Convert PNG image to raw []byte Golang

Question

I have an image in PNG format which is just an array of dimensions 1x512. I needs its raw bytes without the PNG format. How can I convert the PNG to raw bytes in Go.

I have some python code which does what I want, but I have not been able to find the same funtionality in Go:

image = Image.open(io.BytesIO(features))
array = np.frombuffer(image.tobytes(), dtype=np.float32)

Answer 1

Here's a slightly more generic solution than yours. It uses the dimensions of the image itself instead of hardcoded values.

func imageToRGBA(img image.Image) []uint8 {
    sz := img.Bounds()
    raw := make([]uint8, (sz.Max.X-sz.Min.X)*(sz.Max.Y-sz.Min.Y)*4)
    idx := 0
    for y := sz.Min.Y; y < sz.Max.Y; y++ {
        for x := sz.Min.X; x < sz.Max.X; x++ {
            r, g, b, a := img.At(x, y).RGBA()
            raw[idx], raw[idx+1], raw[idx+2], raw[idx+3] = uint8(r), uint8(g), uint8(b), uint8(a)
            idx += 4
        }
    }
    return raw
}