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