Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 592 insertions, 0 deletions

diff --git a/layout/svg/SVGTextFrame.h b/layout/svg/SVGTextFrame.h
new file mode 100644
index 0000000000..6be2bcf01e
--- /dev/null
+++ b/layout/svg/SVGTextFrame.h
@@ -0,0 +1,592 @@
+/* -*- 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_SVGTEXTFRAME_H_
+#define LAYOUT_SVG_SVGTEXTFRAME_H_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/PresShellForwards.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/SVGContainerFrame.h"
+#include "mozilla/gfx/2D.h"
+#include "gfxMatrix.h"
+#include "gfxRect.h"
+#include "gfxTextRun.h"
+#include "nsIContent.h"  // for GetContent
+#include "nsStubMutationObserver.h"
+#include "nsTextFrame.h"
+
+class gfxContext;
+
+namespace mozilla {
+
+class CharIterator;
+class DisplaySVGText;
+class SVGTextFrame;
+class TextFrameIterator;
+class TextNodeCorrespondenceRecorder;
+struct TextRenderedRun;
+class TextRenderedRunIterator;
+
+namespace dom {
+struct DOMPointInit;
+class DOMSVGPoint;
+class SVGRect;
+class SVGGeometryElement;
+}  // namespace dom
+}  // namespace mozilla
+
+nsIFrame* NS_NewSVGTextFrame(mozilla::PresShell* aPresShell,
+                             mozilla::ComputedStyle* aStyle);
+
+namespace mozilla {
+
+/**
+ * Information about the positioning for a single character in an SVG <text>
+ * element.
+ *
+ * During SVG text layout, we use infinity values to represent positions and
+ * rotations that are not explicitly specified with x/y/rotate attributes.
+ */
+struct CharPosition {
+  CharPosition()
+      : mAngle(0),
+        mHidden(false),
+        mUnaddressable(false),
+        mClusterOrLigatureGroupMiddle(false),
+        mRunBoundary(false),
+        mStartOfChunk(false) {}
+
+  CharPosition(gfxPoint aPosition, double aAngle)
+      : mPosition(aPosition),
+        mAngle(aAngle),
+        mHidden(false),
+        mUnaddressable(false),
+        mClusterOrLigatureGroupMiddle(false),
+        mRunBoundary(false),
+        mStartOfChunk(false) {}
+
+  static CharPosition Unspecified(bool aUnaddressable) {
+    CharPosition cp(UnspecifiedPoint(), UnspecifiedAngle());
+    cp.mUnaddressable = aUnaddressable;
+    return cp;
+  }
+
+  bool IsAngleSpecified() const { return mAngle != UnspecifiedAngle(); }
+
+  bool IsXSpecified() const { return mPosition.x != UnspecifiedCoord(); }
+
+  bool IsYSpecified() const { return mPosition.y != UnspecifiedCoord(); }
+
+  gfxPoint mPosition;
+  double mAngle;
+
+  // not displayed due to falling off the end of a <textPath>
+  bool mHidden;
+
+  // skipped in positioning attributes due to being collapsed-away white space
+  bool mUnaddressable;
+
+  // a preceding character is what positioning attributes address
+  bool mClusterOrLigatureGroupMiddle;
+
+  // rendering is split here since an explicit position or rotation was given
+  bool mRunBoundary;
+
+  // an anchored chunk begins here
+  bool mStartOfChunk;
+
+ private:
+  static gfxFloat UnspecifiedCoord() {
+    return std::numeric_limits<gfxFloat>::infinity();
+  }
+
+  static double UnspecifiedAngle() {
+    return std::numeric_limits<double>::infinity();
+  }
+
+  static gfxPoint UnspecifiedPoint() {
+    return gfxPoint(UnspecifiedCoord(), UnspecifiedCoord());
+  }
+};
+
+/**
+ * A runnable to mark glyph positions as needing to be recomputed
+ * and to invalid the bounds of the SVGTextFrame frame.
+ */
+class GlyphMetricsUpdater : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+  explicit GlyphMetricsUpdater(SVGTextFrame* aFrame)
+      : Runnable("GlyphMetricsUpdater"), mFrame(aFrame) {}
+  static void Run(SVGTextFrame* aFrame);
+  void Revoke() { mFrame = nullptr; }
+
+ private:
+  SVGTextFrame* mFrame;
+};
+
+/**
+ * Frame class for SVG <text> elements.
+ *
+ * An SVGTextFrame manages SVG text layout, painting and interaction for
+ * all descendent text content elements.  The frame tree will look like this:
+ *
+ *   SVGTextFrame                     -- for <text>
+ *     <anonymous block frame>
+ *       ns{Block,Inline,Text}Frames  -- for text nodes, <tspan>s, <a>s, etc.
+ *
+ * SVG text layout is done by:
+ *
+ *   1. Reflowing the anonymous block frame.
+ *   2. Inspecting the (app unit) positions of the glyph for each character in
+ *      the nsTextFrames underneath the anonymous block frame.
+ *   3. Determining the (user unit) positions for each character in the <text>
+ *      using the x/y/dx/dy/rotate attributes on all the text content elements,
+ *      and using the step 2 results to fill in any gaps.
+ *   4. Applying any other SVG specific text layout (anchoring and text paths)
+ *      to the positions computed in step 3.
+ *
+ * Rendering of the text is done by splitting up each nsTextFrame into ranges
+ * that can be contiguously painted.  (For example <text x="10 20">abcd</text>
+ * would have two contiguous ranges: one for the "a" and one for the "bcd".)
+ * Each range is called a "text rendered run", represented by a TextRenderedRun
+ * object.  The TextRenderedRunIterator class performs that splitting and
+ * returns a TextRenderedRun for each bit of text to be painted separately.
+ *
+ * Each rendered run is painted by calling nsTextFrame::PaintText.  If the text
+ * formatting is simple enough (solid fill, no stroking, etc.), PaintText will
+ * itself do the painting.  Otherwise, a DrawPathCallback is passed to
+ * PaintText so that we can fill the text geometry with SVG paint servers.
+ */
+class SVGTextFrame final : public SVGDisplayContainerFrame {
+  friend nsIFrame* ::NS_NewSVGTextFrame(mozilla::PresShell* aPresShell,
+                                        ComputedStyle* aStyle);
+
+  friend class CharIterator;
+  friend class DisplaySVGText;
+  friend class GlyphMetricsUpdater;
+  friend class MutationObserver;
+  friend class TextFrameIterator;
+  friend class TextNodeCorrespondenceRecorder;
+  friend struct TextRenderedRun;
+  friend class TextRenderedRunIterator;
+
+  using Range = gfxTextRun::Range;
+  using DrawTarget = gfx::DrawTarget;
+  using Path = gfx::Path;
+  using Point = gfx::Point;
+  using Rect = gfx::Rect;
+
+ protected:
+  explicit SVGTextFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
+      : SVGDisplayContainerFrame(aStyle, aPresContext, kClassID),
+        mTrailingUndisplayedCharacters(0),
+        mFontSizeScaleFactor(1.0f),
+        mLastContextScale(1.0f),
+        mLengthAdjustScaleFactor(1.0f) {
+    AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_SVG_TEXT |
+                 NS_STATE_SVG_TEXT_CORRESPONDENCE_DIRTY |
+                 NS_STATE_SVG_POSITIONING_DIRTY);
+  }
+
+  ~SVGTextFrame() = default;
+
+ public:
+  NS_DECL_QUERYFRAME
+  NS_DECL_FRAMEARENA_HELPERS(SVGTextFrame)
+
+  // nsIFrame:
+  void Init(nsIContent* aContent, nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+
+  nsresult AttributeChanged(int32_t aNamespaceID, nsAtom* aAttribute,
+                            int32_t aModType) override;
+
+  nsContainerFrame* GetContentInsertionFrame() override {
+    return PrincipalChildList().FirstChild()->GetContentInsertionFrame();
+  }
+
+  void BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                        const nsDisplayListSet& aLists) override;
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"SVGText"_ns, aResult);
+  }
+#endif
+
+  /**
+   * Finds the nsTextFrame for the closest rendered run to the specified point.
+   */
+  void FindCloserFrameForSelection(
+      const nsPoint& aPoint, FrameWithDistance* aCurrentBestFrame) override;
+
+  // ISVGDisplayableFrame interface:
+  void NotifySVGChanged(uint32_t aFlags) override;
+  void PaintSVG(gfxContext& aContext, const gfxMatrix& aTransform,
+                imgDrawingParams& aImgParams) override;
+  nsIFrame* GetFrameForPoint(const gfxPoint& aPoint) override;
+  void ReflowSVG() override;
+  SVGBBox GetBBoxContribution(const Matrix& aToBBoxUserspace,
+                              uint32_t aFlags) override;
+
+  // SVG DOM text methods:
+  uint32_t GetNumberOfChars(nsIContent* aContent);
+  float GetComputedTextLength(nsIContent* aContent);
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void SelectSubString(nsIContent* aContent,
+                                                   uint32_t charnum,
+                                                   uint32_t nchars,
+                                                   ErrorResult& aRv);
+  bool RequiresSlowFallbackForSubStringLength();
+  float GetSubStringLengthFastPath(nsIContent* aContent, uint32_t charnum,
+                                   uint32_t nchars, ErrorResult& aRv);
+  /**
+   * This fallback version of GetSubStringLength takes
+   * into account glyph positioning and requires us to have flushed layout
+   * before calling it. As per the SVG 2 spec, typically glyph
+   * positioning does not affect the results of getSubStringLength, but one
+   * exception is text in a textPath where we need to ignore characters that
+   * fall off the end of the textPath path.
+   */
+  float GetSubStringLengthSlowFallback(nsIContent* aContent, uint32_t charnum,
+                                       uint32_t nchars, ErrorResult& aRv);
+
+  int32_t GetCharNumAtPosition(nsIContent* aContent,
+                               const dom::DOMPointInit& aPoint);
+
+  already_AddRefed<dom::DOMSVGPoint> GetStartPositionOfChar(
+      nsIContent* aContent, uint32_t aCharNum, ErrorResult& aRv);
+  already_AddRefed<dom::DOMSVGPoint> GetEndPositionOfChar(nsIContent* aContent,
+                                                          uint32_t aCharNum,
+                                                          ErrorResult& aRv);
+  already_AddRefed<dom::SVGRect> GetExtentOfChar(nsIContent* aContent,
+                                                 uint32_t aCharNum,
+                                                 ErrorResult& aRv);
+  float GetRotationOfChar(nsIContent* aContent, uint32_t aCharNum,
+                          ErrorResult& aRv);
+
+  // SVGTextFrame methods:
+
+  /**
+   * Handles a base or animated attribute value change to a descendant
+   * text content element.
+   */
+  void HandleAttributeChangeInDescendant(dom::Element* aElement,
+                                         int32_t aNameSpaceID,
+                                         nsAtom* aAttribute);
+
+  /**
+   * Calls ScheduleReflowSVGNonDisplayText if this is a non-display frame,
+   * and SVGUtils::ScheduleReflowSVG otherwise.
+   */
+  void ScheduleReflowSVG();
+
+  /**
+   * Reflows the anonymous block frame of this non-display SVGTextFrame.
+   *
+   * When we are under SVGDisplayContainerFrame::ReflowSVG, we need to
+   * reflow any SVGTextFrame frames in the subtree in case they are
+   * being observed (by being for example in a <mask>) and the change
+   * that caused the reflow would not already have caused a reflow.
+   *
+   * Note that displayed SVGTextFrames are reflowed as needed, when PaintSVG
+   * is called or some SVG DOM method is called on the element.
+   */
+  void ReflowSVGNonDisplayText();
+
+  /**
+   * This is a function that behaves similarly to SVGUtils::ScheduleReflowSVG,
+   * but which will skip over any ancestor non-display container frames on the
+   * way to the SVGOuterSVGFrame.  It exists for the situation where a
+   * non-display <text> element has changed and needs to ensure ReflowSVG will
+   * be called on its closest display container frame, so that
+   * SVGDisplayContainerFrame::ReflowSVG will call ReflowSVGNonDisplayText on
+   * it.
+   *
+   * We have to do this in two cases: in response to a style change on a
+   * non-display <text>, where aReason will be
+   * IntrinsicDirty::FrameAncestorsAndDescendants (the common case), and also in
+   * response to glyphs changes on non-display <text> (i.e., animated
+   * SVG-in-OpenType glyphs), in which case aReason will be None, since layout
+   * doesn't need to be recomputed.
+   */
+  void ScheduleReflowSVGNonDisplayText(IntrinsicDirty aReason);
+
+  /**
+   * Updates the mFontSizeScaleFactor value by looking at the range of
+   * font-sizes used within the <text>.
+   *
+   * @return Whether mFontSizeScaleFactor changed.
+   */
+  bool UpdateFontSizeScaleFactor();
+
+  double GetFontSizeScaleFactor() const;
+
+  /**
+   * Takes a point from the <text> element's user space and
+   * converts it to the appropriate frame user space of aChildFrame,
+   * according to which rendered run the point hits.
+   */
+  Point TransformFramePointToTextChild(const Point& aPoint,
+                                       const nsIFrame* aChildFrame);
+
+  /**
+   * Takes an app unit rectangle in the coordinate space of a given descendant
+   * frame of this frame, and returns a rectangle in the <text> element's user
+   * space that covers all parts of rendered runs that intersect with the
+   * rectangle.
+   */
+  gfxRect TransformFrameRectFromTextChild(const nsRect& aRect,
+                                          const nsIFrame* aChildFrame);
+
+  /** As above, but taking and returning a device px rect. */
+  Rect TransformFrameRectFromTextChild(const Rect& aRect,
+                                       const nsIFrame* aChildFrame);
+
+  /** As above, but with a single point */
+  Point TransformFramePointFromTextChild(const Point& aPoint,
+                                         const nsIFrame* aChildFrame);
+
+  // Return our ::-moz-svg-text anonymous box.
+  void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;
+
+ private:
+  /**
+   * Mutation observer used to watch for text positioning attribute changes
+   * on descendent text content elements (like <tspan>s).
+   */
+  class MutationObserver final : public nsStubMutationObserver {
+   public:
+    explicit MutationObserver(SVGTextFrame* aFrame) : mFrame(aFrame) {
+      MOZ_ASSERT(mFrame, "MutationObserver needs a non-null frame");
+      mFrame->GetContent()->AddMutationObserver(this);
+      SetEnabledCallbacks(kCharacterDataChanged | kAttributeChanged |
+                          kContentAppended | kContentInserted |
+                          kContentRemoved);
+    }
+
+    // nsISupports
+    NS_DECL_ISUPPORTS
+
+    // nsIMutationObserver
+    NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
+    NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
+    NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
+    NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATACHANGED
+    NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
+
+   private:
+    ~MutationObserver() { mFrame->GetContent()->RemoveMutationObserver(this); }
+
+    SVGTextFrame* const mFrame;
+  };
+
+  /**
+   * Resolves Bidi for the anonymous block child if it needs it.
+   */
+  void MaybeResolveBidiForAnonymousBlockChild();
+
+  /**
+   * Reflows the anonymous block child if it is dirty or has dirty
+   * children, or if the SVGTextFrame itself is dirty.
+   */
+  void MaybeReflowAnonymousBlockChild();
+
+  /**
+   * Performs the actual work of reflowing the anonymous block child.
+   */
+  void DoReflow();
+
+  /**
+   * Schedules mPositions to be recomputed and the covered region to be
+   * updated.
+   */
+  void NotifyGlyphMetricsChange(bool aUpdateTextCorrespondence);
+
+  /**
+   * Recomputes mPositions by calling DoGlyphPositioning if this information
+   * is out of date.
+   */
+  void UpdateGlyphPositioning();
+
+  /**
+   * Populates mPositions with positioning information for each character
+   * within the <text>.
+   */
+  void DoGlyphPositioning();
+
+  /**
+   * Converts the specified index into mPositions to an addressable
+   * character index (as can be used with the SVG DOM text methods)
+   * relative to the specified text child content element.
+   *
+   * @param aIndex The global character index.
+   * @param aContent The descendant text child content element that
+   *   the returned addressable index will be relative to; null
+   *   means the same as the <text> element.
+   * @return The addressable index, or -1 if the index cannot be
+   *   represented as an addressable index relative to aContent.
+   */
+  int32_t ConvertTextElementCharIndexToAddressableIndex(int32_t aIndex,
+                                                        nsIContent* aContent);
+
+  /**
+   * Recursive helper for ResolvePositions below.
+   *
+   * @param aContent The current node.
+   * @param aIndex (in/out) The current character index.
+   * @param aInTextPath Whether we are currently under a <textPath> element.
+   * @param aForceStartOfChunk (in/out) Whether the next character we find
+   *   should start a new anchored chunk.
+   * @param aDeltas (in/out) Receives the resolved dx/dy values for each
+   *   character.
+   * @return false if we discover that mPositions did not have enough
+   *   elements; true otherwise.
+   */
+  bool ResolvePositionsForNode(nsIContent* aContent, uint32_t& aIndex,
+                               bool aInTextPath, bool& aForceStartOfChunk,
+                               nsTArray<gfxPoint>& aDeltas);
+
+  /**
+   * Initializes mPositions with character position information based on
+   * x/y/rotate attributes, leaving unspecified values in the array if a
+   * position was not given for that character.  Also fills aDeltas with values
+   * based on dx/dy attributes.
+   *
+   * @param aDeltas (in/out) Receives the resolved dx/dy values for each
+   *   character.
+   * @param aRunPerGlyph Whether mPositions should record that a new run begins
+   *   at each glyph.
+   * @return false if we did not record any positions (due to having no
+   *   displayed characters) or if we discover that mPositions did not have
+   *   enough elements; true otherwise.
+   */
+  bool ResolvePositions(nsTArray<gfxPoint>& aDeltas, bool aRunPerGlyph);
+
+  /**
+   * Determines the position, in app units, of each character in the <text> as
+   * laid out by reflow, and appends them to aPositions.  Any characters that
+   * are undisplayed or trimmed away just get the last position.
+   */
+  void DetermineCharPositions(nsTArray<nsPoint>& aPositions);
+
+  /**
+   * Sets mStartOfChunk to true for each character in mPositions that starts a
+   * line of text.
+   */
+  void AdjustChunksForLineBreaks();
+
+  /**
+   * Adjusts recorded character positions in mPositions to account for glyph
+   * boundaries.  Four things are done:
+   *
+   *   1. mClusterOrLigatureGroupMiddle is set to true for all such characters.
+   *
+   *   2. Any run and anchored chunk boundaries that begin in the middle of a
+   *      cluster/ligature group get moved to the start of the next
+   *      cluster/ligature group.
+   *
+   *   3. The position of any character in the middle of a cluster/ligature
+   *      group is updated to take into account partial ligatures and any
+   *      rotation the glyph as a whole has.  (The values that come out of
+   *      DetermineCharPositions which then get written into mPositions in
+   *      ResolvePositions store the same position value for each part of the
+   *      ligature.)
+   *
+   *   4. The rotation of any character in the middle of a cluster/ligature
+   *      group is set to the rotation of the first character.
+   */
+  void AdjustPositionsForClusters();
+
+  /**
+   * Updates the character positions stored in mPositions to account for
+   * text anchoring.
+   */
+  void DoAnchoring();
+
+  /**
+   * Updates character positions in mPositions for those characters inside a
+   * <textPath>.
+   */
+  void DoTextPathLayout();
+
+  /**
+   * Returns whether we need to render the text using
+   * nsTextFrame::DrawPathCallbacks rather than directly painting
+   * the text frames.
+   *
+   * @param aShouldPaintSVGGlyphs (out) Whether SVG glyphs in the text
+   *   should be painted.
+   */
+  bool ShouldRenderAsPath(nsTextFrame* aFrame, bool& aShouldPaintSVGGlyphs);
+
+  // Methods to get information for a <textPath> frame.
+  already_AddRefed<Path> GetTextPath(nsIFrame* aTextPathFrame);
+  gfxFloat GetOffsetScale(nsIFrame* aTextPathFrame);
+  gfxFloat GetStartOffset(nsIFrame* aTextPathFrame);
+
+  /**
+   * The MutationObserver we have registered for the <text> element subtree.
+   */
+  RefPtr<MutationObserver> mMutationObserver;
+
+  /**
+   * The number of characters in the DOM after the final nsTextFrame.  For
+   * example, with
+   *
+   *   <text>abcd<tspan display="none">ef</tspan></text>
+   *
+   * mTrailingUndisplayedCharacters would be 2.
+   */
+  uint32_t mTrailingUndisplayedCharacters;
+
+  /**
+   * Computed position information for each DOM character within the <text>.
+   */
+  nsTArray<CharPosition> mPositions;
+
+  /**
+   * mFontSizeScaleFactor is used to cause the nsTextFrames to create text
+   * runs with a font size different from the actual font-size property value.
+   * This is used so that, for example with:
+   *
+   *   <svg>
+   *     <g transform="scale(2)">
+   *       <text font-size="10">abc</text>
+   *     </g>
+   *   </svg>
+   *
+   * a font size of 20 would be used.  It's preferable to use a font size that
+   * is identical or close to the size that the text will appear on the screen,
+   * because at very small or large font sizes, text metrics will be computed
+   * differently due to the limited precision that text runs have.
+   *
+   * mFontSizeScaleFactor is the amount the actual font-size property value
+   * should be multiplied by to cause the text run font size to (a) be within a
+   * "reasonable" range, and (b) be close to the actual size to be painted on
+   * screen.  (The "reasonable" range as determined by some #defines in
+   * SVGTextFrame.cpp is 8..200.)
+   */
+  float mFontSizeScaleFactor;
+
+  /**
+   * The scale of the context that we last used to compute mFontSizeScaleFactor.
+   * We record this so that we can tell when our scale transform has changed
+   * enough to warrant reflowing the text.
+   */
+  float mLastContextScale;
+
+  /**
+   * The amount that we need to scale each rendered run to account for
+   * lengthAdjust="spacingAndGlyphs".
+   */
+  float mLengthAdjustScaleFactor;
+};
+
+}  // namespace mozilla
+
+#endif  // LAYOUT_SVG_SVGTEXTFRAME_H_