vello_cpu/filter/
offset.rs

1// Copyright 2026 the Vello Authors
2// SPDX-License-Identifier: Apache-2.0 OR MIT
3
4//! `feOffset` filter primitive implementation.
5
6use vello_common::filter::offset::Offset;
7use vello_common::pixmap::Pixmap;
8
9use super::FilterEffect;
10use super::shift::offset_pixels;
11use crate::filter::context::ScratchBuffer;
12
13impl FilterEffect for Offset {
14    fn execute_lowp(&self, pixmap: &mut Pixmap, _: &mut ScratchBuffer) {
15        offset_pixels(pixmap, self.dx, self.dy);
16    }
17
18    fn execute_highp(&self, pixmap: &mut Pixmap, _: &mut ScratchBuffer) {
19        offset_pixels(pixmap, self.dx, self.dy);
20    }
21}
22
23#[cfg(test)]
24mod tests {
25    use super::Offset;
26    use crate::filter::FilterEffect;
27    use crate::filter::context::ScratchBuffer;
28    use vello_common::peniko::color::PremulRgba8;
29    use vello_common::pixmap::Pixmap;
30
31    #[test]
32    fn offset_moves_pixels_and_clears_uncovered_area() {
33        let mut filter_scratch = ScratchBuffer::new();
34        let mut pixmap = Pixmap::new(4, 3);
35        pixmap.set_pixel(1, 1, PremulRgba8::from_u32(0xff_00_00_ff)); // premul red, opaque
36
37        Offset::new(2.0, -1.0).execute_lowp(&mut pixmap, &mut filter_scratch);
38
39        // Original pixel (1,1) moved to (3,0).
40        assert_eq!(pixmap.sample(3, 0), PremulRgba8::from_u32(0xff_00_00_ff));
41        // Original location cleared.
42        assert_eq!(pixmap.sample(1, 1), PremulRgba8::from_u32(0));
43    }
44}
vello_cpu/filter/offset.rs

vello_cpu/filter/
offset.rs
