45 lines
761 B
Go
45 lines
761 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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func NegateRGBA(c color.RGBA) color.RGBA {
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c.R = 255 - c.R
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c.G = 255 - c.G
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c.B = 255 - c.B
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return c
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}
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type Negate struct{ image.Image }
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func (n Negate) ColorModel() color.Model { return n.Image.ColorModel() }
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func (n Negate) Bounds() image.Rectangle { return n.Image.Bounds() }
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func (n Negate) At(x, y int) color.Color {
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c := n.Image.At(x, y)
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r, g, b, a := c.RGBA()
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RGBAColor := color.RGBA{
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R: uint8(r >> 8),
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G: uint8(g >> 8),
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B: uint8(b >> 8),
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A: uint8(a >> 8),
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}
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return NegateRGBA(RGBAColor)
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}
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func check(err error) {
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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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func main() {
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img, err := png.Decode(os.Stdin)
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check(err)
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err = png.Encode(os.Stdout, Negate{img})
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check(err)
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}
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