1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149

/// An RGBA color in the sRGB color space.
#[derive(PartialEq, Clone, Copy, Debug)]
pub struct Color {
    /// Red component.
    pub r: f32,

    /// Green component.
    pub g: f32,

    /// Blue component.
    pub b: f32,

    /// Alpha component.
    pub a: f32,
}

impl Color {
    /// White color.
    pub const WHITE: Self = Self {
        r: 1.0,
        g: 1.0,
        b: 1.0,
        a: 1.0,
    };

    /// Black color.
    pub const BLACK: Self = Self {
        r: 0.0,
        g: 0.0,
        b: 0.0,
        a: 1.0,
    };

    /// Red color.
    pub const RED: Self = Self {
        r: 1.0,
        g: 0.0,
        b: 0.0,
        a: 1.0,
    };

    /// Green color.
    pub const GREEN: Self = Self {
        r: 0.0,
        g: 1.0,
        b: 0.0,
        a: 1.0,
    };

    /// Blue color.
    pub const BLUE: Self = Self {
        r: 0.0,
        g: 0.0,
        b: 1.0,
        a: 1.0,
    };

    /// Creates a new [`Color`] from components in the [0, 1.0] range.
    ///
    /// [`Color`]: struct.Color.html
    pub fn new(r: f32, g: f32, b: f32, a: f32) -> Color {
        debug_assert!(r >= 0.0, "Red component is < 0.0");
        debug_assert!(r <= 1.0, "Red component is > 1.0");
        debug_assert!(g >= 0.0, "Green component is < 0.0");
        debug_assert!(g <= 1.0, "Green component is > 1.0");
        debug_assert!(b >= 0.0, "Blue component is < 0.0");
        debug_assert!(b <= 1.0, "Blue component is > 1.0");
        debug_assert!(a >= 0.0, "Alpha component is < 0.0");
        debug_assert!(a <= 1.0, "Alpha component is > 1.0");
        Color { r, g, b, a }
    }

    /// Creates a new [`Color`] from its RGB components in the [0, 255] range.
    ///
    /// [`Color`]: struct.Color.html
    pub fn from_rgb(r: u8, g: u8, b: u8) -> Color {
        Color {
            r: r as f32 / 255.0,
            g: g as f32 / 255.0,
            b: b as f32 / 255.0,
            a: 1.0,
        }
    }

    /// Creates a new [`Color`] from its RGB representation (0xRRGGBB).
    ///
    /// [`Color`]: struct.Color.html
    pub fn from_rgb_u32(color: u32) -> Color {
        debug_assert!(
            color <= 0xFFFFFF,
            "Color contains value higher than 0xFFFFFF"
        );
        let r = ((color & 0xFF0000) >> 16) as u8;
        let g = ((color & 0x00FF00) >> 8) as u8;
        let b = ((color & 0x0000FF) >> 0) as u8;
        Color::from_rgb(r, g, b)
    }

    /// Returns the [`Color`] components in the [0, 255] range.
    ///
    /// [`Color`]: struct.Color.html
    pub fn to_rgba(&self) -> [u8; 4] {
        [
            (self.r * 255.0).round() as u8,
            (self.g * 255.0).round() as u8,
            (self.b * 255.0).round() as u8,
            (self.a * 255.0).round() as u8,
        ]
    }

    pub(crate) fn into_linear(self) -> [f32; 4] {
        // As described in:
        // https://en.wikipedia.org/wiki/SRGB#The_reverse_transformation
        fn linear_component(u: f32) -> f32 {
            if u < 0.04045 {
                u / 12.92
            } else {
                ((u + 0.055) / 1.055).powf(2.4)
            }
        }

        [
            linear_component(self.r),
            linear_component(self.g),
            linear_component(self.b),
            self.a,
        ]
    }
}

impl From<[u8; 3]> for Color {
    fn from(values: [u8; 3]) -> Color {
        let [r, g, b] = values;

        Color::from_rgb(r, g, b)
    }
}

impl From<Color> for [f32; 4] {
    fn from(color: Color) -> [f32; 4] {
        [color.r, color.g, color.b, color.a]
    }
}

impl From<Color> for [u8; 4] {
    fn from(color: Color) -> [u8; 4] {
        color.to_rgba()
    }
}