The Tor Browser: gfx/thebes/gfxHarfBuzzShaper.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #ifndef GFX_HARFBUZZSHAPER_H

     7 #define GFX_HARFBUZZSHAPER_H

     9 #include "gfxFont.h"

    11 #include "harfbuzz/hb.h"

    13 class gfxHarfBuzzShaper : public gfxFontShaper {

    14 public:

    15     gfxHarfBuzzShaper(gfxFont *aFont);

    16     virtual ~gfxHarfBuzzShaper();

    18     /*

    19      * For HarfBuzz font callback functions, font_data is a ptr to a

    20      * FontCallbackData struct

    21      */

    22     struct FontCallbackData {

    23         gfxHarfBuzzShaper *mShaper;

    24         gfxContext        *mContext;

    25     };

    27     bool Initialize();

    28     virtual bool ShapeText(gfxContext      *aContext,

    29                            const char16_t *aText,

    30                            uint32_t         aOffset,

    31                            uint32_t         aLength,

    32                            int32_t          aScript,

    33                            gfxShapedText   *aShapedText);

    35     // get a given font table in harfbuzz blob form

    36     hb_blob_t * GetFontTable(hb_tag_t aTag) const;

    38     // map unicode character to glyph ID

    39     hb_codepoint_t GetGlyph(hb_codepoint_t unicode,

    40                             hb_codepoint_t variation_selector) const;

    42     // get harfbuzz glyph advance, in font design units

    43     hb_position_t GetGlyphHAdvance(gfxContext *aContext,

    44                                    hb_codepoint_t glyph) const;

    46     // get harfbuzz horizontal advance in 16.16 fixed point format.

    47     static hb_position_t

    48     HBGetGlyphHAdvance(hb_font_t *font, void *font_data,

    49                        hb_codepoint_t glyph, void *user_data);

    51     hb_position_t GetHKerning(uint16_t aFirstGlyph,

    52                               uint16_t aSecondGlyph) const;

    54 protected:

    55     nsresult SetGlyphsFromRun(gfxContext      *aContext,

    56                               gfxShapedText   *aShapedText,

    57                               uint32_t         aOffset,

    58                               uint32_t         aLength,

    59                               const char16_t *aText,

    60                               hb_buffer_t     *aBuffer);

    62     // retrieve glyph positions, applying advance adjustments and attachments

    63     // returns results in appUnits

    64     nscoord GetGlyphPositions(gfxContext *aContext,

    65                               hb_buffer_t *aBuffer,

    66                               nsTArray<nsPoint>& aPositions,

    67                               uint32_t aAppUnitsPerDevUnit);

    69     // harfbuzz face object: we acquire a reference from the font entry

    70     // on shaper creation, and release it in our destructor

    71     hb_face_t         *mHBFace;

    73     // size-specific font object, owned by the gfxHarfBuzzShaper

    74     hb_font_t         *mHBFont;

    76     FontCallbackData   mCallbackData;

    78     // Following table references etc are declared "mutable" because the

    79     // harfbuzz callback functions take a const ptr to the shaper, but

    80     // wish to cache tables here to avoid repeatedly looking them up

    81     // in the font.

    83     // Old-style TrueType kern table, if we're not doing GPOS kerning

    84     mutable hb_blob_t *mKernTable;

    86     // Cached copy of the hmtx table and numLongMetrics field from hhea,

    87     // for use when looking up glyph metrics; initialized to 0 by the

    88     // constructor so we can tell it hasn't been set yet.

    89     // This is a signed value so that we can use -1 to indicate

    90     // an error (if the hhea table was not available).

    91     mutable hb_blob_t *mHmtxTable;

    92     mutable int32_t    mNumLongMetrics;

    94     // Cached pointer to cmap subtable to be used for char-to-glyph mapping.

    95     // This comes from GetFontTablePtr; if it is non-null, our destructor

    96     // must call ReleaseFontTablePtr to avoid permanently caching the table.

    97     mutable hb_blob_t *mCmapTable;

    98     mutable int32_t    mCmapFormat;

    99     mutable uint32_t   mSubtableOffset;

   100     mutable uint32_t   mUVSTableOffset;

   102     // Whether the font implements GetGlyph, or we should read tables

   103     // directly

   104     bool mUseFontGetGlyph;

   105     // Whether the font implements GetGlyphWidth, or we should read tables

   106     // directly to get ideal widths

   107     bool mUseFontGlyphWidths;

   109     bool mInitialized;

   110 };

   112 #endif /* GFX_HARFBUZZSHAPER_H */

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