diff options
Diffstat (limited to 'components/script/dom/canvasrenderingcontext2d.rs')
| -rw-r--r-- | components/script/dom/canvasrenderingcontext2d.rs | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/components/script/dom/canvasrenderingcontext2d.rs b/components/script/dom/canvasrenderingcontext2d.rs index 89d07cf815c..f66913a9417 100644 --- a/components/script/dom/canvasrenderingcontext2d.rs +++ b/components/script/dom/canvasrenderingcontext2d.rs @@ -41,6 +41,7 @@ use std::cell::RefCell; use std::str::FromStr; use std::sync::mpsc::channel; use std::{cmp, fmt}; +use unpremultiplytable::UNPREMULTIPLY_TABLE; use url::Url; use util::str::DOMString; use util::vec::byte_swap; @@ -889,13 +890,11 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D { let mut data = receiver.recv().unwrap(); // Un-premultiply alpha - // TODO: may want a precomputed un-premultiply table to make this fast. - // https://github.com/servo/servo/issues/6969 for chunk in data.chunks_mut(4) { - let alpha = chunk[3] as f32 / 255.; - chunk[0] = (chunk[0] as f32 / alpha) as u8; - chunk[1] = (chunk[1] as f32 / alpha) as u8; - chunk[2] = (chunk[2] as f32 / alpha) as u8; + let alpha = chunk[3] as usize; + chunk[0] = UNPREMULTIPLY_TABLE[256 * alpha + chunk[0] as usize]; + chunk[1] = UNPREMULTIPLY_TABLE[256 * alpha + chunk[1] as usize]; + chunk[2] = UNPREMULTIPLY_TABLE[256 * alpha + chunk[2] as usize]; } Ok(ImageData::new(self.global.root().r(), sw, sh, Some(data))) |