Fix canvas image tests when using webrender.

When webrender is enabled, image decoding doesn't pre-multiply by
alpha, but the canvas code expects the image data to be
pre-multiplied form.
This commit is contained in:
Glenn Watson 2016-08-30 09:54:05 +10:00
parent a338beaa70
commit 119716acb2
2 changed files with 28 additions and 2 deletions

View file

@ -552,3 +552,21 @@ pub fn byte_swap(data: &mut [u8]) {
i += 4;
}
}
pub fn byte_swap_and_premultiply(data: &mut [u8]) {
let length = data.len();
let mut i = 0;
while i < length {
let r = data[i + 2];
let g = data[i + 1];
let b = data[i + 0];
let a = data[i + 3];
data[i + 0] = ((r as u32) * (a as u32) / 255) as u8;
data[i + 1] = ((g as u32) * (a as u32) / 255) as u8;
data[i + 2] = ((b as u32) * (a as u32) / 255) as u8;
i += 4;
}
}