func loadSize(data []byte, max int) *image.RGBA { i, _, err := image.Decode(bytes.NewBuffer(data)) if err != nil { panic(err) } // switch i := i.(type) { // case *image.RGBA64: // i = i.RGBA() // } b := i.Bounds() dx, dy := max, max if b.Dx() > b.Dy() { dy = b.Dy() * dx / b.Dx() } else { dx = b.Dx() * dy / b.Dy() } var irgba *image.RGBA switch i := i.(type) { case *image.RGBA: irgba = qr.ResizeRGBA(i, i.Bounds(), dx, dy) case *image.NRGBA: irgba = qr.ResizeNRGBA(i, i.Bounds(), dx, dy) } return irgba }
// convert2PNG convert any format to PNG func convert2PNG(i image.Image) bytes.Buffer { // Convert image to 128x128 gray+alpha. // i := grayScale(i) b := i.Bounds() const max = 128 // If it's gigantic, it's more efficient to downsample first // and then resize; resizing will smooth out the roughness. var i1 *image.RGBA if b.Dx() > 4*max || b.Dy() > 4*max { w, h := 2*max, 2*max if b.Dx() > b.Dy() { h = b.Dy() * h / b.Dx() } else { w = b.Dx() * w / b.Dy() } i1 = qr.Resample(i, b, w, h) } else { // "Resample" to same size, just to convert to RGBA. i1 = qr.Resample(i, b, b.Dx(), b.Dy()) } b = i1.Bounds() // Encode to PNG. dx, dy := 128, 128 if b.Dx() > b.Dy() { dy = b.Dy() * dx / b.Dx() } else { dx = b.Dx() * dy / b.Dy() } i128 := qr.ResizeRGBA(i1, i1.Bounds(), dx, dy) var buf bytes.Buffer if err := png.Encode(&buf, i128); err != nil { panic(err) } return buf }