// TODO: In the common case where a+b=1, it would be useful to be able to set
// alpha_handling() to INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK. However, right now
// TODO: In the common case where a+b=1, it would be useful to be able to set
// alpha_handling() to INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK. However, right now