Add support for non-square pixels by Kezii · Pull Request #71 · embedded-graphics/simulator

Kezii · 2026-01-03T20:28:28Z

Add support for non-square pixels, using fractional numbers

for example, the display I'm working rn has a 2:3 pixel aspect ratio, this makes the simulator realistic to the device

rfuest · 2026-01-04T03:10:32Z

Thanks for the PR. This is a useful addition, but I would like to change the way it is implemented.

If this setting is named pixel aspect ratio I would expect pixel_aspect_ratio(2, 1) and pixel_aspect_ratio(4, 2) to behave the same. An alternative would be to add a pub fn scale_non_square(mut self, scale: Size) -> Self method to the output settings builder and change the type of OutputSettings::scale to Size. This should have the same functionality without having two interacting settings that determine the output pixel size.

Kezii · 2026-01-26T14:41:53Z

Hello,
I edited the code as requested

rfuest

That's better. Some of the code can be simplified by using the component wise methods that Point and Size implement.

rfuest · 2026-01-26T18:40:11Z

src/display.rs

+        let width = self.size.width.saturating_mul(output_settings.scale.width)
+            + self.size.width.saturating_sub(1) * output_settings.pixel_spacing;
+        let height = self
+            .size
+            .height
+            .saturating_mul(output_settings.scale.height)
+            + self.size.height.saturating_sub(1) * output_settings.pixel_spacing;
+
+        Size::new(width, height)


This can be simplified by using Size::component_mul:

Suggested change

let width = self.size.width.saturating_mul(output_settings.scale.width)

+ self.size.width.saturating_sub(1) * output_settings.pixel_spacing;

let height = self

.size

.height

.saturating_mul(output_settings.scale.height)

+ self.size.height.saturating_sub(1) * output_settings.pixel_spacing;

Size::new(width, height)

self.size.component_mul(output_settings.scale)

+ self.size.saturating_sub(Size::new_equal(1)) * output_settings.pixel_spacing

rfuest · 2026-01-26T18:44:06Z

src/output_image.rs

        .unwrap();

-        if output_settings.scale == 1 {
+        if output_settings.scale == Size::new(1, 1) && output_settings.pixel_spacing == 0 {


Good catch.

rfuest · 2026-01-26T18:45:05Z

src/output_image.rs

+            let pitch_x = (output_settings.scale.width + output_settings.pixel_spacing) as i32;
+            let pitch_y = (output_settings.scale.height + output_settings.pixel_spacing) as i32;


You've added a getter for the pitch:

Suggested change

let pitch_x = (output_settings.scale.width + output_settings.pixel_spacing) as i32;

let pitch_y = (output_settings.scale.height + output_settings.pixel_spacing) as i32;

let pitch = output_settings.pixel_pitch();

rfuest · 2026-01-26T18:49:13Z

src/output_image.rs

                self.fill_solid(
-                    &Rectangle::new(p * pixel_pitch + position, pixel_size),
+                    &Rectangle::new(
+                        Point::new(p.x * pitch_x, p.y * pitch_y) + position,


Suggested change

Point::new(p.x * pitch_x, p.y * pitch_y) + position,

p.component_mul(pitch) + position,

rfuest · 2026-01-26T19:00:57Z

src/output_settings.rs

+    /// Sets the pixel scale to a non-square value. This is useful for displaying
+    /// non-square pixels.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `width` or `height` is `0`.
+    pub fn scale_non_square(mut self, width: u32, height: u32) -> Self {


In embedded-graphics related crates it's preferred to take a Size argument instead of separate width and height. The doc comment should start with a single sentence.

Suggested change

/// Sets the pixel scale to a non-square value. This is useful for displaying

/// non-square pixels.

///

/// # Panics

///

/// Panics if `width` or `height` is `0`.

pub fn scale_non_square(mut self, width: u32, height: u32) -> Self {

/// Sets a non-square pixel scale.

///

/// This is useful for simulating a display with a non-square pixel aspect ratio.

///

/// # Panics

///

/// Panics if `width` or `height` is `0`.

pub fn scale_non_square(mut self, scale: Size) -> Self {

rfuest · 2026-01-26T19:01:26Z

src/output_settings.rs

+    /// Sets the pixel scale to a non-square value. This is useful for displaying
+    /// non-square pixels.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `width` or `height` is `0`.
+    pub fn scale_non_square(mut self, width: u32, height: u32) -> Self {


Please move this function up to be directly below scale.

rfuest · 2026-01-26T19:04:28Z

CHANGELOG.md

+### Added
+
+- Added support for non-square pixels
+


Suggested change

### Added

- Added support for non-square pixels

### Added

- **(breaking)** [#71](https://github.com/embedded-graphics/simulator/pull/71) Added support for non-square pixels.

### Fixed

- [#71](https://github.com/embedded-graphics/simulator/pull/71) Fixed pixel spacing for unscaled outputs.

Kezii · 2026-01-28T18:40:59Z

Hello,
Thank you for your answer

I applied the required changes

rfuest

Unfortunately CI isn't happy with one of the suggestions I made.

rfuest · 2026-01-28T20:06:15Z

src/output_settings.rs

This attribute causes the build without the with-sdl flag to fail, because pixel_pitch is now used with and without SDL support enabled. I would suggest to just remove the cfg attribute, and instead add an #[allow(unused)] attribute to output_to_display method.

Kezii · 2026-01-29T20:48:05Z

updated and tested with cargo build --no-default-features

rfuest

LGTM, thanks.

Kezii force-pushed the master branch 2 times, most recently from d42ebfd to c513b3a Compare January 26, 2026 14:41

rfuest requested changes Jan 26, 2026

View reviewed changes

Kezii force-pushed the master branch from c513b3a to 1be0284 Compare January 28, 2026 18:23

rfuest requested changes Jan 28, 2026

View reviewed changes

add support for non-square pixels

50c5848

Kezii force-pushed the master branch from 1be0284 to 50c5848 Compare January 29, 2026 20:47

rfuest approved these changes Jan 30, 2026

View reviewed changes

rfuest merged commit 7c249c7 into embedded-graphics:master Jan 30, 2026
3 checks passed

		let pitch_x = (output_settings.scale.width + output_settings.pixel_spacing) as i32;
		let pitch_y = (output_settings.scale.height + output_settings.pixel_spacing) as i32;

	let pitch_x = (output_settings.scale.width + output_settings.pixel_spacing) as i32;
	let pitch_y = (output_settings.scale.height + output_settings.pixel_spacing) as i32;
	let pitch = output_settings.pixel_pitch();

	Point::new(p.x * pitch_x, p.y * pitch_y) + position,
	p.component_mul(pitch) + position,

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Kezii commented Jan 3, 2026

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Kezii commented Jan 28, 2026

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Kezii commented Jan 29, 2026

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