Tukar imej RBGA kepada tatasusunan bait RGB dengan cekap

func load(filePath string) *image.RGBA {
    imgFile, err := os.Open(filePath)
    if err != nil {
        fmt.Printf("Cannot read file %v\n", err)
    }
    defer imgFile.Close()

    img, _, err := image.Decode(imgFile)
    if err != nil {
        fmt.Printf("Cannot decode file %v\n", err)
    }
    return img.(*image.RGBA)
}

    img := load("myimg.png")

    bounds := img.Bounds()
    width, height := bounds.Max.X, bounds.Max.Y

    // Convert to RGB? Probably not...
    newImg := image.NewNRGBA(image.Rect(0, 0, width, height))
    draw.Draw(newImg, newImg.Bounds(), img, bounds.Min, draw.Src)
    // Pass image pointer to C function.
    C.PaintOnImage(unsafe.Pointer(&newImg.Pix[0]), C.int(newImg.Bounds().Dy()), C.int(newImg.Bounds().Dx())

bounds := img.bounds()
rgb := make([]byte, bounds.dx()*bounds.dy()*3)
idx := 0
for y := bounds.min.y; y < bounds.max.y; y++ {
    for x := bounds.min.x; x < bounds.max.x; x++ {
        offs := img.pixoffset(x, y)
        copy(rgb[idx:], img.pix[offs:offs+3])
        idx += 3
    }
}

bounds := img.Bounds()
rgb := make([]byte, bounds.Dx()*bounds.Dy()*3)
idx := 0

for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
    offs := img.PixOffset(bounds.Min.X, y)
    for x := bounds.Min.X; x < bounds.Max.X; x++ {
        rgb[idx+0] = img.Pix[offs+0]
        rgb[idx+1] = img.Pix[offs+1]
        rgb[idx+2] = img.Pix[offs+2]
        idx += 3
        offs += 4
    }
}