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Merged
madsmtm merged 1 commit into from
Jan 19, 2026
Merged

Add Buffer::pixel_rows and Buffer::pixels_iter iterators #312

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4 changes: 3 additions & 1 deletion CHANGELOG.md
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
# Unreleased

- **Breaking:** Remove generic type parameters `D` and `W` from `Buffer<'_>` struct.
- Added `Buffer::pixel_rows()` for iterating over rows of the buffer data.
- Added `Buffer::pixels_iter()` for iterating over each pixel with its associated `x`/`y` coordinate.
- **Breaking:** Removed generic type parameters `D` and `W` from `Buffer<'_>` struct.

# 0.4.7

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6 changes: 2 additions & 4 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -110,14 +110,12 @@ fn main() {
.unwrap();

let mut buffer = surface.buffer_mut().unwrap();
for index in 0..(buffer.width().get() * buffer.height().get()) {
let y = index / buffer.width().get();
let x = index % buffer.width().get();
for (x, y, pixel) in buffer.pixels_iter() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;

buffer[index as usize] = blue | (green << 8) | (red << 16);
*pixel = blue | (green << 8) | (red << 16);
}

buffer.present().unwrap();
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20 changes: 8 additions & 12 deletions benches/buffer_mut.rs
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Expand Up @@ -40,35 +40,31 @@ fn buffer_mut(c: &mut criterion::Criterion) {
});
});

c.bench_function("pixels_mut()", |b| {
c.bench_function("data()", |b| {
let mut buffer = surface.buffer_mut().unwrap();
b.iter(|| {
let pixels: &mut [u32] = &mut buffer;
black_box(pixels);
});
});

c.bench_function("fill", |b| {
c.bench_function("fill u32", |b| {
let mut buffer = surface.buffer_mut().unwrap();
b.iter(|| {
let buffer = black_box(&mut buffer);
buffer.fill(0x00000000);
});
});

c.bench_function("render", |b| {
c.bench_function("render pixels_iter", |b| {
let mut buffer = surface.buffer_mut().unwrap();
b.iter(|| {
let buffer = black_box(&mut buffer);
let width = buffer.width().get();
for y in 0..buffer.height().get() {
for x in 0..buffer.width().get() {
let red = (x & 0xff) ^ (y & 0xff);
let green = (x & 0x7f) ^ (y & 0x7f);
let blue = (x & 0x3f) ^ (y & 0x3f);
let value = blue | (green << 8) | (red << 16);
buffer[(y * width + x) as usize] = value;
}
for (x, y, pixel) in buffer.pixels_iter() {
let red = (x & 0xff) ^ (y & 0xff);
let green = (x & 0x7f) ^ (y & 0x7f);
let blue = (x & 0x3f) ^ (y & 0x3f);
*pixel = blue | (green << 8) | (red << 16);
}
});
});
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13 changes: 5 additions & 8 deletions examples/raytracing/game.rs
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Expand Up @@ -108,13 +108,11 @@ impl Game {
}

// Upscale by `scale_factor`.
let width = buffer.width().get() as usize;
buffer.iter_mut().enumerate().for_each(|(i, pixel)| {
let y = i % width;
let x = i / width;
let y = (y as f32 / scale_factor) as usize;
let width = (buffer.width().get() as f32 / scale_factor) as usize;
buffer.pixels_iter().for_each(|(x, y, pixel)| {
let x = (x as f32 / scale_factor) as usize;
if let Some(x) = pixels.get(x * (width as f32 / scale_factor) as usize + y) {
let y = (y as f32 / scale_factor) as usize;
if let Some(x) = pixels.get(x * width + y) {
*pixel = *x;
}
});
Expand Down Expand Up @@ -149,8 +147,7 @@ impl Game {
},
];

let width = buffer.width().get();
for (y, row) in buffer.chunks_exact_mut(width as usize).enumerate() {
for (y, row) in buffer.pixel_rows().enumerate() {
for rect in rects {
let rect_vertical =
(rect.top * scale_factor) as usize..(rect.bottom * scale_factor) as usize;
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21 changes: 9 additions & 12 deletions examples/rectangle.rs
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Expand Up @@ -9,18 +9,15 @@ mod util;
fn redraw(buffer: &mut Buffer<'_>, flag: bool) {
let width = buffer.width().get();
let height = buffer.height().get();
for y in 0..height {
for x in 0..width {
let value = if flag && x >= 100 && x < width - 100 && y >= 100 && y < height - 100 {
0x00ffffff
} else {
let red = (x & 0xff) ^ (y & 0xff);
let green = (x & 0x7f) ^ (y & 0x7f);
let blue = (x & 0x3f) ^ (y & 0x3f);
blue | (green << 8) | (red << 16)
};
buffer[(y * width + x) as usize] = value;
}
for (x, y, pixel) in buffer.pixels_iter() {
*pixel = if flag && x >= 100 && x < width - 100 && y >= 100 && y < height - 100 {
0x00ffffff
} else {
let red = (x & 0xff) ^ (y & 0xff);
let green = (x & 0x7f) ^ (y & 0x7f);
let blue = (x & 0x3f) ^ (y & 0x3f);
blue | (green << 8) | (red << 16)
};
}
}

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13 changes: 5 additions & 8 deletions examples/winit.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -46,14 +46,11 @@ pub(crate) fn entry(event_loop: EventLoop<()>) {
};

let mut buffer = surface.buffer_mut().unwrap();
for y in 0..buffer.height().get() {
for x in 0..buffer.width().get() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;
let index = y * buffer.width().get() + x;
buffer[index as usize] = blue | (green << 8) | (red << 16);
}
for (x, y, pixel) in buffer.pixels_iter() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;
*pixel = blue | (green << 8) | (red << 16);
}

buffer.present().unwrap();
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13 changes: 5 additions & 8 deletions examples/winit_multithread.rs
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Expand Up @@ -32,14 +32,11 @@ pub mod ex {
surface.resize(width, height).unwrap();

let mut buffer = surface.buffer_mut().unwrap();
for y in 0..buffer.height().get() {
for x in 0..buffer.width().get() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;
let index = y * buffer.width().get() + x;
buffer[index as usize] = blue | (green << 8) | (red << 16);
}
for (x, y, pixel) in buffer.pixels_iter() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;
*pixel = blue | (green << 8) | (red << 16);
}

tracing::info!("presenting...");
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15 changes: 5 additions & 10 deletions examples/winit_wrong_sized_buffer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,16 +37,11 @@ fn main() {
};

let mut buffer = surface.buffer_mut().unwrap();
let width = buffer.width().get();
for y in 0..buffer.height().get() {
for x in 0..width {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;

let color = blue | (green << 8) | (red << 16);
buffer[(y * width + x) as usize] = color;
}
for (x, y, pixel) in buffer.pixels_iter() {
let red = x % 255;
let green = y % 255;
let blue = (x * y) % 255;
*pixel = blue | (green << 8) | (red << 16);
}
buffer.present().unwrap();
}
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112 changes: 112 additions & 0 deletions src/lib.rs
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Expand Up @@ -272,6 +272,118 @@ impl Buffer<'_> {
}
}

/// Pixel helper accessors.
impl Buffer<'_> {
/// Iterate over each row of pixels.
///
/// Each slice returned from the iterator has a length of `buffer.width()`.
///
/// # Examples
///
/// Fill each row with alternating black and white.
///
/// ```no_run
/// # let buffer: softbuffer::Buffer<'_> = unimplemented!();
/// for (y, row) in buffer.pixel_rows().enumerate() {
/// if y % 2 == 0 {
/// row.fill(0x00ffffff);
/// } else {
/// row.fill(0x00000000);
/// }
/// }
/// ```
///
/// Fill a red rectangle while skipping over regions that don't need to be modified.
///
/// ```no_run
/// # let buffer: softbuffer::Buffer<'_> = unimplemented!();
/// let x = 100;
/// let y = 200;
/// let width = 10;
/// let height = 20;
///
/// for row in buffer.pixel_rows().skip(y).take(height) {
/// for pixel in row.iter_mut().skip(x).take(width) {
/// *pixel = 0x00ff0000;
/// }
/// }
/// ```
///
/// Iterate over each pixel (similar to what the [`pixels_iter`] method does).
///
/// [`pixels_iter`]: Self::pixels_iter
///
/// ```no_run
/// # let buffer: softbuffer::Buffer<'_> = unimplemented!();
/// # let pixel_value = |x, y| 0x00000000;
/// for (y, row) in buffer.pixel_rows().enumerate() {
/// for (x, pixel) in row.iter_mut().enumerate() {
/// *pixel = pixel_value(x, y);
/// }
/// }
/// ```
#[inline]
pub fn pixel_rows(
&mut self,
) -> impl DoubleEndedIterator<Item = &mut [u32]> + ExactSizeIterator {
let width = self.width().get() as usize;
let pixels = self.buffer_impl.pixels_mut();
assert_eq!(pixels.len() % width, 0, "buffer must be multiple of width");
// NOTE: This won't panic because `width` is `NonZeroU32`
pixels.chunks_mut(width)
Comment on lines +329 to +333
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@MarijnS95 MarijnS95 Jan 19, 2026

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I hope that we can soon drive this from the buffer instead, taking a stride into account.

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@madsmtm madsmtm Jan 19, 2026

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Working on it ;)

}

/// Iterate over each pixel in the data.
///
/// The returned iterator contains the `x` and `y` coordinates and a mutable reference to the
/// pixel at that position.
///
/// # Examples
///
/// Draw a red rectangle with a margin of 10 pixels, and fill the background with blue.
///
/// ```no_run
/// # let buffer: softbuffer::Buffer<'_> = unimplemented!();
/// let width = buffer.width().get();
/// let height = buffer.height().get();
/// let left = 10;
/// let top = 10;
/// let right = width.saturating_sub(10);
/// let bottom = height.saturating_sub(10);
///
/// for (x, y, pixel) in buffer.pixels_iter() {
/// if (left..=right).contains(&x) && (top..=bottom).contains(&y) {
/// // Inside rectangle.
/// *pixel = 0x00ff0000;
/// } else {
/// // Outside rectangle.
/// *pixel = 0x000000ff;
/// };
/// }
/// ```
///
/// Iterate over the pixel data in reverse, and draw a red rectangle in the top-left corner.
///
/// ```no_run
/// # let buffer: softbuffer::Buffer<'_> = unimplemented!();
/// // Only reverses iteration order, x and y are still relative to the top-left corner.
/// for (x, y, pixel) in buffer.pixels_iter().rev() {
/// if x <= 100 && y <= 100 {
/// *pixel = 0x00ff0000;
/// }
/// }
/// ```
#[inline]
pub fn pixels_iter(&mut self) -> impl DoubleEndedIterator<Item = (u32, u32, &mut u32)> {
self.pixel_rows().enumerate().flat_map(|(y, pixels)| {
pixels
.iter_mut()
.enumerate()
.map(move |(x, pixel)| (x as u32, y as u32, pixel))
})
}
}

impl ops::Deref for Buffer<'_> {
type Target = [u32];

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