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113 lines
4.2 KiB
C++
113 lines
4.2 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef GFX_HARFBUZZSHAPER_H
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#define GFX_HARFBUZZSHAPER_H
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#include "gfxFont.h"
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#include "harfbuzz/hb.h"
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class gfxHarfBuzzShaper : public gfxFontShaper {
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public:
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gfxHarfBuzzShaper(gfxFont *aFont);
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virtual ~gfxHarfBuzzShaper();
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/*
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* For HarfBuzz font callback functions, font_data is a ptr to a
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* FontCallbackData struct
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*/
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struct FontCallbackData {
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gfxHarfBuzzShaper *mShaper;
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gfxContext *mContext;
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};
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bool Initialize();
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virtual bool ShapeText(gfxContext *aContext,
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const char16_t *aText,
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uint32_t aOffset,
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uint32_t aLength,
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int32_t aScript,
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gfxShapedText *aShapedText);
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// get a given font table in harfbuzz blob form
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hb_blob_t * GetFontTable(hb_tag_t aTag) const;
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// map unicode character to glyph ID
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hb_codepoint_t GetGlyph(hb_codepoint_t unicode,
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hb_codepoint_t variation_selector) const;
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// get harfbuzz glyph advance, in font design units
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hb_position_t GetGlyphHAdvance(gfxContext *aContext,
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hb_codepoint_t glyph) const;
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// get harfbuzz horizontal advance in 16.16 fixed point format.
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static hb_position_t
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HBGetGlyphHAdvance(hb_font_t *font, void *font_data,
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hb_codepoint_t glyph, void *user_data);
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hb_position_t GetHKerning(uint16_t aFirstGlyph,
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uint16_t aSecondGlyph) const;
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protected:
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nsresult SetGlyphsFromRun(gfxContext *aContext,
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gfxShapedText *aShapedText,
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uint32_t aOffset,
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uint32_t aLength,
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const char16_t *aText,
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hb_buffer_t *aBuffer);
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// retrieve glyph positions, applying advance adjustments and attachments
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// returns results in appUnits
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nscoord GetGlyphPositions(gfxContext *aContext,
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hb_buffer_t *aBuffer,
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nsTArray<nsPoint>& aPositions,
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uint32_t aAppUnitsPerDevUnit);
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// harfbuzz face object: we acquire a reference from the font entry
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// on shaper creation, and release it in our destructor
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hb_face_t *mHBFace;
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// size-specific font object, owned by the gfxHarfBuzzShaper
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hb_font_t *mHBFont;
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FontCallbackData mCallbackData;
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// Following table references etc are declared "mutable" because the
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// harfbuzz callback functions take a const ptr to the shaper, but
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// wish to cache tables here to avoid repeatedly looking them up
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// in the font.
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// Old-style TrueType kern table, if we're not doing GPOS kerning
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mutable hb_blob_t *mKernTable;
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// Cached copy of the hmtx table and numLongMetrics field from hhea,
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// for use when looking up glyph metrics; initialized to 0 by the
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// constructor so we can tell it hasn't been set yet.
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// This is a signed value so that we can use -1 to indicate
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// an error (if the hhea table was not available).
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mutable hb_blob_t *mHmtxTable;
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mutable int32_t mNumLongMetrics;
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// Cached pointer to cmap subtable to be used for char-to-glyph mapping.
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// This comes from GetFontTablePtr; if it is non-null, our destructor
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// must call ReleaseFontTablePtr to avoid permanently caching the table.
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mutable hb_blob_t *mCmapTable;
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mutable int32_t mCmapFormat;
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mutable uint32_t mSubtableOffset;
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mutable uint32_t mUVSTableOffset;
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// Whether the font implements GetGlyph, or we should read tables
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// directly
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bool mUseFontGetGlyph;
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// Whether the font implements GetGlyphWidth, or we should read tables
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// directly to get ideal widths
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bool mUseFontGlyphWidths;
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bool mInitialized;
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};
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#endif /* GFX_HARFBUZZSHAPER_H */
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