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//! Monochrome colour with transparency representation.
use num_traits::Float;
use std::fmt::{Display, Formatter, Result as FmtResult};
use crate::{
error::{Result, validate_unit_component},
impl_transparent_colour, impl_transparent_convert, impl_transparent_display,
spaces::{Grey, Hsl, HslAlpha, Hsv, HsvAlpha, Lab, LabAlpha, Rgb, RgbAlpha, Srgb, SrgbAlpha, Xyz, XyzAlpha},
traits::{Colour, Convert},
};
/// Grey with alpha channel.
#[derive(Debug, Clone, Copy)]
pub struct GreyAlpha<T: Float + Send + Sync> {
/// Base colour
colour: Grey<T>,
/// Alpha component in range [0, 1].
alpha: T,
}
impl<T: Float + Send + Sync> GreyAlpha<T> {
/// Create a new `GreyAlpha` instance.
///
/// # Arguments
///
/// * `grey` - The grey component, must be in range [0, 1]
/// * `alpha` - The alpha (transparency) component, must be in range [0, 1]
///
/// # Errors
///
/// Returns an error if any component is outside the range [0, 1].
pub fn new(grey: T, alpha: T) -> Result<Self> {
validate_unit_component(alpha, "alpha")?;
Ok(Self {
colour: Grey::new(grey)?,
alpha,
})
}
/// Create a new `GreyAlpha` instance from a `Grey` colour and an alpha component.
///
/// # Arguments
///
/// * `colour` - The base grey colour
/// * `alpha` - The alpha (transparency) component, must be in range [0, 1]
///
/// # Errors
///
/// Returns an error if the alpha component is outside the range [0, 1].
fn new_colour_with_alpha(colour: Grey<T>, alpha: T) -> Result<Self> {
validate_unit_component(alpha, "alpha")?;
Ok(Self { colour, alpha })
}
/// Get the base `colour`.
const fn colour(&self) -> &Grey<T> {
&self.colour
}
/// Get the `grey` component.
pub const fn grey(&self) -> T {
self.colour.grey()
}
/// Get the `alpha` component.
pub const fn alpha(&self) -> T {
self.alpha
}
/// Set the `grey` component.
///
/// # Arguments
///
/// * `grey` - The new grey value, must be in range [0, 1]
///
/// # Errors
///
/// Returns an error if the value is outside the range [0, 1].
pub fn set_grey(&mut self, grey: T) -> Result<()> {
self.colour.set_grey(grey)
}
/// Set the `alpha` component.
///
/// # Arguments
///
/// * `alpha` - The new alpha value, must be in range [0, 1]
///
/// # Errors
///
/// Returns an error if the value is outside the range [0, 1].
pub fn set_alpha(&mut self, alpha: T) -> Result<()> {
validate_unit_component(alpha, "alpha")?;
self.alpha = alpha;
Ok(())
}
/// Set both components at once with validation.
///
/// # Arguments
///
/// * `grey` - The grey component, must be in range [0, 1]
/// * `alpha` - The alpha component, must be in range [0, 1]
///
/// # Errors
///
/// Returns an error if any component is outside the range [0, 1].
pub fn set_components(&mut self, grey: T, alpha: T) -> Result<()> {
self.colour.set_grey(grey)?;
validate_unit_component(alpha, "alpha")?;
self.alpha = alpha;
Ok(())
}
}
impl_transparent_colour!(GreyAlpha<T>, Grey<T>, 1);
impl_transparent_convert!(GreyAlpha<T>, Grey<T>);
impl_transparent_display!(GreyAlpha<T>);