Auto merge of #21914 - Eijebong:canvas-cleanup, r=jdm

Use pixels::get_rect in CanvasData::draw_image

Those functions are the same except that get_rect isn't failible, so we
have to check that the rect we want is actually in the image.

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bors-servo 2018-11-01 03:29:06 -04:00 committed by GitHub
commit 8aded34bf6
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@ -68,7 +68,11 @@ impl<'a> CanvasData<'a> {
// We round up the floating pixel values to draw the pixels
let source_rect = source_rect.ceil();
// It discards the extra pixels (if any) that won't be painted
let image_data = crop_image(image_data, image_size, source_rect);
let image_data = if Rect::from_size(image_size).contains_rect(&source_rect) {
pixels::get_rect(&image_data, image_size.to_u32(), source_rect.to_u32()).into()
} else {
image_data.into()
};
let writer = |draw_target: &DrawTarget| {
write_image(&draw_target, image_data, source_rect.size, dest_rect,
@ -577,42 +581,6 @@ fn is_zero_size_gradient(pattern: &Pattern) -> bool {
false
}
/// Used by drawImage to get rid of the extra pixels of the image data that
/// won't be copied to the canvas
/// image_data: Color pixel data of the image
/// image_size: Image dimensions
/// crop_rect: It determines the area of the image we want to keep
fn crop_image(
image_data: Vec<u8>,
image_size: Size2D<f64>,
crop_rect: Rect<f64>
) -> Vec<u8> {
// We're going to iterate over a pixel values array so we need integers
let crop_rect = crop_rect.to_i32();
let image_size = image_size.to_i32();
if crop_rect == Rect::from_size(image_size) {
return image_data;
}
// Assuming 4 bytes per pixel and row-major order for storage
// (consecutive elements in a pixel row of the image are contiguous in memory)
let stride = image_size.width * 4;
let image_bytes_length = image_size.height * image_size.width * 4;
let crop_area_bytes_length = crop_rect.size.height * crop_rect.size.width * 4;
// If the image size is less or equal than the crop area we do nothing
if image_bytes_length <= crop_area_bytes_length {
return image_data;
}
let mut new_image_data = Vec::new();
let mut src = (crop_rect.origin.y * stride + crop_rect.origin.x * 4) as usize;
for _ in 0..crop_rect.size.height {
let row = &image_data[src .. src + (4 * crop_rect.size.width) as usize];
new_image_data.extend_from_slice(row);
src += stride as usize;
}
new_image_data
}
/// It writes an image to the destination target
/// draw_target: the destination target where the image_data will be copied
/// image_data: Pixel information of the image to be written. It takes RGBA8