error);
void Translate(double x, double y, mozilla::ErrorResult& error);
void Transform(double m11, double m12, double m21, double m22, double dx,
double dy, mozilla::ErrorResult& error);
void SetTransform(double m11, double m12, double m21, double m22, double dx,
double dy, mozilla::ErrorResult& error);
void ResetTransform(mozilla::ErrorResult& error);
double GlobalAlpha()
{
return CurrentState().globalAlpha;
}
// Useful for silencing cast warnings
static mozilla::gfx::Float ToFloat(double aValue) { return mozilla::gfx::Float(aValue); }
void SetGlobalAlpha(double globalAlpha)
{
if (globalAlpha >= 0.0 && globalAlpha <= 1.0) {
CurrentState().globalAlpha = ToFloat(globalAlpha);
}
}
void GetGlobalCompositeOperation(nsAString& op, mozilla::ErrorResult& error);
void SetGlobalCompositeOperation(const nsAString& op,
mozilla::ErrorResult& error);
void GetStrokeStyle(OwningStringOrCanvasGradientOrCanvasPattern& value)
{
GetStyleAsUnion(value, Style::STROKE);
}
void SetStrokeStyle(const StringOrCanvasGradientOrCanvasPattern& value)
{
SetStyleFromUnion(value, Style::STROKE);
}
void GetFillStyle(OwningStringOrCanvasGradientOrCanvasPattern& value)
{
GetStyleAsUnion(value, Style::FILL);
}
void SetFillStyle(const StringOrCanvasGradientOrCanvasPattern& value)
{
SetStyleFromUnion(value, Style::FILL);
}
already_AddRefed<CanvasGradient>
CreateLinearGradient(double x0, double y0, double x1, double y1);
already_AddRefed<CanvasGradient>
CreateRadialGradient(double x0, double y0, double r0, double x1, double y1,
double r1, ErrorResult& aError);
already_AddRefed<CanvasPattern>
CreatePattern(const CanvasImageSource& element,
const nsAString& repeat, ErrorResult& error);
double ShadowOffsetX()
{
return CurrentState().shadowOffset.x;
}
void SetShadowOffsetX(double shadowOffsetX)
{
CurrentState().shadowOffset.x = ToFloat(shadowOffsetX);
}
double ShadowOffsetY()
{
return CurrentState().shadowOffset.y;
}
void SetShadowOffsetY(double shadowOffsetY)
{
CurrentState().shadowOffset.y = ToFloat(shadowOffsetY);
}
double ShadowBlur()
{
return CurrentState().shadowBlur;
}
void SetShadowBlur(double shadowBlur)
{
if (shadowBlur >= 0.0) {
CurrentState().shadowBlur = ToFloat(shadowBlur);
}
}
void GetShadowColor(nsAString& shadowColor)
{
StyleColorToString(CurrentState().shadowColor, shadowColor);
}
void GetFilter(nsAString& filter)
{
filter = CurrentState().filterString;
}
void SetShadowColor(const nsAString& shadowColor);
void SetFilter(const nsAString& filter, mozilla::ErrorResult& error);
void ClearRect(double x, double y, double w, double h);
void FillRect(double x, double y, double w, double h);
void StrokeRect(double x, double y, double w, double h);
void BeginPath();
void Fill(const CanvasWindingRule& winding);
void Fill(const CanvasPath& path, const CanvasWindingRule& winding);
void Stroke();
void Stroke(const CanvasPath& path);
void DrawFocusIfNeeded(mozilla::dom::Element& element, ErrorResult& aRv);
bool DrawCustomFocusRing(mozilla::dom::Element& element);
void Clip(const CanvasWindingRule& winding);
void Clip(const CanvasPath& path, const CanvasWindingRule& winding);
bool IsPointInPath(double x, double y, const CanvasWindingRule& winding);
bool IsPointInPath(const CanvasPath& path, double x, double y, const CanvasWindingRule& winding);
bool IsPointInStroke(double x, double y);
bool IsPointInStroke(const CanvasPath& path, double x, double y);
void FillText(const nsAString& text, double x, double y,
const Optional<double>& maxWidth,
mozilla::ErrorResult& error);
void StrokeText(const nsAString& text, double x, double y,
const Optional<double>& maxWidth,
mozilla::ErrorResult& error);
TextMetrics*
MeasureText(const nsAString& rawText, mozilla::ErrorResult& error);
void AddHitRegion(const HitRegionOptions& options, mozilla::ErrorResult& error);
void RemoveHitRegion(const nsAString& id);
void ClearHitRegions();
void DrawImage(const CanvasImageSource& image,
double dx, double dy, mozilla::ErrorResult& error)
{
DrawImage(image, 0.0, 0.0, 0.0, 0.0, dx, dy, 0.0, 0.0, 0, error);
}
void DrawImage(const CanvasImageSource& image,
double dx, double dy, double dw, double dh,
mozilla::ErrorResult& error)
{
DrawImage(image, 0.0, 0.0, 0.0, 0.0, dx, dy, dw, dh, 2, error);
}
void DrawImage(const CanvasImageSource& image,
double sx, double sy, double sw, double sh, double dx,
double dy, double dw, double dh, mozilla::ErrorResult& error)
{
DrawImage(image, sx, sy, sw, sh, dx, dy, dw, dh, 6, error);
}
already_AddRefed<ImageData>
CreateImageData(JSContext* cx, double sw, double sh,
mozilla::ErrorResult& error);
already_AddRefed<ImageData>
CreateImageData(JSContext* cx, ImageData& imagedata,
mozilla::ErrorResult& error);
already_AddRefed<ImageData>
GetImageData(JSContext* cx, double sx, double sy, double sw, double sh,
mozilla::ErrorResult& error);
void PutImageData(ImageData& imageData,
double dx, double dy, mozilla::ErrorResult& error);
void PutImageData(ImageData& imageData,
double dx, double dy, double dirtyX, double dirtyY,
double dirtyWidth, double dirtyHeight,
mozilla::ErrorResult& error);
double LineWidth()
{
return CurrentState().lineWidth;
}
void SetLineWidth(double width)
{
if (width > 0.0) {
CurrentState().lineWidth = ToFloat(width);
}
}
void GetLineCap(nsAString& linecap);
void SetLineCap(const nsAString& linecap);
void GetLineJoin(nsAString& linejoin, mozilla::ErrorResult& error);
void SetLineJoin(const nsAString& linejoin);
double MiterLimit()
{
return CurrentState().miterLimit;
}
void SetMiterLimit(double miter)
{
if (miter > 0.0) {
CurrentState().miterLimit = ToFloat(miter);
}
}
void GetFont(nsAString& font)
{
font = GetFont();
}
void SetFont(const nsAString& font, mozilla::ErrorResult& error);
void GetTextAlign(nsAString& textAlign);
void SetTextAlign(const nsAString& textAlign);
void GetTextBaseline(nsAString& textBaseline);
void SetTextBaseline(const nsAString& textBaseline);
void ClosePath()
{
EnsureWritablePath();
if (mPathBuilder) {
mPathBuilder->Close();
} else {
mDSPathBuilder->Close();
}
}
void MoveTo(double x, double y)
{
EnsureWritablePath();
if (mPathBuilder) {
mPathBuilder->MoveTo(mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
} else {
mDSPathBuilder->MoveTo(mTarget->GetTransform() *
mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
}
}
void LineTo(double x, double y)
{
EnsureWritablePath();
LineTo(mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
}
void QuadraticCurveTo(double cpx, double cpy, double x, double y)
{
EnsureWritablePath();
if (mPathBuilder) {
mPathBuilder->QuadraticBezierTo(mozilla::gfx::Point(ToFloat(cpx), ToFloat(cpy)),
mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
} else {
mozilla::gfx::Matrix transform = mTarget->GetTransform();
mDSPathBuilder->QuadraticBezierTo(transform *
mozilla::gfx::Point(ToFloat(cpx), ToFloat(cpy)),
transform *
mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
}
}
void BezierCurveTo(double cp1x, double cp1y, double cp2x, double cp2y, double x, double y)
{
EnsureWritablePath();
BezierTo(mozilla::gfx::Point(ToFloat(cp1x), ToFloat(cp1y)),
mozilla::gfx::Point(ToFloat(cp2x), ToFloat(cp2y)),
mozilla::gfx::Point(ToFloat(x), ToFloat(y)));
}
void ArcTo(double x1, double y1, double x2, double y2, double radius,
mozilla::ErrorResult& error);
void Rect(double x, double y, double w, double h);
void Arc(double x, double y, double radius, double startAngle,
double endAngle, bool anticlockwise, mozilla::ErrorResult& error);
void GetMozCurrentTransform(JSContext* cx,
JS::MutableHandle<JSObject*> result,
mozilla::ErrorResult& error) const;
void SetMozCurrentTransform(JSContext* cx,
JS::Handle<JSObject*> currentTransform,
mozilla::ErrorResult& error);
void GetMozCurrentTransformInverse(JSContext* cx,
JS::MutableHandle<JSObject*> result,
mozilla::ErrorResult& error) const;
void SetMozCurrentTransformInverse(JSContext* cx,
JS::Handle<JSObject*> currentTransform,
mozilla::ErrorResult& error);
void GetFillRule(nsAString& fillRule);
void SetFillRule(const nsAString& fillRule);
void GetMozDash(JSContext* cx, JS::MutableHandle<JS::Value> retval,
mozilla::ErrorResult& error);
void SetMozDash(JSContext* cx, const JS::Value& mozDash,
mozilla::ErrorResult& error);
void SetLineDash(const Sequence<double>& mSegments,
mozilla::ErrorResult& aRv);
void GetLineDash(nsTArray<double>& mSegments) const;
void SetLineDashOffset(double mOffset);
double LineDashOffset() const;
double MozDashOffset()
{
return CurrentState().dashOffset;
}
void SetMozDashOffset(double mozDashOffset);
void GetMozTextStyle(nsAString& mozTextStyle)
{
GetFont(mozTextStyle);
}
void SetMozTextStyle(const nsAString& mozTextStyle,
mozilla::ErrorResult& error)
{
SetFont(mozTextStyle, error);
}
bool ImageSmoothingEnabled()
{
return CurrentState().imageSmoothingEnabled;
}
void SetImageSmoothingEnabled(bool imageSmoothingEnabled)
{
if (imageSmoothingEnabled != CurrentState().imageSmoothingEnabled) {
CurrentState().imageSmoothingEnabled = imageSmoothingEnabled;
}
}
void DrawWindow(nsGlobalWindow& window, double x, double y, double w, double h,
const nsAString& bgColor, uint32_t flags,
mozilla::ErrorResult& error);
void DrawWidgetAsOnScreen(nsGlobalWindow& aWindow, mozilla::ErrorResult& error);
void AsyncDrawXULElement(nsXULElement& elem, double x, double y, double w,
double h, const nsAString& bgColor, uint32_t flags,
mozilla::ErrorResult& error);
enum RenderingMode {
SoftwareBackendMode,
OpenGLBackendMode,
DefaultBackendMode
};
bool SwitchRenderingMode(RenderingMode aRenderingMode);
// Eventually this should be deprecated. Keeping for now to keep the binding functional.
void Demote();
nsresult Redraw();
virtual int32_t GetWidth() const override;
virtual int32_t GetHeight() const override;
// nsICanvasRenderingContextInternal
/**
* Gets the pres shell from either the canvas element or the doc shell
*/
virtual nsIPresShell *GetPresShell() override {
if (mCanvasElement) {
return mCanvasElement->OwnerDoc()->GetShell();
}
if (mDocShell) {
return mDocShell->GetPresShell();
}
return nullptr;
}
NS_IMETHOD SetDimensions(int32_t width, int32_t height) override;
NS_IMETHOD InitializeWithSurface(nsIDocShell *shell, gfxASurface *surface, int32_t width, int32_t height) override;
NS_IMETHOD GetInputStream(const char* aMimeType,
const char16_t* aEncoderOptions,
nsIInputStream **aStream) override;
already_AddRefed<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(bool* aPremultAlpha = nullptr) override
{
EnsureTarget();
if (aPremultAlpha) {
*aPremultAlpha = true;
}
return mTarget->Snapshot();
}
NS_IMETHOD SetIsOpaque(bool isOpaque) override;
bool GetIsOpaque() override { return mOpaque; }
NS_IMETHOD Reset() override;
mozilla::layers::PersistentBufferProvider* GetBufferProvider(mozilla::layers::LayerManager* aManager);
already_AddRefed<CanvasLayer> GetCanvasLayer(nsDisplayListBuilder* aBuilder,
CanvasLayer *aOldLayer,
LayerManager *aManager) override;
virtual bool ShouldForceInactiveLayer(LayerManager *aManager) override;
void MarkContextClean() override;
void MarkContextCleanForFrameCapture() override;
bool IsContextCleanForFrameCapture() override;
NS_IMETHOD SetIsIPC(bool isIPC) override;
// this rect is in canvas device space
void Redraw(const mozilla::gfx::Rect &r);
NS_IMETHOD Redraw(const gfxRect &r) override { Redraw(ToRect(r)); return NS_OK; }
NS_IMETHOD SetContextOptions(JSContext* aCx,
JS::Handle<JS::Value> aOptions,
ErrorResult& aRvForDictionaryInit) override;
/**
* An abstract base class to be implemented by callers wanting to be notified
* that a refresh has occurred. Callers must ensure an observer is removed
* before it is destroyed.
*/
virtual void DidRefresh() override;
// this rect is in mTarget's current user space
void RedrawUser(const gfxRect &r);
// nsISupports interface + CC
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(CanvasRenderingContext2D)
enum class CanvasMultiGetterType : uint8_t {
STRING = 0,
PATTERN = 1,
GRADIENT = 2
};
enum class Style : uint8_t {
STROKE = 0,
FILL,
MAX
};
nsINode* GetParentObject()
{
return mCanvasElement;
}
void LineTo(const mozilla::gfx::Point& aPoint)
{
if (mPathBuilder) {
mPathBuilder->LineTo(aPoint);
} else {
mDSPathBuilder->LineTo(mTarget->GetTransform() * aPoint);
}
}
void BezierTo(const mozilla::gfx::Point& aCP1,
const mozilla::gfx::Point& aCP2,
const mozilla::gfx::Point& aCP3)
{
if (mPathBuilder) {
mPathBuilder->BezierTo(aCP1, aCP2, aCP3);
} else {
mozilla::gfx::Matrix transform = mTarget->GetTransform();
mDSPathBuilder->BezierTo(transform * aCP1,
transform * aCP2,
transform * aCP3);
}
}
friend class CanvasRenderingContext2DUserData;
virtual UniquePtr<uint8_t[]> GetImageBuffer(int32_t* aFormat) override;
// Given a point, return hit region ID if it exists
nsString GetHitRegion(const mozilla::gfx::Point& aPoint) override;
// return true and fills in the bound rect if element has a hit region.
bool GetHitRegionRect(Element* aElement, nsRect& aRect) override;
protected:
nsresult GetImageDataArray(JSContext* aCx, int32_t aX, int32_t aY,
uint32_t aWidth, uint32_t aHeight,
JSObject** aRetval);
nsresult PutImageData_explicit(int32_t x, int32_t y, uint32_t w, uint32_t h,
dom::Uint8ClampedArray* aArray,
bool hasDirtyRect, int32_t dirtyX, int32_t dirtyY,
int32_t dirtyWidth, int32_t dirtyHeight);
/**
* Internal method to complete initialisation, expects mTarget to have been set
*/
nsresult Initialize(int32_t width, int32_t height);
nsresult InitializeWithTarget(mozilla::gfx::DrawTarget *surface,
int32_t width, int32_t height);
/**
* The number of living nsCanvasRenderingContexts. When this goes down to
* 0, we free the premultiply and unpremultiply tables, if they exist.
*/
static uint32_t sNumLivingContexts;
/**
* Lookup table used to speed up GetImageData().
*/
static uint8_t (*sUnpremultiplyTable)[256];
/**
* Lookup table used to speed up PutImageData().
*/
static uint8_t (*sPremultiplyTable)[256];
static mozilla::gfx::DrawTarget* sErrorTarget;
// Some helpers. Doesn't modify a color on failure.
void SetStyleFromUnion(const StringOrCanvasGradientOrCanvasPattern& value,
Style whichStyle);
void SetStyleFromString(const nsAString& str, Style whichStyle);
void SetStyleFromGradient(CanvasGradient& gradient, Style whichStyle)
{
CurrentState().SetGradientStyle(whichStyle, &gradient);
}
void SetStyleFromPattern(CanvasPattern& pattern, Style whichStyle)
{
CurrentState().SetPatternStyle(whichStyle, &pattern);
}
void GetStyleAsUnion(OwningStringOrCanvasGradientOrCanvasPattern& aValue,
Style aWhichStyle);
// Returns whether a color was successfully parsed.
bool ParseColor(const nsAString& aString, nscolor* aColor);
static void StyleColorToString(const nscolor& aColor, nsAString& aStr);
// Returns whether a filter was successfully parsed.
bool ParseFilter(const nsAString& aString,
nsTArray<nsStyleFilter>& aFilterChain,
ErrorResult& error);
// Returns whether the font was successfully updated.
bool SetFontInternal(const nsAString& font, mozilla::ErrorResult& error);
/**
* Creates the error target, if it doesn't exist
*/
static void EnsureErrorTarget();
/* This function ensures there is a writable pathbuilder available, this
* pathbuilder may be working in user space or in device space or
* device space.
* After calling this function mPathTransformWillUpdate will be false
*/
void EnsureWritablePath();
// Ensures a path in UserSpace is available.
void EnsureUserSpacePath(const CanvasWindingRule& winding = CanvasWindingRule::Nonzero);
/**
* Needs to be called before updating the transform. This makes a call to
* EnsureTarget() so you don't have to.
*/
void TransformWillUpdate();
// Report the fillRule has changed.
void FillRuleChanged();
/**
* Create the backing surfacing, if it doesn't exist. If there is an error
* in creating the target then it will put sErrorTarget in place. If there
* is in turn an error in creating the sErrorTarget then they would both
* be null so IsTargetValid() would still return null.
*
* Returns the actual rendering mode being used by the created target.
*/
RenderingMode EnsureTarget(RenderingMode aRenderMode = RenderingMode::DefaultBackendMode);
/**
* Disposes an old target and prepares to lazily create a new target.
*/
void ClearTarget();
/*
* Returns the target to the buffer provider. i.e. this will queue a frame for
* rendering.
*/
void ReturnTarget();
/**
* Check if the target is valid after calling EnsureTarget.
*/
bool IsTargetValid() const {
return (sErrorTarget == nullptr || mTarget != sErrorTarget) && (mBufferProvider != nullptr || mTarget);
}
/**
* Returns the surface format this canvas should be allocated using. Takes
* into account mOpaque, platform requirements, etc.
*/
mozilla::gfx::SurfaceFormat GetSurfaceFormat() const;
/**
* Update CurrentState().filter with the filter description for
* CurrentState().filterChain.
*/
void UpdateFilter();
nsLayoutUtils::SurfaceFromElementResult
CachedSurfaceFromElement(Element* aElement);
void DrawImage(const CanvasImageSource &imgElt,
double sx, double sy, double sw, double sh,
double dx, double dy, double dw, double dh,
uint8_t optional_argc, mozilla::ErrorResult& error);
void DrawDirectlyToCanvas(const nsLayoutUtils::DirectDrawInfo& image,
mozilla::gfx::Rect* bounds,
mozilla::gfx::Rect dest,
mozilla::gfx::Rect src,
gfx::IntSize imgSize);
nsString& GetFont()
{
/* will initilize the value if not set, else does nothing */
GetCurrentFontStyle();
return CurrentState().font;
}
// This function maintains a list of raw pointers to cycle-collected
// objects. We need to ensure that no entries persist beyond unlink,
// since the objects are logically destructed at that point.
static std::vector<CanvasRenderingContext2D*>& DemotableContexts();
static void DemoteOldestContextIfNecessary();
static void AddDemotableContext(CanvasRenderingContext2D* context);
static void RemoveDemotableContext(CanvasRenderingContext2D* context);
RenderingMode mRenderingMode;
// Texture informations for fast video rendering
unsigned int mVideoTexture;
nsIntSize mCurrentVideoSize;
// Member vars
int32_t mWidth, mHeight;
// This is true when the canvas is valid, but of zero size, this requires
// specific behavior on some operations.
bool mZero;
bool mOpaque;
// This is true when the next time our layer is retrieved we need to
// recreate it (i.e. our backing surface changed)
bool mResetLayer;
// This is needed for drawing in drawAsyncXULElement
bool mIPC;
// True if the current DrawTarget is using skia-gl, used so we can avoid
// requesting the DT from mBufferProvider to check.
bool mIsSkiaGL;
nsTArray<CanvasRenderingContext2DUserData*> mUserDatas;
// If mCanvasElement is not provided, then a docshell is
nsCOMPtr<nsIDocShell> mDocShell;
// This is created lazily so it is necessary to call EnsureTarget before
// accessing it. In the event of an error it will be equal to
// sErrorTarget.
RefPtr<mozilla::gfx::DrawTarget> mTarget;
RefPtr<mozilla::layers::PersistentBufferProvider> mBufferProvider;
uint32_t SkiaGLTex() const;
// This observes our draw calls at the beginning of the canvas
// lifetime and switches to software or GPU mode depending on
// what it thinks is best
CanvasDrawObserver* mDrawObserver;
void RemoveDrawObserver();
/**
* Flag to avoid duplicate calls to InvalidateFrame. Set to true whenever
* Redraw is called, reset to false when Render is called.
*/
bool mIsEntireFrameInvalid;
/**
* When this is set, the first call to Redraw(gfxRect) should set
* mIsEntireFrameInvalid since we expect it will be followed by
* many more Redraw calls.
*/
bool mPredictManyRedrawCalls;
/**
* Flag to avoid unnecessary surface copies to FrameCaptureListeners in the
* case when the canvas is not currently being drawn into and not rendered
* but canvas capturing is still ongoing.
*/
bool mIsCapturedFrameInvalid;
// This is stored after GetThebesSurface has been called once to avoid
// excessive ThebesSurface initialization overhead.
RefPtr<gfxASurface> mThebesSurface;
/**
* We also have a device space pathbuilder. The reason for this is as
* follows, when a path is being built, but the transform changes, we
* can no longer keep a single path in userspace, considering there's
* several 'user spaces' now. We therefore transform the current path
* into device space, and add all operations to this path in device
* space.
*
* When then finally executing a render, the Azure drawing API expects
* the path to be in userspace. We could then set an identity transform
* on the DrawTarget and do all drawing in device space. This is
* undesirable because it requires transforming patterns, gradients,
* clips, etc. into device space and it would not work for stroking.
* What we do instead is convert the path back to user space when it is
* drawn, and draw it with the current transform. This makes all drawing
* occur correctly.
*
* There's never both a device space path builder and a user space path
* builder present at the same time. There is also never a path and a
* path builder present at the same time. When writing proceeds on an
* existing path the Path is cleared and a new builder is created.
*
* mPath is always in user-space.
*/
RefPtr<mozilla::gfx::Path> mPath;
RefPtr<mozilla::gfx::PathBuilder> mDSPathBuilder;
RefPtr<mozilla::gfx::PathBuilder> mPathBuilder;
bool mPathTransformWillUpdate;
mozilla::gfx::Matrix mPathToDS;
/**
* Number of times we've invalidated before calling redraw
*/
uint32_t mInvalidateCount;
static const uint32_t kCanvasMaxInvalidateCount = 100;
/**
* State information for hit regions
*/
struct RegionInfo
{
nsString mId;
// fallback element for a11y
RefPtr<Element> mElement;
// Path of the hit region in the 2d context coordinate space (not user space)
RefPtr<gfx::Path> mPath;
};
nsTArray<RegionInfo> mHitRegionsOptions;
/**
* Returns true if a shadow should be drawn along with a
* drawing operation.
*/
bool NeedToDrawShadow()
{
const ContextState& state = CurrentState();
// The spec says we should not draw shadows if the operator is OVER.
// If it's over and the alpha value is zero, nothing needs to be drawn.
return NS_GET_A(state.shadowColor) != 0 &&
(state.shadowBlur != 0.f || state.shadowOffset.x != 0.f || state.shadowOffset.y != 0.f);
}
/**
* Returns true if the result of a drawing operation should be
* drawn with a filter.
*/
bool NeedToApplyFilter()
{
const ContextState& state = CurrentState();
return state.filter.mPrimitives.Length() > 0;
}
bool NeedToCalculateBounds()
{
return NeedToDrawShadow() || NeedToApplyFilter();
}
mozilla::gfx::CompositionOp UsedOperation()
{
if (NeedToDrawShadow() || NeedToApplyFilter()) {
// In this case the shadow or filter rendering will use the operator.
return mozilla::gfx::CompositionOp::OP_OVER;
}
return CurrentState().op;
}
// text
protected:
enum class TextAlign : uint8_t {
START,
END,
LEFT,
RIGHT,
CENTER
};
enum class TextBaseline : uint8_t {
TOP,
HANGING,
MIDDLE,
ALPHABETIC,
IDEOGRAPHIC,
BOTTOM
};
enum class TextDrawOperation : uint8_t {
FILL,
STROKE,
MEASURE
};
protected:
gfxFontGroup *GetCurrentFontStyle();
/**
* Implementation of the fillText, strokeText, and measure functions with
* the operation abstracted to a flag.
*/
nsresult DrawOrMeasureText(const nsAString& text,
float x,
float y,
const Optional<double>& maxWidth,
TextDrawOperation op,
float* aWidth);
bool CheckSizeForSkiaGL(mozilla::gfx::IntSize size);
// state stack handling
class ContextState {
public:
ContextState() : textAlign(TextAlign::START),
textBaseline(TextBaseline::ALPHABETIC),
lineWidth(1.0f),
miterLimit(10.0f),
globalAlpha(1.0f),
shadowBlur(0.0),
dashOffset(0.0f),
op(mozilla::gfx::CompositionOp::OP_OVER),
fillRule(mozilla::gfx::FillRule::FILL_WINDING),
lineCap(mozilla::gfx::CapStyle::BUTT),
lineJoin(mozilla::gfx::JoinStyle::MITER_OR_BEVEL),
filterString(MOZ_UTF16("none")),
imageSmoothingEnabled(true),
fontExplicitLanguage(false)
{ }
ContextState(const ContextState& other)
: fontGroup(other.fontGroup),
fontLanguage(other.fontLanguage),
fontFont(other.fontFont),
gradientStyles(other.gradientStyles),
patternStyles(other.patternStyles),
colorStyles(other.colorStyles),
font(other.font),
textAlign(other.textAlign),
textBaseline(other.textBaseline),
shadowColor(other.shadowColor),
transform(other.transform),
shadowOffset(other.shadowOffset),
lineWidth(other.lineWidth),
miterLimit(other.miterLimit),
globalAlpha(other.globalAlpha),
shadowBlur(other.shadowBlur),
dash(other.dash),
dashOffset(other.dashOffset),
op(other.op),
fillRule(other.fillRule),
lineCap(other.lineCap),
lineJoin(other.lineJoin),
filterString(other.filterString),
filterChain(other.filterChain),
filterChainObserver(other.filterChainObserver),
filter(other.filter),
filterAdditionalImages(other.filterAdditionalImages),
imageSmoothingEnabled(other.imageSmoothingEnabled),
fontExplicitLanguage(other.fontExplicitLanguage)
{ }
void SetColorStyle(Style whichStyle, nscolor color)
{
colorStyles[whichStyle] = color;
gradientStyles[whichStyle] = nullptr;
patternStyles[whichStyle] = nullptr;
}
void SetPatternStyle(Style whichStyle, CanvasPattern* pat)
{
gradientStyles[whichStyle] = nullptr;
patternStyles[whichStyle] = pat;
}
void SetGradientStyle(Style whichStyle, CanvasGradient* grad)
{
gradientStyles[whichStyle] = grad;
patternStyles[whichStyle] = nullptr;
}
/**
* returns true iff the given style is a solid color.
*/
bool StyleIsColor(Style whichStyle) const
{
return !(patternStyles[whichStyle] || gradientStyles[whichStyle]);
}
int32_t ShadowBlurRadius() const
{
static const gfxFloat GAUSSIAN_SCALE_FACTOR = (3 * sqrt(2 * M_PI) / 4) * 1.5;
return (int32_t)floor(ShadowBlurSigma() * GAUSSIAN_SCALE_FACTOR + 0.5);
}
mozilla::gfx::Float ShadowBlurSigma() const
{
return std::min(SIGMA_MAX, shadowBlur / 2.0f);
}
nsTArray<RefPtr<mozilla::gfx::Path> > clipsPushed;
RefPtr<gfxFontGroup> fontGroup;
nsCOMPtr<nsIAtom> fontLanguage;
nsFont fontFont;
EnumeratedArray<Style, Style::MAX, RefPtr<CanvasGradient>> gradientStyles;
EnumeratedArray<Style, Style::MAX, RefPtr<CanvasPattern>> patternStyles;
EnumeratedArray<Style, Style::MAX, nscolor> colorStyles;
nsString font;
TextAlign textAlign;
TextBaseline textBaseline;
nscolor shadowColor;
mozilla::gfx::Matrix transform;
mozilla::gfx::Point shadowOffset;
mozilla::gfx::Float lineWidth;
mozilla::gfx::Float miterLimit;
mozilla::gfx::Float globalAlpha;
mozilla::gfx::Float shadowBlur;
nsTArray<mozilla::gfx::Float> dash;
mozilla::gfx::Float dashOffset;
mozilla::gfx::CompositionOp op;
mozilla::gfx::FillRule fillRule;
mozilla::gfx::CapStyle lineCap;
mozilla::gfx::JoinStyle lineJoin;
nsString filterString;
nsTArray<nsStyleFilter> filterChain;
RefPtr<nsSVGFilterChainObserver> filterChainObserver;
mozilla::gfx::FilterDescription filter;
nsTArray<RefPtr<mozilla::gfx::SourceSurface>> filterAdditionalImages;
bool imageSmoothingEnabled;
bool fontExplicitLanguage;
};
nsAutoTArray<ContextState, 3> mStyleStack;
inline ContextState& CurrentState() {
return mStyleStack[mStyleStack.Length() - 1];
}
inline const ContextState& CurrentState() const {
return mStyleStack[mStyleStack.Length() - 1];
}
friend class CanvasGeneralPattern;
friend class CanvasFilterChainObserver;
friend class AdjustedTarget;
friend class AdjustedTargetForShadow;
friend class AdjustedTargetForFilter;
// other helpers
void GetAppUnitsValues(int32_t *perDevPixel, int32_t *perCSSPixel)
{
// If we don't have a canvas element, we just return something generic.
int32_t devPixel = 60;
int32_t cssPixel = 60;
nsIPresShell *ps = GetPresShell();
nsPresContext *pc;
if (!ps) goto FINISH;
pc = ps->GetPresContext();
if (!pc) goto FINISH;
devPixel = pc->AppUnitsPerDevPixel();
cssPixel = pc->AppUnitsPerCSSPixel();
FINISH:
if (perDevPixel)
*perDevPixel = devPixel;
if (perCSSPixel)
*perCSSPixel = cssPixel;
}
friend struct CanvasBidiProcessor;
friend class CanvasDrawObserver;
};
} // namespace dom
} // namespace mozilla
#endif /* CanvasRenderingContext2D_h */
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