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gecko-dev/gfx/thebes/gfxTextRun.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=4 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef GFX_TEXTRUN_H
#define GFX_TEXTRUN_H
#include <stdint.h>
#include "gfxTypes.h"
#include "gfxPoint.h"
#include "gfxFont.h"
#include "gfxFontConstants.h"
#include "gfxSkipChars.h"
#include "gfxPlatform.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/RefPtr.h"
#include "nsPoint.h"
#include "nsString.h"
#include "nsTArray.h"
#include "nsTextFrameUtils.h"
#include "DrawMode.h"
#include "harfbuzz/hb.h"
#include "nsUnicodeScriptCodes.h"
#include "nsColor.h"
#include "X11UndefineNone.h"
#ifdef DEBUG
# include <stdio.h>
#endif
class gfxContext;
class gfxFontGroup;
class gfxUserFontEntry;
class gfxUserFontSet;
class nsAtom;
class nsLanguageAtomService;
class gfxMissingFontRecorder;
namespace mozilla {
class SVGContextPaint;
enum class StyleHyphens : uint8_t;
}; // namespace mozilla
/**
* 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();
}
bool CharIsFormattingControl(uint32_t aPos) const {
MOZ_ASSERT(aPos < GetLength());
return mCharacterGlyphs[aPos].CharIsFormattingControl();
}
// 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);
enum class HyphenType : uint8_t {
// Code in BreakAndMeasureText depends on the ordering of these values!
None,
Explicit,
Soft,
AutoWithManualInSameWord,
AutoWithoutManualInSameWord
};
struct HyphenationState {
uint32_t mostRecentBoundary = 0;
bool hasManualHyphen = false;
bool hasExplicitHyphen = false;
bool hasAutoHyphen = false;
};
/**
* 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,
HyphenType* aBreakBefore) const = 0;
// Returns the provider's hyphenation setting, so callers can decide
// whether it is necessary to call GetHyphenationBreaks.
// Result is an StyleHyphens value.
virtual mozilla::StyleHyphens GetHyphensOption() const = 0;
// Returns the extra width that will be consumed by a hyphen. This should
// be constant for a given textrun.
virtual gfxFloat GetHyphenWidth() const = 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) const = 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() const = 0;
// Return the appUnitsPerDevUnit value to be used when measuring.
// Only called if the hyphen width is requested.
virtual uint32_t GetAppUnitsPerDevUnit() const = 0;
};
struct MOZ_STACK_CLASS 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, mozilla::gfx::Point 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, mozilla::gfx::Point 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);
}
/**
* Computes the minimum advance width for a substring assuming line
* breaking is allowed everywhere.
*/
gfxFloat GetMinAdvanceWidth(Range aRange);
/**
* 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
};
void ClassifyAutoHyphenations(uint32_t aStart, Range aRange,
nsTArray<HyphenType>& aHyphenBuffer,
HyphenationState* aWordState);
/**
* Finds the longest substring that will fit into the given width.
* Uses GetHyphenationBreaks and GetSpacing from aProvider.
* Guarantees the following:
* -- 0 <= result <= aMaxLength
* -- result is the maximal value of N such that either
* N < aMaxLength && line break at N &&
* GetAdvanceWidth(Range(aStart, N), aProvider) <= aWidth
* OR N < aMaxLength && hyphen break at N &&
* GetAdvanceWidth(Range(aStart, N), aProvider) +
* GetHyphenWidth() <= aWidth
* OR N == aMaxLength &&
* GetAdvanceWidth(Range(aStart, N), aProvider) <= aWidth
* where GetAdvanceWidth assumes the effect of
* SetLineBreaks(Range(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(Range(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 aHangWhitespace true if we allow whitespace to overflow the
* container at a soft-wrap
* @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(Range(aStart, N), aProvider) <= aWidth
* OR N < aMaxLength && hyphen break at N &&
* GetAdvanceWidth(Range(aStart, N), aProvider) +
* GetHyphenWidth() <= aWidth
* or UINT32_MAX if no such N exists, where GetAdvanceWidth assumes
* the effect of
* SetLineBreaks(Range(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(nsTextFrameUtils::Flags aFlags) { mFlags2 |= aFlags; }
void ClearFlagBits(nsTextFrameUtils::Flags aFlags) { mFlags2 &= ~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, mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2);
// The text is divided into GlyphRuns as necessary. (In the vast majority
// of cases, a gfxTextRun contains just a single GlyphRun.)
struct GlyphRun {
RefPtr<gfxFont> mFont; // never null in a valid GlyphRun
uint32_t mCharacterOffset; // into original UTF16 string
mozilla::gfx::ShapedTextFlags
mOrientation; // gfxTextRunFactory::TEXT_ORIENT_* value
gfxTextRange::MatchType mMatchType;
};
class MOZ_STACK_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, gfxTextRange::MatchType aMatchType,
uint32_t aStartCharIndex, bool aForceNewRun,
mozilla::gfx::ShapedTextFlags aOrientation);
void ResetGlyphRuns() {
if (mHasGlyphRunArray) {
MOZ_ASSERT(mGlyphRunArray.Length() > 1);
// Discard all but the first GlyphRun...
mGlyphRunArray.TruncateLength(1);
// ...and then convert to the single-run representation.
ConvertFromGlyphRunArray();
}
// Clear out the one remaining GlyphRun.
mSingleGlyphRun.mFont = nullptr;
}
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,
mozilla::gfx::ShapedTextFlags 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,
mozilla::gfx::ShapedTextFlags 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();
}
void SetIsFormattingControl(uint32_t aIndex) {
EnsureComplexGlyph(aIndex).SetIsFormattingControl();
}
/**
* 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 {
if (mHasGlyphRunArray) {
*aNumGlyphRuns = mGlyphRunArray.Length();
return mGlyphRunArray.Elements();
} else {
*aNumGlyphRuns = mSingleGlyphRun.mFont ? 1 : 0;
return &mSingleGlyphRun;
}
}
// 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;
nsTextFrameUtils::Flags GetFlags2() const { return mFlags2; }
// Get the size, if it hasn't already been gotten, marking as it goes.
size_t MaybeSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) {
if (mFlags2 & nsTextFrameUtils::Flags::TEXT_RUN_SIZE_ACCOUNTED) {
return 0;
}
mFlags2 |= nsTextFrameUtils::Flags::TEXT_RUN_SIZE_ACCOUNTED;
return SizeOfIncludingThis(aMallocSizeOf);
}
void ResetSizeOfAccountingFlags() {
mFlags2 &= ~nsTextFrameUtils::Flags::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 : uint8_t {
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, mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2);
/**
* 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,
mozilla::gfx::Point* aPt,
PropertyProvider* aProvider,
TextRunDrawParams& aParams,
mozilla::gfx::ShapedTextFlags 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,
mozilla::gfx::ShapedTextFlags aOrientation, Metrics* aMetrics) const;
// **** measurement helper ****
void AccumulateMetricsForRun(gfxFont* aFont, Range aRange,
gfxFont::BoundingBoxType aBoundingBoxType,
DrawTarget* aRefDrawTarget,
PropertyProvider* aProvider, Range aSpacingRange,
mozilla::gfx::ShapedTextFlags aOrientation,
Metrics* aMetrics) const;
// **** drawing helper ****
void DrawGlyphs(gfxFont* aFont, Range aRange, mozilla::gfx::Point* aPt,
PropertyProvider* aProvider, Range aSpacingRange,
TextRunDrawParams& aParams,
mozilla::gfx::ShapedTextFlags aOrientation) const;
// The textrun holds either a single GlyphRun -or- an array;
// the flag mHasGlyphRunArray tells us which is present.
union {
GlyphRun mSingleGlyphRun;
nsTArray<GlyphRun> mGlyphRunArray;
};
void ConvertToGlyphRunArray() {
MOZ_ASSERT(!mHasGlyphRunArray && mSingleGlyphRun.mFont);
GlyphRun tmp = std::move(mSingleGlyphRun);
mSingleGlyphRun.~GlyphRun();
new (&mGlyphRunArray) nsTArray<GlyphRun>(2);
mGlyphRunArray.AppendElement(std::move(tmp));
mHasGlyphRunArray = true;
}
void ConvertFromGlyphRunArray() {
MOZ_ASSERT(mHasGlyphRunArray && mGlyphRunArray.Length() == 1);
GlyphRun tmp = std::move(mGlyphRunArray[0]);
mGlyphRunArray.~nsTArray<GlyphRun>();
new (&mSingleGlyphRun) GlyphRun(std::move(tmp));
mHasGlyphRunArray = false;
}
void* mUserData;
// mFontGroup is usually a strong reference, but refcounting is managed
// manually because it may be explicitly released by ReleaseFontGroup()
// in the case where the font group actually owns the textrun.
gfxFontGroup* MOZ_OWNING_REF mFontGroup;
gfxSkipChars mSkipChars;
nsTextFrameUtils::Flags
mFlags2; // additional flags (see also gfxShapedText::mFlags)
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
bool mHasGlyphRunArray; // whether we're using an array or
// just storing a single glyphrun
// shaping state for handling variant fallback features
// such as subscript/superscript variant glyphs
ShapingState mShapingState;
};
class gfxFontGroup final : public gfxTextRunFactory {
public:
typedef mozilla::unicode::Script Script;
typedef gfxShapedText::CompressedGlyph CompressedGlyph;
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.
// aGeneric: if non-null, returns the CSS generic type that was mapped to
// this font
gfxFont* GetFirstValidFont(uint32_t aCh = 0x20,
mozilla::FontFamilyType* aGeneric = nullptr);
// 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; }
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.
*/
already_AddRefed<gfxTextRun> MakeTextRun(const char16_t* aString,
uint32_t aLength,
const Parameters* aParams,
mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2,
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.
*/
already_AddRefed<gfxTextRun> MakeTextRun(const uint8_t* aString,
uint32_t aLength,
const Parameters* aParams,
mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2,
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,
mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2,
gfxMissingFontRecorder* aMFR) {
gfxTextRunFactory::Parameters params = {
aRefDrawTarget, nullptr, nullptr, nullptr, 0, aAppUnitsPerDevUnit};
return MakeTextRun(aString, aLength, &params, aFlags, aFlags2, aMFR);
}
// Get the (possibly-cached) width of the hyphen character.
gfxFloat GetHyphenWidth(const 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 };
gfxFloat GetUnderlineOffset();
gfxFont* FindFontForChar(uint32_t ch, uint32_t prevCh, uint32_t aNextCh,
Script aRunScript, gfxFont* aPrevMatchedFont,
gfxTextRange::MatchType* 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.
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, mozilla::gfx::ShapedTextFlags aFlags,
LazyReferenceDrawTargetGetter& aRefDrawTargetGetter);
protected:
// search through pref fonts for a character, return nullptr if no matching
// pref font
gfxFont* WhichPrefFontSupportsChar(uint32_t aCh, uint32_t aNextCh);
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,
mozilla::gfx::ShapedTextFlags aOrientation);
class FamilyFace {
public:
FamilyFace()
: mFamily(nullptr),
mFontEntry(nullptr),
mGeneric(mozilla::eFamily_none),
mFontCreated(false),
mLoading(false),
mInvalid(false),
mCheckForFallbackFaces(false) {}
FamilyFace(gfxFontFamily* aFamily, gfxFont* aFont,
mozilla::FontFamilyType aGeneric)
: mFamily(aFamily),
mGeneric(aGeneric),
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,
mozilla::FontFamilyType aGeneric)
: mFamily(aFamily),
mGeneric(aGeneric),
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),
mGeneric(aOtherFamilyFace.mGeneric),
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;
mGeneric = aOther.mGeneric;
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;
}
mozilla::FontFamilyType Generic() const { return mGeneric; }
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 {
// Whichever of these fields is actually present will be a strong
// reference, with refcounting handled manually.
gfxFont* MOZ_OWNING_REF mFont;
gfxFontEntry* MOZ_OWNING_REF mFontEntry;
};
mozilla::FontFamilyType mGeneric;
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)
/**
* 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, mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2);
already_AddRefed<gfxTextRun> MakeSpaceTextRun(
const Parameters* aParams, mozilla::gfx::ShapedTextFlags aFlags,
nsTextFrameUtils::Flags aFlags2);
already_AddRefed<gfxTextRun> MakeBlankTextRun(
uint32_t aLength, const Parameters* aParams,
mozilla::gfx::ShapedTextFlags aFlags, nsTextFrameUtils::Flags aFlags2);
// 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
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
gfxFont* FindFallbackFaceForChar(gfxFontFamily* aFamily, uint32_t aCh);
// helper methods for looking up fonts
// lookup and add a font with a given name (i.e. *not* a generic!)
void AddPlatformFont(const nsACString& aName,
nsTArray<FamilyAndGeneric>& aFamilyList);
// do style selection and add entries to list
void AddFamilyToFontList(gfxFontFamily* aFamily,
mozilla::FontFamilyType aGeneric);
};
// 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
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