Struct Color 

pub struct Color(pub f32, pub f32, pub f32, pub f32);

An RGBA color in the sRGB space. The four fields are red, green, blue and alpha, each from 0.0 to 1.0. Compose’s Color.

Tuple Fields

0: f32

1: f32

2: f32

3: f32

Implementations

impl Color

pub const BLACK: Color

Opaque black.

pub const WHITE: Color

Opaque white.

pub const RED: Color

Opaque red.

pub const GREEN: Color

Opaque green.

pub const BLUE: Color

Opaque blue.

pub const TRANSPARENT: Color

Fully transparent black, with every channel 0.0.

pub const fn rgb(r: f32, g: f32, b: f32) -> Self

Creates an opaque color from red, green and blue channels, each from 0.0 to 1.0.

pub const fn rgba(r: f32, g: f32, b: f32, a: f32) -> Self

Creates a color from red, green, blue and alpha channels, each from 0.0 to 1.0.

pub const fn from_rgba_u8(r: u8, g: u8, b: u8, a: u8) -> Self

Creates a color from red, green, blue and alpha channels of 0 to 255.

pub const fn from_rgb_u8(r: u8, g: u8, b: u8) -> Self

Creates an opaque color from red, green and blue channels of 0 to 255.

pub fn r(&self) -> f32

Red channel, from 0.0 to 1.0.

pub fn g(&self) -> f32

Green channel, from 0.0 to 1.0.

pub fn b(&self) -> f32

Blue channel, from 0.0 to 1.0.

pub fn a(&self) -> f32

Alpha (opacity) channel, from 0.0 (transparent) to 1.0 (opaque).

pub fn with_alpha(&self, alpha: f32) -> Self

Returns this color with its alpha channel replaced by alpha, from 0.0 (transparent) to 1.0 (opaque).

pub fn srgb_8bit(self) -> Self

This colour as the platform’s colour type actually holds it: eight bits per channel.

androidx.compose.ui.graphics.Color is a float-shaped API over an 8-bit value. Building one in the sRGB space snaps every channel on the spot — the bytecode of ColorKt.Color(float, float, float, float, ColorSpace) is coerceIn(0f, 1f), * 255.0f, + 0.5f, f2i, packed into an ARGB int — so a colour an app computes in float is already a whole channel value before anything paints with it, and the rasterizer never sees the fraction.

A renderer that carries the fraction to the framebuffer instead leaves the rounding to whatever converts float to unorm there. That agrees nearly everywhere and disagrees on an exact half. It is not a rare shape: a theme that lerps between two byte colours lands on one routinely — mix(rail, background, 0.55) puts a Wear settings capsule at exactly 22.5/255 on green, where this rule gives 23 and a converter that breaks ties to even gives 22. One level, and then the row’s layer alpha multiplies it and keeps it.

Ties go up, which is what (int)(x + 0.5f), Skia’s SkScalarRoundToInt and Rust’s f32::round all give for a channel clamped into 0..=1.

Trait Implementations

impl Clone for Color

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Color

impl Debug for Color

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Color> for Brush

A colour paints as a solid brush wherever a brush is taken, as Compose takes a Color beside each Brush overload.

fn from(color: Color) -> Self

Converts to this type from the input type.

impl PartialEq for Color

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl RenderHash for Color

fn render_hash(&self) -> u64

Returns a hash over exactly the values that change what is drawn. Equal values give equal hashes.

impl StructuralPartialEq for Color