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Abstract some stuff common to ctx.getImageData and ctx.putImageData
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@nox
nox committed Oct 8, 2018
1 parent e62dbab commit 77c28bd
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Showing 4 changed files with 97 additions and 147 deletions.
27 changes: 10 additions & 17 deletions components/canvas/canvas_data.rs
View file
Expand Up @@ -441,24 +441,20 @@ impl<'a> CanvasData<'a> {
}

// https://html.spec.whatwg.org/multipage/#dom-context-2d-putimagedata
pub fn put_image_data(
&mut self,
mut imagedata: Vec<u8>,
offset: Vector2D<i32>,
imagedata_size: Size2D<i32>,
) {
assert_eq!(imagedata_size.area() * 4, imagedata.len() as i32);
pub fn put_image_data(&mut self, mut imagedata: Vec<u8>, rect: Rect<u32>) {
assert_eq!(imagedata.len() % 4, 0);
assert_eq!(rect.size.area() as usize, imagedata.len() / 4);
pixels::byte_swap_and_premultiply_inplace(&mut imagedata);
let source_surface = self.drawtarget.create_source_surface_from_data(
&imagedata,
imagedata_size,
imagedata_size.width * 4,
rect.size.to_i32(),
rect.size.width as i32 * 4,
SurfaceFormat::B8G8R8A8,
).unwrap();
self.drawtarget.copy_surface(
source_surface,
Rect::from_size(imagedata_size),
offset.to_point(),
Rect::from_size(rect.size.to_i32()),
rect.origin.to_i32(),
);
}

Expand Down Expand Up @@ -517,14 +513,11 @@ impl<'a> CanvasData<'a> {
/// canvas_size: The size of the canvas we're reading from
/// read_rect: The area of the canvas we want to read from
#[allow(unsafe_code)]
pub fn read_pixels(&self, read_rect: Rect<i32>, canvas_size: Size2D<i32>) -> Vec<u8> {
pub fn read_pixels(&self, read_rect: Rect<u32>, canvas_size: Size2D<u32>) -> Vec<u8> {
let canvas_rect = Rect::from_size(canvas_size);
let src_read_rect = canvas_rect.intersection(&read_rect).unwrap_or(Rect::zero());

if src_read_rect.is_empty() || canvas_size.width <= 0 && canvas_size.height <= 0 {
return vec![];
if canvas_rect.intersection(&read_rect).map_or(true, |rect| rect.is_empty()) {
return vec![];
}

let data_surface = self.drawtarget.snapshot().get_data_surface();
pixels::get_rect(unsafe { data_surface.data() }, canvas_size.to_u32(), read_rect.to_u32()).into_owned()
}
Expand Down
12 changes: 4 additions & 8 deletions components/canvas/canvas_paint_thread.rs
View file
Expand Up @@ -162,8 +162,8 @@ impl<'a> CanvasPaintThread <'a> {
smoothing
) => {
let image_data = self.canvas(canvas_id).read_pixels(
source_rect.to_i32(),
image_size.to_i32(),
source_rect.to_u32(),
image_size.to_u32(),
);
self.canvas(other_canvas_id).draw_image(
image_data.into(),
Expand Down Expand Up @@ -242,12 +242,8 @@ impl<'a> CanvasPaintThread <'a> {
let pixels = self.canvas(canvas_id).read_pixels(dest_rect, canvas_size);
sender.send(&pixels).unwrap();
},
Canvas2dMsg::PutImageData(receiver, offset, imagedata_size) => {
self.canvas(canvas_id).put_image_data(
receiver.recv().unwrap(),
offset,
imagedata_size,
)
Canvas2dMsg::PutImageData(rect, receiver) => {
self.canvas(canvas_id).put_image_data(receiver.recv().unwrap(), rect);
},
Canvas2dMsg::SetShadowOffsetX(value) => {
self.canvas(canvas_id).set_shadow_offset_x(value)
Expand Down
6 changes: 3 additions & 3 deletions components/canvas_traits/canvas.rs
View file
Expand Up @@ -3,7 +3,7 @@
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use cssparser::RGBA;
use euclid::{Transform2D, Point2D, Vector2D, Rect, Size2D};
use euclid::{Transform2D, Point2D, Rect, Size2D};
use ipc_channel::ipc::{IpcBytesReceiver, IpcBytesSender, IpcSender};
use serde_bytes::ByteBuf;
use std::default::Default;
Expand Down Expand Up @@ -50,11 +50,11 @@ pub enum Canvas2dMsg {
Fill,
FillText(String, f64, f64, Option<f64>),
FillRect(Rect<f32>),
GetImageData(Rect<i32>, Size2D<i32>, IpcBytesSender),
GetImageData(Rect<u32>, Size2D<u32>, IpcBytesSender),
IsPointInPath(f64, f64, FillRule, IpcSender<bool>),
LineTo(Point2D<f32>),
MoveTo(Point2D<f32>),
PutImageData(IpcBytesReceiver, Vector2D<i32>, Size2D<i32>),
PutImageData(Rect<u32>, IpcBytesReceiver),
QuadraticCurveTo(Point2D<f32>, Point2D<f32>),
Rect(Rect<f32>),
RestoreContext,
Expand Down
199 changes: 80 additions & 119 deletions components/script/dom/canvasrenderingcontext2d.rs
View file
Expand Up @@ -1130,13 +1130,7 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
}

// https://html.spec.whatwg.org/multipage/#dom-context-2d-getimagedata
fn GetImageData(
&self,
mut sx: i32,
mut sy: i32,
mut sw: i32,
mut sh: i32,
) -> Fallible<DomRoot<ImageData>> {
fn GetImageData(&self, sx: i32, sy: i32, sw: i32, sh: i32) -> Fallible<DomRoot<ImageData>> {
// FIXME(nox): There are many arithmetic operations here that can
// overflow or underflow, this should probably be audited.

Expand All @@ -1148,57 +1142,30 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
return Err(Error::Security);
}

if sw < 0 {
sw = -sw;
sx -= sw;
}
if sh < 0 {
sh = -sh;
sy -= sh;
}

let data_width = sw;
let data_height = sh;

if sx < 0 {
sw += sx;
sx = 0;
}
if sy < 0 {
sh += sy;
sy = 0;
}

if sw <= 0 || sh <= 0 {
// All the pixels are before the start of the canvas surface.
return ImageData::new(&self.global(), data_width as u32, data_height as u32, None);
}

let (sender, receiver) = ipc::bytes_channel().unwrap();
let src_rect = Rect::new(Point2D::new(sx, sy), Size2D::new(sw, sh));
let (origin, size) = adjust_size_sign(Point2D::new(sx, sy), Size2D::new(sw, sh));
// FIXME(nox): This is probably wrong when this is a context for an
// offscreen canvas.
let canvas_size = self.canvas
.as_ref()
.map_or(Size2D::zero(), |c| c.get_size())
.try_cast().unwrap();
let canvas_rect = Rect::from_size(canvas_size);
let read_rect = match src_rect.intersection(&canvas_rect) {
Some(rect) if !rect.is_empty() => rect,
_ => {
// All the pixels are past the end of the canvas surface.
return ImageData::new(&self.global(), data_width as u32, data_height as u32, None);
}
let canvas_size = self.canvas.as_ref().map_or(Size2D::zero(), |c| c.get_size());
let read_rect = match clip(origin, size, canvas_size) {
Some(rect) => rect,
None => {
// All the pixels are outside the canvas surface.
return ImageData::new(&self.global(), size.width, size.height, None);
},
};

let (sender, receiver) = ipc::bytes_channel().unwrap();
self.send_canvas_2d_msg(Canvas2dMsg::GetImageData(read_rect, canvas_size, sender));
let mut pixels = receiver.recv().unwrap();
let mut pixels = receiver.recv().unwrap().to_vec();

for chunk in pixels.chunks_mut(4) {
let b = chunk[0];
chunk[0] = UNPREMULTIPLY_TABLE[256 * (chunk[3] as usize) + chunk[2] as usize];
chunk[1] = UNPREMULTIPLY_TABLE[256 * (chunk[3] as usize) + chunk[1] as usize];
chunk[2] = UNPREMULTIPLY_TABLE[256 * (chunk[3] as usize) + b as usize];
}
ImageData::new(&self.global(), sw as u32, sh as u32, Some(pixels.to_vec()))

ImageData::new(&self.global(), size.width, size.height, Some(pixels))
}

// https://html.spec.whatwg.org/multipage/#dom-context-2d-putimagedata
Expand All @@ -1213,17 +1180,17 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
imagedata: &ImageData,
dx: i32,
dy: i32,
mut dirty_x: i32,
mut dirty_y: i32,
mut dirty_width: i32,
mut dirty_height: i32,
dirty_x: i32,
dirty_y: i32,
dirty_width: i32,
dirty_height: i32,
) {
// FIXME(nox): There are many arithmetic operations here that can
// overflow or underflow, this should probably be audited.


let imagedata_size = Size2D::new(imagedata.Width() as i32, imagedata.Height() as i32);
if imagedata_size.width <= 0 || imagedata_size.height <= 0 {
let imagedata_size = Size2D::new(imagedata.Width(), imagedata.Height());
if imagedata_size.area() == 0 {
return;
}

Expand All @@ -1233,76 +1200,37 @@ impl CanvasRenderingContext2DMethods for CanvasRenderingContext2D {
// Step 2.
// TODO: throw InvalidState if buffer is detached.

// Step 3.
if dirty_width < 0 {
dirty_x += dirty_width;
dirty_width = -dirty_width;
}
if dirty_height < 0 {
dirty_y += dirty_height;
dirty_height = -dirty_height;
}

// Ignore any pixel that would be drawn before the beginning of the
// canvas surface.
let mut dest_x = dx + dirty_x;
let mut dest_y = dy + dirty_y;
if dest_x < 0 {
dirty_x -= dest_x;
dirty_width += dest_x;
dest_x = 0;
}
if dest_y < 0 {
dirty_y -= dest_y;
dirty_height += dest_y;
dest_y = 0;
}

// Step 4.
if dirty_x < 0 {
dirty_width += dirty_x;
dirty_x = 0;
}
if dirty_y < 0 {
dirty_height += dirty_y;
dirty_y = 0;
}

// Step 5.
if dirty_x + dirty_width > imagedata_size.width {
dirty_width = imagedata_size.width - dirty_x;
}
if dirty_y + dirty_height > imagedata_size.height {
dirty_height = imagedata_size.height - dirty_y;
}

// FIXME(nox): This is probably wrong when this is a context for an
// offscreen canvas.
let canvas_size = self.canvas.as_ref().map_or(Size2D::zero(), |c| c.get_size()).to_i32();
let origin = Point2D::new(dest_x, dest_y);
let drawable_size = (origin - canvas_size.to_vector().to_point()).to_size().abs();

// We take care of ignoring any pixel that would be drawn after the end
// of the canvas surface.
dirty_width = dirty_width.min(drawable_size.width);
dirty_height = dirty_height.min(drawable_size.height);

// Step 6.
if dirty_width <= 0 || dirty_height <= 0 {
return;
}
let canvas_size = self.canvas.as_ref().map_or(Size2D::zero(), |c| c.get_size());

let dirty_size = Size2D::new(dirty_width, dirty_height);
let dirty_rect = Rect::new(Point2D::new(dirty_x, dirty_y), dirty_size);
// Steps 3-6.
let (src_origin, src_size) = adjust_size_sign(
Point2D::new(dirty_x, dirty_y),
Size2D::new(dirty_width, dirty_height),
);
let src_rect = match clip(src_origin, src_size, imagedata_size) {
Some(rect) => rect,
None => return,
};
let (dst_origin, _) = adjust_size_sign(
Point2D::new(dirty_x.saturating_add(dx), dirty_y.saturating_add(dy)),
Size2D::new(dirty_width, dirty_height),
);
// By clipping to the canvas surface, we avoid sending any pixel
// that would fall outside it.
let dst_rect = match clip(dst_origin, src_rect.size, canvas_size) {
Some(rect) => rect,
None => return,
};

// Step 7.
let (sender, receiver) = ipc::bytes_channel().unwrap();
self.send_canvas_2d_msg(Canvas2dMsg::PutImageData(
receiver,
origin.to_vector(),
dirty_size,
));
sender.send(unsafe { &imagedata.get_rect(dirty_rect.try_cast().unwrap()) }).unwrap();
let pixels = unsafe {
&imagedata.get_rect(Rect::new(src_rect.origin, dst_rect.size))
};
self.send_canvas_2d_msg(Canvas2dMsg::PutImageData(dst_rect, receiver));
sender.send(pixels).unwrap();
self.mark_as_dirty();
}

Expand Down Expand Up @@ -1552,7 +1480,7 @@ fn is_rect_valid(rect: Rect<f64>) -> bool {
rect.size.width > 0.0 && rect.size.height > 0.0
}

// https://html.spec.whatwg.org/multipage/#serialisation-of-a-colour
// https://html.spec.whatwg.org/multipage/#serialisation-of-a-color
fn serialize<W>(color: &RGBA, dest: &mut W) -> fmt::Result
where
W: fmt::Write,
Expand Down Expand Up @@ -1583,3 +1511,36 @@ where
)
}
}

fn adjust_size_sign(
mut origin: Point2D<i32>,
mut size: Size2D<i32>,
) -> (Point2D<i32>, Size2D<u32>) {
if size.width < 0 {
size.width = -size.width;
origin.x = origin.x.saturating_sub(size.width);
}
if size.height < 0 {
size.height = -size.height;
origin.y = origin.y.saturating_sub(size.height);
}
(origin, size.to_u32())
}

fn clip(
mut origin: Point2D<i32>,
mut size: Size2D<u32>,
surface: Size2D<u32>,
) -> Option<Rect<u32>> {
if origin.x < 0 {
size.width = size.width.saturating_sub(-origin.x as u32);
origin.x = 0;
}
if origin.y < 0 {
size.height = size.height.saturating_sub(-origin.y as u32);
origin.y = 0;
}
Rect::new(origin.to_u32(), size)
.intersection(&Rect::from_size(surface))
.filter(|rect| !rect.is_empty())
}

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