Merge some byte swap/premultiply functions in their own crate

components/canvas/Cargo.toml

@@ -24,6 +24,7 @@ ipc-channel = "0.11"
 log = "0.4"
 num-traits = "0.2"
 offscreen_gl_context = {version = "0.21", features = ["serde", "osmesa"]}
+pixels = {path = "../pixels"}
 serde_bytes = "0.10"
 servo_config = {path = "../config"}
 webrender = {git = "https://github.com/servo/webrender"}

components/canvas/canvas_paint_thread.rs

@@ -7,6 +7,7 @@ use canvas_data::*;
 use canvas_traits::canvas::*;
 use euclid::Size2D;
 use ipc_channel::ipc::{self, IpcSender};
+use pixels;
 use std::borrow::ToOwned;
 use std::collections::HashMap;
 use std::thread;
@@ -141,7 +142,7 @@ impl<'a> CanvasPaintThread <'a> {
                 let data = match imagedata {
                     None => vec![0; image_size.width as usize * image_size.height as usize * 4],
                     Some(mut data) => {
-                        byte_swap(&mut data);
+                        pixels::byte_swap_colors_inplace(&mut data);
                         data.into()
                     },
                 };

components/canvas/lib.rs

@@ -15,6 +15,7 @@ extern crate ipc_channel;
 #[macro_use] extern crate log;
 extern crate num_traits;
 extern crate offscreen_gl_context;
+extern crate pixels;
 extern crate serde_bytes;
 extern crate servo_config;
 extern crate webrender;

components/canvas/webgl_thread.rs

@@ -2,13 +2,13 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use canvas_traits::canvas::byte_swap;
 use canvas_traits::webgl::*;
 use euclid::Size2D;
 use fnv::FnvHashMap;
 use gleam::gl;
 use ipc_channel::ipc::IpcBytesSender;
 use offscreen_gl_context::{GLContext, GLContextAttributes, GLLimits, NativeGLContextMethods};
+use pixels;
 use std::thread;
 use super::gl_context::{GLContextFactory, GLContextWrapper};
 use webrender;
@@ -562,7 +562,7 @@ impl<VR: WebVRRenderHandler + 'static> WebGLThread<VR> {
             let src_slice = &orig_pixels[src_start .. src_start + stride];
             (&mut pixels[dst_start .. dst_start + stride]).clone_from_slice(&src_slice[..stride]);
         }
-        byte_swap(&mut pixels);
+        pixels::byte_swap_colors_inplace(&mut pixels);
         pixels
     }
 

components/canvas_traits/canvas.rs

@@ -382,38 +382,3 @@ impl FromStr for CompositionOrBlending {
         Err(())
     }
 }
-
-// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
-pub fn byte_swap(data: &mut [u8]) {
-    let length = data.len();
-    // FIXME(rust #27741): Range::step_by is not stable yet as of this writing.
-    let mut i = 0;
-    while i < length {
-        let r = data[i + 2];
-        data[i + 2] = data[i + 0];
-        data[i + 0] = r;
-        i += 4;
-    }
-}
-
-pub fn multiply_u8_pixel(a: u8, b: u8) -> u8 {
-    return (a as u32 * b as u32 / 255) as u8;
-}
-
-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] = multiply_u8_pixel(r, a);
-        data[i + 1] = multiply_u8_pixel(g, a);
-        data[i + 2] = multiply_u8_pixel(b, a);
-
-        i += 4;
-    }
-}

components/net/Cargo.toml

@@ -34,6 +34,7 @@ mime_guess = "1.8.0"
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
 openssl = "0.9"
+pixels = {path = "../pixels"}
 profile_traits = {path = "../profile_traits"}
 serde = "1.0"
 serde_json = "1.0"

components/net/image_cache.rs

@@ -9,6 +9,7 @@ use net_traits::image::base::{Image, ImageMetadata, PixelFormat, load_from_memor
 use net_traits::image_cache::{CanRequestImages, ImageCache, ImageResponder};
 use net_traits::image_cache::{ImageOrMetadataAvailable, ImageResponse, ImageState};
 use net_traits::image_cache::{PendingImageId, UsePlaceholder};
+use pixels;
 use servo_url::ServoUrl;
 use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
@@ -52,7 +53,7 @@ fn set_webrender_image_key(webrender_api: &webrender_api::RenderApi, image: &mut
     let is_opaque = match image.format {
         PixelFormat::BGRA8 => {
             bytes.extend_from_slice(&*image.bytes);
-            premultiply(bytes.as_mut_slice())
+            pixels::premultiply_inplace(bytes.as_mut_slice())
         }
         PixelFormat::RGB8 => {
             for bgr in image.bytes.chunks(3) {
@@ -86,30 +87,6 @@ fn set_webrender_image_key(webrender_api: &webrender_api::RenderApi, image: &mut
     image.id = Some(image_key);
 }
 
-// Returns true if the image was found to be
-// completely opaque.
-fn premultiply(data: &mut [u8]) -> bool {
-    let mut is_opaque = true;
-    let length = data.len();
-
-    let mut i = 0;
-    while i < length {
-        let b = data[i + 0] as u32;
-        let g = data[i + 1] as u32;
-        let r = data[i + 2] as u32;
-        let a = data[i + 3] as u32;
-
-        data[i + 0] = (b * a / 255) as u8;
-        data[i + 1] = (g * a / 255) as u8;
-        data[i + 2] = (r * a / 255) as u8;
-
-        i += 4;
-        is_opaque = is_opaque && a == 255;
-    }
-
-    is_opaque
-}
-
 // ======================================================================
 // Aux structs and enums.
 // ======================================================================

components/net/lib.rs

@@ -27,6 +27,7 @@ extern crate mime_guess;
 extern crate msg;
 extern crate net_traits;
 extern crate openssl;
+extern crate pixels;
 #[macro_use]
 extern crate profile_traits;
 #[macro_use] extern crate serde;

components/net_traits/Cargo.toml

@@ -24,6 +24,7 @@ malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 msg = {path = "../msg"}
 num-traits = "0.2"
+pixels = {path = "../pixels"}
 serde = "1.0"
 servo_arc = {path = "../servo_arc"}
 servo_config = {path = "../config"}

components/net_traits/image/base.rs

@@ -4,6 +4,7 @@
 
 use ipc_channel::ipc::IpcSharedMemory;
 use piston_image::{self, DynamicImage, ImageFormat};
+use pixels;
 use std::fmt;
 use webrender_api;
 
@@ -46,24 +47,6 @@ pub struct ImageMetadata {
 // FIXME: Images must not be copied every frame. Instead we should atomically
 // reference count them.
 
-// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
-fn byte_swap_colors_inplace(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];
-
-        data[i + 0] = r;
-        data[i + 1] = g;
-        data[i + 2] = b;
-
-        i += 4;
-    }
-}
-
 pub fn load_from_memory(buffer: &[u8]) -> Option<Image> {
     if buffer.is_empty() {
         return None;
@@ -82,7 +65,7 @@ pub fn load_from_memory(buffer: &[u8]) -> Option<Image> {
                         DynamicImage::ImageRgba8(rgba) => rgba,
                         image => image.to_rgba(),
                     };
-                    byte_swap_colors_inplace(&mut *rgba);
+                    pixels::byte_swap_colors_inplace(&mut *rgba);
                     Some(Image {
                         width: rgba.width(),
                         height: rgba.height(),

components/net_traits/lib.rs

@@ -17,6 +17,7 @@ extern crate ipc_channel;
 #[macro_use] extern crate malloc_size_of_derive;
 extern crate msg;
 extern crate num_traits;
+extern crate pixels;
 #[macro_use] extern crate serde;
 extern crate servo_arc;
 extern crate servo_url;

components/pixels/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "pixels"
+version = "0.0.1"
+authors = ["The Servo Project Developers"]
+license = "MPL-2.0"
+publish = false
+
+[lib]
+name = "pixels"
+path = "lib.rs"

components/pixels/lib.rs

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
+pub fn byte_swap_colors_inplace(pixels: &mut [u8]) {
+    assert!(pixels.len() % 4 == 0);
+    for rgba in pixels.chunks_mut(4) {
+        let b = rgba[0];
+        rgba[0] = rgba[2];
+        rgba[2] = b;
+    }
+}
+
+pub fn byte_swap_and_premultiply_inplace(pixels: &mut [u8]) {
+    assert!(pixels.len() % 4 == 0);
+    for rgba in pixels.chunks_mut(4) {
+        let b = rgba[0];
+        rgba[0] = multiply_u8_color(rgba[2], rgba[3]);
+        rgba[1] = multiply_u8_color(rgba[1], rgba[3]);
+        rgba[2] = multiply_u8_color(b, rgba[3]);
+    }
+}
+
+/// Returns true if the pixels were found to be completely opaque.
+pub fn premultiply_inplace(pixels: &mut [u8]) -> bool {
+    assert!(pixels.len() % 4 == 0);
+    let mut is_opaque = true;
+    for rgba in pixels.chunks_mut(4) {
+        rgba[0] = multiply_u8_color(rgba[0], rgba[3]);
+        rgba[1] = multiply_u8_color(rgba[1], rgba[3]);
+        rgba[2] = multiply_u8_color(rgba[2], rgba[3]);
+        is_opaque = is_opaque && rgba[3] == 255;
+    }
+    is_opaque
+}
+
+pub fn multiply_u8_color(a: u8, b: u8) -> u8 {
+    return (a as u32 * b as u32 / 255) as u8;
+}

components/script/Cargo.toml

@@ -75,6 +75,7 @@ num-traits = "0.2"
 offscreen_gl_context = {version = "0.21", features = ["serde"]}
 parking_lot = "0.6"
 phf = "0.7.18"
+pixels = {path = "../pixels"}
 profile_traits = {path = "../profile_traits"}
 ref_filter_map = "1.0.1"
 ref_slice = "1.0"

components/script/dom/canvasrenderingcontext2d.rs

@@ -5,7 +5,7 @@
 use canvas_traits::canvas::{Canvas2dMsg, CanvasMsg, CanvasId};
 use canvas_traits::canvas::{CompositionOrBlending, FillOrStrokeStyle, FillRule};
 use canvas_traits::canvas::{LineCapStyle, LineJoinStyle, LinearGradientStyle};
-use canvas_traits::canvas::{RadialGradientStyle, RepetitionStyle, byte_swap_and_premultiply};
+use canvas_traits::canvas::{RadialGradientStyle, RepetitionStyle};
 use cssparser::{Parser, ParserInput, RGBA};
 use cssparser::Color as CSSColor;
 use dom::bindings::cell::DomRefCell;
@@ -41,6 +41,7 @@ use net_traits::image_cache::ImageResponse;
 use net_traits::image_cache::ImageState;
 use net_traits::image_cache::UsePlaceholder;
 use num_traits::ToPrimitive;
+use pixels;
 use profile_traits::ipc as profiled_ipc;
 use script_traits::ScriptMsg;
 use servo_url::ServoUrl;
@@ -410,7 +411,7 @@ impl CanvasRenderingContext2D {
             Some((mut data, size)) => {
                 // Pixels come from cache in BGRA order and drawImage expects RGBA so we
                 // have to swap the color values
-                byte_swap_and_premultiply(&mut data);
+                pixels::byte_swap_and_premultiply_inplace(&mut data);
                 let size = Size2D::new(size.width as f64, size.height as f64);
                 (data, size)
             },