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      1 /*
      2  * Copyright (c) 2011 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
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     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 "core/platform/graphics/Font.h"
     33 
     34 #include "core/platform/LayoutTestSupport.h"
     35 #include "core/platform/graphics/FontSmoothingMode.h"
     36 #include "core/platform/graphics/GlyphBuffer.h"
     37 #include "core/platform/graphics/GraphicsContext.h"
     38 #include "core/platform/graphics/SimpleFontData.h"
     39 
     40 #include "third_party/skia/include/core/SkCanvas.h"
     41 #include "third_party/skia/include/core/SkPaint.h"
     42 #include "third_party/skia/include/core/SkTypeface.h"
     43 #include "third_party/skia/include/ports/SkTypeface_mac.h"
     44 
     45 namespace WebCore {
     46 
     47 bool Font::canReturnFallbackFontsForComplexText()
     48 {
     49     return true;
     50 }
     51 
     52 bool Font::canExpandAroundIdeographsInComplexText()
     53 {
     54     return true;
     55 }
     56 
     57 static void setupPaint(SkPaint* paint, const SimpleFontData* fontData, const Font* font, bool shouldAntialias, bool shouldSmoothFonts)
     58 {
     59     const FontPlatformData& platformData = fontData->platformData();
     60     const float textSize = platformData.m_size >= 0 ? platformData.m_size : 12;
     61 
     62     paint->setAntiAlias(shouldAntialias);
     63     paint->setEmbeddedBitmapText(false);
     64     paint->setTextSize(SkFloatToScalar(textSize));
     65     paint->setVerticalText(platformData.orientation() == Vertical);
     66     SkTypeface* typeface = SkCreateTypefaceFromCTFont(platformData.ctFont());
     67     SkAutoUnref autoUnref(typeface);
     68     paint->setTypeface(typeface);
     69     paint->setFakeBoldText(platformData.m_syntheticBold);
     70     paint->setTextSkewX(platformData.m_syntheticOblique ? -SK_Scalar1 / 4 : 0);
     71     paint->setAutohinted(false); // freetype specific
     72     paint->setLCDRenderText(shouldSmoothFonts);
     73     paint->setSubpixelText(true);
     74 
     75 #if OS(DARWIN)
     76     // When using CoreGraphics, disable hinting when webkit-font-smoothing:antialiased is used.
     77     // See crbug.com/152304
     78     if (font->fontDescription().fontSmoothing() == Antialiased)
     79         paint->setHinting(SkPaint::kNo_Hinting);
     80 #endif
     81 
     82     if (font->fontDescription().textRenderingMode() == GeometricPrecision)
     83         paint->setHinting(SkPaint::kNo_Hinting);
     84 }
     85 
     86 // TODO: This needs to be split into helper functions to better scope the
     87 // inputs/outputs, and reduce duplicate code.
     88 // This issue is tracked in https://bugs.webkit.org/show_bug.cgi?id=62989
     89 void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
     90                       const GlyphBuffer& glyphBuffer,  int from, int numGlyphs,
     91                       const FloatPoint& point, const FloatRect& textRect) const {
     92     COMPILE_ASSERT(sizeof(GlyphBufferGlyph) == sizeof(uint16_t), GlyphBufferGlyphSize_equals_uint16_t);
     93 
     94     bool shouldSmoothFonts = true;
     95     bool shouldAntialias = true;
     96 
     97     switch (fontDescription().fontSmoothing()) {
     98     case Antialiased:
     99         shouldSmoothFonts = false;
    100         break;
    101     case SubpixelAntialiased:
    102         break;
    103     case NoSmoothing:
    104         shouldAntialias = false;
    105         shouldSmoothFonts = false;
    106         break;
    107     case AutoSmoothing:
    108         // For the AutoSmooth case, don't do anything! Keep the default settings.
    109         break;
    110     }
    111 
    112     if (!shouldUseSmoothing() || isRunningLayoutTest()) {
    113         shouldSmoothFonts = false;
    114         shouldAntialias = false;
    115     }
    116 
    117     const GlyphBufferGlyph* glyphs = glyphBuffer.glyphs(from);
    118     SkScalar x = SkFloatToScalar(point.x());
    119     SkScalar y = SkFloatToScalar(point.y());
    120 
    121     if (font->platformData().orientation() == Vertical)
    122         y += SkFloatToScalar(font->fontMetrics().floatAscent(IdeographicBaseline) - font->fontMetrics().floatAscent());
    123     // FIXME: text rendering speed:
    124     // Android has code in their WebCore fork to special case when the
    125     // GlyphBuffer has no advances other than the defaults. In that case the
    126     // text drawing can proceed faster. However, it's unclear when those
    127     // patches may be upstreamed to WebKit so we always use the slower path
    128     // here.
    129     const GlyphBufferAdvance* adv = glyphBuffer.advances(from);
    130     SkAutoSTMalloc<32, SkPoint> storage(numGlyphs);
    131     SkPoint* pos = storage.get();
    132 
    133     for (int i = 0; i < numGlyphs; i++) {
    134         pos[i].set(x, y);
    135         x += SkFloatToScalar(adv[i].width());
    136         y += SkFloatToScalar(adv[i].height());
    137     }
    138 
    139     if (font->platformData().orientation() == Vertical) {
    140         gc->save();
    141         gc->rotate(-0.5 * SK_ScalarPI);
    142         SkMatrix rotator;
    143         rotator.reset();
    144         rotator.setRotate(90);
    145         rotator.mapPoints(pos, numGlyphs);
    146     }
    147     TextDrawingModeFlags textMode = gc->textDrawingMode();
    148 
    149     // We draw text up to two times (once for fill, once for stroke).
    150     if (textMode & TextModeFill) {
    151         SkPaint paint;
    152         gc->setupPaintForFilling(&paint);
    153         setupPaint(&paint, font, this, shouldAntialias, shouldSmoothFonts);
    154         gc->adjustTextRenderMode(&paint);
    155         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
    156 
    157         gc->drawPosText(glyphs, numGlyphs * sizeof(uint16_t), pos, textRect, paint);
    158     }
    159 
    160     if ((textMode & TextModeStroke)
    161         && gc->strokeStyle() != NoStroke
    162         && gc->strokeThickness() > 0) {
    163 
    164         SkPaint paint;
    165         gc->setupPaintForStroking(&paint);
    166         setupPaint(&paint, font, this, shouldAntialias, shouldSmoothFonts);
    167         gc->adjustTextRenderMode(&paint);
    168         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
    169 
    170         if (textMode & TextModeFill) {
    171             // If we also filled, we don't want to draw shadows twice.
    172             // See comment in FontChromiumWin.cpp::paintSkiaText() for more details.
    173             paint.setLooper(0);
    174         }
    175 
    176         gc->drawPosText(glyphs, numGlyphs * sizeof(uint16_t), pos, textRect, paint);
    177     }
    178     if (font->platformData().orientation() == Vertical)
    179         gc->restore();
    180 }
    181 
    182 } // namespace WebCore
    183