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/* 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/. */
use std::iter::range_step;
use stb_image::image as stb_image;
use png;
// FIXME: Images must not be copied every frame. Instead we should atomically
// reference count them.
pub type Image = png::Image;
static TEST_IMAGE: &'static [u8] = include_bin!("test.jpeg");
pub fn test_image_bin() -> Vec<u8> {
TEST_IMAGE.iter().map(|&x| x).collect()
}
// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
fn byte_swap(data: &mut [u8]) {
let length = data.len();
for i in range_step(0, length, 4) {
let r = data[i + 2];
data[i + 2] = data[i + 0];
data[i + 0] = r;
}
}
// TODO(pcwalton): Speed up with SIMD, or better yet, find some way to not do this.
fn byte_swap_and_premultiply(data: &mut [u8]) {
let length = data.len();
for i in range_step(0, length, 4) {
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;
}
}
pub fn load_from_memory(buffer: &[u8]) -> Option<Image> {
if buffer.len() == 0 {
return None;
}
if png::is_png(buffer) {
match png::load_png_from_memory(buffer) {
Ok(mut png_image) => {
match png_image.pixels {
png::PixelsByColorType::RGB8(ref mut data) => byte_swap(data.as_mut_slice()),
png::PixelsByColorType::RGBA8(ref mut data) => {
byte_swap_and_premultiply(data.as_mut_slice())
}
_ => {}
}
Some(png_image)
}
Err(_err) => None,
}
} else {
// For non-png images, we use stb_image
// Can't remember why we do this. Maybe it's what cairo wants
static FORCE_DEPTH: uint = 4;
match stb_image::load_from_memory_with_depth(buffer, FORCE_DEPTH, true) {
stb_image::LoadResult::ImageU8(mut image) => {
assert!(image.depth == 4);
byte_swap(image.data.as_mut_slice());
Some(png::Image {
width: image.width as u32,
height: image.height as u32,
pixels: png::PixelsByColorType::RGBA8(image.data)
})
}
stb_image::LoadResult::ImageF32(_image) => {
error!("HDR images not implemented");
None
}
stb_image::LoadResult::Error(e) => {
error!("stb_image failed: {}", e);
None
}
}
}
}
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