SimpleFontDataSkia.cpp [plain text]
#include "config.h"
#include "SimpleFontData.h"
#include "FloatRect.h"
#include "Font.h"
#include "FontCache.h"
#include "FontDescription.h"
#include "Logging.h"
#include "SkFontHost.h"
#include "SkPaint.h"
#include "SkTime.h"
#include "SkTypeface.h"
#include "SkTypes.h"
#include "VDMXParser.h"
namespace WebCore {
static const float smallCapsFraction = 0.7f;
static const float emphasisMarkFraction = .5;
static const size_t maxVDMXTableSize = 1024 * 1024;
void SimpleFontData::platformInit()
{
if (!m_platformData.size()) {
m_fontMetrics.reset();
m_avgCharWidth = 0;
m_maxCharWidth = 0;
return;
}
SkPaint paint;
SkPaint::FontMetrics metrics;
m_platformData.setupPaint(&paint);
paint.getFontMetrics(&metrics);
const SkFontID fontID = m_platformData.uniqueID();
static const uint32_t vdmxTag = SkSetFourByteTag('V', 'D', 'M', 'X');
int pixelSize = m_platformData.size() + 0.5;
int vdmxAscent, vdmxDescent;
bool isVDMXValid = false;
size_t vdmxSize = SkFontHost::GetTableSize(fontID, vdmxTag);
if (vdmxSize && vdmxSize < maxVDMXTableSize) {
uint8_t* vdmxTable = (uint8_t*) fastMalloc(vdmxSize);
if (vdmxTable
&& SkFontHost::GetTableData(fontID, vdmxTag, 0, vdmxSize, vdmxTable) == vdmxSize
&& parseVDMX(&vdmxAscent, &vdmxDescent, vdmxTable, vdmxSize, pixelSize))
isVDMXValid = true;
fastFree(vdmxTable);
}
float ascent;
float descent;
if (isVDMXValid) {
ascent = vdmxAscent;
descent = -vdmxDescent;
} else {
SkScalar height = -metrics.fAscent + metrics.fDescent + metrics.fLeading;
ascent = SkScalarRound(-metrics.fAscent);
descent = SkScalarRound(height) - ascent;
}
m_fontMetrics.setAscent(ascent);
m_fontMetrics.setDescent(descent);
float xHeight;
if (metrics.fXHeight)
xHeight = metrics.fXHeight;
else {
xHeight = ascent * 0.56f;
}
float lineGap = SkScalarToFloat(metrics.fLeading);
m_fontMetrics.setLineGap(lineGap);
m_fontMetrics.setXHeight(xHeight);
m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));
if (platformData().orientation() == Vertical && !isTextOrientationFallback()) {
static const uint32_t vheaTag = SkSetFourByteTag('v', 'h', 'e', 'a');
static const uint32_t vorgTag = SkSetFourByteTag('V', 'O', 'R', 'G');
size_t vheaSize = SkFontHost::GetTableSize(fontID, vheaTag);
size_t vorgSize = SkFontHost::GetTableSize(fontID, vorgTag);
if ((vheaSize > 0) || (vorgSize > 0))
m_hasVerticalGlyphs = true;
}
SkScalar xRange = metrics.fXMax - metrics.fXMin;
m_maxCharWidth = SkScalarRound(xRange * SkScalarRound(m_platformData.size()));
if (metrics.fAvgCharWidth)
m_avgCharWidth = SkScalarRound(metrics.fAvgCharWidth);
else {
m_avgCharWidth = xHeight;
GlyphPage* glyphPageZero = GlyphPageTreeNode::getRootChild(this, 0)->page();
if (glyphPageZero) {
static const UChar32 xChar = 'x';
const Glyph xGlyph = glyphPageZero->glyphDataForCharacter(xChar).glyph;
if (xGlyph) {
m_zeroWidthSpaceGlyph = 0;
m_avgCharWidth = widthForGlyph(xGlyph);
}
}
}
}
void SimpleFontData::platformCharWidthInit()
{
}
void SimpleFontData::platformDestroy()
{
}
PassOwnPtr<SimpleFontData> SimpleFontData::createScaledFontData(const FontDescription& fontDescription, float scaleFactor) const
{
const float scaledSize = lroundf(fontDescription.computedSize() * scaleFactor);
return adoptPtr(new SimpleFontData(FontPlatformData(m_platformData, scaledSize), isCustomFont(), false));
}
SimpleFontData* SimpleFontData::smallCapsFontData(const FontDescription& fontDescription) const
{
if (!m_derivedFontData)
m_derivedFontData = DerivedFontData::create(isCustomFont());
if (!m_derivedFontData->smallCaps)
m_derivedFontData->smallCaps = createScaledFontData(fontDescription, smallCapsFraction);
return m_derivedFontData->smallCaps.get();
}
SimpleFontData* SimpleFontData::emphasisMarkFontData(const FontDescription& fontDescription) const
{
if (!m_derivedFontData)
m_derivedFontData = DerivedFontData::create(isCustomFont());
if (!m_derivedFontData->emphasisMark)
m_derivedFontData->emphasisMark = createScaledFontData(fontDescription, emphasisMarkFraction);
return m_derivedFontData->emphasisMark.get();
}
bool SimpleFontData::containsCharacters(const UChar* characters, int length) const
{
SkPaint paint;
static const unsigned maxBufferCount = 64;
uint16_t glyphs[maxBufferCount];
m_platformData.setupPaint(&paint);
paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
while (length > 0) {
int n = SkMin32(length, SK_ARRAY_COUNT(glyphs));
int count = paint.textToGlyphs(characters, n * 2, glyphs);
for (int i = 0; i < count; i++) {
if (!glyphs[i])
return false; }
characters += n;
length -= n;
}
return true;
}
void SimpleFontData::determinePitch()
{
m_treatAsFixedPitch = platformData().isFixedPitch();
}
FloatRect SimpleFontData::platformBoundsForGlyph(Glyph) const
{
return FloatRect();
}
float SimpleFontData::platformWidthForGlyph(Glyph glyph) const
{
if (!m_platformData.size())
return 0;
SkASSERT(sizeof(glyph) == 2);
SkPaint paint;
m_platformData.setupPaint(&paint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
SkScalar width = paint.measureText(&glyph, 2);
return round(SkScalarToFloat(width));
}
}