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fix(canvas): preserve signed pixel rectangles through clipping

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This commit is contained in:
ldm0
2026-10-13 22:09:09 +08:00
committed by Donough Liu
parent 1e7b796d78
commit cd24b7d260
5 changed files with 165 additions and 158 deletions
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moli-canvas/src/blit.rs
+35 -66
View File
@@ -1,27 +1,22 @@
use crate::pixel::{copy_rgba8_rect, scale_rgba8};
use crate::types::{DrawImageBlit, Rgba8Rect, ScaleFilter, byte_len, surface_matches_len};
use crate::types::{
DrawImageBlit, ImageDataRect, Rgba8Rect, ScaleFilter, byte_len, surface_matches_len,
};
pub fn extract_image_data(
pixels: &[u8],
canvas_width: u32,
canvas_height: u32,
source_x: i32,
source_y: i32,
width: u32,
height: u32,
rect: ImageDataRect,
) -> Vec<u8> {
let (width, height) = (rect.width, rect.height);
let mut out = vec![0; byte_len(width, height).unwrap_or(0)];
if !surface_matches_len(pixels, canvas_width, canvas_height) {
return out;
}
let Some((source_rect, dest_x, dest_y)) = clipped_source_rect_for_extract(
source_x,
source_y,
width,
height,
canvas_width,
canvas_height,
) else {
let Some((source_rect, dest_x, dest_y)) =
clipped_source_rect_for_extract(rect, canvas_width, canvas_height)
else {
return out;
};
let _ = copy_rgba8_rect(
@@ -39,17 +34,14 @@ pub fn extract_image_data(
}
fn clipped_source_rect_for_extract(
source_x: i32,
source_y: i32,
width: u32,
height: u32,
rect: ImageDataRect,
canvas_width: u32,
canvas_height: u32,
) -> Option<(Rgba8Rect, u32, u32)> {
let left = source_x as i64;
let top = source_y as i64;
let right = left.checked_add(width as i64)?;
let bottom = top.checked_add(height as i64)?;
let left = rect.x;
let top = rect.y;
let right = left + i64::from(rect.width);
let bottom = top + i64::from(rect.height);
let copy_left = left.max(0).min(canvas_width as i64);
let copy_top = top.max(0).min(canvas_height as i64);
let copy_right = right.max(0).min(canvas_width as i64);
@@ -80,15 +72,12 @@ pub fn blit_image_data(
source_height: u32,
dx: i32,
dy: i32,
dirty_x: i32,
dirty_y: i32,
dirty_width: i32,
dirty_height: i32,
dirty_rect: ImageDataRect,
) {
if !surface_matches_len(pixels, canvas_width, canvas_height)
|| !surface_matches_len(source, source_width, source_height)
|| dirty_width <= 0
|| dirty_height <= 0
|| dirty_rect.width == 0
|| dirty_rect.height == 0
{
return;
}
@@ -99,10 +88,7 @@ pub fn blit_image_data(
canvas_height,
dx,
dy,
dirty_x,
dirty_y,
dirty_width,
dirty_height,
dirty_rect,
) else {
return;
};
@@ -119,7 +105,6 @@ pub fn blit_image_data(
);
}
#[allow(clippy::too_many_arguments)]
fn clipped_blit_rect(
source_width: u32,
source_height: u32,
@@ -127,40 +112,20 @@ fn clipped_blit_rect(
dest_height: u32,
dest_x: i32,
dest_y: i32,
dirty_x: i32,
dirty_y: i32,
dirty_width: i32,
dirty_height: i32,
dirty_rect: ImageDataRect,
) -> Option<(Rgba8Rect, u32, u32)> {
let mut source_left = (dirty_x as i64).max(0).min(source_width as i64);
let mut source_top = (dirty_y as i64).max(0).min(source_height as i64);
let mut source_right = (dirty_x as i64)
.checked_add(dirty_width as i64)?
.max(0)
.min(source_width as i64);
let mut source_bottom = (dirty_y as i64)
.checked_add(dirty_height as i64)?
.max(0)
.min(source_height as i64);
let mut target_x = dest_x as i64;
let mut target_y = dest_y as i64;
if target_x < 0 {
let skip = -target_x;
source_left += skip;
target_x = 0;
}
if target_y < 0 {
let skip = -target_y;
source_top += skip;
target_y = 0;
}
if target_x + (source_right - source_left) > dest_width as i64 {
source_right -= target_x + (source_right - source_left) - dest_width as i64;
}
if target_y + (source_bottom - source_top) > dest_height as i64 {
source_bottom -= target_y + (source_bottom - source_top) - dest_height as i64;
}
// Intersect in source coordinates. A source pixel (x, y) is always written
// to (dest_x + x, dest_y + y), even when the dirty rectangle is clipped.
let dest_x = i64::from(dest_x);
let dest_y = i64::from(dest_y);
let source_left = dirty_rect.x.max(0).max(-dest_x);
let source_top = dirty_rect.y.max(0).max(-dest_y);
let source_right = (dirty_rect.x + i64::from(dirty_rect.width))
.min(i64::from(source_width))
.min(i64::from(dest_width) - dest_x);
let source_bottom = (dirty_rect.y + i64::from(dirty_rect.height))
.min(i64::from(source_height))
.min(i64::from(dest_height) - dest_y);
if source_left >= source_right || source_top >= source_bottom {
return None;
}
@@ -170,7 +135,11 @@ fn clipped_blit_rect(
(source_right - source_left) as u32,
(source_bottom - source_top) as u32,
)?;
Some((source_rect, target_x as u32, target_y as u32))
Some((
source_rect,
(dest_x + source_left) as u32,
(dest_y + source_top) as u32,
))
}
pub fn blit_draw_image(
moli-canvas/src/lib.rs
+83 -15
View File
@@ -17,8 +17,8 @@ pub use pixel::{
pub use rect::{canonicalize_fill_style, fill_style_rgba, normalize_rect, paint_rect};
pub use text::{draw_text, measure_text_width};
pub use types::{
CanvasRect, DEFAULT_FILL_STYLE, DEFAULT_FONT, DrawImageBlit, MAX_RGBA8_BYTE_LENGTH, Rgba8Rect,
ScaleFilter, byte_len,
CanvasRect, DEFAULT_FILL_STYLE, DEFAULT_FONT, DrawImageBlit, ImageDataRect,
MAX_RGBA8_BYTE_LENGTH, Rgba8Rect, ScaleFilter, byte_len,
};
#[cfg(test)]
@@ -264,7 +264,7 @@ mod tests {
.expect("copy should fit");
assert_eq!(
extract_image_data(&dest, 4, 3, 1, 1, 2, 2),
extract_image_data(&dest, 4, 3, ImageDataRect::new(1, 1, 2, 2)),
vec![
2, 0, 0, 255, 3, 0, 0, 255, //
5, 0, 0, 255, 6, 0, 0, 255,
@@ -404,15 +404,28 @@ mod tests {
255, 0, 0, 255, 0, 255, 0, 255, 0, 0, 255, 255, 255, 255, 0, 255,
];
blit_image_data(&mut dst, 2, 2, &src, 2, 2, 0, 0, 0, 0, 2, 2);
assert_eq!(extract_image_data(&dst, 2, 2, 0, 0, 2, 2), src);
blit_image_data(
&mut dst,
2,
2,
&src,
2,
2,
0,
0,
ImageDataRect::new(0, 0, 2, 2),
);
assert_eq!(
extract_image_data(&dst, 2, 2, ImageDataRect::new(0, 0, 2, 2)),
src
);
}
#[test]
fn extract_image_data_out_of_bounds_fills_transparent_black() {
let pixels = vec![255, 0, 0, 255];
assert_eq!(
extract_image_data(&pixels, 1, 1, -1, -1, 2, 2),
extract_image_data(&pixels, 1, 1, ImageDataRect::new(-1, -1, 2, 2)),
vec![
0, 0, 0, 0, 0, 0, 0, 0, //
0, 0, 0, 0, 255, 0, 0, 255,
@@ -420,6 +433,44 @@ mod tests {
);
}
#[test]
fn image_data_extreme_rectangles_clip_without_wrapping() {
let source = vec![255, 0, 0, 255, 0, 255, 0, 255];
let mut target = vec![0; 8];
blit_image_data(
&mut target,
2,
1,
&source,
2,
1,
0,
0,
ImageDataRect::new(1, 0, i32::MIN, 1),
);
assert_eq!(target, [255, 0, 0, 255, 0, 0, 0, 0]);
assert_eq!(
extract_image_data(&source, 2, 1, ImageDataRect::new(2, 1, -2, -1)),
source,
);
assert_eq!(
extract_image_data(&source, 2, 1, ImageDataRect::new(i32::MIN, 0, -2, 1)),
[0; 8],
);
blit_image_data(
&mut target,
2,
1,
&source,
2,
1,
i32::MAX,
0,
ImageDataRect::new(i32::MIN, 0, i32::MIN, 1),
);
assert_eq!(target, [255, 0, 0, 255, 0, 0, 0, 0]);
}
#[test]
fn blit_image_data_honors_dirty_rect_and_destination_clipping() {
let source = vec![
@@ -428,17 +479,37 @@ mod tests {
];
let mut dst = vec![0; byte_len(2, 2).expect("buffer len")];
blit_image_data(&mut dst, 2, 2, &source, 2, 2, 0, 0, 1, 0, 1, 2);
blit_image_data(
&mut dst,
2,
2,
&source,
2,
2,
0,
0,
ImageDataRect::new(1, 0, 1, 2),
);
assert_eq!(
dst,
vec![
0, 255, 0, 255, 0, 0, 0, 0, //
255, 255, 0, 255, 0, 0, 0, 0,
0, 0, 0, 0, 0, 255, 0, 255, //
0, 0, 0, 0, 255, 255, 0, 255,
]
);
let mut clipped = vec![0; byte_len(1, 2).expect("buffer len")];
blit_image_data(&mut clipped, 1, 2, &source, 2, 2, -1, 0, 0, 0, 2, 2);
blit_image_data(
&mut clipped,
1,
2,
&source,
2,
2,
-1,
0,
ImageDataRect::new(0, 0, 2, 2),
);
assert_eq!(
clipped,
vec![
@@ -457,10 +528,7 @@ mod tests {
2,
-1,
0,
0,
0,
2,
2,
ImageDataRect::new(0, 0, 2, 2),
);
assert_eq!(
negative_destination,
@@ -488,7 +556,7 @@ mod tests {
2,
DrawImageBlit::new(0.0, 0.0, 2.0, 2.0, 1.0, 1.0, 2.0, 2.0).expect("valid blit"),
);
let scaled_crop = extract_image_data(&scaled, 4, 4, 1, 1, 2, 2);
let scaled_crop = extract_image_data(&scaled, 4, 4, ImageDataRect::new(1, 1, 2, 2));
assert_eq!(
scaled_crop,
vec![
moli-canvas/src/types.rs
+29
View File
@@ -4,6 +4,35 @@ pub const MAX_RGBA8_BYTE_LENGTH: usize = 2_147_483_647;
pub type CanvasRect = (i32, i32, i32, i32);
/// A pixel rectangle normalized from WebIDL long coordinates and signed spans.
/// Keep its origin wide: normalizing a negative span can leave the i32 range.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct ImageDataRect {
pub(crate) x: i64,
pub(crate) y: i64,
pub(crate) width: u32,
pub(crate) height: u32,
}
impl ImageDataRect {
pub fn new(x: i32, y: i32, width: i32, height: i32) -> Self {
Self {
x: i64::from(x) + i64::from(width.min(0)),
y: i64::from(y) + i64::from(height.min(0)),
width: width.unsigned_abs(),
height: height.unsigned_abs(),
}
}
pub fn width(self) -> u32 {
self.width
}
pub fn height(self) -> u32 {
self.height
}
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct Rgba8Rect {
pub x: u32,
moli-renderer-v8/src/context_bootstrap/canvas/context2d.rs
+12 -74
View File
@@ -1991,15 +1991,12 @@ pub(crate) fn canvas_context_put_image_data_callback<'s>(
else {
return;
};
let Some(dirty_rect) = normalized_image_data_dirty_rect(
scope,
let dirty_rect = moli_canvas::ImageDataRect::new(
parsed.dirty_x,
parsed.dirty_y,
parsed.dirty_width,
parsed.dirty_height,
) else {
return;
};
);
(parsed.image_data, parsed.dx, parsed.dy, Some(dirty_rect))
} else {
let Some(parsed) = webidl::parse_args::<CanvasContextPutImageDataArgs>(scope, &args) else {
@@ -2019,11 +2016,9 @@ pub(crate) fn canvas_context_put_image_data_callback<'s>(
return;
};
let (dirty_x, dirty_y, dirty_width, dirty_height) = if args.length() >= 7 {
dirty_rect.unwrap_or((0, 0, 0, 0))
} else {
(0, 0, source_width as i32, source_height as i32)
};
let dirty_rect = dirty_rect.unwrap_or_else(|| {
moli_canvas::ImageDataRect::new(0, 0, source_width as i32, source_height as i32)
});
let _ = with_canvas_like_pixels_mut(scope, canvas, |pixels, width, height| {
blit_image_data(
@@ -2035,10 +2030,7 @@ pub(crate) fn canvas_context_put_image_data_callback<'s>(
source_height,
dx,
dy,
dirty_x,
dirty_y,
dirty_width,
dirty_height,
dirty_rect,
);
});
}
@@ -2052,33 +2044,21 @@ pub(crate) fn canvas_context_get_image_data_callback<'s>(
rv.set(v8::undefined(scope).into());
return;
};
let Some(width) = positive_image_data_dimension_from_long(scope, parsed.sw) else {
rv.set(v8::undefined(scope).into());
let rect = moli_canvas::ImageDataRect::new(parsed.sx, parsed.sy, parsed.sw, parsed.sh);
let (width, height) = (rect.width(), rect.height());
if width == 0 || height == 0 {
webidl::throw_index_size_error(scope);
return;
};
let Some(height) = positive_image_data_dimension_from_long(scope, parsed.sh) else {
rv.set(v8::undefined(scope).into());
return;
};
}
if byte_len(width, height).is_none() {
webidl::throw_index_size_error(scope);
rv.set(v8::undefined(scope).into());
return;
}
let source_x = parsed.sx;
let source_y = parsed.sy;
let bytes = if let Some(canvas) = canvas_owner_from_context(scope, args.this()) {
canvas_like_pixels_copy(scope, canvas)
.map(|(pixels, canvas_width, canvas_height)| {
extract_image_data(
&pixels,
canvas_width,
canvas_height,
source_x,
source_y,
width,
height,
)
extract_image_data(&pixels, canvas_width, canvas_height, rect)
})
.unwrap_or_else(|| blank_image_data(width, height))
} else {
@@ -2115,48 +2095,6 @@ fn image_data_dimension_from_long(scope: &mut v8::PinScope<'_, '_>, value: i32)
Some(value.unsigned_abs())
}
fn positive_image_data_dimension_from_long(
scope: &mut v8::PinScope<'_, '_>,
value: i32,
) -> Option<u32> {
if value <= 0 {
webidl::throw_index_size_error(scope);
return None;
}
Some(value as u32)
}
fn normalized_image_data_dirty_rect(
scope: &mut v8::PinScope<'_, '_>,
dirty_x: i32,
dirty_y: i32,
dirty_width: i32,
dirty_height: i32,
) -> Option<(i32, i32, i32, i32)> {
let (dirty_x, dirty_width) = normalized_dirty_axis(scope, dirty_x, dirty_width)?;
let (dirty_y, dirty_height) = normalized_dirty_axis(scope, dirty_y, dirty_height)?;
Some((dirty_x, dirty_y, dirty_width, dirty_height))
}
fn normalized_dirty_axis(
scope: &mut v8::PinScope<'_, '_>,
start: i32,
span: i32,
) -> Option<(i32, i32)> {
if span >= 0 {
return Some((start, span));
}
if span == i32::MIN {
webidl::throw_index_size_error(scope);
return None;
}
let start = start.checked_add(span).or_else(|| {
webidl::throw_index_size_error(scope);
None
})?;
Some((start, -span))
}
fn normalized_rect<'s>(
scope: &mut v8::PinScope<'s, '_>,
args: &v8::FunctionCallbackArguments<'s>,
moli-renderer-v8/src/script_vm/tests/canvas_webgl.rs
+6 -3
View File
@@ -1781,7 +1781,7 @@ fn html_canvas_put_image_data_honors_dirty_rect() {
)
.expect("canvas putImageData dirty rect should evaluate");
assert_eq!(result, "[0,255,0,255,0,0,0,0,255,255,0,255,0,0,0,0]");
assert_eq!(result, "[0,0,0,0,0,255,0,255,0,0,0,0,255,255,0,255]");
}
#[test]
@@ -1813,7 +1813,10 @@ fn html_canvas_image_data_methods_parse_webidl_enforce_range_long() {
});
const createZero = probe(() => ctx.createImageData(0, 1));
const createSymbol = probe(() => ctx.createImageData(Symbol('width'), 1));
const getNegative = probe(() => ctx.getImageData(2, 2, -2, -2));
const getNegative = probe(() => {
const data = ctx.getImageData(2, 2, -2, -2);
return [data.width, data.height, Array.from(data.data).join(',')].join('|');
});
const getMissing = probe(() => ctx.getImageData(0, 0, 1));
const getNan = probe(() => ctx.getImageData(NaN, 0, 1, 1));
const getZero = probe(() => ctx.getImageData(0, 0, 0, 1));
@@ -1869,7 +1872,7 @@ fn html_canvas_image_data_methods_parse_webidl_enforce_range_long() {
assert_eq!(
result,
r#"{"created":"2:3","createZero":"IndexSizeError","createSymbol":"TypeError","getNegative":"IndexSizeError","getMissing":"TypeError","getNan":"TypeError","getZero":"IndexSizeError","constructorOversized":"IndexSizeError","getOversized":"IndexSizeError","putCoerced":"0,0,0,0,255,0,0,255,0,255,0,255","putSymbol":"TypeError","afterBadPut":true,"dirtyNegative":"255,0,0,255,0,0,0,0","putPlainObject":"TypeError"}"#
r#"{"created":"2:3","createZero":"IndexSizeError","createSymbol":"TypeError","getNegative":"2|2|255,0,0,255,255,0,0,255,255,0,0,255,255,0,0,255","getMissing":"TypeError","getNan":"TypeError","getZero":"IndexSizeError","constructorOversized":"IndexSizeError","getOversized":"IndexSizeError","putCoerced":"0,0,0,0,255,0,0,255,0,255,0,255","putSymbol":"TypeError","afterBadPut":true,"dirtyNegative":"255,0,0,255,0,0,0,0","putPlainObject":"TypeError"}"#
);
}