func drawText(font *truetype.Font, c *freetype.Context, color color.Color, rgba *image.RGBA, text string) (int, int) {
fg := image.NewUniform(color)
bg := image.Transparent
draw.Draw(rgba, rgba.Bounds(), bg, image.ZP, draw.Src)
c.SetFont(font)
c.SetDst(rgba)
c.SetSrc(fg)
c.SetClip(rgba.Bounds())
// height is the fraction of the font that is above the line, 1.0 would mean
// that the font never falls below the line
// TODO: wtf - this is all wrong!
// fix fonts - we can't change the font size easily
height := 1.3
pt := freetype.Pt(0, int(float64(c.PointToFixed(*size)>>8)*height))
adv, _ := c.DrawString(text, pt)
pt.X += adv.X
py := int(float64(pt.Y>>8)/height + 0.01)
return int(pt.X >> 8), py
}
func NewFontFace(path string, size float64, fg, bg color.Color) (fontface *FontFace, err error) {
var (
font *truetype.Font
fontbytes []byte
bounds truetype.Bounds
context *freetype.Context
scale float32
)
if fontbytes, err = ioutil.ReadFile(path); err != nil {
return
}
if font, err = freetype.ParseFont(fontbytes); err != nil {
return
}
bounds = font.Bounds(1)
fmt.Printf("bounds %v\n", bounds)
context = freetype.NewContext()
context.SetFont(font)
context.SetFontSize(size)
context.SetDPI(72)
scale = float32(context.PointToFixed(size) / 64)
fontface = &FontFace{
font: font,
charw: scale * float32(bounds.XMax-bounds.XMin),
charh: scale * float32(bounds.YMax-bounds.YMin),
fg: fg,
bg: bg,
context: context,
}
return
}