64 lines
1.1 KiB
Go
64 lines
1.1 KiB
Go
package dithering
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import (
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"image"
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"image/color"
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)
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const side = 16
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type grid struct {
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color.Gray
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}
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func (_ grid) ColorModel() color.Model {
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return color.RGBAModel
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}
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func (_ grid) Bounds() image.Rectangle {
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return image.Rect(0, 0, side, side)
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}
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func (g grid) At(x, y int) color.Color {
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n := uint8(g.Gray.Y * 10)
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if n == 0 {
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return color.Black
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}
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step := int((side*side-1) / n)
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if (y*side+x)%step == 0 {
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return color.White
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}
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return color.Black
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}
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type uniformGrid struct {
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image.Image
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}
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func (g uniformGrid) ColorModel() color.Model {
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return g.Image.ColorModel()
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}
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func (g uniformGrid) Bounds() image.Rectangle {
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// just need to return something
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return g.Image.Bounds()
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}
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func (g uniformGrid) At(x, y int) color.Color {
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dx, dy := g.Image.Bounds().Dx(), g.Image.Bounds().Dy()
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return g.Image.At(x%dx, y%dy)
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}
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type Dithering struct {
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image.Image
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}
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func (d Dithering) ColorModel() color.Model { return color.GrayModel }
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func (d Dithering) Bounds() image.Rectangle { return d.Image.Bounds() }
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func (d Dithering) At(x, y int) color.Color {
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c := color.GrayModel.Convert(d.Image.At(x, y))
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return uniformGrid{grid{c.(color.Gray)}}.
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At(x, y)
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}
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