Trait palette::encoding::pixel::Pixel

source · [−]
pub unsafe trait Pixel<T>: Sized {
    const CHANNELS: usize;

    fn as_raw<P: RawPixel<T> + ?Sized>(&self) -> &P { ... }
    fn as_raw_mut<P: RawPixel<T> + ?Sized>(&mut self) -> &mut P { ... }
    fn into_raw<P: RawPixelSized<T>>(self) -> P { ... }
    fn from_raw<P: RawPixel<T> + ?Sized>(pixel: &P) -> &Self { ... }
    fn from_raw_mut<P: RawPixel<T> + ?Sized>(pixel: &mut P) -> &mut Self { ... }
    fn from_raw_slice(slice: &[T]) -> &[Self]ⓘNotable traits for &[u8]impl<'_> Read for &[u8]impl<'_> Write for &mut [u8] { ... }
    fn from_raw_slice_mut(slice: &mut [T]) -> &mut [Self]ⓘNotable traits for &[u8]impl<'_> Read for &[u8]impl<'_> Write for &mut [u8] { ... }
    fn into_raw_slice(slice: &[Self]) -> &[T]ⓘNotable traits for &[u8]impl<'_> Read for &[u8]impl<'_> Write for &mut [u8] { ... }
    fn into_raw_slice_mut(slice: &mut [Self]) -> &mut [T]ⓘNotable traits for &[u8]impl<'_> Read for &[u8]impl<'_> Write for &mut [u8] { ... }
}
Expand description

Represents colors that can be serialized and deserialized from raw color components.

This uses bit by bit conversion, so make sure that anything that implements it can be represented as a contiguous sequence of a single type T. This is most safely done using #[derive(Pixel)].

Deriving

Pixel can be automatically derived. The only requirements are that the type is a struct, that it has a #[repr(C)] attribute, and that all of its fields have the same types. It stays on the conservative side and will show an error if any of those requirements are not fulfilled. If some fields have different types, but the same memory layout, or are zero-sized, they can be marked with attributes to show that their types are safe to use.

Field Attributes

  • #[palette_unsafe_same_layout_as = "SomeType"]: Mark the field as having the same memory layout as SomeType.

    Unsafety: corrupt data and undefined behavior may occur if this is not true!

  • #[palette_unsafe_zero_sized]: Mark the field as being zero-sized, and thus not taking up any memory space. This means that it can be ignored.

    Unsafety: corrupt data and undefined behavior may occur if this is not true!

Examples

Basic use:

use palette::Pixel;

#[derive(PartialEq, Debug, Pixel)]
#[repr(C)]
struct MyCmyk {
    cyan: f32,
    magenta: f32,
    yellow: f32,
    key: f32,
}

let buffer = [0.1, 0.2, 0.3, 0.4];
let color = MyCmyk::from_raw(&buffer);

assert_eq!(
    color,
    &MyCmyk {
        cyan: 0.1,
        magenta: 0.2,
        yellow: 0.3,
        key: 0.4,
    }
);

Heterogenous field types:

use std::marker::PhantomData;

use palette::{Pixel, RgbHue};
use palette::rgb::RgbStandard;
use palette::encoding::Srgb;

#[derive(PartialEq, Debug, Pixel)]
#[repr(C)]
struct MyCoolColor<S: RgbStandard> {
    #[palette(unsafe_zero_sized)]
    standard: PhantomData<S>,
    // RgbHue is a wrapper with `#[repr(C)]`, so it can safely
    // be converted straight from `f32`.
    #[palette(unsafe_same_layout_as = "f32")]
    hue: RgbHue<f32>,
    lumen: f32,
    chroma: f32,
}

let buffer = [172.0, 100.0, 0.3];
let color = MyCoolColor::<Srgb>::from_raw(&buffer);

assert_eq!(
    color,
    &MyCoolColor {
        hue: 172.0.into(),
        lumen: 100.0,
        chroma: 0.3,
        standard: PhantomData,
    }
);

Required Associated Constants

The number of color channels.

Provided Methods

Cast as a reference to raw color components.

Cast as a mutable reference to raw color components.

Convert into raw color components.

Cast from a reference to raw color components.

Cast from a mutable reference to raw color components.

Cast a slice of raw color components to a slice of colors.

use palette::{Pixel, Srgb};

let raw = &[255u8, 128, 64, 10, 20, 30];
let colors = Srgb::from_raw_slice(raw);

assert_eq!(colors.len(), 2);
assert_eq!(colors[0].blue, 64);
assert_eq!(colors[1].red, 10);

Cast a mutable slice of raw color components to a mutable slice of colors.

use palette::{Pixel, Srgb};

let raw = &mut [255u8, 128, 64, 10, 20, 30];
{
    let colors = Srgb::from_raw_slice_mut(raw);
    assert_eq!(colors.len(), 2);

    // These changes affects the raw slice, since they are the same data
    colors[0].blue = 100;
    colors[1].red = 200;
}

// Notice the two values in the middle:
assert_eq!(raw, &[255, 128, 100, 200, 20, 30]);

Cast a slice of colors to a slice of raw color components.

use palette::{Pixel, Srgb};

let colors = &[Srgb::new(255u8, 128, 64), Srgb::new(10, 20, 30)];
let raw = Srgb::into_raw_slice(colors);

assert_eq!(raw.len(), 6);
assert_eq!(raw, &[255u8, 128, 64, 10, 20, 30]);

Cast a mutable slice of colors to a mutable slice of raw color components.

use palette::{Pixel, Srgb};

let colors = &mut [Srgb::new(255u8, 128, 64), Srgb::new(10, 20, 30)];
{
    let raw = Srgb::into_raw_slice_mut(colors);
    assert_eq!(raw.len(), 6);

    // These changes affects the color slice, since they are the same data
    raw[2] = 100;
    raw[3] = 200;
}

assert_eq!(colors[0].blue, 100);
assert_eq!(colors[1].red, 200);

Implementors