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 "platform/fonts/Font.h"
33
34#include "platform/LayoutTestSupport.h"
35#include "platform/fonts/FontSmoothingMode.h"
36#include "platform/fonts/GlyphBuffer.h"
37#include "platform/fonts/SimpleFontData.h"
38#include "platform/graphics/GraphicsContext.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
45namespace WebCore {
46
47bool Font::canReturnFallbackFontsForComplexText()
48{
49    return true;
50}
51
52bool Font::canExpandAroundIdeographsInComplexText()
53{
54    return true;
55}
56
57static 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(MACOSX)
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
89void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
90    const GlyphBuffer& glyphBuffer, unsigned from, unsigned numGlyphs,
91    const FloatPoint& point, const FloatRect& textRect) const
92{
93    COMPILE_ASSERT(sizeof(GlyphBufferGlyph) == sizeof(uint16_t), GlyphBufferGlyphSize_equals_uint16_t);
94
95    bool shouldSmoothFonts = true;
96    bool shouldAntialias = true;
97
98    switch (fontDescription().fontSmoothing()) {
99    case Antialiased:
100        shouldSmoothFonts = false;
101        break;
102    case SubpixelAntialiased:
103        break;
104    case NoSmoothing:
105        shouldAntialias = false;
106        shouldSmoothFonts = false;
107        break;
108    case AutoSmoothing:
109        // For the AutoSmooth case, don't do anything! Keep the default settings.
110        break;
111    }
112
113    if (!shouldUseSmoothing() || isRunningLayoutTest()) {
114        shouldSmoothFonts = false;
115        shouldAntialias = false;
116    }
117
118    const GlyphBufferGlyph* glyphs = glyphBuffer.glyphs(from);
119    SkScalar x = SkFloatToScalar(point.x());
120    SkScalar y = SkFloatToScalar(point.y());
121
122    if (font->platformData().orientation() == Vertical)
123        y += SkFloatToScalar(font->fontMetrics().floatAscent(IdeographicBaseline) - font->fontMetrics().floatAscent());
124    // FIXME: text rendering speed:
125    // Android has code in their WebCore fork to special case when the
126    // GlyphBuffer has no advances other than the defaults. In that case the
127    // text drawing can proceed faster. However, it's unclear when those
128    // patches may be upstreamed to WebKit so we always use the slower path
129    // here.
130    const GlyphBufferAdvance* adv = glyphBuffer.advances(from);
131    SkAutoSTMalloc<32, SkPoint> storage(numGlyphs);
132    SkPoint* pos = storage.get();
133
134    for (unsigned i = 0; i < numGlyphs; i++) {
135        pos[i].set(x, y);
136        x += SkFloatToScalar(adv[i].width());
137        y += SkFloatToScalar(adv[i].height());
138    }
139
140    if (font->platformData().orientation() == Vertical) {
141        gc->save();
142        gc->rotate(-0.5 * SK_ScalarPI);
143        SkMatrix rotator;
144        rotator.reset();
145        rotator.setRotate(90);
146        rotator.mapPoints(pos, numGlyphs);
147    }
148    TextDrawingModeFlags textMode = gc->textDrawingMode();
149
150    // We draw text up to two times (once for fill, once for stroke).
151    if (textMode & TextModeFill) {
152        SkPaint paint;
153        gc->setupPaintForFilling(&paint);
154        setupPaint(&paint, font, this, shouldAntialias, shouldSmoothFonts);
155        gc->adjustTextRenderMode(&paint);
156        paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
157
158        gc->drawPosText(glyphs, numGlyphs * sizeof(uint16_t), pos, textRect, paint);
159    }
160
161    if ((textMode & TextModeStroke)
162        && gc->strokeStyle() != NoStroke
163        && gc->strokeThickness() > 0) {
164
165        SkPaint paint;
166        gc->setupPaintForStroking(&paint);
167        setupPaint(&paint, font, this, shouldAntialias, shouldSmoothFonts);
168        gc->adjustTextRenderMode(&paint);
169        paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
170
171        if (textMode & TextModeFill) {
172            // If we also filled, we don't want to draw shadows twice.
173            // See comment in FontChromiumWin.cpp::paintSkiaText() for more details.
174            paint.setLooper(0);
175        }
176
177        gc->drawPosText(glyphs, numGlyphs * sizeof(uint16_t), pos, textRect, paint);
178    }
179    if (font->platformData().orientation() == Vertical)
180        gc->restore();
181}
182
183} // namespace WebCore
184