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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /gfx/thebes/gfxTextRun.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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diff --git a/gfx/thebes/gfxTextRun.h b/gfx/thebes/gfxTextRun.h
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=4 et sw=4 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 GFX_TEXTRUN_H
+#define GFX_TEXTRUN_H
+
+#include "gfxTypes.h"
+#include "nsString.h"
+#include "gfxPoint.h"
+#include "gfxFont.h"
+#include "gfxFontConstants.h"
+#include "nsTArray.h"
+#include "gfxSkipChars.h"
+#include "gfxPlatform.h"
+#include "mozilla/MemoryReporting.h"
+#include "DrawMode.h"
+#include "harfbuzz/hb.h"
+#include "nsUnicodeScriptCodes.h"
+#include "nsColor.h"
+
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+
+class gfxContext;
+class gfxFontGroup;
+class gfxUserFontEntry;
+class gfxUserFontSet;
+class nsIAtom;
+class nsILanguageAtomService;
+class gfxMissingFontRecorder;
+
+namespace mozilla {
+class SVGContextPaint;
+};
+
+/**
+ * Callback for Draw() to use when drawing text with mode
+ * DrawMode::GLYPH_PATH.
+ */
+struct gfxTextRunDrawCallbacks {
+
+ /**
+ * Constructs a new DrawCallbacks object.
+ *
+ * @param aShouldPaintSVGGlyphs If true, SVG glyphs will be painted. If
+ * false, SVG glyphs will not be painted; fallback plain glyphs are not
+ * emitted either.
+ */
+ explicit gfxTextRunDrawCallbacks(bool aShouldPaintSVGGlyphs = false)
+ : mShouldPaintSVGGlyphs(aShouldPaintSVGGlyphs)
+ {
+ }
+
+ /**
+ * Called when a path has been emitted to the gfxContext when
+ * painting a text run. This can be called any number of times,
+ * due to partial ligatures and intervening SVG glyphs.
+ */
+ virtual void NotifyGlyphPathEmitted() = 0;
+
+ bool mShouldPaintSVGGlyphs;
+};
+
+/**
+ * gfxTextRun is an abstraction for drawing and measuring substrings of a run
+ * of text. It stores runs of positioned glyph data, each run having a single
+ * gfxFont. The glyphs are associated with a string of source text, and the
+ * gfxTextRun APIs take parameters that are offsets into that source text.
+ *
+ * gfxTextRuns are mostly immutable. The only things that can change are
+ * inter-cluster spacing and line break placement. Spacing is always obtained
+ * lazily by methods that need it, it is not cached. Line breaks are stored
+ * persistently (insofar as they affect the shaping of glyphs; gfxTextRun does
+ * not actually do anything to explicitly account for line breaks). Initially
+ * there are no line breaks. The textrun can record line breaks before or after
+ * any given cluster. (Line breaks specified inside clusters are ignored.)
+ *
+ * It is important that zero-length substrings are handled correctly. This will
+ * be on the test!
+ */
+class gfxTextRun : public gfxShapedText
+{
+ NS_INLINE_DECL_REFCOUNTING(gfxTextRun);
+
+protected:
+ // Override operator delete to properly free the object that was
+ // allocated via malloc.
+ void operator delete(void* p) {
+ free(p);
+ }
+
+ virtual ~gfxTextRun();
+
+public:
+ typedef gfxFont::RunMetrics Metrics;
+ typedef mozilla::gfx::DrawTarget DrawTarget;
+
+ // Public textrun API for general use
+
+ bool IsClusterStart(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].IsClusterStart();
+ }
+ bool IsLigatureGroupStart(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].IsLigatureGroupStart();
+ }
+ bool CanBreakLineBefore(uint32_t aPos) const {
+ return CanBreakBefore(aPos) == CompressedGlyph::FLAG_BREAK_TYPE_NORMAL;
+ }
+ bool CanHyphenateBefore(uint32_t aPos) const {
+ return CanBreakBefore(aPos) == CompressedGlyph::FLAG_BREAK_TYPE_HYPHEN;
+ }
+
+ // Returns a gfxShapedText::CompressedGlyph::FLAG_BREAK_TYPE_* value
+ // as defined in gfxFont.h (may be NONE, NORMAL or HYPHEN).
+ uint8_t CanBreakBefore(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].CanBreakBefore();
+ }
+
+ bool CharIsSpace(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].CharIsSpace();
+ }
+ bool CharIsTab(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].CharIsTab();
+ }
+ bool CharIsNewline(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].CharIsNewline();
+ }
+ bool CharMayHaveEmphasisMark(uint32_t aPos) const {
+ MOZ_ASSERT(aPos < GetLength());
+ return mCharacterGlyphs[aPos].CharMayHaveEmphasisMark();
+ }
+
+ // All offsets are in terms of the string passed into MakeTextRun.
+
+ // Describe range [start, end) of a text run. The range is
+ // restricted to grapheme cluster boundaries.
+ struct Range
+ {
+ uint32_t start;
+ uint32_t end;
+ uint32_t Length() const { return end - start; }
+
+ Range() : start(0), end(0) {}
+ Range(uint32_t aStart, uint32_t aEnd)
+ : start(aStart), end(aEnd) {}
+ explicit Range(const gfxTextRun* aTextRun)
+ : start(0), end(aTextRun->GetLength()) {}
+ };
+
+ // All coordinates are in layout/app units
+
+ /**
+ * Set the potential linebreaks for a substring of the textrun. These are
+ * the "allow break before" points. Initially, there are no potential
+ * linebreaks.
+ *
+ * This can change glyphs and/or geometry! Some textruns' shapes
+ * depend on potential line breaks (e.g., title-case-converting textruns).
+ * This function is virtual so that those textruns can reshape themselves.
+ *
+ * @return true if this changed the linebreaks, false if the new line
+ * breaks are the same as the old
+ */
+ virtual bool SetPotentialLineBreaks(Range aRange,
+ const uint8_t* aBreakBefore);
+
+ /**
+ * Layout provides PropertyProvider objects. These allow detection of
+ * potential line break points and computation of spacing. We pass the data
+ * this way to allow lazy data acquisition; for example BreakAndMeasureText
+ * will want to only ask for properties of text it's actually looking at.
+ *
+ * NOTE that requested spacing may not actually be applied, if the textrun
+ * is unable to apply it in some context. Exception: spacing around a
+ * whitespace character MUST always be applied.
+ */
+ class PropertyProvider {
+ public:
+ // Detect hyphenation break opportunities in the given range; breaks
+ // not at cluster boundaries will be ignored.
+ virtual void GetHyphenationBreaks(Range aRange, bool *aBreakBefore) = 0;
+
+ // Returns the provider's hyphenation setting, so callers can decide
+ // whether it is necessary to call GetHyphenationBreaks.
+ // Result is an NS_STYLE_HYPHENS_* value.
+ virtual int8_t GetHyphensOption() = 0;
+
+ // Returns the extra width that will be consumed by a hyphen. This should
+ // be constant for a given textrun.
+ virtual gfxFloat GetHyphenWidth() = 0;
+
+ typedef gfxFont::Spacing Spacing;
+
+ /**
+ * Get the spacing around the indicated characters. Spacing must be zero
+ * inside clusters. In other words, if character i is not
+ * CLUSTER_START, then character i-1 must have zero after-spacing and
+ * character i must have zero before-spacing.
+ */
+ virtual void GetSpacing(Range aRange, Spacing *aSpacing) = 0;
+
+ // Returns a gfxContext that can be used to measure the hyphen glyph.
+ // Only called if the hyphen width is requested.
+ virtual already_AddRefed<DrawTarget> GetDrawTarget() = 0;
+
+ // Return the appUnitsPerDevUnit value to be used when measuring.
+ // Only called if the hyphen width is requested.
+ virtual uint32_t GetAppUnitsPerDevUnit() = 0;
+ };
+
+ struct DrawParams
+ {
+ gfxContext* context;
+ DrawMode drawMode = DrawMode::GLYPH_FILL;
+ nscolor textStrokeColor = 0;
+ gfxPattern* textStrokePattern = nullptr;
+ const mozilla::gfx::StrokeOptions *strokeOpts = nullptr;
+ const mozilla::gfx::DrawOptions *drawOpts = nullptr;
+ PropertyProvider* provider = nullptr;
+ // If non-null, the advance width of the substring is set.
+ gfxFloat* advanceWidth = nullptr;
+ mozilla::SVGContextPaint* contextPaint = nullptr;
+ gfxTextRunDrawCallbacks* callbacks = nullptr;
+ explicit DrawParams(gfxContext* aContext) : context(aContext) {}
+ };
+
+ /**
+ * Draws a substring. Uses only GetSpacing from aBreakProvider.
+ * The provided point is the baseline origin on the left of the string
+ * for LTR, on the right of the string for RTL.
+ *
+ * Drawing should respect advance widths in the sense that for LTR runs,
+ * Draw(Range(start, middle), pt, ...) followed by
+ * Draw(Range(middle, end), gfxPoint(pt.x + advance, pt.y), ...)
+ * should have the same effect as
+ * Draw(Range(start, end), pt, ...)
+ *
+ * For RTL runs the rule is:
+ * Draw(Range(middle, end), pt, ...) followed by
+ * Draw(Range(start, middle), gfxPoint(pt.x + advance, pt.y), ...)
+ * should have the same effect as
+ * Draw(Range(start, end), pt, ...)
+ *
+ * Glyphs should be drawn in logical content order, which can be significant
+ * if they overlap (perhaps due to negative spacing).
+ */
+ void Draw(Range aRange, gfxPoint aPt, const DrawParams& aParams) const;
+
+ /**
+ * Draws the emphasis marks for this text run. Uses only GetSpacing
+ * from aProvider. The provided point is the baseline origin of the
+ * line of emphasis marks.
+ */
+ void DrawEmphasisMarks(gfxContext* aContext, gfxTextRun* aMark,
+ gfxFloat aMarkAdvance, gfxPoint aPt,
+ Range aRange, PropertyProvider* aProvider) const;
+
+ /**
+ * Computes the ReflowMetrics for a substring.
+ * Uses GetSpacing from aBreakProvider.
+ * @param aBoundingBoxType which kind of bounding box (loose/tight)
+ */
+ Metrics MeasureText(Range aRange,
+ gfxFont::BoundingBoxType aBoundingBoxType,
+ DrawTarget* aDrawTargetForTightBoundingBox,
+ PropertyProvider* aProvider) const;
+
+ Metrics MeasureText(gfxFont::BoundingBoxType aBoundingBoxType,
+ DrawTarget* aDrawTargetForTightBoundingBox,
+ PropertyProvider* aProvider = nullptr) const {
+ return MeasureText(Range(this), aBoundingBoxType,
+ aDrawTargetForTightBoundingBox, aProvider);
+ }
+
+ /**
+ * Computes just the advance width for a substring.
+ * Uses GetSpacing from aBreakProvider.
+ * If aSpacing is not null, the spacing attached before and after
+ * the substring would be returned in it. NOTE: the spacing is
+ * included in the advance width.
+ */
+ gfxFloat GetAdvanceWidth(Range aRange, PropertyProvider *aProvider,
+ PropertyProvider::Spacing*
+ aSpacing = nullptr) const;
+
+ gfxFloat GetAdvanceWidth() const {
+ return GetAdvanceWidth(Range(this), nullptr);
+ }
+
+ /**
+ * Clear all stored line breaks for the given range (both before and after),
+ * and then set the line-break state before aRange.start to aBreakBefore and
+ * after the last cluster to aBreakAfter.
+ *
+ * We require that before and after line breaks be consistent. For clusters
+ * i and i+1, we require that if there is a break after cluster i, a break
+ * will be specified before cluster i+1. This may be temporarily violated
+ * (e.g. after reflowing line L and before reflowing line L+1); to handle
+ * these temporary violations, we say that there is a break betwen i and i+1
+ * if a break is specified after i OR a break is specified before i+1.
+ *
+ * This can change textrun geometry! The existence of a linebreak can affect
+ * the advance width of the cluster before the break (when kerning) or the
+ * geometry of one cluster before the break or any number of clusters
+ * after the break. (The one-cluster-before-the-break limit is somewhat
+ * arbitrary; if some scripts require breaking it, then we need to
+ * alter nsTextFrame::TrimTrailingWhitespace, perhaps drastically becase
+ * it could affect the layout of frames before it...)
+ *
+ * We return true if glyphs or geometry changed, false otherwise. This
+ * function is virtual so that gfxTextRun subclasses can reshape
+ * properly.
+ *
+ * @param aAdvanceWidthDelta if non-null, returns the change in advance
+ * width of the given range.
+ */
+ virtual bool SetLineBreaks(Range aRange,
+ bool aLineBreakBefore, bool aLineBreakAfter,
+ gfxFloat* aAdvanceWidthDelta);
+
+ enum SuppressBreak {
+ eNoSuppressBreak,
+ // Measure the range of text as if there is no break before it.
+ eSuppressInitialBreak,
+ // Measure the range of text as if it contains no break
+ eSuppressAllBreaks
+ };
+
+ /**
+ * Finds the longest substring that will fit into the given width.
+ * Uses GetHyphenationBreaks and GetSpacing from aBreakProvider.
+ * Guarantees the following:
+ * -- 0 <= result <= aMaxLength
+ * -- result is the maximal value of N such that either
+ * N < aMaxLength && line break at N && GetAdvanceWidth(aStart, N) <= aWidth
+ * OR N < aMaxLength && hyphen break at N && GetAdvanceWidth(aStart, N) + GetHyphenWidth() <= aWidth
+ * OR N == aMaxLength && GetAdvanceWidth(aStart, N) <= aWidth
+ * where GetAdvanceWidth assumes the effect of
+ * SetLineBreaks(aStart, N, aLineBreakBefore, N < aMaxLength, aProvider)
+ * -- if no such N exists, then result is the smallest N such that
+ * N < aMaxLength && line break at N
+ * OR N < aMaxLength && hyphen break at N
+ * OR N == aMaxLength
+ *
+ * The call has the effect of
+ * SetLineBreaks(aStart, result, aLineBreakBefore, result < aMaxLength, aProvider)
+ * and the returned metrics and the invariants above reflect this.
+ *
+ * @param aMaxLength this can be UINT32_MAX, in which case the length used
+ * is up to the end of the string
+ * @param aLineBreakBefore set to true if and only if there is an actual
+ * line break at the start of this string.
+ * @param aSuppressBreak what break should be suppressed.
+ * @param aTrimWhitespace if non-null, then we allow a trailing run of
+ * spaces to be trimmed; the width of the space(s) will not be included in
+ * the measured string width for comparison with the limit aWidth, and
+ * trimmed spaces will not be included in returned metrics. The width
+ * of the trimmed spaces will be returned in aTrimWhitespace.
+ * Trimmed spaces are still counted in the "characters fit" result.
+ * @param aMetrics if non-null, we fill this in for the returned substring.
+ * If a hyphenation break was used, the hyphen is NOT included in the returned metrics.
+ * @param aBoundingBoxType whether to make the bounding box in aMetrics tight
+ * @param aDrawTargetForTightBoundingbox a reference DrawTarget to get the
+ * tight bounding box, if requested
+ * @param aUsedHyphenation if non-null, records if we selected a hyphenation break
+ * @param aLastBreak if non-null and result is aMaxLength, we set this to
+ * the maximal N such that
+ * N < aMaxLength && line break at N && GetAdvanceWidth(aStart, N) <= aWidth
+ * OR N < aMaxLength && hyphen break at N && GetAdvanceWidth(aStart, N) + GetHyphenWidth() <= aWidth
+ * or UINT32_MAX if no such N exists, where GetAdvanceWidth assumes
+ * the effect of
+ * SetLineBreaks(aStart, N, aLineBreakBefore, N < aMaxLength, aProvider)
+ *
+ * @param aCanWordWrap true if we can break between any two grapheme
+ * clusters. This is set by overflow-wrap|word-wrap: break-word
+ *
+ * @param aBreakPriority in/out the priority of the break opportunity
+ * saved in the line. If we are prioritizing break opportunities, we will
+ * not set a break with a lower priority. @see gfxBreakPriority.
+ *
+ * Note that negative advance widths are possible especially if negative
+ * spacing is provided.
+ */
+ uint32_t BreakAndMeasureText(uint32_t aStart, uint32_t aMaxLength,
+ bool aLineBreakBefore, gfxFloat aWidth,
+ PropertyProvider *aProvider,
+ SuppressBreak aSuppressBreak,
+ gfxFloat *aTrimWhitespace,
+ bool aHangWhitespace,
+ Metrics *aMetrics,
+ gfxFont::BoundingBoxType aBoundingBoxType,
+ DrawTarget* aDrawTargetForTightBoundingBox,
+ bool *aUsedHyphenation,
+ uint32_t *aLastBreak,
+ bool aCanWordWrap,
+ gfxBreakPriority *aBreakPriority);
+
+ // Utility getters
+
+ void *GetUserData() const { return mUserData; }
+ void SetUserData(void *aUserData) { mUserData = aUserData; }
+
+ void SetFlagBits(uint32_t aFlags) {
+ NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
+ "Only user flags should be mutable");
+ mFlags |= aFlags;
+ }
+ void ClearFlagBits(uint32_t aFlags) {
+ NS_ASSERTION(!(aFlags & ~gfxTextRunFactory::SETTABLE_FLAGS),
+ "Only user flags should be mutable");
+ mFlags &= ~aFlags;
+ }
+ const gfxSkipChars& GetSkipChars() const { return mSkipChars; }
+ gfxFontGroup *GetFontGroup() const { return mFontGroup; }
+
+
+ // Call this, don't call "new gfxTextRun" directly. This does custom
+ // allocation and initialization
+ static already_AddRefed<gfxTextRun>
+ Create(const gfxTextRunFactory::Parameters *aParams,
+ uint32_t aLength, gfxFontGroup *aFontGroup,
+ uint32_t aFlags);
+
+ // The text is divided into GlyphRuns as necessary
+ struct GlyphRun {
+ RefPtr<gfxFont> mFont; // never null
+ uint32_t mCharacterOffset; // into original UTF16 string
+ uint8_t mMatchType;
+ uint16_t mOrientation; // gfxTextRunFactory::TEXT_ORIENT_* value
+ };
+
+ class GlyphRunIterator {
+ public:
+ GlyphRunIterator(const gfxTextRun *aTextRun, Range aRange)
+ : mTextRun(aTextRun)
+ , mStartOffset(aRange.start)
+ , mEndOffset(aRange.end) {
+ mNextIndex = mTextRun->FindFirstGlyphRunContaining(aRange.start);
+ }
+ bool NextRun();
+ const GlyphRun *GetGlyphRun() const { return mGlyphRun; }
+ uint32_t GetStringStart() const { return mStringStart; }
+ uint32_t GetStringEnd() const { return mStringEnd; }
+ private:
+ const gfxTextRun *mTextRun;
+ MOZ_INIT_OUTSIDE_CTOR const GlyphRun *mGlyphRun;
+ MOZ_INIT_OUTSIDE_CTOR uint32_t mStringStart;
+ MOZ_INIT_OUTSIDE_CTOR uint32_t mStringEnd;
+ uint32_t mNextIndex;
+ uint32_t mStartOffset;
+ uint32_t mEndOffset;
+ };
+
+ class GlyphRunOffsetComparator {
+ public:
+ bool Equals(const GlyphRun& a,
+ const GlyphRun& b) const
+ {
+ return a.mCharacterOffset == b.mCharacterOffset;
+ }
+
+ bool LessThan(const GlyphRun& a,
+ const GlyphRun& b) const
+ {
+ return a.mCharacterOffset < b.mCharacterOffset;
+ }
+ };
+
+ friend class GlyphRunIterator;
+ friend class FontSelector;
+
+ // API for setting up the textrun glyphs. Should only be called by
+ // things that construct textruns.
+ /**
+ * We've found a run of text that should use a particular font. Call this
+ * only during initialization when font substitution has been computed.
+ * Call it before setting up the glyphs for the characters in this run;
+ * SetMissingGlyph requires that the correct glyphrun be installed.
+ *
+ * If aForceNewRun, a new glyph run will be added, even if the
+ * previously added run uses the same font. If glyph runs are
+ * added out of strictly increasing aStartCharIndex order (via
+ * force), then SortGlyphRuns must be called after all glyph runs
+ * are added before any further operations are performed with this
+ * TextRun.
+ */
+ nsresult AddGlyphRun(gfxFont *aFont, uint8_t aMatchType,
+ uint32_t aStartCharIndex, bool aForceNewRun,
+ uint16_t aOrientation);
+ void ResetGlyphRuns() { mGlyphRuns.Clear(); }
+ void SortGlyphRuns();
+ void SanitizeGlyphRuns();
+
+ const CompressedGlyph* GetCharacterGlyphs() const final {
+ MOZ_ASSERT(mCharacterGlyphs, "failed to initialize mCharacterGlyphs");
+ return mCharacterGlyphs;
+ }
+ CompressedGlyph* GetCharacterGlyphs() final {
+ MOZ_ASSERT(mCharacterGlyphs, "failed to initialize mCharacterGlyphs");
+ return mCharacterGlyphs;
+ }
+
+ // clean out results from shaping in progress, used for fallback scenarios
+ void ClearGlyphsAndCharacters();
+
+ void SetSpaceGlyph(gfxFont* aFont, DrawTarget* aDrawTarget,
+ uint32_t aCharIndex, uint16_t aOrientation);
+
+ // Set the glyph data for the given character index to the font's
+ // space glyph, IF this can be done as a "simple" glyph record
+ // (not requiring a DetailedGlyph entry). This avoids the need to call
+ // the font shaper and go through the shaped-word cache for most spaces.
+ //
+ // The parameter aSpaceChar is the original character code for which
+ // this space glyph is being used; if this is U+0020, we need to record
+ // that it could be trimmed at a run edge, whereas other kinds of space
+ // (currently just U+00A0) would not be trimmable/breakable.
+ //
+ // Returns true if it was able to set simple glyph data for the space;
+ // if it returns false, the caller needs to fall back to some other
+ // means to create the necessary (detailed) glyph data.
+ bool SetSpaceGlyphIfSimple(gfxFont *aFont, uint32_t aCharIndex,
+ char16_t aSpaceChar, uint16_t aOrientation);
+
+ // Record the positions of specific characters that layout may need to
+ // detect in the textrun, even though it doesn't have an explicit copy
+ // of the original text. These are recorded using flag bits in the
+ // CompressedGlyph record; if necessary, we convert "simple" glyph records
+ // to "complex" ones as the Tab and Newline flags are not present in
+ // simple CompressedGlyph records.
+ void SetIsTab(uint32_t aIndex) {
+ EnsureComplexGlyph(aIndex).SetIsTab();
+ }
+ void SetIsNewline(uint32_t aIndex) {
+ EnsureComplexGlyph(aIndex).SetIsNewline();
+ }
+ void SetNoEmphasisMark(uint32_t aIndex) {
+ EnsureComplexGlyph(aIndex).SetNoEmphasisMark();
+ }
+
+ /**
+ * Prefetch all the glyph extents needed to ensure that Measure calls
+ * on this textrun not requesting tight boundingBoxes will succeed. Note
+ * that some glyph extents might not be fetched due to OOM or other
+ * errors.
+ */
+ void FetchGlyphExtents(DrawTarget* aRefDrawTarget);
+
+ uint32_t CountMissingGlyphs() const;
+ const GlyphRun* GetGlyphRuns(uint32_t* aNumGlyphRuns) const {
+ *aNumGlyphRuns = mGlyphRuns.Length();
+ return mGlyphRuns.Elements();
+ }
+ // Returns the index of the GlyphRun containing the given offset.
+ // Returns mGlyphRuns.Length() when aOffset is mCharacterCount.
+ uint32_t FindFirstGlyphRunContaining(uint32_t aOffset) const;
+
+ // Copy glyph data from a ShapedWord into this textrun.
+ void CopyGlyphDataFrom(gfxShapedWord *aSource, uint32_t aStart);
+
+ // Copy glyph data for a range of characters from aSource to this
+ // textrun.
+ void CopyGlyphDataFrom(gfxTextRun *aSource, Range aRange, uint32_t aDest);
+
+ // Tell the textrun to release its reference to its creating gfxFontGroup
+ // immediately, rather than on destruction. This is used for textruns
+ // that are actually owned by a gfxFontGroup, so that they don't keep it
+ // permanently alive due to a circular reference. (The caller of this is
+ // taking responsibility for ensuring the textrun will not outlive its
+ // mFontGroup.)
+ void ReleaseFontGroup();
+
+ struct LigatureData {
+ // textrun range of the containing ligature
+ Range mRange;
+ // appunits advance to the start of the ligature part within the ligature;
+ // never includes any spacing
+ gfxFloat mPartAdvance;
+ // appunits width of the ligature part; includes before-spacing
+ // when the part is at the start of the ligature, and after-spacing
+ // when the part is as the end of the ligature
+ gfxFloat mPartWidth;
+
+ bool mClipBeforePart;
+ bool mClipAfterPart;
+ };
+
+ // return storage used by this run, for memory reporter;
+ // nsTransformedTextRun needs to override this as it holds additional data
+ virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf)
+ MOZ_MUST_OVERRIDE;
+ virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
+ MOZ_MUST_OVERRIDE;
+
+ // Get the size, if it hasn't already been gotten, marking as it goes.
+ size_t MaybeSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
+ if (mFlags & gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED) {
+ return 0;
+ }
+ mFlags |= gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED;
+ return SizeOfIncludingThis(aMallocSizeOf);
+ }
+ void ResetSizeOfAccountingFlags() {
+ mFlags &= ~gfxTextRunFactory::TEXT_RUN_SIZE_ACCOUNTED;
+ }
+
+ // shaping state - for some font features, fallback is required that
+ // affects the entire run. for example, fallback for one script/font
+ // portion of a textrun requires fallback to be applied to the entire run
+
+ enum ShapingState {
+ eShapingState_Normal, // default state
+ eShapingState_ShapingWithFeature, // have shaped with feature
+ eShapingState_ShapingWithFallback, // have shaped with fallback
+ eShapingState_Aborted, // abort initial iteration
+ eShapingState_ForceFallbackFeature // redo with fallback forced on
+ };
+
+ ShapingState GetShapingState() const { return mShapingState; }
+ void SetShapingState(ShapingState aShapingState) {
+ mShapingState = aShapingState;
+ }
+
+ int32_t GetAdvanceForGlyph(uint32_t aIndex) const
+ {
+ const CompressedGlyph& glyphData = mCharacterGlyphs[aIndex];
+ if (glyphData.IsSimpleGlyph()) {
+ return glyphData.GetSimpleAdvance();
+ }
+ uint32_t glyphCount = glyphData.GetGlyphCount();
+ if (!glyphCount) {
+ return 0;
+ }
+ const DetailedGlyph* details = GetDetailedGlyphs(aIndex);
+ int32_t advance = 0;
+ for (uint32_t j = 0; j < glyphCount; ++j, ++details) {
+ advance += details->mAdvance;
+ }
+ return advance;
+ }
+
+#ifdef DEBUG
+ void Dump(FILE* aOutput);
+#endif
+
+protected:
+ /**
+ * Create a textrun, and set its mCharacterGlyphs to point immediately
+ * after the base object; this is ONLY used in conjunction with placement
+ * new, after allocating a block large enough for the glyph records to
+ * follow the base textrun object.
+ */
+ gfxTextRun(const gfxTextRunFactory::Parameters *aParams,
+ uint32_t aLength, gfxFontGroup *aFontGroup, uint32_t aFlags);
+
+ /**
+ * Helper for the Create() factory method to allocate the required
+ * glyph storage for a textrun object with the basic size aSize,
+ * plus room for aLength glyph records.
+ */
+ static void* AllocateStorageForTextRun(size_t aSize, uint32_t aLength);
+
+ // Pointer to the array of CompressedGlyph records; must be initialized
+ // when the object is constructed.
+ CompressedGlyph *mCharacterGlyphs;
+
+private:
+ // **** general helpers ****
+
+ // Get the total advance for a range of glyphs.
+ int32_t GetAdvanceForGlyphs(Range aRange) const;
+
+ // Spacing for characters outside the range aSpacingStart/aSpacingEnd
+ // is assumed to be zero; such characters are not passed to aProvider.
+ // This is useful to protect aProvider from being passed character indices
+ // it is not currently able to handle.
+ bool GetAdjustedSpacingArray(Range aRange, PropertyProvider *aProvider,
+ Range aSpacingRange,
+ nsTArray<PropertyProvider::Spacing>*
+ aSpacing) const;
+
+ CompressedGlyph& EnsureComplexGlyph(uint32_t aIndex)
+ {
+ gfxShapedText::EnsureComplexGlyph(aIndex, mCharacterGlyphs[aIndex]);
+ return mCharacterGlyphs[aIndex];
+ }
+
+ // **** ligature helpers ****
+ // (Platforms do the actual ligaturization, but we need to do a bunch of stuff
+ // to handle requests that begin or end inside a ligature)
+
+ // if aProvider is null then mBeforeSpacing and mAfterSpacing are set to zero
+ LigatureData ComputeLigatureData(Range aPartRange,
+ PropertyProvider *aProvider) const;
+ gfxFloat ComputePartialLigatureWidth(Range aPartRange,
+ PropertyProvider *aProvider) const;
+ void DrawPartialLigature(gfxFont *aFont, Range aRange,
+ gfxPoint *aPt, PropertyProvider *aProvider,
+ TextRunDrawParams& aParams,
+ uint16_t aOrientation) const;
+ // Advance aRange.start to the start of the nearest ligature, back
+ // up aRange.end to the nearest ligature end; may result in
+ // aRange->start == aRange->end.
+ void ShrinkToLigatureBoundaries(Range* aRange) const;
+ // result in appunits
+ gfxFloat GetPartialLigatureWidth(Range aRange,
+ PropertyProvider *aProvider) const;
+ void AccumulatePartialLigatureMetrics(gfxFont *aFont, Range aRange,
+ gfxFont::BoundingBoxType aBoundingBoxType,
+ DrawTarget* aRefDrawTarget,
+ PropertyProvider *aProvider,
+ uint16_t aOrientation,
+ Metrics *aMetrics) const;
+
+ // **** measurement helper ****
+ void AccumulateMetricsForRun(gfxFont *aFont, Range aRange,
+ gfxFont::BoundingBoxType aBoundingBoxType,
+ DrawTarget* aRefDrawTarget,
+ PropertyProvider *aProvider,
+ Range aSpacingRange,
+ uint16_t aOrientation,
+ Metrics *aMetrics) const;
+
+ // **** drawing helper ****
+ void DrawGlyphs(gfxFont *aFont, Range aRange, gfxPoint *aPt,
+ PropertyProvider *aProvider, Range aSpacingRange,
+ TextRunDrawParams& aParams, uint16_t aOrientation) const;
+
+ // XXX this should be changed to a GlyphRun plus a maybe-null GlyphRun*,
+ // for smaller size especially in the super-common one-glyphrun case
+ AutoTArray<GlyphRun,1> mGlyphRuns;
+
+ void *mUserData;
+ gfxFontGroup *mFontGroup; // addrefed on creation, but our reference
+ // may be released by ReleaseFontGroup()
+ gfxSkipChars mSkipChars;
+
+ bool mSkipDrawing; // true if the font group we used had a user font
+ // download that's in progress, so we should hide text
+ // until the download completes (or timeout fires)
+ bool mReleasedFontGroup; // we already called NS_RELEASE on
+ // mFontGroup, so don't do it again
+
+ // shaping state for handling variant fallback features
+ // such as subscript/superscript variant glyphs
+ ShapingState mShapingState;
+};
+
+class gfxFontGroup : public gfxTextRunFactory {
+public:
+ typedef mozilla::unicode::Script Script;
+
+ static void Shutdown(); // platform must call this to release the languageAtomService
+
+ gfxFontGroup(const mozilla::FontFamilyList& aFontFamilyList,
+ const gfxFontStyle* aStyle,
+ gfxTextPerfMetrics* aTextPerf,
+ gfxUserFontSet* aUserFontSet,
+ gfxFloat aDevToCssSize);
+
+ virtual ~gfxFontGroup();
+
+ // Returns first valid font in the fontlist or default font.
+ // Initiates userfont loads if userfont not loaded
+ virtual gfxFont* GetFirstValidFont(uint32_t aCh = 0x20);
+
+ // Returns the first font in the font-group that has an OpenType MATH table,
+ // or null if no such font is available. The GetMathConstant methods may be
+ // called on the returned font.
+ gfxFont *GetFirstMathFont();
+
+ const gfxFontStyle *GetStyle() const { return &mStyle; }
+
+ virtual gfxFontGroup *Copy(const gfxFontStyle *aStyle);
+
+ /**
+ * The listed characters should be treated as invisible and zero-width
+ * when creating textruns.
+ */
+ static bool IsInvalidChar(uint8_t ch);
+ static bool IsInvalidChar(char16_t ch);
+
+ /**
+ * Make a textrun for a given string.
+ * If aText is not persistent (aFlags & TEXT_IS_PERSISTENT), the
+ * textrun will copy it.
+ * This calls FetchGlyphExtents on the textrun.
+ */
+ virtual already_AddRefed<gfxTextRun>
+ MakeTextRun(const char16_t *aString, uint32_t aLength,
+ const Parameters *aParams, uint32_t aFlags,
+ gfxMissingFontRecorder *aMFR);
+ /**
+ * Make a textrun for a given string.
+ * If aText is not persistent (aFlags & TEXT_IS_PERSISTENT), the
+ * textrun will copy it.
+ * This calls FetchGlyphExtents on the textrun.
+ */
+ virtual already_AddRefed<gfxTextRun>
+ MakeTextRun(const uint8_t *aString, uint32_t aLength,
+ const Parameters *aParams, uint32_t aFlags,
+ gfxMissingFontRecorder *aMFR);
+
+ /**
+ * Textrun creation helper for clients that don't want to pass
+ * a full Parameters record.
+ */
+ template<typename T>
+ already_AddRefed<gfxTextRun>
+ MakeTextRun(const T* aString, uint32_t aLength,
+ DrawTarget* aRefDrawTarget,
+ int32_t aAppUnitsPerDevUnit,
+ uint32_t aFlags,
+ gfxMissingFontRecorder *aMFR)
+ {
+ gfxTextRunFactory::Parameters params = {
+ aRefDrawTarget, nullptr, nullptr, nullptr, 0, aAppUnitsPerDevUnit
+ };
+ return MakeTextRun(aString, aLength, &params, aFlags, aMFR);
+ }
+
+ /**
+ * Get the (possibly-cached) width of the hyphen character.
+ * The aCtx and aAppUnitsPerDevUnit parameters will be used only if
+ * needed to initialize the cached hyphen width; otherwise they are
+ * ignored.
+ */
+ gfxFloat GetHyphenWidth(gfxTextRun::PropertyProvider* aProvider);
+
+ /**
+ * Make a text run representing a single hyphen character.
+ * This will use U+2010 HYPHEN if available in the first font,
+ * otherwise fall back to U+002D HYPHEN-MINUS.
+ * The caller is responsible for deleting the returned text run
+ * when no longer required.
+ */
+ already_AddRefed<gfxTextRun>
+ MakeHyphenTextRun(DrawTarget* aDrawTarget, uint32_t aAppUnitsPerDevUnit);
+
+ /**
+ * Check whether a given font (specified by its gfxFontEntry)
+ * is already in the fontgroup's list of actual fonts
+ */
+ bool HasFont(const gfxFontEntry *aFontEntry);
+
+ // This returns the preferred underline for this font group.
+ // Some CJK fonts have wrong underline offset in its metrics.
+ // If this group has such "bad" font, each platform's gfxFontGroup
+ // initialized mUnderlineOffset. The value should be lower value of
+ // first font's metrics and the bad font's metrics. Otherwise, this
+ // returns from first font's metrics.
+ enum { UNDERLINE_OFFSET_NOT_SET = INT16_MAX };
+ virtual gfxFloat GetUnderlineOffset();
+
+ virtual already_AddRefed<gfxFont>
+ FindFontForChar(uint32_t ch, uint32_t prevCh, uint32_t aNextCh,
+ Script aRunScript, gfxFont *aPrevMatchedFont,
+ uint8_t *aMatchType);
+
+ gfxUserFontSet* GetUserFontSet();
+
+ // With downloadable fonts, the composition of the font group can change as fonts are downloaded
+ // for each change in state of the user font set, the generation value is bumped to avoid picking up
+ // previously created text runs in the text run word cache. For font groups based on stylesheets
+ // with no @font-face rule, this always returns 0.
+ uint64_t GetGeneration();
+
+ // generation of the latest fontset rebuild, 0 when no fontset present
+ uint64_t GetRebuildGeneration();
+
+ // used when logging text performance
+ gfxTextPerfMetrics *GetTextPerfMetrics() { return mTextPerf; }
+
+ // This will call UpdateUserFonts() if the user font set is changed.
+ void SetUserFontSet(gfxUserFontSet *aUserFontSet);
+
+ void ClearCachedData()
+ {
+ mUnderlineOffset = UNDERLINE_OFFSET_NOT_SET;
+ mSkipDrawing = false;
+ mHyphenWidth = -1;
+ mCachedEllipsisTextRun = nullptr;
+ }
+
+ // If there is a user font set, check to see whether the font list or any
+ // caches need updating.
+ virtual void UpdateUserFonts();
+
+ // search for a specific userfont in the list of fonts
+ bool ContainsUserFont(const gfxUserFontEntry* aUserFont);
+
+ bool ShouldSkipDrawing() const {
+ return mSkipDrawing;
+ }
+
+ class LazyReferenceDrawTargetGetter {
+ public:
+ virtual already_AddRefed<DrawTarget> GetRefDrawTarget() = 0;
+ };
+ // The gfxFontGroup keeps ownership of this textrun.
+ // It is only guaranteed to exist until the next call to GetEllipsisTextRun
+ // (which might use a different appUnitsPerDev value or flags) for the font
+ // group, or until UpdateUserFonts is called, or the fontgroup is destroyed.
+ // Get it/use it/forget it :) - don't keep a reference that might go stale.
+ gfxTextRun* GetEllipsisTextRun(int32_t aAppUnitsPerDevPixel, uint32_t aFlags,
+ LazyReferenceDrawTargetGetter& aRefDrawTargetGetter);
+
+protected:
+ // search through pref fonts for a character, return nullptr if no matching pref font
+ already_AddRefed<gfxFont> WhichPrefFontSupportsChar(uint32_t aCh);
+
+ already_AddRefed<gfxFont>
+ WhichSystemFontSupportsChar(uint32_t aCh, uint32_t aNextCh,
+ Script aRunScript);
+
+ template<typename T>
+ void ComputeRanges(nsTArray<gfxTextRange>& mRanges,
+ const T *aString, uint32_t aLength,
+ Script aRunScript, uint16_t aOrientation);
+
+ class FamilyFace {
+ public:
+ FamilyFace() : mFamily(nullptr), mFontEntry(nullptr),
+ mNeedsBold(false), mFontCreated(false),
+ mLoading(false), mInvalid(false),
+ mCheckForFallbackFaces(false)
+ { }
+
+ FamilyFace(gfxFontFamily* aFamily, gfxFont* aFont)
+ : mFamily(aFamily), mNeedsBold(false), mFontCreated(true),
+ mLoading(false), mInvalid(false), mCheckForFallbackFaces(false)
+ {
+ NS_ASSERTION(aFont, "font pointer must not be null");
+ NS_ASSERTION(!aFamily ||
+ aFamily->ContainsFace(aFont->GetFontEntry()),
+ "font is not a member of the given family");
+ mFont = aFont;
+ NS_ADDREF(aFont);
+ }
+
+ FamilyFace(gfxFontFamily* aFamily, gfxFontEntry* aFontEntry,
+ bool aNeedsBold)
+ : mFamily(aFamily), mNeedsBold(aNeedsBold), mFontCreated(false),
+ mLoading(false), mInvalid(false), mCheckForFallbackFaces(false)
+ {
+ NS_ASSERTION(aFontEntry, "font entry pointer must not be null");
+ NS_ASSERTION(!aFamily ||
+ aFamily->ContainsFace(aFontEntry),
+ "font is not a member of the given family");
+ mFontEntry = aFontEntry;
+ NS_ADDREF(aFontEntry);
+ }
+
+ FamilyFace(const FamilyFace& aOtherFamilyFace)
+ : mFamily(aOtherFamilyFace.mFamily),
+ mNeedsBold(aOtherFamilyFace.mNeedsBold),
+ mFontCreated(aOtherFamilyFace.mFontCreated),
+ mLoading(aOtherFamilyFace.mLoading),
+ mInvalid(aOtherFamilyFace.mInvalid),
+ mCheckForFallbackFaces(aOtherFamilyFace.mCheckForFallbackFaces)
+ {
+ if (mFontCreated) {
+ mFont = aOtherFamilyFace.mFont;
+ NS_ADDREF(mFont);
+ } else {
+ mFontEntry = aOtherFamilyFace.mFontEntry;
+ NS_IF_ADDREF(mFontEntry);
+ }
+ }
+
+ ~FamilyFace()
+ {
+ if (mFontCreated) {
+ NS_RELEASE(mFont);
+ } else {
+ NS_IF_RELEASE(mFontEntry);
+ }
+ }
+
+ FamilyFace& operator=(const FamilyFace& aOther)
+ {
+ if (mFontCreated) {
+ NS_RELEASE(mFont);
+ } else {
+ NS_IF_RELEASE(mFontEntry);
+ }
+
+ mFamily = aOther.mFamily;
+ mNeedsBold = aOther.mNeedsBold;
+ mFontCreated = aOther.mFontCreated;
+ mLoading = aOther.mLoading;
+ mInvalid = aOther.mInvalid;
+
+ if (mFontCreated) {
+ mFont = aOther.mFont;
+ NS_ADDREF(mFont);
+ } else {
+ mFontEntry = aOther.mFontEntry;
+ NS_IF_ADDREF(mFontEntry);
+ }
+
+ return *this;
+ }
+
+ gfxFontFamily* Family() const { return mFamily.get(); }
+ gfxFont* Font() const {
+ return mFontCreated ? mFont : nullptr;
+ }
+
+ gfxFontEntry* FontEntry() const {
+ return mFontCreated ? mFont->GetFontEntry() : mFontEntry;
+ }
+
+ bool NeedsBold() const { return mNeedsBold; }
+ bool IsUserFontContainer() const {
+ return FontEntry()->mIsUserFontContainer;
+ }
+ bool IsLoading() const { return mLoading; }
+ bool IsInvalid() const { return mInvalid; }
+ void CheckState(bool& aSkipDrawing);
+ void SetLoading(bool aIsLoading) { mLoading = aIsLoading; }
+ void SetInvalid() { mInvalid = true; }
+ bool CheckForFallbackFaces() const { return mCheckForFallbackFaces; }
+ void SetCheckForFallbackFaces() { mCheckForFallbackFaces = true; }
+
+ void SetFont(gfxFont* aFont)
+ {
+ NS_ASSERTION(aFont, "font pointer must not be null");
+ NS_ADDREF(aFont);
+ if (mFontCreated) {
+ NS_RELEASE(mFont);
+ } else {
+ NS_IF_RELEASE(mFontEntry);
+ }
+ mFont = aFont;
+ mFontCreated = true;
+ mLoading = false;
+ }
+
+ bool EqualsUserFont(const gfxUserFontEntry* aUserFont) const;
+
+ private:
+ RefPtr<gfxFontFamily> mFamily;
+ // either a font or a font entry exists
+ union {
+ gfxFont* mFont;
+ gfxFontEntry* mFontEntry;
+ };
+ bool mNeedsBold : 1;
+ bool mFontCreated : 1;
+ bool mLoading : 1;
+ bool mInvalid : 1;
+ bool mCheckForFallbackFaces : 1;
+ };
+
+ // List of font families, either named or generic.
+ // Generic names map to system pref fonts based on language.
+ mozilla::FontFamilyList mFamilyList;
+
+ // Fontlist containing a font entry for each family found. gfxFont objects
+ // are created as needed and userfont loads are initiated when needed.
+ // Code should be careful about addressing this array directly.
+ nsTArray<FamilyFace> mFonts;
+
+ RefPtr<gfxFont> mDefaultFont;
+ gfxFontStyle mStyle;
+
+ gfxFloat mUnderlineOffset;
+ gfxFloat mHyphenWidth;
+ gfxFloat mDevToCssSize;
+
+ RefPtr<gfxUserFontSet> mUserFontSet;
+ uint64_t mCurrGeneration; // track the current user font set generation, rebuild font list if needed
+
+ gfxTextPerfMetrics *mTextPerf;
+
+ // Cache a textrun representing an ellipsis (useful for CSS text-overflow)
+ // at a specific appUnitsPerDevPixel size and orientation
+ RefPtr<gfxTextRun> mCachedEllipsisTextRun;
+
+ // cache the most recent pref font to avoid general pref font lookup
+ RefPtr<gfxFontFamily> mLastPrefFamily;
+ RefPtr<gfxFont> mLastPrefFont;
+ eFontPrefLang mLastPrefLang; // lang group for last pref font
+ eFontPrefLang mPageLang;
+ bool mLastPrefFirstFont; // is this the first font in the list of pref fonts for this lang group?
+
+ bool mSkipDrawing; // hide text while waiting for a font
+ // download to complete (or fallback
+ // timer to fire)
+
+ // xxx - gfxPangoFontGroup skips UpdateUserFonts
+ bool mSkipUpdateUserFonts;
+
+ /**
+ * Textrun creation short-cuts for special cases where we don't need to
+ * call a font shaper to generate glyphs.
+ */
+ already_AddRefed<gfxTextRun>
+ MakeEmptyTextRun(const Parameters *aParams, uint32_t aFlags);
+
+ already_AddRefed<gfxTextRun>
+ MakeSpaceTextRun(const Parameters *aParams, uint32_t aFlags);
+
+ already_AddRefed<gfxTextRun>
+ MakeBlankTextRun(uint32_t aLength, const Parameters *aParams,
+ uint32_t aFlags);
+
+ // Initialize the list of fonts
+ void BuildFontList();
+
+ // Get the font at index i within the fontlist.
+ // Will initiate userfont load if not already loaded.
+ // May return null if userfont not loaded or if font invalid
+ virtual gfxFont* GetFontAt(int32_t i, uint32_t aCh = 0x20);
+
+ // Whether there's a font loading for a given family in the fontlist
+ // for a given character
+ bool FontLoadingForFamily(gfxFontFamily* aFamily, uint32_t aCh) const;
+
+ // will always return a font or force a shutdown
+ gfxFont* GetDefaultFont();
+
+ // Init this font group's font metrics. If there no bad fonts, you don't need to call this.
+ // But if there are one or more bad fonts which have bad underline offset,
+ // you should call this with the *first* bad font.
+ void InitMetricsForBadFont(gfxFont* aBadFont);
+
+ // Set up the textrun glyphs for an entire text run:
+ // find script runs, and then call InitScriptRun for each
+ template<typename T>
+ void InitTextRun(DrawTarget* aDrawTarget,
+ gfxTextRun *aTextRun,
+ const T *aString,
+ uint32_t aLength,
+ gfxMissingFontRecorder *aMFR);
+
+ // InitTextRun helper to handle a single script run, by finding font ranges
+ // and calling each font's InitTextRun() as appropriate
+ template<typename T>
+ void InitScriptRun(DrawTarget* aDrawTarget,
+ gfxTextRun *aTextRun,
+ const T *aString,
+ uint32_t aScriptRunStart,
+ uint32_t aScriptRunEnd,
+ Script aRunScript,
+ gfxMissingFontRecorder *aMFR);
+
+ // Helper for font-matching:
+ // search all faces in a family for a fallback in cases where it's unclear
+ // whether the family might have a font for a given character
+ already_AddRefed<gfxFont>
+ FindFallbackFaceForChar(gfxFontFamily* aFamily, uint32_t aCh,
+ Script aRunScript);
+
+ // helper methods for looking up fonts
+
+ // lookup and add a font with a given name (i.e. *not* a generic!)
+ void AddPlatformFont(const nsAString& aName,
+ nsTArray<gfxFontFamily*>& aFamilyList);
+
+ // do style selection and add entries to list
+ void AddFamilyToFontList(gfxFontFamily* aFamily);
+
+ static nsILanguageAtomService* gLangService;
+};
+
+// A "missing font recorder" is to be used during text-run creation to keep
+// a record of any scripts encountered for which font coverage was lacking;
+// when Flush() is called, it sends a notification that front-end code can use
+// to download fonts on demand (or whatever else it wants to do).
+
+#define GFX_MISSING_FONTS_NOTIFY_PREF "gfx.missing_fonts.notify"
+
+class gfxMissingFontRecorder {
+public:
+ gfxMissingFontRecorder()
+ {
+ MOZ_COUNT_CTOR(gfxMissingFontRecorder);
+ memset(&mMissingFonts, 0, sizeof(mMissingFonts));
+ }
+
+ ~gfxMissingFontRecorder()
+ {
+#ifdef DEBUG
+ for (uint32_t i = 0; i < kNumScriptBitsWords; i++) {
+ NS_ASSERTION(mMissingFonts[i] == 0,
+ "failed to flush the missing-font recorder");
+ }
+#endif
+ MOZ_COUNT_DTOR(gfxMissingFontRecorder);
+ }
+
+ // record this script code in our mMissingFonts bitset
+ void RecordScript(mozilla::unicode::Script aScriptCode)
+ {
+ mMissingFonts[static_cast<uint32_t>(aScriptCode) >> 5] |=
+ (1 << (static_cast<uint32_t>(aScriptCode) & 0x1f));
+ }
+
+ // send a notification of any missing-scripts that have been
+ // recorded, and clear the mMissingFonts set for re-use
+ void Flush();
+
+ // forget any missing-scripts that have been recorded up to now;
+ // called before discarding a recorder we no longer care about
+ void Clear()
+ {
+ memset(&mMissingFonts, 0, sizeof(mMissingFonts));
+ }
+
+private:
+ // Number of 32-bit words needed for the missing-script flags
+ static const uint32_t kNumScriptBitsWords =
+ ((static_cast<int>(mozilla::unicode::Script::NUM_SCRIPT_CODES) + 31) / 32);
+ uint32_t mMissingFonts[kNumScriptBitsWords];
+};
+
+#endif