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558 lines
24 KiB
C++
558 lines
24 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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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 nsBidiPresUtils_h___
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#define nsBidiPresUtils_h___
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#include "nsBidi.h"
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#include "nsBidiUtils.h"
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#include "nsHashKeys.h"
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#include "nsCoord.h"
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#ifdef DrawText
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#undef DrawText
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#endif
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struct BidiParagraphData;
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struct BidiLineData;
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class nsFontMetrics;
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class nsIFrame;
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class nsBlockFrame;
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class nsPresContext;
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class nsRenderingContext;
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class nsBlockInFlowLineIterator;
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class nsStyleContext;
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struct nsSize;
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template<class T> class nsTHashtable;
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namespace mozilla { class WritingMode; }
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/**
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* A structure representing some continuation state for each frame on the line,
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* used to determine the first and the last continuation frame for each
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* continuation chain on the line.
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*/
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struct nsFrameContinuationState : public nsVoidPtrHashKey
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{
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explicit nsFrameContinuationState(const void *aFrame) : nsVoidPtrHashKey(aFrame) {}
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/**
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* The first visual frame in the continuation chain containing this frame, or
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* nullptr if this frame is the first visual frame in the chain.
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*/
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nsIFrame* mFirstVisualFrame;
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/**
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* The number of frames in the continuation chain containing this frame, if
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* this frame is the first visual frame of the chain, or 0 otherwise.
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*/
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uint32_t mFrameCount;
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/**
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* TRUE if this frame is the first visual frame of its continuation chain on
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* this line and the chain has some frames on the previous lines.
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*/
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bool mHasContOnPrevLines;
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/**
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* TRUE if this frame is the first visual frame of its continuation chain on
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* this line and the chain has some frames left for next lines.
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*/
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bool mHasContOnNextLines;
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};
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/*
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* Following type is used to pass needed hashtable to reordering methods
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*/
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typedef nsTHashtable<nsFrameContinuationState> nsContinuationStates;
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/**
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* A structure representing a logical position which should be resolved
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* into its visual position during BiDi processing.
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*/
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struct nsBidiPositionResolve
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{
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// [in] Logical index within string.
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int32_t logicalIndex;
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// [out] Visual index within string.
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// If the logical position was not found, set to kNotFound.
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int32_t visualIndex;
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// [out] Visual position of the character, from the left (on the X axis), in twips.
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// Eessentially, this is the X position (relative to the rendering context) where the text was drawn + the font metric of the visual string to the left of the given logical position.
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// If the logical position was not found, set to kNotFound.
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int32_t visualLeftTwips;
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// [out] Visual width of the character, in twips.
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// If the logical position was not found, set to kNotFound.
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int32_t visualWidth;
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};
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class nsBidiPresUtils {
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public:
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nsBidiPresUtils();
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~nsBidiPresUtils();
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/**
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* Interface for the processor used by ProcessText. Used by process text to
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* collect information about the width of subruns and to notify where each
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* subrun should be rendered.
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*/
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class BidiProcessor {
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public:
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virtual ~BidiProcessor() { }
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/**
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* Sets the current text with the given length and the given direction.
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*
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* @remark The reason that the function gives a string instead of an index
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* is that ProcessText copies and modifies the string passed to it, so
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* passing an index would be impossible.
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*
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* @param aText The string of text.
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* @param aLength The length of the string of text.
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* @param aDirection The direction of the text. The string will never have
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* mixed direction.
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*/
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virtual void SetText(const char16_t* aText,
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int32_t aLength,
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nsBidiDirection aDirection) = 0;
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/**
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* Returns the measured width of the text given in SetText. If SetText was
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* not called with valid parameters, the result of this call is undefined.
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* This call is guaranteed to only be called once between SetText calls.
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* Will be invoked before DrawText.
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*/
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virtual nscoord GetWidth() = 0;
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/**
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* Draws the text given in SetText to a rendering context. If SetText was
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* not called with valid parameters, the result of this call is undefined.
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* This call is guaranteed to only be called once between SetText calls.
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*
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* @param aXOffset The offset of the left side of the substring to be drawn
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* from the beginning of the overall string passed to ProcessText.
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* @param aWidth The width returned by GetWidth.
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*/
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virtual void DrawText(nscoord aXOffset,
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nscoord aWidth) = 0;
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};
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/**
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* Make Bidi engine calculate the embedding levels of the frames that are
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* descendants of a given block frame.
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*
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* @param aBlockFrame The block frame
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*
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* @lina 06/18/2000
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*/
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static nsresult Resolve(nsBlockFrame* aBlockFrame);
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static nsresult ResolveParagraph(nsBlockFrame* aBlockFrame,
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BidiParagraphData* aBpd);
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static void ResolveParagraphWithinBlock(nsBlockFrame* aBlockFrame,
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BidiParagraphData* aBpd);
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/**
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* Reorder this line using Bidi engine.
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* Update frame array, following the new visual sequence.
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*
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* @lina 05/02/2000
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*/
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static void ReorderFrames(nsIFrame* aFirstFrameOnLine,
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int32_t aNumFramesOnLine,
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mozilla::WritingMode aLineWM,
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const nsSize& aContainerSize,
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nscoord aStart);
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/**
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* Format Unicode text, taking into account bidi capabilities
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* of the platform. The formatting includes: reordering, Arabic shaping,
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* symmetric and numeric swapping, removing control characters.
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*
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* @lina 06/18/2000
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*/
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static nsresult FormatUnicodeText(nsPresContext* aPresContext,
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char16_t* aText,
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int32_t& aTextLength,
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nsCharType aCharType,
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nsBidiDirection aDir);
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/**
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* Reorder plain text using the Unicode Bidi algorithm and send it to
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* a rendering context for rendering.
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*
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* @param[in] aText the string to be rendered (in logical order)
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* @param aLength the number of characters in the string
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* @param aBaseLevel the base embedding level of the string
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* odd values are right-to-left; even values are left-to-right, plus special
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* constants as follows (defined in nsBidi.h)
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* NSBIDI_LTR - left-to-right string
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* NSBIDI_RTL - right-to-left string
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* NSBIDI_DEFAULT_LTR - auto direction determined by first strong character,
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* default is left-to-right
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* NSBIDI_DEFAULT_RTL - auto direction determined by first strong character,
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* default is right-to-left
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*
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* @param aPresContext the presentation context
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* @param aRenderingContext the rendering context to render to
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* @param aTextRunConstructionContext the rendering context to be used to construct the textrun (affects font hinting)
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* @param aX the x-coordinate to render the string
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* @param aY the y-coordinate to render the string
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* @param[in,out] aPosResolve array of logical positions to resolve into visual positions; can be nullptr if this functionality is not required
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* @param aPosResolveCount number of items in the aPosResolve array
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*/
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static nsresult RenderText(const char16_t* aText,
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int32_t aLength,
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nsBidiLevel aBaseLevel,
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nsPresContext* aPresContext,
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nsRenderingContext& aRenderingContext,
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nsRenderingContext& aTextRunConstructionContext,
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nsFontMetrics& aFontMetrics,
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nscoord aX,
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nscoord aY,
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nsBidiPositionResolve* aPosResolve = nullptr,
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int32_t aPosResolveCount = 0)
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{
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return ProcessTextForRenderingContext(aText, aLength, aBaseLevel, aPresContext, aRenderingContext,
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aTextRunConstructionContext,
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aFontMetrics,
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MODE_DRAW, aX, aY, aPosResolve, aPosResolveCount, nullptr);
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}
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static nscoord MeasureTextWidth(const char16_t* aText,
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int32_t aLength,
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nsBidiLevel aBaseLevel,
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nsPresContext* aPresContext,
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nsRenderingContext& aRenderingContext,
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nsFontMetrics& aFontMetrics)
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{
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nscoord length;
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nsresult rv = ProcessTextForRenderingContext(aText, aLength, aBaseLevel, aPresContext,
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aRenderingContext, aRenderingContext,
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aFontMetrics,
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MODE_MEASURE, 0, 0, nullptr, 0, &length);
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return NS_SUCCEEDED(rv) ? length : 0;
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}
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/**
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* Check if a line is reordered, i.e., if the child frames are not
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* all laid out left-to-right.
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* @param aFirstFrameOnLine : first frame of the line to be tested
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* @param aNumFramesOnLine : number of frames on this line
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* @param[out] aLeftMost : leftmost frame on this line
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* @param[out] aRightMost : rightmost frame on this line
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*/
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static bool CheckLineOrder(nsIFrame* aFirstFrameOnLine,
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int32_t aNumFramesOnLine,
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nsIFrame** aLeftmost,
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nsIFrame** aRightmost);
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/**
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* Get the frame to the right of the given frame, on the same line.
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* @param aFrame : We're looking for the frame to the right of this frame.
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* If null, return the leftmost frame on the line.
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* @param aFirstFrameOnLine : first frame of the line to be tested
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* @param aNumFramesOnLine : number of frames on this line
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*/
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static nsIFrame* GetFrameToRightOf(const nsIFrame* aFrame,
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nsIFrame* aFirstFrameOnLine,
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int32_t aNumFramesOnLine);
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/**
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* Get the frame to the left of the given frame, on the same line.
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* @param aFrame : We're looking for the frame to the left of this frame.
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* If null, return the rightmost frame on the line.
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* @param aFirstFrameOnLine : first frame of the line to be tested
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* @param aNumFramesOnLine : number of frames on this line
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*/
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static nsIFrame* GetFrameToLeftOf(const nsIFrame* aFrame,
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nsIFrame* aFirstFrameOnLine,
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int32_t aNumFramesOnLine);
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static nsIFrame* GetFirstLeaf(nsIFrame* aFrame);
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/**
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* Get the bidi embedding level of the given (inline) frame.
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*/
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static nsBidiLevel GetFrameEmbeddingLevel(nsIFrame* aFrame);
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/**
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* Get the paragraph depth of the given (inline) frame.
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*/
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static uint8_t GetParagraphDepth(nsIFrame* aFrame);
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/**
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* Get the bidi base level of the given (inline) frame.
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*/
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static nsBidiLevel GetFrameBaseLevel(nsIFrame* aFrame);
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/**
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* Get an nsBidiDirection representing the direction implied by the
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* bidi base level of the frame.
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* @return NSBIDI_LTR (left-to-right) or NSBIDI_RTL (right-to-left)
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* NSBIDI_MIXED will never be returned.
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*/
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static nsBidiDirection ParagraphDirection(nsIFrame* aFrame) {
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return DIRECTION_FROM_LEVEL(GetFrameBaseLevel(aFrame));
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}
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/**
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* Get an nsBidiDirection representing the direction implied by the
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* bidi embedding level of the frame.
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* @return NSBIDI_LTR (left-to-right) or NSBIDI_RTL (right-to-left)
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* NSBIDI_MIXED will never be returned.
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*/
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static nsBidiDirection FrameDirection(nsIFrame* aFrame) {
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return DIRECTION_FROM_LEVEL(GetFrameEmbeddingLevel(aFrame));
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}
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static bool IsFrameInParagraphDirection(nsIFrame* aFrame) {
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return ParagraphDirection(aFrame) == FrameDirection(aFrame);
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}
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enum Mode { MODE_DRAW, MODE_MEASURE };
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/**
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* Reorder plain text using the Unicode Bidi algorithm and send it to
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* a processor for rendering or measuring
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*
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* @param[in] aText the string to be processed (in logical order)
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* @param aLength the number of characters in the string
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* @param aBaseLevel the base embedding level of the string
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* odd values are right-to-left; even values are left-to-right, plus special
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* constants as follows (defined in nsBidi.h)
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* NSBIDI_LTR - left-to-right string
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* NSBIDI_RTL - right-to-left string
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* NSBIDI_DEFAULT_LTR - auto direction determined by first strong character,
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* default is left-to-right
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* NSBIDI_DEFAULT_RTL - auto direction determined by first strong character,
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* default is right-to-left
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*
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* @param aPresContext the presentation context
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* @param aprocessor the bidi processor
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* @param aMode the operation to process
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* MODE_DRAW - invokes DrawText on the processor for each substring
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* MODE_MEASURE - does not invoke DrawText on the processor
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* Note that the string is always measured, regardless of mode
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* @param[in,out] aPosResolve array of logical positions to resolve into
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* visual positions; can be nullptr if this functionality is not required
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* @param aPosResolveCount number of items in the aPosResolve array
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* @param[out] aWidth Pointer to where the width will be stored (may be null)
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*/
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static nsresult ProcessText(const char16_t* aText,
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int32_t aLength,
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nsBidiLevel aBaseLevel,
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nsPresContext* aPresContext,
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BidiProcessor& aprocessor,
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Mode aMode,
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nsBidiPositionResolve* aPosResolve,
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int32_t aPosResolveCount,
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nscoord* aWidth,
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nsBidi* aBidiEngine);
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/**
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* Make a copy of a string, converting from logical to visual order
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*
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* @param aSource the source string
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* @param aDest the destination string
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* @param aBaseDirection the base direction of the string
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* (NSBIDI_LTR or NSBIDI_RTL to force the base direction;
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* NSBIDI_DEFAULT_LTR or NSBIDI_DEFAULT_RTL to let the bidi engine
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* determine the direction from rules P2 and P3 of the bidi algorithm.
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* @see nsBidi::GetPara
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* @param aOverride if TRUE, the text has a bidi override, according to
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* the direction in aDir
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*/
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static void CopyLogicalToVisual(const nsAString& aSource,
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nsAString& aDest,
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nsBidiLevel aBaseDirection,
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bool aOverride);
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/**
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* Use style attributes to determine the base paragraph level to pass to the
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* bidi algorithm.
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*
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* If |unicode-bidi| is set to "[-moz-]plaintext", returns NSBIDI_DEFAULT_LTR,
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* in other words the direction is determined from the first strong character
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* in the text according to rules P2 and P3 of the bidi algorithm, or LTR if
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* there is no strong character.
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*
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* Otherwise returns NSBIDI_LTR or NSBIDI_RTL depending on the value of
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* |direction|
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*/
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static nsBidiLevel BidiLevelFromStyle(nsStyleContext* aStyleContext);
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private:
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static nsresult
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ProcessTextForRenderingContext(const char16_t* aText,
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int32_t aLength,
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nsBidiLevel aBaseLevel,
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nsPresContext* aPresContext,
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nsRenderingContext& aRenderingContext,
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nsRenderingContext& aTextRunConstructionContext,
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nsFontMetrics& aFontMetrics,
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Mode aMode,
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nscoord aX, // DRAW only
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nscoord aY, // DRAW only
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nsBidiPositionResolve* aPosResolve, /* may be null */
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int32_t aPosResolveCount,
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nscoord* aWidth /* may be null */);
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/**
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* Traverse the child frames of the block element and:
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* Set up an array of the frames in logical order
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* Create a string containing the text content of all the frames
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* If we encounter content that requires us to split the element into more
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* than one paragraph for bidi resolution, resolve the paragraph up to that
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* point.
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*/
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static void TraverseFrames(nsBlockFrame* aBlockFrame,
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nsBlockInFlowLineIterator* aLineIter,
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nsIFrame* aCurrentFrame,
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BidiParagraphData* aBpd);
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/*
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* Position aFrame and its descendants to their visual places. Also if aFrame
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* is not leaf, resize it to embrace its children.
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*
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* @param aFrame The frame which itself and its children are
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* going to be repositioned
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* @param aIsEvenLevel TRUE means the embedding level of this frame
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* is even (LTR)
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* @param[in,out] aStart IN value is the starting position of aFrame
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* (without considering its inline-start margin)
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* OUT value will be the ending position of aFrame
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* (after adding its inline-end margin)
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* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
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*/
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static void RepositionFrame(nsIFrame* aFrame,
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bool aIsEvenLevel,
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nscoord& aStart,
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nsContinuationStates* aContinuationStates,
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mozilla::WritingMode aContainerWM,
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const nsSize& aContainerSize);
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/*
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* Initialize the continuation state(nsFrameContinuationState) to
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* (nullptr, 0) for aFrame and its descendants.
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*
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* @param aFrame The frame which itself and its descendants will
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* be initialized
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* @param aContinuationStates A map from nsIFrame* to nsFrameContinuationState
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*/
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static void InitContinuationStates(nsIFrame* aFrame,
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nsContinuationStates* aContinuationStates);
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/*
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* Determine if aFrame is first or last, and set aIsFirst and
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* aIsLast values. Also set continuation states of
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* aContinuationStates.
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*
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* A frame is first if it's the first appearance of its continuation
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* chain on the line and the chain is on its first line.
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* A frame is last if it's the last appearance of its continuation
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* chain on the line and the chain is on its last line.
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*
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* N.B: "First appearance" and "Last appearance" in the previous
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* paragraph refer to the frame's inline direction, not necessarily
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* the line's.
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*
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* @param aContinuationStates A map from nsIFrame* to
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* nsFrameContinuationState
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* @param[in] aSpanDirMatchesLineDir TRUE means that the inline
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* direction of aFrame is the same
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* as its container
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* @param[out] aIsFirst TRUE means aFrame is first frame
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* or continuation
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* @param[out] aIsLast TRUE means aFrame is last frame
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* or continuation
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*/
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static void IsFirstOrLast(nsIFrame* aFrame,
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nsContinuationStates* aContinuationStates,
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bool aSpanInLineOrder /* in */,
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bool& aIsFirst /* out */,
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bool& aIsLast /* out */);
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/**
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* Adjust frame positions following their visual order
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*
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* @param aFirstChild the first kid
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*
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* @lina 04/11/2000
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*/
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static void RepositionInlineFrames(BidiLineData* aBld,
|
|
nsIFrame* aFirstChild,
|
|
mozilla::WritingMode aLineWM,
|
|
const nsSize& aContainerSize,
|
|
nscoord aStart);
|
|
|
|
/**
|
|
* Helper method for Resolve()
|
|
* Truncate a text frame to the end of a single-directional run and possibly
|
|
* create a continuation frame for the remainder of its content.
|
|
*
|
|
* @param aFrame the original frame
|
|
* @param aNewFrame [OUT] the new frame that was created
|
|
* @param aFrameIndex [IN/OUT] index of aFrame in mLogicalFrames
|
|
* @param aStart [IN] the start of the content mapped by aFrame (and
|
|
* any fluid continuations)
|
|
* @param aEnd [IN] the offset of the end of the single-directional
|
|
* text run.
|
|
* @see Resolve()
|
|
* @see RemoveBidiContinuation()
|
|
*/
|
|
static inline
|
|
nsresult EnsureBidiContinuation(nsIFrame* aFrame,
|
|
nsIFrame** aNewFrame,
|
|
int32_t& aFrameIndex,
|
|
int32_t aStart,
|
|
int32_t aEnd);
|
|
|
|
/**
|
|
* Helper method for Resolve()
|
|
* Convert one or more bidi continuation frames created in a previous reflow by
|
|
* EnsureBidiContinuation() into fluid continuations.
|
|
* @param aFrame the frame whose continuations are to be removed
|
|
* @param aFirstIndex index of aFrame in mLogicalFrames
|
|
* @param aLastIndex index of the last frame to be removed
|
|
* @param aOffset [OUT] count of directional frames removed. Since
|
|
* directional frames have control characters
|
|
* corresponding to them in mBuffer, the pointers to
|
|
* mBuffer in Resolve() will need to be updated after
|
|
* deleting the frames.
|
|
*
|
|
* @see Resolve()
|
|
* @see EnsureBidiContinuation()
|
|
*/
|
|
static void RemoveBidiContinuation(BidiParagraphData* aBpd,
|
|
nsIFrame* aFrame,
|
|
int32_t aFirstIndex,
|
|
int32_t aLastIndex,
|
|
int32_t& aOffset);
|
|
static void CalculateCharType(nsBidi* aBidiEngine,
|
|
const char16_t* aText,
|
|
int32_t& aOffset,
|
|
int32_t aCharTypeLimit,
|
|
int32_t& aRunLimit,
|
|
int32_t& aRunLength,
|
|
int32_t& aRunCount,
|
|
uint8_t& aCharType,
|
|
uint8_t& aPrevCharType);
|
|
|
|
static void StripBidiControlCharacters(char16_t* aText,
|
|
int32_t& aTextLength);
|
|
|
|
static bool WriteLogicalToVisual(const char16_t* aSrc,
|
|
uint32_t aSrcLength,
|
|
char16_t* aDest,
|
|
nsBidiLevel aBaseDirection,
|
|
nsBidi* aBidiEngine);
|
|
|
|
static void WriteReverse(const char16_t* aSrc,
|
|
uint32_t aSrcLength,
|
|
char16_t* aDest);
|
|
};
|
|
|
|
#endif /* nsBidiPresUtils_h___ */
|