static void glyphsToAdvances(HB_Font hbFont, const HB_Glyph* glyphs, hb_uint32 numGlyphs, HB_Fixed* advances, int flags)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
font->setupPaint(&paint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
OwnArrayPtr<uint16_t> glyphs16(new uint16_t[numGlyphs]);
if (!glyphs16.get())
return;
for (unsigned i = 0; i < numGlyphs; ++i)
glyphs16[i] = glyphs[i];
paint.getTextWidths(glyphs16.get(), numGlyphs * sizeof(uint16_t), reinterpret_cast<SkScalar*>(advances));
// The |advances| values which Skia outputs are SkScalars, which are floats
// in Chromium. However, Harfbuzz wants them in 26.6 fixed point format.
// These two formats are both 32-bits long.
for (unsigned i = 0; i < numGlyphs; ++i) {
float value;
// We use a memcpy to avoid breaking strict aliasing rules.
memcpy(&value, reinterpret_cast<char*>(advances) + sizeof(float) * i, sizeof(float));
advances[i] = SkiaScalarToHarfbuzzFixed(value);
}
}
static HB_Bool stringToGlyphs(HB_Font hbFont, const HB_UChar16* characters, hb_uint32 length, HB_Glyph* glyphs, hb_uint32* glyphsSize, HB_Bool isRTL)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
font->setupPaint(&paint);
paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
unsigned codepoints = 0;
for (hb_uint32 i = 0; i < length; i++) {
if (!SkUTF16_IsHighSurrogate(characters[i]))
codepoints++;
if (codepoints > *glyphsSize)
return 0;
}
int numGlyphs = paint.textToGlyphs(characters, length * sizeof(uint16_t), reinterpret_cast<uint16_t*>(glyphs));
// HB_Glyph is 32-bit, but Skia outputs only 16-bit numbers. So our
// |glyphs| array needs to be converted.
for (int i = numGlyphs - 1; i >= 0; --i) {
uint16_t value;
// We use a memcpy to avoid breaking strict aliasing rules.
memcpy(&value, reinterpret_cast<char*>(glyphs) + sizeof(uint16_t) * i, sizeof(uint16_t));
glyphs[i] = value;
}
*glyphsSize = numGlyphs;
return 1;
}
static HB_Error getOutlinePoint(HB_Font hbFont, HB_Glyph glyph, int flags, hb_uint32 point, HB_Fixed* xPos, HB_Fixed* yPos, hb_uint32* resultingNumPoints)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
if (flags & HB_ShaperFlag_UseDesignMetrics)
return HB_Err_Invalid_Argument; // This is requesting pre-hinted positions. We can't support this.
font->setupPaint(&paint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
uint16_t glyph16 = glyph;
SkPath path;
paint.getTextPath(&glyph16, sizeof(glyph16), 0, 0, &path);
int numPoints = path.getPoints(0, 0);
if (point >= static_cast<unsigned>(numPoints))
return HB_Err_Invalid_SubTable;
SkPoint* points = reinterpret_cast<SkPoint*>(fastMalloc(sizeof(SkPoint) * (point + 1)));
if (!points)
return HB_Err_Invalid_SubTable;
// Skia does let us get a single point from the path.
path.getPoints(points, point + 1);
*xPos = SkiaScalarToHarfbuzzFixed(points[point].fX);
*yPos = SkiaScalarToHarfbuzzFixed(points[point].fY);
*resultingNumPoints = numPoints;
fastFree(points);
return HB_Err_Ok;
}
static HB_Fixed getFontMetric(HB_Font hbFont, HB_FontMetric metric)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
font->setupPaint(&paint);
SkPaint::FontMetrics skiaMetrics;
paint.getFontMetrics(&skiaMetrics);
switch (metric) {
case HB_FontAscent:
return SkiaScalarToHarfbuzzFixed(-skiaMetrics.fAscent);
// We don't support getting the rest of the metrics and Harfbuzz doesn't seem to need them.
default:
return 0;
}
}
static void getGlyphMetrics(HB_Font hbFont, HB_Glyph glyph, HB_GlyphMetrics* metrics)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
font->setupPaint(&paint);
paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
uint16_t glyph16 = glyph;
SkScalar width;
SkRect bounds;
paint.getTextWidths(&glyph16, sizeof(glyph16), &width, &bounds);
metrics->x = SkiaScalarToHarfbuzzFixed(bounds.fLeft);
metrics->y = SkiaScalarToHarfbuzzFixed(bounds.fTop);
metrics->width = SkiaScalarToHarfbuzzFixed(bounds.width());
metrics->height = SkiaScalarToHarfbuzzFixed(bounds.height());
metrics->xOffset = SkiaScalarToHarfbuzzFixed(width);
// We can't actually get the |y| correct because Skia doesn't export
// the vertical advance. However, nor we do ever render vertical text at
// the moment so it's unimportant.
metrics->yOffset = 0;
}
static HB_Bool canRender(HB_Font hbFont, const HB_UChar16* characters, hb_uint32 length)
{
FontPlatformData* font = reinterpret_cast<FontPlatformData*>(hbFont->userData);
SkPaint paint;
font->setupPaint(&paint);
paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
OwnArrayPtr<uint16_t> glyphs16(new uint16_t[length]);
if (!glyphs16.get())
return 0;
int numGlyphs = paint.textToGlyphs(characters, length * sizeof(uint16_t), glyphs16.get());
bool canRender = true;
for (int i = 0; i < numGlyphs; ++i) {
if (!glyphs16[i]) {
canRender = false;
break;
}
}
return canRender;
}