42 lines
814 B
Go
42 lines
814 B
Go
package main
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import (
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"image"
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"image/color"
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"image/png"
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"os"
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)
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// processImage takes input png image from stdin, processes it with f and outputs it to stdout.
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func processImage(f func(image.Image) image.Image) error {
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img, err := png.Decode(os.Stdin)
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if err != nil {
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return err
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}
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err = png.Encode(os.Stdout, f(img))
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if err != nil {
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return err
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}
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return err
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}
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type convert struct {
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image.Image
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color.Model
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}
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func (c convert) ColorModel() color.Model { return c.Model }
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func (c convert) Bounds() image.Rectangle { return c.Image.Bounds() }
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func (c convert) At(x, y int) color.Color { return c.Model.Convert(c.Image.At(x, y)) }
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func grayscale(img image.Image) image.Image {
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return convert{img, color.GrayModel}
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}
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func main() {
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err := processImage(grayscale)
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if err != nil {
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panic(err)
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}
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}
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