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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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_HARFBUZZSHAPER_H
#define GFX_HARFBUZZSHAPER_H
#include "gfxFont.h"
#include "harfbuzz/hb.h"
#include "nsUnicodeProperties.h"
#include "mozilla/gfx/2D.h"
using namespace mozilla;
class gfxHarfBuzzShaper : public gfxFontShaper {
public:
explicit gfxHarfBuzzShaper(gfxFont *aFont);
virtual ~gfxHarfBuzzShaper();
/*
* For HarfBuzz font callback functions, font_data is a ptr to a
* FontCallbackData struct
*/
struct FontCallbackData {
gfxHarfBuzzShaper* mShaper;
mozilla::gfx::DrawTarget* mDrawTarget;
};
bool Initialize();
virtual bool ShapeText(DrawTarget *aDrawTarget,
const char16_t *aText,
uint32_t aOffset,
uint32_t aLength,
Script aScript,
bool aVertical,
gfxShapedText *aShapedText);
// get a given font table in harfbuzz blob form
hb_blob_t * GetFontTable(hb_tag_t aTag) const;
// map unicode character to glyph ID
hb_codepoint_t GetNominalGlyph(hb_codepoint_t unicode) const;
hb_codepoint_t GetVariationGlyph(hb_codepoint_t unicode,
hb_codepoint_t variation_selector) const;
// get harfbuzz glyph advance, in font design units
hb_position_t GetGlyphHAdvance(hb_codepoint_t glyph) const;
hb_position_t GetGlyphVAdvance(hb_codepoint_t glyph) const;
void GetGlyphVOrigin(hb_codepoint_t aGlyph,
hb_position_t *aX, hb_position_t *aY) const;
// get harfbuzz horizontal advance in 16.16 fixed point format.
static hb_position_t
HBGetGlyphHAdvance(hb_font_t *font, void *font_data,
hb_codepoint_t glyph, void *user_data);
// get harfbuzz vertical advance in 16.16 fixed point format.
static hb_position_t
HBGetGlyphVAdvance(hb_font_t *font, void *font_data,
hb_codepoint_t glyph, void *user_data);
static hb_bool_t
HBGetGlyphVOrigin(hb_font_t *font, void *font_data,
hb_codepoint_t glyph,
hb_position_t *x, hb_position_t *y,
void *user_data);
hb_position_t GetHKerning(uint16_t aFirstGlyph,
uint16_t aSecondGlyph) const;
hb_bool_t GetGlyphExtents(hb_codepoint_t aGlyph,
hb_glyph_extents_t *aExtents) const;
bool UseVerticalPresentationForms() const
{
return mUseVerticalPresentationForms;
}
static hb_script_t
GetHBScriptUsedForShaping(Script aScript) {
// Decide what harfbuzz script code will be used for shaping
hb_script_t hbScript;
if (aScript <= Script::INHERITED) {
// For unresolved "common" or "inherited" runs,
// default to Latin for now.
hbScript = HB_SCRIPT_LATIN;
} else {
hbScript =
hb_script_t(mozilla::unicode::GetScriptTagForCode(aScript));
}
return hbScript;
}
protected:
nsresult SetGlyphsFromRun(DrawTarget *aDrawTarget,
gfxShapedText *aShapedText,
uint32_t aOffset,
uint32_t aLength,
const char16_t *aText,
hb_buffer_t *aBuffer,
bool aVertical);
// retrieve glyph positions, applying advance adjustments and attachments
// returns results in appUnits
nscoord GetGlyphPositions(gfxContext *aContext,
hb_buffer_t *aBuffer,
nsTArray<nsPoint>& aPositions,
uint32_t aAppUnitsPerDevUnit);
bool InitializeVertical();
bool LoadHmtxTable();
struct Glyf { // we only need the bounding-box at the beginning
// of the glyph record, not the actual outline data
AutoSwap_PRInt16 numberOfContours;
AutoSwap_PRInt16 xMin;
AutoSwap_PRInt16 yMin;
AutoSwap_PRInt16 xMax;
AutoSwap_PRInt16 yMax;
};
const Glyf *FindGlyf(hb_codepoint_t aGlyph, bool *aEmptyGlyf) const;
// harfbuzz face object: we acquire a reference from the font entry
// on shaper creation, and release it in our destructor
hb_face_t *mHBFace;
// size-specific font object, owned by the gfxHarfBuzzShaper
hb_font_t *mHBFont;
FontCallbackData mCallbackData;
// Following table references etc are declared "mutable" because the
// harfbuzz callback functions take a const ptr to the shaper, but
// wish to cache tables here to avoid repeatedly looking them up
// in the font.
// Old-style TrueType kern table, if we're not doing GPOS kerning
mutable hb_blob_t *mKernTable;
// Cached copy of the hmtx table.
mutable hb_blob_t *mHmtxTable;
// For vertical fonts, cached vmtx and VORG table, if present.
mutable hb_blob_t *mVmtxTable;
mutable hb_blob_t *mVORGTable;
// And for vertical TrueType (not CFF) fonts that have vmtx,
// we also use loca and glyf to get glyph bounding boxes.
mutable hb_blob_t *mLocaTable;
mutable hb_blob_t *mGlyfTable;
// Cached pointer to cmap subtable to be used for char-to-glyph mapping.
// This comes from GetFontTablePtr; if it is non-null, our destructor
// must call ReleaseFontTablePtr to avoid permanently caching the table.
mutable hb_blob_t *mCmapTable;
mutable int32_t mCmapFormat;
mutable uint32_t mSubtableOffset;
mutable uint32_t mUVSTableOffset;
// Cached copy of numLongMetrics field from the hhea table,
// for use when looking up glyph metrics; initialized to 0 by the
// constructor so we can tell it hasn't been set yet.
// This is a signed value so that we can use -1 to indicate
// an error (if the hhea table was not available).
mutable int32_t mNumLongHMetrics;
// Similarly for vhea if it's a vertical font.
mutable int32_t mNumLongVMetrics;
// Whether the font implements GetGlyph, or we should read tables
// directly
bool mUseFontGetGlyph;
// Whether the font implements GetGlyphWidth, or we should read tables
// directly to get ideal widths
bool mUseFontGlyphWidths;
bool mInitialized;
bool mVerticalInitialized;
// Whether to use vertical presentation forms for CJK characters
// when available (only set if the 'vert' feature is not available).
bool mUseVerticalPresentationForms;
// these are set from the FindGlyf callback on first use of the glyf data
mutable bool mLoadedLocaGlyf;
mutable bool mLocaLongOffsets;
};
#endif /* GFX_HARFBUZZSHAPER_H */
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