rotate90 method
Implementation
UGrayImage rotate90() {
final Uint8List out = Uint8List(width * height);
for (int y = 0; y < height; y++) {
final int src = y * stride;
for (int x = 0; x < width; x++) {
out[x * height + (height - 1 - y)] = data[src + x];
}
}
return UGrayImage(out, height, width, left: left, top: top, sourceWidth: sourceWidth, sourceHeight: sourceHeight);
}