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79 lines
1.8 KiB
79 lines
1.8 KiB
package main
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import (
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"os"
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"image"
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"log"
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"image/png"
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"github.com/disintegration/gift"
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"flag"
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"math"
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"lcthw.dev/go/jankifier/filters"
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)
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func LoadImage(filename string) image.Image {
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reader, err := os.Open(filename)
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if err != nil { log.Fatal(err) }
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defer reader.Close()
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img, _, err := image.Decode(reader)
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if err != nil { log.Fatal(err) }
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return img
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}
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func SaveImage(filename string, img image.Image) {
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out, err := os.Create(filename)
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if err != nil {
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log.Fatalf("can't write file %s: %v", filename, err)
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}
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defer out.Close()
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err = png.Encode(out, img)
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if err != nil {
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log.Fatalf("can't png encode %s: %v", filename, err)
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}
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}
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type Opts struct {
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InFile string
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OutFile string
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PixelWidth int
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ColorDepth int
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DitherType int
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}
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func ParseOpts() Opts {
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var opts Opts
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flag.StringVar(&opts.InFile, "input", "", "input file.png")
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flag.StringVar(&opts.OutFile, "output", "", "output file.png")
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flag.IntVar(&opts.PixelWidth, "pixel-width", 4, "pixel width")
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flag.IntVar(&opts.ColorDepth, "color-depth", 16, "number of colors in the palette")
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flag.IntVar(&opts.DitherType, "dither", 0, "0=none, 1=floyd, 2=atkinson")
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flag.Parse()
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if opts.ColorDepth > math.MaxUint8 {
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log.Fatalf("color-depth can't be greater than %d", math.MaxUint8);
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}
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return opts
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}
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func main() {
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opts := ParseOpts()
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src := LoadImage(opts.InFile)
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bounds := src.Bounds()
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resize := gift.Resize(bounds.Max.X / opts.PixelWidth, 0, gift.NearestNeighborResampling)
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posterize := filters.Posterize(uint16(opts.ColorDepth), opts.DitherType)
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upscale := filters.Upscale(bounds, opts.PixelWidth)
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sharpen := gift.UnsharpMask(1, 1, 0)
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g := gift.New(resize, posterize, upscale, sharpen)
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smaller := image.NewNRGBA(g.Bounds(bounds))
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g.Draw(smaller, src)
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SaveImage(opts.OutFile, smaller)
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}
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