func (c *Canvas) textImage(font vg.Font, str string) *image.RGBA {
w := font.Width(str).Dots(c)
h := font.Extents().Height.Dots(c)
img := image.NewRGBA(image.Rect(0, 0, int(w+0.5), int(h+0.5)))
gc := draw2d.NewGraphicContext(img)
gc.SetDPI(int(c.DPI()))
gc.SetFillColor(c.color[len(c.color)-1])
gc.SetStrokeColor(c.color[len(c.color)-1])
data, ok := fontMap[font.Name()]
if !ok {
panic(fmt.Sprintf("Font name %s is unknown", font.Name()))
}
if !registeredFont[font.Name()] {
draw2d.RegisterFont(data, font.Font())
registeredFont[font.Name()] = true
}
gc.SetFontData(data)
gc.SetFontSize(font.Size.Points())
gc.MoveTo(0, h+font.Extents().Descent.Dots(c))
gc.FillString(str)
return img
}
