tins2020/cmd/imadapt/setalpha.go

26 lines
475 B
Go

package main
import (
"image"
"image/color"
)
func setAlpha(path string, alpha int) error {
src, err := decodeImage(path)
if err != nil {
return err
}
bounds := src.Bounds()
dst := image.NewNRGBA(bounds)
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
for x := bounds.Min.X; x < bounds.Max.X; x++ {
c := color.NRGBAModel.Convert(src.At(x, y)).(color.NRGBA)
if c.A > 0 {
c.A = uint8(alpha)
}
dst.Set(x, y, c)
}
}
return encodePNG(path, dst)
}