src/third_party/WebKit/Source/platform/fonts/harfbuzz/HarfBuzzFaceSkia.cpp

   1 /*
   2  * Copyright (c) 2012 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include "config.h"
  32 #include "platform/fonts/harfbuzz/HarfBuzzFace.h"
  33
  34 #include "SkPaint.h"
  35 #include "SkPath.h"
  36 #include "SkPoint.h"
  37 #include "SkRect.h"
  38 #include "SkTypeface.h"
  39 #include "SkUtils.h"
  40 #include "platform/fonts/FontPlatformData.h"
  41 #include "platform/fonts/SimpleFontData.h"
  42 #include "platform/fonts/GlyphBuffer.h"
  43 #include "platform/fonts/harfbuzz/HarfBuzzShaper.h"
  44
  45 #include "hb.h"
  46 #include "wtf/HashMap.h"
  47
  48 namespace WebCore {
  49
  50 // Our implementation of the callbacks which HarfBuzz requires by using Skia
  51 // calls. See the HarfBuzz source for references about what these callbacks do.
  52
  53 struct HarfBuzzFontData {
  54     HarfBuzzFontData(WTF::HashMap<uint32_t, uint16_t>* glyphCacheForFaceCacheEntry)
  55         : m_glyphCacheForFaceCacheEntry(glyphCacheForFaceCacheEntry)
  56     { }
  57     SkPaint m_paint;
  58     WTF::HashMap<uint32_t, uint16_t>* m_glyphCacheForFaceCacheEntry;
  59 };
  60
  61 static hb_position_t SkiaScalarToHarfBuzzPosition(SkScalar value)
  62 {
  63     return SkScalarToFixed(value);
  64 }
  65
  66 static void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
  67 {
  68     ASSERT(codepoint <= 0xFFFF);
  69     paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
  70
  71     SkScalar skWidth;
  72     SkRect skBounds;
  73     uint16_t glyph = codepoint;
  74
  75     paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
  76     if (width)
  77         *width = SkiaScalarToHarfBuzzPosition(skWidth);
  78     if (extents) {
  79         // Invert y-axis because Skia is y-grows-down but we set up HarfBuzz to be y-grows-up.
  80         extents->x_bearing = SkiaScalarToHarfBuzzPosition(skBounds.fLeft);
  81         extents->y_bearing = SkiaScalarToHarfBuzzPosition(-skBounds.fTop);
  82         extents->width = SkiaScalarToHarfBuzzPosition(skBounds.width());
  83         extents->height = SkiaScalarToHarfBuzzPosition(-skBounds.height());
  84     }
  85 }
  86
  87 static hb_bool_t harfBuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
  88 {
  89     HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
  90
  91     WTF::HashMap<uint32_t, uint16_t>::AddResult result = hbFontData->m_glyphCacheForFaceCacheEntry->add(unicode, 0);
  92     if (result.isNewEntry) {
  93         SkPaint* paint = &hbFontData->m_paint;
  94         paint->setTextEncoding(SkPaint::kUTF32_TextEncoding);
  95         uint16_t glyph16;
  96         paint->textToGlyphs(&unicode, sizeof(hb_codepoint_t), &glyph16);
  97         result.storedValue->value = glyph16;
  98         *glyph = glyph16;
  99     }
 100     *glyph = result.storedValue->value;
 101     return !!*glyph;
 102 }
 103
 104 static hb_position_t harfBuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
 105 {
 106     HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
 107     hb_position_t advance = 0;
 108
 109     SkiaGetGlyphWidthAndExtents(&hbFontData->m_paint, glyph, &advance, 0);
 110     return advance;
 111 }
 112
 113 static hb_bool_t harfBuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
 114 {
 115     // Just return true, following the way that HarfBuzz-FreeType
 116     // implementation does.
 117     return true;
 118 }
 119
 120 static hb_bool_t harfBuzzGetGlyphExtents(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_glyph_extents_t* extents, void* userData)
 121 {
 122     HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
 123
 124     SkiaGetGlyphWidthAndExtents(&hbFontData->m_paint, glyph, 0, extents);
 125     return true;
 126 }
 127
 128 static hb_font_funcs_t* harfBuzzSkiaGetFontFuncs()
 129 {
 130     static hb_font_funcs_t* harfBuzzSkiaFontFuncs = 0;
 131
 132     // We don't set callback functions which we can't support.
 133     // HarfBuzz will use the fallback implementation if they aren't set.
 134     if (!harfBuzzSkiaFontFuncs) {
 135         harfBuzzSkiaFontFuncs = hb_font_funcs_create();
 136         hb_font_funcs_set_glyph_func(harfBuzzSkiaFontFuncs, harfBuzzGetGlyph, 0, 0);
 137         hb_font_funcs_set_glyph_h_advance_func(harfBuzzSkiaFontFuncs, harfBuzzGetGlyphHorizontalAdvance, 0, 0);
 138         hb_font_funcs_set_glyph_h_origin_func(harfBuzzSkiaFontFuncs, harfBuzzGetGlyphHorizontalOrigin, 0, 0);
 139         hb_font_funcs_set_glyph_extents_func(harfBuzzSkiaFontFuncs, harfBuzzGetGlyphExtents, 0, 0);
 140         hb_font_funcs_make_immutable(harfBuzzSkiaFontFuncs);
 141     }
 142     return harfBuzzSkiaFontFuncs;
 143 }
 144
 145 static hb_blob_t* harfBuzzSkiaGetTable(hb_face_t* face, hb_tag_t tag, void* userData)
 146 {
 147     SkTypeface* typeface = reinterpret_cast<SkTypeface*>(userData);
 148
 149     const size_t tableSize = typeface->getTableSize(tag);
 150     if (!tableSize)
 151         return 0;
 152
 153     char* buffer = reinterpret_cast<char*>(fastMalloc(tableSize));
 154     if (!buffer)
 155         return 0;
 156     size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
 157     if (tableSize != actualSize) {
 158         fastFree(buffer);
 159         return 0;
 160     }
 161
 162     return hb_blob_create(const_cast<char*>(buffer), tableSize, HB_MEMORY_MODE_WRITABLE, buffer, fastFree);
 163 }
 164
 165 static void destroyHarfBuzzFontData(void* userData)
 166 {
 167     HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(userData);
 168     delete hbFontData;
 169 }
 170
 171 hb_face_t* HarfBuzzFace::createFace()
 172 {
 173     hb_face_t* face = hb_face_create_for_tables(harfBuzzSkiaGetTable, m_platformData->typeface(), 0);
 174     ASSERT(face);
 175     return face;
 176 }
 177
 178 hb_font_t* HarfBuzzFace::createFont()
 179 {
 180     HarfBuzzFontData* hbFontData = new HarfBuzzFontData(m_glyphCacheForFaceCacheEntry);
 181     m_platformData->setupPaint(&hbFontData->m_paint);
 182     hb_font_t* font = hb_font_create(m_face);
 183     hb_font_set_funcs(font, harfBuzzSkiaGetFontFuncs(), hbFontData, destroyHarfBuzzFontData);
 184     float size = m_platformData->size();
 185     int scale = SkiaScalarToHarfBuzzPosition(size);
 186     hb_font_set_scale(font, scale, scale);
 187     hb_font_make_immutable(font);
 188     return font;
 189 }
 190
 191 GlyphBufferAdvance HarfBuzzShaper::createGlyphBufferAdvance(float width, float height)
 192 {
 193     return GlyphBufferAdvance(width, height);
 194 }
 195
 196 } // namespace WebCore