GraphiteEditor/Graphite · error

Failed to convert bytes to pixel

Error message

Failed to convert bytes to pixel

What it means

Pixel::from_bytes converts a byte slice into a pixel value with bytemuck::try_from_bytes, which succeeds only when the slice length exactly equals size_of::<Self>() (with matching alignment). Any other length — a truncated buffer or a channel count different from the pixel type — fails the check and panics with this message.

Source

Thrown at node-graph/libraries/no-std-types/src/color/color_traits.rs:97

pub trait Rec709Primaries {}
impl<T: Rec709Primaries> RGBPrimaries for T {
	const RED: DVec2 = DVec2::new(0.64, 0.33);
	const GREEN: DVec2 = DVec2::new(0.3, 0.6);
	const BLUE: DVec2 = DVec2::new(0.15, 0.06);
	const WHITE: DVec2 = DVec2::new(0.3127, 0.329);
}

pub trait SRGB: Rec709Primaries {}

// TODO: Come up with a better name for this trait
pub trait Pixel: Clone + Pod + Zeroable + Default {
	#[cfg(feature = "std")]
	fn to_bytes(&self) -> Vec<u8> {
		bytemuck::bytes_of(self).to_vec()
	}
	// TODO: use u8 for Color
	fn from_bytes(bytes: &[u8]) -> Self {
		*bytemuck::try_from_bytes(bytes).expect("Failed to convert bytes to pixel")
	}

	fn byte_size() -> usize {
		size_of::<Self>()
	}
}
pub trait RGB: Pixel {
	type ColorChannel: Channel;

	fn red(&self) -> Self::ColorChannel;
	fn r(&self) -> Self::ColorChannel {
		self.red()
	}
	fn green(&self) -> Self::ColorChannel;
	fn g(&self) -> Self::ColorChannel {
		self.green()
	}
	fn blue(&self) -> Self::ColorChannel;

View on GitHub (pinned to c507b35645)

Solutions

1. Assert bytes.len() == Self::byte_size() before calling from_bytes
2. Choose the Pixel type that matches the source's channel count and order (for example Rgba8 vs Rgb8)
3. For bulk buffers, iterate chunks_exact(byte_size()) and convert element by element

Example fix

// before
let pixel = P::from_bytes(bytes);

// after
assert_eq!(bytes.len(), P::byte_size(), "pixel buffer must be exactly one pixel wide");
let pixel = P::from_bytes(bytes);

fn is_pixel_sized<P: Pixel>(bytes: &[u8]) -> bool {
	bytes.len() == P::byte_size()
}

When it happens

Trigger: Feeding an RGBA (4-byte) buffer into an RGB pixel type or vice versa; slicing a buffer at a length that is not exactly the pixel size; empty slices produced by failed reads or zero-length image data.

Common situations: Converting between pixel layouts without re-interleaving channels; off-by-one stride handling when slicing image rows; deserialized buffers carrying wrong length fields.

AI-assisted analysis of GraphiteEditor/Graphite@c507b35645 (2026-08-16). Data as JSON: /api/errors/c59e49d50fa8bf2b. Report an issue: GitHub.