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utils.go
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/
utils.go
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package fontnik
import (
"image"
"image/color"
"image/png"
"log"
"math"
"os"
)
func DrawGlyph(glyph *Glyph, smoothstep bool) image.Image {
width := int(*glyph.Width + 6)
height := int(*glyph.Height + 6)
img := image.NewRGBA(image.Rectangle{Min: image.Point{0, 0}, Max: image.Point{width, height}})
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
i := x + y*width
a := glyph.Bitmap[i]
if smoothstep {
img.Set(x, y, color.RGBA{0, 0, 0,
alpha(136, 168, float64(a)),
})
} else {
img.Set(x, y, color.RGBA{0, 0, 0,
uint8(a),
})
}
}
}
return img
}
func alpha(e0 float64, e1 float64, x float64) uint8 {
a := math.Max(math.Min((x-e1)/(e1-e0), 1), 0)
return uint8((a * a * (3 - 2*a)) * float64(x))
}
func SavePNG(path string, img image.Image) {
f, err := os.Create(path)
if err != nil {
log.Fatal(err)
}
defer f.Close()
err = png.Encode(f, img)
if err != nil {
log.Fatal(err)
}
}