1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/ports/SkHarfBuzzFont.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,182 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2009 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#include "SkHarfBuzzFont.h"
1.14 +#include "SkFontHost.h"
1.15 +#include "SkPaint.h"
1.16 +#include "SkPath.h"
1.17 +
1.18 +// HB_Fixed is a 26.6 fixed point format.
1.19 +static inline HB_Fixed SkScalarToHarfbuzzFixed(SkScalar value) {
1.20 + return static_cast<HB_Fixed>(value * 64);
1.21 +}
1.22 +
1.23 +static HB_Bool stringToGlyphs(HB_Font hbFont, const HB_UChar16* characters,
1.24 + hb_uint32 length, HB_Glyph* glyphs,
1.25 + hb_uint32* glyphsSize, HB_Bool isRTL) {
1.26 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.27 + SkPaint paint;
1.28 +
1.29 + paint.setTypeface(font->getTypeface());
1.30 + paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
1.31 + int numGlyphs = paint.textToGlyphs(characters, length * sizeof(uint16_t),
1.32 + reinterpret_cast<uint16_t*>(glyphs));
1.33 +
1.34 + // HB_Glyph is 32-bit, but Skia outputs only 16-bit numbers. So our
1.35 + // |glyphs| array needs to be converted.
1.36 + for (int i = numGlyphs - 1; i >= 0; --i) {
1.37 + uint16_t value;
1.38 + // We use a memcpy to avoid breaking strict aliasing rules.
1.39 + memcpy(&value, reinterpret_cast<char*>(glyphs) + sizeof(uint16_t) * i, sizeof(uint16_t));
1.40 + glyphs[i] = value;
1.41 + }
1.42 +
1.43 + *glyphsSize = numGlyphs;
1.44 + return 1;
1.45 +}
1.46 +
1.47 +static void glyphsToAdvances(HB_Font hbFont, const HB_Glyph* glyphs,
1.48 + hb_uint32 numGlyphs, HB_Fixed* advances, int flags) {
1.49 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.50 + SkPaint paint;
1.51 +
1.52 + font->setupPaint(&paint);
1.53 + paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
1.54 +
1.55 + SkAutoMalloc storage(numGlyphs * (sizeof(SkScalar) + sizeof(uint16_t)));
1.56 + SkScalar* scalarWidths = reinterpret_cast<SkScalar*>(storage.get());
1.57 + uint16_t* glyphs16 = reinterpret_cast<uint16_t*>(scalarWidths + numGlyphs);
1.58 +
1.59 + // convert HB 32bit glyphs to skia's 16bit
1.60 + for (hb_uint32 i = 0; i < numGlyphs; ++i) {
1.61 + glyphs16[i] = SkToU16(glyphs[i]);
1.62 + }
1.63 + paint.getTextWidths(glyphs16, numGlyphs * sizeof(uint16_t), scalarWidths);
1.64 +
1.65 + for (hb_uint32 i = 0; i < numGlyphs; ++i) {
1.66 + advances[i] = SkScalarToHarfbuzzFixed(scalarWidths[i]);
1.67 + }
1.68 +}
1.69 +
1.70 +static HB_Bool canRender(HB_Font hbFont, const HB_UChar16* characters,
1.71 + hb_uint32 length) {
1.72 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.73 + SkPaint paint;
1.74 +
1.75 + paint.setTypeface(font->getTypeface());
1.76 + paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
1.77 + return paint.containsText(characters, length * sizeof(uint16_t));
1.78 +}
1.79 +
1.80 +static HB_Error getOutlinePoint(HB_Font hbFont, HB_Glyph glyph, int flags,
1.81 + hb_uint32 index, HB_Fixed* xPos, HB_Fixed* yPos,
1.82 + hb_uint32* resultingNumPoints) {
1.83 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.84 + SkPaint paint;
1.85 +
1.86 + font->setupPaint(&paint);
1.87 + paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
1.88 + if (flags & HB_ShaperFlag_UseDesignMetrics) {
1.89 + paint.setHinting(SkPaint::kNo_Hinting);
1.90 + }
1.91 +
1.92 + SkPath path;
1.93 + uint16_t glyph16 = SkToU16(glyph);
1.94 + paint.getTextPath(&glyph16, sizeof(glyph16), 0, 0, &path);
1.95 + int numPoints = path.countPoints();
1.96 + if (index >= numPoints) {
1.97 + return HB_Err_Invalid_SubTable;
1.98 + }
1.99 +
1.100 + SkPoint pt = path.getPoint(index);
1.101 + *xPos = SkScalarToHarfbuzzFixed(pt.fX);
1.102 + *yPos = SkScalarToHarfbuzzFixed(pt.fY);
1.103 + *resultingNumPoints = numPoints;
1.104 +
1.105 + return HB_Err_Ok;
1.106 +}
1.107 +
1.108 +static void getGlyphMetrics(HB_Font hbFont, HB_Glyph glyph,
1.109 + HB_GlyphMetrics* metrics) {
1.110 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.111 + SkPaint paint;
1.112 +
1.113 + font->setupPaint(&paint);
1.114 + paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
1.115 +
1.116 + SkScalar width;
1.117 + SkRect bounds;
1.118 + uint16_t glyph16 = SkToU16(glyph);
1.119 + paint.getTextWidths(&glyph16, sizeof(glyph16), &width, &bounds);
1.120 +
1.121 + metrics->x = SkScalarToHarfbuzzFixed(bounds.fLeft);
1.122 + metrics->y = SkScalarToHarfbuzzFixed(bounds.fTop);
1.123 + metrics->width = SkScalarToHarfbuzzFixed(bounds.width());
1.124 + metrics->height = SkScalarToHarfbuzzFixed(bounds.height());
1.125 +
1.126 + metrics->xOffset = SkScalarToHarfbuzzFixed(width);
1.127 + // We can't actually get the |y| correct because Skia doesn't export
1.128 + // the vertical advance. However, nor we do ever render vertical text at
1.129 + // the moment so it's unimportant.
1.130 + metrics->yOffset = 0;
1.131 +}
1.132 +
1.133 +static HB_Fixed getFontMetric(HB_Font hbFont, HB_FontMetric metric)
1.134 +{
1.135 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData);
1.136 + SkPaint paint;
1.137 + SkPaint::FontMetrics skiaMetrics;
1.138 +
1.139 + font->setupPaint(&paint);
1.140 + paint.getFontMetrics(&skiaMetrics);
1.141 +
1.142 + switch (metric) {
1.143 + case HB_FontAscent:
1.144 + return SkScalarToHarfbuzzFixed(-skiaMetrics.fAscent);
1.145 + default:
1.146 + SkDebugf("--- unknown harfbuzz metric enum %d\n", metric);
1.147 + return 0;
1.148 + }
1.149 +}
1.150 +
1.151 +static HB_FontClass gSkHarfBuzzFontClass = {
1.152 + stringToGlyphs,
1.153 + glyphsToAdvances,
1.154 + canRender,
1.155 + getOutlinePoint,
1.156 + getGlyphMetrics,
1.157 + getFontMetric,
1.158 +};
1.159 +
1.160 +const HB_FontClass& SkHarfBuzzFont::GetFontClass() {
1.161 + return gSkHarfBuzzFontClass;
1.162 +}
1.163 +
1.164 +HB_Error SkHarfBuzzFont::GetFontTableFunc(void* voidface, const HB_Tag tag,
1.165 + HB_Byte* buffer, HB_UInt* len) {
1.166 + SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(voidface);
1.167 + SkTypeface* typeface = font->getTypeface();
1.168 +
1.169 + const size_t tableSize = typeface->getTableSize(tag);
1.170 + if (!tableSize) {
1.171 + return HB_Err_Invalid_Argument;
1.172 + }
1.173 + // If Harfbuzz specified a NULL buffer then it's asking for the size.
1.174 + if (!buffer) {
1.175 + *len = tableSize;
1.176 + return HB_Err_Ok;
1.177 + }
1.178 +
1.179 + if (*len < tableSize) {
1.180 + // is this right, or should we just copy less than the full table?
1.181 + return HB_Err_Invalid_Argument;
1.182 + }
1.183 + typeface->getTableData(tag, 0, tableSize, buffer);
1.184 + return HB_Err_Ok;
1.185 +}
