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
}
// CenterX returns the Point at which string s will be centered within rect r
// along the X coordinate when passed to c.DrawString. The Y coordinate will be 0.
// Clip is set to r before returning.
func CenterX(c *freetype.Context, s string, r image.Rectangle) (fixed.Point26_6, error) {
w, err := DrawWidth(c, s)
c.SetClip(r)
if err != nil {
return fixed.Point26_6{}, err
}
half := Int26_6(0.5)
xmin := freetype.Pt(r.Min.X, 0)
return freetype.Pt(r.Dx(), 0).Mul(half).Sub(w.Mul(half)).Add(xmin), nil
}
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
}
func NewFontFace(path string, pixels float32, fg, bg color.Color) (fontface *FontFace, err error) {
var (
font *truetype.Font
fontbytes []byte
bounds fixed.Rectangle26_6
context *freetype.Context
points float32
dpi float32 = 96
)
if fontbytes, err = ioutil.ReadFile(path); err != nil {
return
}
if font, err = freetype.ParseFont(fontbytes); err != nil {
return
}
points = pixels * 72 / dpi
bounds = font.Bounds(fixed.I(int(pixels)))
context = freetype.NewContext()
context.SetFont(font)
context.SetFontSize(float64(points))
context.SetDPI(float64(dpi))
fontface = &FontFace{
font: font,
charw: float32(bounds.Max.X-bounds.Min.X) / 64,
charh: float32(bounds.Max.Y-bounds.Min.Y) / 64,
offy: float32(bounds.Min.Y) / 64,
fg: fg,
bg: bg,
context: context,
}
return
}
// DrawWidth simulates drawing s using Context c and returns the raster.Point
// where X is the width of the drawn string. The context's src and dst are
// unused, but the font should already be set. Clip is set to an empty Rectangle
// and should be reset afterwards.
func DrawWidth(c *freetype.Context, s string) (fixed.Point26_6, error) {
// nil rectangle is always empty so draw is never called
c.SetClip(image.Rectangle{})
p, err := c.DrawString(s, fixed.Point26_6{}) // 0,0
return p, err
}
