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
}