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32 #include "platform/fonts/SimpleFontData.h"
34 #include <unicode/normlzr.h>
37 #include "SkTypeface.h"
39 #include "platform/fonts/FontDescription.h"
40 #include "platform/fonts/VDMXParser.h"
41 #include "platform/geometry/FloatRect.h"
42 #include "wtf/unicode/Unicode.h"
45 #include "platform/win/HWndDC.h"
50 // This is the largest VDMX table which we'll try to load and parse.
51 static const size_t maxVDMXTableSize = 1024 * 1024; // 1 MB
53 void SimpleFontData::platformInit()
55 if (!m_platformData.size()) {
56 m_fontMetrics.reset();
63 SkPaint::FontMetrics metrics;
65 m_platformData.setupPaint(&paint);
66 paint.getFontMetrics(&metrics);
67 SkTypeface* face = paint.getTypeface();
70 int vdmxAscent = 0, vdmxDescent = 0;
71 bool isVDMXValid = false;
73 #if OS(LINUX) || OS(ANDROID)
74 // Manually digging up VDMX metrics is only applicable when bytecode hinting using FreeType.
75 // With GDI, the metrics will already have taken this into account (as needed).
76 // With DirectWrite or CoreText, no bytecode hinting is ever done.
77 // This code should be pushed into FreeType (hinted font metrics).
78 static const uint32_t vdmxTag = SkSetFourByteTag('V', 'D', 'M', 'X');
79 int pixelSize = m_platformData.size() + 0.5;
80 if (!paint.isAutohinted()
81 && (paint.getHinting() == SkPaint::kFull_Hinting
82 || paint.getHinting() == SkPaint::kNormal_Hinting))
84 size_t vdmxSize = face->getTableSize(vdmxTag);
85 if (vdmxSize && vdmxSize < maxVDMXTableSize) {
86 uint8_t* vdmxTable = (uint8_t*) fastMalloc(vdmxSize);
88 && face->getTableData(vdmxTag, 0, vdmxSize, vdmxTable) == vdmxSize
89 && parseVDMX(&vdmxAscent, &vdmxDescent, vdmxTable, vdmxSize, pixelSize))
99 // Beware those who step here: This code is designed to match Win32 font
100 // metrics *exactly* (except the adjustment of ascent/descent on Linux/Android).
103 descent = -vdmxDescent;
105 ascent = SkScalarRoundToInt(-metrics.fAscent);
106 descent = SkScalarRoundToInt(metrics.fDescent);
107 #if OS(LINUX) || OS(ANDROID)
108 // When subpixel positioning is enabled, if the descent is rounded down, the descent part
109 // of the glyph may be truncated when displayed in a 'overflow: hidden' container.
110 // To avoid that, borrow 1 unit from the ascent when possible.
111 // FIXME: This can be removed if sub-pixel ascent/descent is supported.
112 if (platformData().fontRenderStyle().useSubpixelPositioning && descent < SkScalarToFloat(metrics.fDescent) && ascent >= 1) {
119 m_fontMetrics.setAscent(ascent);
120 m_fontMetrics.setDescent(descent);
123 if (metrics.fXHeight) {
124 xHeight = metrics.fXHeight;
125 m_fontMetrics.setXHeight(xHeight);
127 xHeight = ascent * 0.56; // Best guess from Windows font metrics.
128 m_fontMetrics.setXHeight(xHeight);
129 m_fontMetrics.setHasXHeight(false);
132 float lineGap = SkScalarToFloat(metrics.fLeading);
133 m_fontMetrics.setLineGap(lineGap);
134 m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));
136 // For now Skia does not support underline Thickness, once patch is comitted we can uncomment following
137 // code, till then setting Underline Thickness to Zero so that default calculation is done.
138 // float underlineThickness = SkScalarToFloat(metrics.fUnderlineThickness);
139 // m_fontMetrics.setUnderlineThickness(underlineThickness);
140 m_fontMetrics.setUnderlineThickness(0.f);
142 if (platformData().orientation() == Vertical && !isTextOrientationFallback()) {
143 static const uint32_t vheaTag = SkSetFourByteTag('v', 'h', 'e', 'a');
144 static const uint32_t vorgTag = SkSetFourByteTag('V', 'O', 'R', 'G');
145 size_t vheaSize = face->getTableSize(vheaTag);
146 size_t vorgSize = face->getTableSize(vorgTag);
147 if ((vheaSize > 0) || (vorgSize > 0))
148 m_hasVerticalGlyphs = true;
151 // In WebKit/WebCore/platform/graphics/SimpleFontData.cpp, m_spaceWidth is
152 // calculated for us, but we need to calculate m_maxCharWidth and
153 // m_avgCharWidth in order for text entry widgets to be sized correctly.
155 m_maxCharWidth = SkScalarRoundToInt(metrics.fMaxCharWidth);
157 // FIXME: This seems incorrect and should probably use fMaxCharWidth as
158 // the code path above.
159 SkScalar xRange = metrics.fXMax - metrics.fXMin;
160 m_maxCharWidth = SkScalarRoundToInt(xRange * SkScalarRoundToInt(m_platformData.size()));
163 if (metrics.fAvgCharWidth)
164 m_avgCharWidth = SkScalarRoundToInt(metrics.fAvgCharWidth);
166 m_avgCharWidth = xHeight;
168 GlyphPage* glyphPageZero = GlyphPageTreeNode::getRootChild(this, 0)->page();
171 static const UChar32 xChar = 'x';
172 const Glyph xGlyph = glyphPageZero->glyphForCharacter(xChar);
175 // In widthForGlyph(), xGlyph will be compared with
176 // m_zeroWidthSpaceGlyph, which isn't initialized yet here.
177 // Initialize it with zero to make sure widthForGlyph() returns
179 m_zeroWidthSpaceGlyph = 0;
180 m_avgCharWidth = widthForGlyph(xGlyph);
185 if (int unitsPerEm = face->getUnitsPerEm())
186 m_fontMetrics.setUnitsPerEm(unitsPerEm);
189 void SimpleFontData::platformCharWidthInit()
191 // charwidths are set in platformInit.
194 void SimpleFontData::platformDestroy()
198 PassRefPtr<SimpleFontData> SimpleFontData::platformCreateScaledFontData(const FontDescription& fontDescription, float scaleFactor) const
200 const float scaledSize = lroundf(fontDescription.computedSize() * scaleFactor);
201 return SimpleFontData::create(FontPlatformData(m_platformData, scaledSize), isCustomFont() ? CustomFontData::create(false) : 0);
204 void SimpleFontData::determinePitch()
206 m_treatAsFixedPitch = platformData().isFixedPitch();
209 static inline void getSkiaBoundsForGlyph(SkPaint& paint, Glyph glyph, SkRect& bounds)
211 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
214 paint.getTextPath(&glyph, sizeof(glyph), 0, 0, &path);
215 bounds = path.getBounds();
217 if (!paint.isSubpixelText()) {
224 FloatRect SimpleFontData::platformBoundsForGlyph(Glyph glyph) const
226 if (!m_platformData.size())
229 SkASSERT(sizeof(glyph) == 2); // compile-time assert
232 m_platformData.setupPaint(&paint);
235 getSkiaBoundsForGlyph(paint, glyph, bounds);
236 return FloatRect(bounds);
239 float SimpleFontData::platformWidthForGlyph(Glyph glyph) const
241 if (!m_platformData.size())
244 SkASSERT(sizeof(glyph) == 2); // compile-time assert
248 m_platformData.setupPaint(&paint);
250 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
251 SkScalar width = paint.measureText(&glyph, 2);
252 if (!paint.isSubpixelText())
253 width = SkScalarRoundToInt(width);
254 return SkScalarToFloat(width);
258 bool SimpleFontData::canRenderCombiningCharacterSequence(const UChar* characters, size_t length) const
260 if (!m_combiningCharacterSequenceSupport)
261 m_combiningCharacterSequenceSupport = adoptPtr(new HashMap<String, bool>);
263 WTF::HashMap<String, bool>::AddResult addResult = m_combiningCharacterSequenceSupport->add(String(characters, length), false);
264 if (!addResult.isNewEntry)
265 return addResult.storedValue->value;
267 UErrorCode error = U_ZERO_ERROR;
268 Vector<UChar, 4> normalizedCharacters(length);
269 int32_t normalizedLength = unorm_normalize(characters, length, UNORM_NFC, UNORM_UNICODE_3_2, &normalizedCharacters[0], length, &error);
270 // Can't render if we have an error or no composition occurred.
271 if (U_FAILURE(error) || (static_cast<size_t>(normalizedLength) == length))
275 m_platformData.setupPaint(&paint);
276 paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
277 if (paint.textToGlyphs(&normalizedCharacters[0], normalizedLength * 2, 0)) {
278 addResult.storedValue->value = true;
285 } // namespace WebCore