1 files changed, 176 insertions, 0 deletions
diff --git a/layout/svg/SVGClipPathFrame.h b/layout/svg/SVGClipPathFrame.h
new file mode 100644
index 0000000000..40d73f036b
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+++ b/layout/svg/SVGClipPathFrame.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 LAYOUT_SVG_SVGCLIPPATHFRAME_H_
+#define LAYOUT_SVG_SVGCLIPPATHFRAME_H_
+
+#include "gfxMatrix.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/SVGContainerFrame.h"
+
+class gfxContext;
+
+namespace mozilla {
+class ISVGDisplayableFrame;
+class PresShell;
+}  // namespace mozilla
+
+nsIFrame* NS_NewSVGClipPathFrame(mozilla::PresShell* aPresShell,
+                                 mozilla::ComputedStyle* aStyle);
+
+namespace mozilla {
+
+class SVGClipPathFrame final : public SVGContainerFrame {
+  friend nsIFrame* ::NS_NewSVGClipPathFrame(mozilla::PresShell* aPresShell,
+                                            ComputedStyle* aStyle);
+
+  using Matrix = gfx::Matrix;
+  using SourceSurface = gfx::SourceSurface;
+  using imgDrawingParams = image::imgDrawingParams;
+
+ protected:
+  explicit SVGClipPathFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
+      : SVGContainerFrame(aStyle, aPresContext, kClassID),
+        mIsBeingProcessed(false) {
+    AddStateBits(NS_FRAME_IS_NONDISPLAY | NS_STATE_SVG_CLIPPATH_CHILD |
+                 NS_FRAME_MAY_BE_TRANSFORMED);
+  }
+
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(SVGClipPathFrame)
+
+  // nsIFrame methods:
+  void BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists) override {}
+
+  bool IsSVGTransformed(Matrix* aOwnTransforms,
+                        Matrix* aFromParentTransforms) const override;
+
+  // SVGClipPathFrame methods:
+
+  /**
+   * Applies the clipPath by pushing a clip path onto the DrawTarget.
+   *
+   * This method must only be used if IsTrivial() returns true, otherwise use
+   * GetClipMask.
+   *
+   * @param aContext The context that the clip path is to be applied to.
+   * @param aClippedFrame The/an nsIFrame of the element that references this
+   *   clipPath that is currently being processed.
+   * @param aMatrix The transform from aClippedFrame's user space to aContext's
+   *   current transform.
+   */
+  void ApplyClipPath(gfxContext& aContext, nsIFrame* aClippedFrame,
+                     const gfxMatrix& aMatrix);
+
+  /**
+   * Returns an alpha mask surface containing the clipping geometry.
+   *
+   * This method must only be used if IsTrivial() returns false, otherwise use
+   * ApplyClipPath.
+   *
+   * @param aReferenceContext Used to determine the backend for and size of the
+   *   returned SourceSurface, the size being limited to the device space clip
+   *   extents on the context.
+   * @param aClippedFrame The/an nsIFrame of the element that references this
+   *   clipPath that is currently being processed.
+   * @param aMatrix The transform from aClippedFrame's user space to aContext's
+   *   current transform.
+   * @param [in, optional] aExtraMask An extra surface that the returned
+   *   surface should be masked with.
+   */
+  already_AddRefed<SourceSurface> GetClipMask(
+      gfxContext& aReferenceContext, nsIFrame* aClippedFrame,
+      const gfxMatrix& aMatrix, SourceSurface* aExtraMask = nullptr);
+
+  /**
+   * Paint mask directly onto a given context(aMaskContext).
+   *
+   * @param aMaskContext The target of mask been painting on.
+   * @param aClippedFrame The/an nsIFrame of the element that references this
+   *   clipPath that is currently being processed.
+   * @param aMatrix The transform from aClippedFrame's user space to
+   *   current transform.
+   * @param [in, optional] aExtraMask An extra surface that the returned
+   *   surface should be masked with.
+   */
+  void PaintClipMask(gfxContext& aMaskContext, nsIFrame* aClippedFrame,
+                     const gfxMatrix& aMatrix, SourceSurface* aExtraMask);
+
+  /**
+   * aPoint is expected to be in aClippedFrame's SVG user space.
+   */
+  bool PointIsInsideClipPath(nsIFrame* aClippedFrame, const gfxPoint& aPoint);
+
+  // Check if this clipPath is made up of more than one geometry object.
+  // If so, the clipping API in cairo isn't enough and we need to use
+  // mask based clipping.
+  bool IsTrivial(ISVGDisplayableFrame** aSingleChild = nullptr);
+
+  bool IsValid();
+
+  // nsIFrame interface:
+  nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
+                            int32_t aModType) override;
+
+#ifdef DEBUG
+  void Init(nsIContent* aContent, nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+#endif
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"SVGClipPath"_ns, aResult);
+  }
+#endif
+
+  SVGBBox GetBBoxForClipPathFrame(const SVGBBox& aBBox,
+                                  const gfxMatrix& aMatrix, uint32_t aFlags);
+
+  /**
+   * If the clipPath element transforms its children due to
+   * clipPathUnits="objectBoundingBox" being set on it and/or due to the
+   * 'transform' attribute being set on it, this function returns the resulting
+   * transform.
+   */
+  gfxMatrix GetClipPathTransform(nsIFrame* aClippedFrame);
+
+ private:
+  // SVGContainerFrame methods:
+  gfxMatrix GetCanvasTM() override;
+
+  already_AddRefed<DrawTarget> CreateClipMask(gfxContext& aReferenceContext,
+                                              gfx::IntPoint& aOffset);
+
+  void PaintFrameIntoMask(nsIFrame* aFrame, nsIFrame* aClippedFrame,
+                          gfxContext& aTarget);
+
+  void PaintChildren(gfxContext& aMaskContext, nsIFrame* aClippedFrame,
+                     const gfxMatrix& aMatrix);
+
+  // Set, during a GetClipMask() call, to the transform that still needs to be
+  // concatenated to the transform of the DrawTarget that was passed to
+  // GetClipMask in order to establish the coordinate space that the clipPath
+  // establishes for its contents (i.e. including applying 'clipPathUnits' and
+  // any 'transform' attribute set on the clipPath) specifically for clipping
+  // the frame that was passed to GetClipMask at that moment in time.  This is
+  // set so that if our GetCanvasTM method is called while GetClipMask is
+  // painting its children, the returned matrix will include the transforms
+  // that should be used when creating the mask for the frame passed to
+  // GetClipMask.
+  //
+  // Note: The removal of GetCanvasTM is nearly complete, so our GetCanvasTM
+  // may not even be called soon/any more.
+  gfxMatrix mMatrixForChildren;
+
+  // Flag used to indicate whether a methods that may reenter due to
+  // following a reference to another instance is currently executing.
+  bool mIsBeingProcessed;
+};
+
+}  // namespace mozilla
+
+#endif  // LAYOUT_SVG_SVGCLIPPATHFRAME_H_