36 lines
765 B
Go
36 lines
765 B
Go
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package thumbnail
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import (
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"image/color"
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)
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func Blend(a, b color.Color) color.Color {
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switch a.(type) {
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case color.RGBA:
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return BlendRGBA(a.(color.RGBA), b.(color.RGBA)) // FIXME there's syntax for this
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case color.YCbCr:
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return BlendYCbCr(a.(color.YCbCr), b.(color.YCbCr))
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default:
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return a // ??? unknown color format
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}
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}
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func BlendYCbCr(a, b color.YCbCr) color.YCbCr {
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return color.YCbCr{
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Y: uint8((int(a.Y) + int(b.Y)) / 2),
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Cb: uint8((int(a.Cb) + int(b.Cb)) / 2),
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Cr: uint8((int(a.Cr) + int(b.Cr)) / 2),
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}
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}
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func BlendRGBA(a, b color.RGBA) color.RGBA {
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return color.RGBA{
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R: uint8((int(a.R) + int(b.R)) / 2),
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G: uint8((int(a.G) + int(b.G)) / 2),
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B: uint8((int(a.B) + int(b.B)) / 2),
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A: uint8((int(a.A) + int(b.A)) / 2),
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}
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}
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