// enumerate returns all glyphs with a valid index.
func enumerate(f *truetype.Font, fc font.Face) []*glyph {
var gs []*glyph
for r := rune(1); r < (1<<16)-1; r++ {
if r == '\uFEFF' {
continue // ignore BOM
}
if f.Index(r) != 0 {
b, a, _ := fc.GlyphBounds(r)
gs = append(gs, &glyph{r: r, b: b, a: a})
}
}
return gs
}
// https://code.google.com/p/plotinum/source/browse/vg/font.go#160
func widthOfString(font *truetype.Font, size float64, s string) float64 {
// scale converts truetype.FUnit to float64
scale := size / float64(font.FUnitsPerEm())
width := 0
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := font.Index(rune)
if hasPrev {
width += int(font.Kern(fixed.Int26_6(font.FUnitsPerEm()), prev, index))
}
width += int(font.HMetric(fixed.Int26_6(font.FUnitsPerEm()), index).AdvanceWidth)
prev, hasPrev = index, true
}
return float64(width) * scale
}
func loadRanges(f *truetype.Font) (ret [][2]rune) {
rr := [2]rune{-1, -1}
for r := rune(0); r <= unicode.MaxRune; r++ {
if privateUseArea(r) {
continue
}
if f.Index(r) == 0 {
continue
}
if rr[1] == r {
rr[1] = r + 1
continue
}
if rr[0] != -1 {
ret = append(ret, rr)
}
rr = [2]rune{r, r + 1}
}
if rr[0] != -1 {
ret = append(ret, rr)
}
return ret
}