// Metrics computes the pixel unit metrics for the glyph.
func (f *Face) Metrics(dst *Metrics, ch rune) error {
errno := C.FT_Load_Char(f.handle, C.FT_ULong(ch), C.FT_LOAD_DEFAULT)
if errno != 0 {
return fmt.Errorf("freetype2: %s", errstr(errno))
}
m := &f.handle.glyph.metrics
/*
s := &f.handle.size.metrics
invEM := 64.0 / float64(f.handle.units_per_EM)
xscale := float64(s.x_ppem) * invEM
yscale := float64(s.y_ppem) * invEM
dst.Width = int(float64(m.width) * xscale)
dst.Height = int(float64(m.height) * yscale)
dst.HorizontalBearingX = int(float64(m.horiBearingX) * xscale)
dst.HorizontalBearingY = int(float64(m.horiBearingY) * yscale)
dst.AdvanceWidth = int(float64(m.horiAdvance) * xscale)
dst.VerticalBearingX = int(float64(m.vertBearingX) * xscale)
dst.VerticalBearingY = int(float64(m.vertBearingY) * yscale)
dst.AdvanceHeight = int(float64(m.vertAdvance) * yscale)
*/
dst.Width = int(m.width >> 6)
dst.Height = int(m.height >> 6)
dst.HorizontalBearingX = int(m.horiBearingX >> 6)
dst.HorizontalBearingY = int(m.horiBearingY >> 6)
dst.AdvanceWidth = int(m.horiAdvance >> 6)
dst.VerticalBearingX = int(m.vertBearingX >> 6)
dst.VerticalBearingY = int(m.vertBearingY >> 6)
dst.AdvanceHeight = int(m.vertAdvance >> 6)
return nil
}
// Image directly copies the rendered bitmap data for the glyph into dst with
// its top-left corner at pt. Currently, only *image.Alpha is supported.
func (f *Face) Image(dst draw.Image, pt image.Point, ch rune) error {
errno := C.FT_Load_Char(f.handle, C.FT_ULong(ch), C.FT_LOAD_RENDER)
if errno != 0 {
return fmt.Errorf("freetype2: %s", errstr(errno))
}
bitmap := &f.handle.glyph.bitmap
if bitmap.pixel_mode != C.FT_PIXEL_MODE_GRAY || bitmap.num_grays != 256 {
return fmt.Errorf("freetype2: unsupported pixel mode")
}
src := imageFromBitmap(bitmap)
switch dst.(type) {
case *image.Alpha:
drawAlpha(dst.(*image.Alpha), pt, src)
default:
return fmt.Errorf("freetype2: unsupported dst type %T", dst)
}
return nil
}
