Add saturating_add and saturating_sub for integer based colors

[Finomnis]

• Add crate::num::SaturatingAdd and crate::num::SaturatingSub traits
• Implement them for all unsigned integers
• Implement them for unsigned integer based hues
• Implement them for unsigned integer based colors
• Implement them for unsigned integer based alpha

Example:

use palette::{
    num::{SaturatingAdd, SaturatingSub},
    Srgb,
};

fn main() {
    let color1 = Srgb::<u8>::new(200, 20, 20);
    let color2 = Srgb::<u8>::new(100, 10, 10);

    let color_sum = color1.saturating_add(color2);
    println!("{:?}", color_sum);

    let color_diff = color2.saturating_sub(30);
    println!("{:?}", color_diff);
}

Rgb { red: 255, green: 30, blue: 30, standard: PhantomData<palette::encoding::srgb::Srgb> }
Rgb { red: 70, green: 0, blue: 0, standard: PhantomData<palette::encoding::srgb::Srgb> }

Closed Issues

• Closes #322, by implementing the proposed functionality.

[Ogeon]

Oh, nice, thanks for both suggesting and implementing this! Could you also add it for Alpha, for completeness sake? It would be for when both the color and alpha type supports it.

[Finomnis]

@Ogeon Fixed

[Ogeon]

Awesome! Thanks a lot!

[Ogeon]

All checks are green, let's merge 🎉

bors r+

[bors[bot]]

Build succeeded:

• ci