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32 #include "platform/fonts/SimpleFontData.h"
34 #include <unicode/normlzr.h>
37 #include "SkTypeface.h"
40 #include "platform/fonts/FontDescription.h"
41 #include "platform/fonts/GlyphPage.h"
42 #include "platform/fonts/VDMXParser.h"
43 #include "platform/geometry/FloatRect.h"
44 #include "wtf/unicode/Unicode.h"
48 // This is the largest VDMX table which we'll try to load and parse.
49 static const size_t maxVDMXTableSize = 1024 * 1024; // 1 MB
51 void SimpleFontData::platformInit()
53 if (!m_platformData.size()) {
54 m_fontMetrics.reset();
61 SkPaint::FontMetrics metrics;
63 m_platformData.setupPaint(&paint);
64 paint.getFontMetrics(&metrics);
65 SkTypeface* face = paint.getTypeface();
68 int vdmxAscent = 0, vdmxDescent = 0;
69 bool isVDMXValid = false;
71 #if OS(LINUX) || OS(ANDROID)
72 // Manually digging up VDMX metrics is only applicable when bytecode hinting using FreeType.
73 // With GDI, the metrics will already have taken this into account (as needed).
74 // With DirectWrite or CoreText, no bytecode hinting is ever done.
75 // This code should be pushed into FreeType (hinted font metrics).
76 static const uint32_t vdmxTag = SkSetFourByteTag('V', 'D', 'M', 'X');
77 int pixelSize = m_platformData.size() + 0.5;
78 if (!paint.isAutohinted()
79 && (paint.getHinting() == SkPaint::kFull_Hinting
80 || paint.getHinting() == SkPaint::kNormal_Hinting))
82 size_t vdmxSize = face->getTableSize(vdmxTag);
83 if (vdmxSize && vdmxSize < maxVDMXTableSize) {
84 uint8_t* vdmxTable = (uint8_t*) fastMalloc(vdmxSize);
86 && face->getTableData(vdmxTag, 0, vdmxSize, vdmxTable) == vdmxSize
87 && parseVDMX(&vdmxAscent, &vdmxDescent, vdmxTable, vdmxSize, pixelSize))
97 // Beware those who step here: This code is designed to match Win32 font
98 // metrics *exactly* (except the adjustment of ascent/descent on Linux/Android).
101 descent = -vdmxDescent;
103 ascent = SkScalarRoundToInt(-metrics.fAscent);
104 descent = SkScalarRoundToInt(metrics.fDescent);
105 #if OS(LINUX) || OS(ANDROID)
106 // When subpixel positioning is enabled, if the descent is rounded down, the descent part
107 // of the glyph may be truncated when displayed in a 'overflow: hidden' container.
108 // To avoid that, borrow 1 unit from the ascent when possible.
109 // FIXME: This can be removed if sub-pixel ascent/descent is supported.
110 if (platformData().fontRenderStyle().useSubpixelPositioning && descent < SkScalarToFloat(metrics.fDescent) && ascent >= 1) {
117 m_fontMetrics.setAscent(ascent);
118 m_fontMetrics.setDescent(descent);
121 if (metrics.fXHeight) {
122 xHeight = metrics.fXHeight;
123 m_fontMetrics.setXHeight(xHeight);
125 xHeight = ascent * 0.56; // Best guess from Windows font metrics.
126 m_fontMetrics.setXHeight(xHeight);
127 m_fontMetrics.setHasXHeight(false);
130 float lineGap = SkScalarToFloat(metrics.fLeading);
131 m_fontMetrics.setLineGap(lineGap);
132 m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));
134 SkScalar underlineThickness, underlinePosition;
135 if (metrics.hasUnderlineThickness(&underlineThickness)
136 && metrics.hasUnderlinePosition(&underlinePosition)) {
137 m_fontMetrics.setUnderlineThickness(SkScalarToFloat(underlineThickness));
138 m_fontMetrics.setUnderlinePosition(SkScalarToFloat(-underlinePosition));
141 if (platformData().orientation() == Vertical && !isTextOrientationFallback()) {
142 static const uint32_t vheaTag = SkSetFourByteTag('v', 'h', 'e', 'a');
143 static const uint32_t vorgTag = SkSetFourByteTag('V', 'O', 'R', 'G');
144 size_t vheaSize = face->getTableSize(vheaTag);
145 size_t vorgSize = face->getTableSize(vorgTag);
146 if ((vheaSize > 0) || (vorgSize > 0))
147 m_hasVerticalGlyphs = true;
150 // In WebKit/WebCore/platform/graphics/SimpleFontData.cpp, m_spaceWidth is
151 // calculated for us, but we need to calculate m_maxCharWidth and
152 // m_avgCharWidth in order for text entry widgets to be sized correctly.
154 m_maxCharWidth = SkScalarRoundToInt(metrics.fMaxCharWidth);
156 // Older version of the DirectWrite API doesn't implement support for max
157 // char width. Fall back on a multiple of the ascent. This is entirely
158 // arbitrary but comes pretty close to the expected value in most cases.
159 if (m_maxCharWidth < 1)
160 m_maxCharWidth = ascent * 2;
162 // FIXME: This seems incorrect and should probably use fMaxCharWidth as
163 // the code path above.
164 SkScalar xRange = metrics.fXMax - metrics.fXMin;
165 m_maxCharWidth = SkScalarRoundToInt(xRange * SkScalarRoundToInt(m_platformData.size()));
168 if (metrics.fAvgCharWidth)
169 m_avgCharWidth = SkScalarRoundToInt(metrics.fAvgCharWidth);
171 m_avgCharWidth = xHeight;
173 GlyphPage* glyphPageZero = GlyphPageTreeNode::getRootChild(this, 0)->page();
176 static const UChar32 xChar = 'x';
177 const Glyph xGlyph = glyphPageZero->glyphForCharacter(xChar);
180 // In widthForGlyph(), xGlyph will be compared with
181 // m_zeroWidthSpaceGlyph, which isn't initialized yet here.
182 // Initialize it with zero to make sure widthForGlyph() returns
184 m_zeroWidthSpaceGlyph = 0;
185 m_avgCharWidth = widthForGlyph(xGlyph);
190 if (int unitsPerEm = face->getUnitsPerEm())
191 m_fontMetrics.setUnitsPerEm(unitsPerEm);
194 void SimpleFontData::platformCharWidthInit()
196 // charwidths are set in platformInit.
199 void SimpleFontData::platformDestroy()
203 PassRefPtr<SimpleFontData> SimpleFontData::platformCreateScaledFontData(const FontDescription& fontDescription, float scaleFactor) const
205 const float scaledSize = lroundf(fontDescription.computedSize() * scaleFactor);
206 return SimpleFontData::create(FontPlatformData(m_platformData, scaledSize), isCustomFont() ? CustomFontData::create() : nullptr);
209 void SimpleFontData::determinePitch()
211 m_treatAsFixedPitch = platformData().isFixedPitch();
214 static inline void getSkiaBoundsForGlyph(SkPaint& paint, Glyph glyph, SkRect& bounds)
216 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
219 paint.getTextPath(&glyph, sizeof(glyph), 0, 0, &path);
220 bounds = path.getBounds();
222 if (!paint.isSubpixelText()) {
229 FloatRect SimpleFontData::platformBoundsForGlyph(Glyph glyph) const
231 if (!m_platformData.size())
234 SkASSERT(sizeof(glyph) == 2); // compile-time assert
237 m_platformData.setupPaint(&paint);
240 getSkiaBoundsForGlyph(paint, glyph, bounds);
241 return FloatRect(bounds);
244 float SimpleFontData::platformWidthForGlyph(Glyph glyph) const
246 if (!m_platformData.size())
249 SkASSERT(sizeof(glyph) == 2); // compile-time assert
253 m_platformData.setupPaint(&paint);
255 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
256 SkScalar width = paint.measureText(&glyph, 2);
257 if (!paint.isSubpixelText())
258 width = SkScalarRoundToInt(width);
259 return SkScalarToFloat(width);
262 bool SimpleFontData::canRenderCombiningCharacterSequence(const UChar* characters, size_t length) const
264 if (!m_combiningCharacterSequenceSupport)
265 m_combiningCharacterSequenceSupport = adoptPtr(new HashMap<String, bool>);
267 WTF::HashMap<String, bool>::AddResult addResult = m_combiningCharacterSequenceSupport->add(String(characters, length), false);
268 if (!addResult.isNewEntry)
269 return addResult.storedValue->value;
271 UErrorCode error = U_ZERO_ERROR;
272 Vector<UChar, 4> normalizedCharacters(length);
273 int32_t normalizedLength = unorm_normalize(characters, length, UNORM_NFC, UNORM_UNICODE_3_2, &normalizedCharacters[0], length, &error);
274 // Can't render if we have an error or no composition occurred.
275 if (U_FAILURE(error) || (static_cast<size_t>(normalizedLength) == length))
279 m_platformData.setupPaint(&paint);
280 paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
281 if (paint.textToGlyphs(&normalizedCharacters[0], normalizedLength * 2, 0)) {
282 addResult.storedValue->value = true;
288 bool SimpleFontData::fillGlyphPage(GlyphPage* pageToFill, unsigned offset, unsigned length, UChar* buffer, unsigned bufferLength) const
290 if (SkUTF16_IsHighSurrogate(buffer[bufferLength-1])) {
291 SkDebugf("%s last char is high-surrogate", __FUNCTION__);
295 SkAutoSTMalloc<GlyphPage::size, uint16_t> glyphStorage(length);
297 uint16_t* glyphs = glyphStorage.get();
298 SkTypeface* typeface = platformData().typeface();
299 typeface->charsToGlyphs(buffer, SkTypeface::kUTF16_Encoding, glyphs, length);
301 bool haveGlyphs = false;
302 for (unsigned i = 0; i < length; i++) {
304 pageToFill->setGlyphDataForIndex(offset + i, glyphs[i], this);