зеркало из https://github.com/mozilla/gecko-dev.git
606 строки
20 KiB
C++
606 строки
20 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_SVGTEXTFRAME_H
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#define MOZILLA_SVGTEXTFRAME_H
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#include "mozilla/Attributes.h"
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#include "mozilla/RefPtr.h"
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#include "mozilla/gfx/2D.h"
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#include "gfxMatrix.h"
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#include "gfxRect.h"
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#include "gfxTextRun.h"
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#include "nsAutoPtr.h"
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#include "nsIContent.h" // for GetContent
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#include "nsStubMutationObserver.h"
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#include "nsSVGContainerFrame.h"
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class gfxContext;
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class nsDisplaySVGText;
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class SVGTextFrame;
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class nsTextFrame;
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namespace mozilla {
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class CharIterator;
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class nsISVGPoint;
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class TextFrameIterator;
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class TextNodeCorrespondenceRecorder;
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struct TextRenderedRun;
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class TextRenderedRunIterator;
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namespace dom {
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class SVGIRect;
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class SVGGeometryElement;
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} // namespace dom
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/**
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* Information about the positioning for a single character in an SVG <text>
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* element.
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*
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* During SVG text layout, we use infinity values to represent positions and
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* rotations that are not explicitly specified with x/y/rotate attributes.
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*/
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struct CharPosition
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{
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CharPosition()
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: mAngle(0),
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mHidden(false),
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mUnaddressable(false),
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mClusterOrLigatureGroupMiddle(false),
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mRunBoundary(false),
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mStartOfChunk(false)
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{
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}
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CharPosition(gfxPoint aPosition, double aAngle)
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: mPosition(aPosition),
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mAngle(aAngle),
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mHidden(false),
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mUnaddressable(false),
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mClusterOrLigatureGroupMiddle(false),
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mRunBoundary(false),
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mStartOfChunk(false)
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{
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}
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static CharPosition Unspecified(bool aUnaddressable)
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{
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CharPosition cp(UnspecifiedPoint(), UnspecifiedAngle());
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cp.mUnaddressable = aUnaddressable;
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return cp;
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}
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bool IsAngleSpecified() const
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{
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return mAngle != UnspecifiedAngle();
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}
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bool IsXSpecified() const
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{
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return mPosition.x != UnspecifiedCoord();
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}
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bool IsYSpecified() const
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{
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return mPosition.y != UnspecifiedCoord();
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}
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gfxPoint mPosition;
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double mAngle;
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// not displayed due to falling off the end of a <textPath>
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bool mHidden;
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// skipped in positioning attributes due to being collapsed-away white space
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bool mUnaddressable;
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// a preceding character is what positioning attributes address
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bool mClusterOrLigatureGroupMiddle;
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// rendering is split here since an explicit position or rotation was given
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bool mRunBoundary;
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// an anchored chunk begins here
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bool mStartOfChunk;
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private:
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static gfxFloat UnspecifiedCoord()
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{
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return std::numeric_limits<gfxFloat>::infinity();
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}
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static double UnspecifiedAngle()
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{
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return std::numeric_limits<double>::infinity();
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}
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static gfxPoint UnspecifiedPoint()
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{
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return gfxPoint(UnspecifiedCoord(), UnspecifiedCoord());
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}
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};
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/**
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* A runnable to mark glyph positions as needing to be recomputed
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* and to invalid the bounds of the SVGTextFrame frame.
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*/
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class GlyphMetricsUpdater : public Runnable {
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public:
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NS_DECL_NSIRUNNABLE
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explicit GlyphMetricsUpdater(SVGTextFrame* aFrame)
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: Runnable("GlyphMetricsUpdater")
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, mFrame(aFrame)
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{
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}
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static void Run(SVGTextFrame* aFrame);
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void Revoke() { mFrame = nullptr; }
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private:
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SVGTextFrame* mFrame;
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};
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} // namespace mozilla
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/**
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* Frame class for SVG <text> elements.
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*
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* An SVGTextFrame manages SVG text layout, painting and interaction for
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* all descendent text content elements. The frame tree will look like this:
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*
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* SVGTextFrame -- for <text>
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* <anonymous block frame>
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* ns{Block,Inline,Text}Frames -- for text nodes, <tspan>s, <a>s, etc.
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*
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* SVG text layout is done by:
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*
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* 1. Reflowing the anonymous block frame.
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* 2. Inspecting the (app unit) positions of the glyph for each character in
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* the nsTextFrames underneath the anonymous block frame.
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* 3. Determining the (user unit) positions for each character in the <text>
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* using the x/y/dx/dy/rotate attributes on all the text content elements,
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* and using the step 2 results to fill in any gaps.
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* 4. Applying any other SVG specific text layout (anchoring and text paths)
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* to the positions computed in step 3.
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*
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* Rendering of the text is done by splitting up each nsTextFrame into ranges
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* that can be contiguously painted. (For example <text x="10 20">abcd</text>
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* would have two contiguous ranges: one for the "a" and one for the "bcd".)
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* Each range is called a "text rendered run", represented by a TextRenderedRun
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* object. The TextRenderedRunIterator class performs that splitting and
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* returns a TextRenderedRun for each bit of text to be painted separately.
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*
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* Each rendered run is painted by calling nsTextFrame::PaintText. If the text
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* formatting is simple enough (solid fill, no stroking, etc.), PaintText will
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* itself do the painting. Otherwise, a DrawPathCallback is passed to
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* PaintText so that we can fill the text geometry with SVG paint servers.
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*/
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class SVGTextFrame final : public nsSVGDisplayContainerFrame
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{
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friend nsIFrame*
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NS_NewSVGTextFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
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friend class mozilla::CharIterator;
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friend class mozilla::GlyphMetricsUpdater;
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friend class mozilla::TextFrameIterator;
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friend class mozilla::TextNodeCorrespondenceRecorder;
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friend struct mozilla::TextRenderedRun;
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friend class mozilla::TextRenderedRunIterator;
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friend class MutationObserver;
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friend class nsDisplaySVGText;
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typedef gfxTextRun::Range Range;
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typedef mozilla::gfx::DrawTarget DrawTarget;
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typedef mozilla::gfx::Path Path;
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typedef mozilla::gfx::Point Point;
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protected:
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explicit SVGTextFrame(ComputedStyle* aStyle)
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: nsSVGDisplayContainerFrame(aStyle, kClassID)
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, mTrailingUndisplayedCharacters(0)
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, mFontSizeScaleFactor(1.0f)
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, mLastContextScale(1.0f)
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, mLengthAdjustScaleFactor(1.0f)
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{
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AddStateBits(NS_STATE_SVG_TEXT_CORRESPONDENCE_DIRTY |
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NS_STATE_SVG_POSITIONING_DIRTY);
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}
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~SVGTextFrame() {}
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public:
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NS_DECL_QUERYFRAME
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NS_DECL_FRAMEARENA_HELPERS(SVGTextFrame)
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// nsIFrame:
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virtual void Init(nsIContent* aContent,
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nsContainerFrame* aParent,
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nsIFrame* aPrevInFlow) override;
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virtual nsresult AttributeChanged(int32_t aNamespaceID,
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nsAtom* aAttribute,
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int32_t aModType) override;
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virtual nsContainerFrame* GetContentInsertionFrame() override
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{
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return PrincipalChildList().FirstChild()->GetContentInsertionFrame();
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}
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virtual void BuildDisplayList(nsDisplayListBuilder* aBuilder,
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const nsDisplayListSet& aLists) override;
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#ifdef DEBUG_FRAME_DUMP
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virtual nsresult GetFrameName(nsAString& aResult) const override
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{
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return MakeFrameName(NS_LITERAL_STRING("SVGText"), aResult);
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}
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#endif
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virtual void DidSetComputedStyle(ComputedStyle* aOldComputedStyle) override;
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/**
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* Finds the nsTextFrame for the closest rendered run to the specified point.
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*/
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virtual void FindCloserFrameForSelection(const nsPoint& aPoint,
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FrameWithDistance* aCurrentBestFrame) override;
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// nsSVGDisplayableFrame interface:
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virtual void NotifySVGChanged(uint32_t aFlags) override;
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virtual void PaintSVG(gfxContext& aContext,
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const gfxMatrix& aTransform,
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imgDrawingParams& aImgParams,
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const nsIntRect* aDirtyRect = nullptr) override;
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virtual nsIFrame* GetFrameForPoint(const gfxPoint& aPoint) override;
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virtual void ReflowSVG() override;
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virtual SVGBBox GetBBoxContribution(const Matrix& aToBBoxUserspace,
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uint32_t aFlags) override;
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// SVG DOM text methods:
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uint32_t GetNumberOfChars(nsIContent* aContent);
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float GetComputedTextLength(nsIContent* aContent);
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nsresult SelectSubString(nsIContent* aContent, uint32_t charnum, uint32_t nchars);
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nsresult GetSubStringLength(nsIContent* aContent, uint32_t charnum,
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uint32_t nchars, float* aResult);
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int32_t GetCharNumAtPosition(nsIContent* aContent, mozilla::nsISVGPoint* point);
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nsresult GetStartPositionOfChar(nsIContent* aContent, uint32_t aCharNum,
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mozilla::nsISVGPoint** aResult);
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nsresult GetEndPositionOfChar(nsIContent* aContent, uint32_t aCharNum,
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mozilla::nsISVGPoint** aResult);
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nsresult GetExtentOfChar(nsIContent* aContent, uint32_t aCharNum,
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mozilla::dom::SVGIRect** aResult);
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nsresult GetRotationOfChar(nsIContent* aContent, uint32_t aCharNum,
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float* aResult);
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// SVGTextFrame methods:
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/**
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* Handles a base or animated attribute value change to a descendant
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* text content element.
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*/
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void HandleAttributeChangeInDescendant(mozilla::dom::Element* aElement,
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int32_t aNameSpaceID,
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nsAtom* aAttribute);
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/**
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* Schedules mPositions to be recomputed and the covered region to be
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* updated.
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*/
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void NotifyGlyphMetricsChange();
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/**
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* Calls ScheduleReflowSVGNonDisplayText if this is a non-display frame,
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* and nsSVGUtils::ScheduleReflowSVG otherwise.
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*/
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void ScheduleReflowSVG();
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/**
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* Reflows the anonymous block frame of this non-display SVGTextFrame.
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*
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* When we are under nsSVGDisplayContainerFrame::ReflowSVG, we need to
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* reflow any SVGTextFrame frames in the subtree in case they are
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* being observed (by being for example in a <mask>) and the change
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* that caused the reflow would not already have caused a reflow.
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*
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* Note that displayed SVGTextFrames are reflowed as needed, when PaintSVG
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* is called or some SVG DOM method is called on the element.
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*/
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void ReflowSVGNonDisplayText();
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/**
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* This is a function that behaves similarly to nsSVGUtils::ScheduleReflowSVG,
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* but which will skip over any ancestor non-display container frames on the
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* way to the nsSVGOuterSVGFrame. It exists for the situation where a
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* non-display <text> element has changed and needs to ensure ReflowSVG will
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* be called on its closest display container frame, so that
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* nsSVGDisplayContainerFrame::ReflowSVG will call ReflowSVGNonDisplayText on
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* it.
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*
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* We have to do this in two cases: in response to a style change on a
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* non-display <text>, where aReason will be eStyleChange (the common case),
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* and also in response to glyphs changes on non-display <text> (i.e.,
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* animated SVG-in-OpenType glyphs), in which case aReason will be eResize,
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* since layout doesn't need to be recomputed.
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*/
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void ScheduleReflowSVGNonDisplayText(nsIPresShell::IntrinsicDirty aReason);
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/**
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* Updates the mFontSizeScaleFactor value by looking at the range of
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* font-sizes used within the <text>.
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*
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* @return Whether mFontSizeScaleFactor changed.
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*/
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bool UpdateFontSizeScaleFactor();
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double GetFontSizeScaleFactor() const;
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/**
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* Takes a point from the <text> element's user space and
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* converts it to the appropriate frame user space of aChildFrame,
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* according to which rendered run the point hits.
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*/
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Point TransformFramePointToTextChild(const Point& aPoint,
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nsIFrame* aChildFrame);
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/**
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* Takes an app unit rectangle in the coordinate space of a given descendant
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* frame of this frame, and returns a rectangle in the <text> element's user
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* space that covers all parts of rendered runs that intersect with the
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* rectangle.
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*/
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gfxRect TransformFrameRectFromTextChild(const nsRect& aRect,
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const nsIFrame* aChildFrame);
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// Return our ::-moz-svg-text anonymous box.
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void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;
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private:
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/**
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* Mutation observer used to watch for text positioning attribute changes
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* on descendent text content elements (like <tspan>s).
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*/
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class MutationObserver final : public nsStubMutationObserver {
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public:
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explicit MutationObserver(SVGTextFrame* aFrame)
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: mFrame(aFrame)
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{
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MOZ_ASSERT(mFrame, "MutationObserver needs a non-null frame");
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mFrame->GetContent()->AddMutationObserver(this);
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}
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// nsISupports
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NS_DECL_ISUPPORTS
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// nsIMutationObserver
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NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
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NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
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NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
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NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATACHANGED
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NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
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private:
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~MutationObserver()
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{
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mFrame->GetContent()->RemoveMutationObserver(this);
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}
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SVGTextFrame* const mFrame;
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};
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/**
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* Resolves Bidi for the anonymous block child if it needs it.
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*/
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void MaybeResolveBidiForAnonymousBlockChild();
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/**
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* Reflows the anonymous block child if it is dirty or has dirty
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* children, or if the SVGTextFrame itself is dirty.
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*/
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void MaybeReflowAnonymousBlockChild();
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/**
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* Performs the actual work of reflowing the anonymous block child.
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*/
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void DoReflow();
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/**
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* Recomputes mPositions by calling DoGlyphPositioning if this information
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* is out of date.
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*/
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void UpdateGlyphPositioning();
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/**
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* Populates mPositions with positioning information for each character
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* within the <text>.
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*/
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void DoGlyphPositioning();
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/**
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* This fallback version of GetSubStringLength that flushes layout and takes
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* into account glyph positioning. As per the SVG 2 spec, typically glyph
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* positioning does not affect the results of getSubStringLength, but one
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* exception is text in a textPath where we need to ignore characters that
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* fall off the end of the textPath path.
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*/
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nsresult GetSubStringLengthSlowFallback(nsIContent* aContent,
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uint32_t charnum,
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uint32_t nchars,
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float* aResult);
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/**
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* Converts the specified index into mPositions to an addressable
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* character index (as can be used with the SVG DOM text methods)
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* relative to the specified text child content element.
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*
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* @param aIndex The global character index.
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* @param aContent The descendant text child content element that
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* the returned addressable index will be relative to; null
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* means the same as the <text> element.
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* @return The addressable index, or -1 if the index cannot be
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* represented as an addressable index relative to aContent.
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*/
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int32_t
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ConvertTextElementCharIndexToAddressableIndex(int32_t aIndex,
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nsIContent* aContent);
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/**
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* Recursive helper for ResolvePositions below.
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*
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* @param aContent The current node.
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* @param aIndex (in/out) The current character index.
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* @param aInTextPath Whether we are currently under a <textPath> element.
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* @param aForceStartOfChunk (in/out) Whether the next character we find
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* should start a new anchored chunk.
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* @param aDeltas (in/out) Receives the resolved dx/dy values for each
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* character.
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* @return false if we discover that mPositions did not have enough
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* elements; true otherwise.
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*/
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bool ResolvePositionsForNode(nsIContent* aContent, uint32_t& aIndex,
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bool aInTextPath, bool& aForceStartOfChunk,
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nsTArray<gfxPoint>& aDeltas);
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/**
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* Initializes mPositions with character position information based on
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* x/y/rotate attributes, leaving unspecified values in the array if a position
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* was not given for that character. Also fills aDeltas with values based on
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* dx/dy attributes.
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*
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* @param aDeltas (in/out) Receives the resolved dx/dy values for each
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* character.
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* @param aRunPerGlyph Whether mPositions should record that a new run begins
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* at each glyph.
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* @return false if we did not record any positions (due to having no
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* displayed characters) or if we discover that mPositions did not have
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* enough elements; true otherwise.
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*/
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bool ResolvePositions(nsTArray<gfxPoint>& aDeltas, bool aRunPerGlyph);
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/**
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* Determines the position, in app units, of each character in the <text> as
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* laid out by reflow, and appends them to aPositions. Any characters that
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* are undisplayed or trimmed away just get the last position.
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*/
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void DetermineCharPositions(nsTArray<nsPoint>& aPositions);
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/**
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* Sets mStartOfChunk to true for each character in mPositions that starts a
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* line of text.
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*/
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void AdjustChunksForLineBreaks();
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/**
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* Adjusts recorded character positions in mPositions to account for glyph
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* boundaries. Four things are done:
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*
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* 1. mClusterOrLigatureGroupMiddle is set to true for all such characters.
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*
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* 2. Any run and anchored chunk boundaries that begin in the middle of a
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* cluster/ligature group get moved to the start of the next
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* cluster/ligature group.
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*
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* 3. The position of any character in the middle of a cluster/ligature
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* group is updated to take into account partial ligatures and any
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* rotation the glyph as a whole has. (The values that come out of
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* 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.
|
|
mozilla::dom::SVGGeometryElement*
|
|
GetTextPathGeometryElement(nsIFrame* aTextPathFrame);
|
|
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<mozilla::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;
|
|
};
|
|
|
|
#endif
|