Author: Nigel Tao <nigeltao@golang.org>  2015-03-25 18:47:24
Committer: Nigel Tao <nigeltao@golang.org>  2015-03-26 18:30:55
Parent: b5c3a9e572a1257c0db47d74b45f8e03f2f91f27 (image: add image.CMYK and color.CMYK types.)
Child:  0def13ac3f5a5e9f8e5540d3f5469cd469bddfad (image/color: have CMYK.RGBA work in 16-bit color, per the Color interface.)
Branches: master, remotes/origin/dev.ssa, remotes/origin/master
Follows: go1.4beta1
Precedes: go1.5beta1

    image/color: have YCbCr.RGBA work in 16-bit color, per the Color
    interface.

    Change-Id: Ie025753df08ae93e7a5095a3426aff15fa2016fd
    Reviewed-on: https://go-review.googlesource.com/8073
    Reviewed-by: Rob Pike <r@golang.org>

package main

import (
    "image"
    "image/color"
    _ "image/jpeg"
    "image/png"
    "log"
    "os"
)

func main() {
    r, err := os.Open("start_screen.jpg")
    check(err)
    defer r.Close()

    img, _, err := image.Decode(r)
    check(err)

    b := img.Bounds()
    rgba := image.NewRGBA(b)
    for y := b.Min.Y; y < b.Max.Y; y++ {
        for x := b.Min.X; x < b.Max.X; x++ {
            r32, g32, b32, a32 := img.At(x, y).RGBA()
            c := color.RGBA{uint8(r32), uint8(g32), uint8(b32), uint8(a32)}
            rgba.SetRGBA(x, y, c)
        }
    }

    w, err := os.Create("test.png")
    check(err)
    defer w.Close()

    err = png.Encode(w, rgba)
    check(err)
}

func check(err error) {
    if err != nil {
        log.Fatal(err)
    }
}