static HB_Error getOutlinePoint(HB_Font hbFont, HB_Glyph glyph, int flags, hb_uint32 point,
HB_Fixed* xPos, HB_Fixed* yPos, hb_uint32* resultingNumPoints)
{
if (flags & HB_ShaperFlag_UseDesignMetrics)
// This is requesting pre-hinted positions. We can't support this.
return HB_Err_Invalid_Argument;
SkPaint* paint = static_cast<SkPaint*>(hbFont->userData);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
uint16_t glyph16 = glyph;
SkPath path;
paint->getTextPath(&glyph16, sizeof(glyph16), 0, 0, &path);
uint32_t numPoints = path.getPoints(0, 0);
if (point >= numPoints)
return HB_Err_Invalid_SubTable;
SkPoint* points = static_cast<SkPoint*>(malloc(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 = SkScalarToHBFixed(points[point].fX);
*yPos = SkScalarToHBFixed(points[point].fY);
*resultingNumPoints = numPoints;
delete points;
return HB_Err_Ok;
}
static void glyphsToAdvances(HB_Font hbFont, const HB_Glyph* glyphs, hb_uint32 numGlyphs,
HB_Fixed* advances, int flags)
{
SkPaint* paint = static_cast<SkPaint*>(hbFont->userData);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
uint16_t* glyphs16 = new uint16_t[numGlyphs];
if (!glyphs16)
return;
for (unsigned i = 0; i < numGlyphs; ++i)
glyphs16[i] = glyphs[i];
SkScalar* scalarAdvances = reinterpret_cast<SkScalar*>(advances);
paint->getTextWidths(glyphs16, numGlyphs * sizeof(uint16_t), scalarAdvances);
// 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) {
advances[i] = SkScalarToHBFixed(scalarAdvances[i]);
#if DEBUG_ADVANCES
ALOGD("glyphsToAdvances -- advances[%d]=%d", i, advances[i]);
#endif
}
delete[] glyphs16;
}
static void getGlyphMetrics(HB_Font hbFont, HB_Glyph glyph, HB_GlyphMetrics* metrics)
{
SkPaint* paint = static_cast<SkPaint*>(hbFont->userData);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
uint16_t glyph16 = glyph;
SkScalar width;
SkRect bounds;
paint->getTextWidths(&glyph16, sizeof(glyph16), &width, &bounds);
metrics->x = SkScalarToHBFixed(bounds.fLeft);
metrics->y = SkScalarToHBFixed(bounds.fTop);
metrics->width = SkScalarToHBFixed(bounds.width());
metrics->height = SkScalarToHBFixed(bounds.height());
metrics->xOffset = SkScalarToHBFixed(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 void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
{
ALOG_ASSERT(codepoint <= 0xFFFF);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
SkScalar skWidth;
SkRect skBounds;
uint16_t glyph = codepoint;
paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
if (kDebugGlyphs) {
ALOGD("returned glyph for %i: width = %f", codepoint, skWidth);
}
if (width)
*width = SkScalarToHBFixed(skWidth);
if (extents) {
// Invert y-axis because Skia is y-grows-down but we set up harfbuzz to be y-grows-up.
extents->x_bearing = SkScalarToHBFixed(skBounds.fLeft);
extents->y_bearing = SkScalarToHBFixed(-skBounds.fTop);
extents->width = SkScalarToHBFixed(skBounds.width());
extents->height = SkScalarToHBFixed(-skBounds.height());
}
}
static HB_Fixed getFontMetric(HB_Font hbFont, HB_FontMetric metric)
{
SkPaint* paint = static_cast<SkPaint*>(hbFont->userData);
SkPaint::FontMetrics skiaMetrics;
paint->getFontMetrics(&skiaMetrics);
switch (metric) {
case HB_FontAscent:
return SkScalarToHBFixed(-skiaMetrics.fAscent);
// We don't support getting the rest of the metrics and Harfbuzz doesn't seem to need them.
default:
return 0;
}
return 0;
}
