func (f *Font) TextDimensions(text string) (int, int, int) {
fnt := f.ttf
size := f.Size
var (
totalWidth = fixed.Int26_6(0)
totalHeight = fixed.Int26_6(size)
maxYBearing = fixed.Int26_6(0)
)
fupe := fixed.Int26_6(fnt.FUnitsPerEm())
for _, char := range text {
idx := fnt.Index(char)
hm := fnt.HMetric(fupe, idx)
vm := fnt.VMetric(fupe, idx)
g := truetype.GlyphBuf{}
err := g.Load(fnt, fupe, idx, font.HintingNone)
if err != nil {
log.Println(err)
return 0, 0, 0
}
totalWidth += hm.AdvanceWidth
yB := (vm.TopSideBearing * fixed.Int26_6(size)) / fupe
if yB > maxYBearing {
maxYBearing = yB
}
}
// Scale to actual pixel size
totalWidth *= fixed.Int26_6(size)
totalWidth /= fupe
return int(totalWidth), int(totalHeight), int(maxYBearing)
}
// our avatar image is square
func (g *drawer) Draw(s string, size int, bg *color.RGBA) image.Image {
// draw the background
dst := image.NewRGBA(image.Rect(0, 0, size, size))
draw.Draw(dst, dst.Bounds(), &image.Uniform{bg}, image.ZP, draw.Src)
// draw the text
drawer := &font.Drawer{
Dst: dst,
Src: image.White,
Face: g.face,
}
// font index
fi := g.font.Index([]rune(s)[0])
// glyph example: http://www.freetype.org/freetype2/docs/tutorial/metrics.png
var gbuf truetype.GlyphBuf
var err error
var _fsize fixed.Int26_6 = fixed.Int26_6(g.fontSize * g.dpi * (64.0 / 72.0))
err = gbuf.Load(g.font, _fsize, fi, font.HintingFull)
if err != nil {
// fixme
drawer.DrawString("")
return dst
}
// center
dY := int((size - int(gbuf.Bounds.Max.Y-gbuf.Bounds.Min.Y)>>6) / 2)
dX := int((size - int(gbuf.Bounds.Max.X-gbuf.Bounds.Min.X)>>6) / 2)
y := int(gbuf.Bounds.Max.Y>>6) + dY
x := 0 - int(gbuf.Bounds.Min.X>>6) + dX
//y := 10 + int(math.Ceil(g.fontSize*g.dpi/72)) //FIXME: what does it mean?
drawer.Dot = fixed.Point26_6{
X: fixed.I(x), //(fixed.I(size) - drawer.MeasureString(s)) / 2,
Y: fixed.I(y),
}
drawer.DrawString(s)
return dst
}