pix 0.15.0

Pixel / raster image library
Documentation 
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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247

// oklab.rs        Oklab color model.
//
// Copyright (c) 2023-2024  Douglas P Lau
//
//! [Oklab] color model and types.
//!
//! [OkLab]: https://bottosson.github.io/posts/oklab/
#![allow(clippy::excessive_precision)]

use crate::ColorModel;
use crate::chan::{Ch8, Ch16, Ch32, Channel, Linear, Premultiplied, Straight};
use crate::el::{Pix, PixRgba, Pixel};
use std::ops::Range;

/// [Oklab] [color model]
///
/// The components are *[L]*, *[a]*, *[b]* and optional *[alpha]*.
///
/// [alpha]: ../el/trait.Pixel.html#method.alpha
/// [a]: #method.a
/// [b]: #method.b
/// [color model]: ../trait.ColorModel.html
/// [L]: #method.l
/// [OkLab]: https://bottosson.github.io/posts/oklab/
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
pub struct Oklab {}

impl Oklab {
    /// Get the *L* component (perceived lightness).
    ///
    /// # Example: Oklab *L*
    /// ```
    /// use pix::chan::Ch32;
    /// use pix::oklab::{Oklab, Oklab32};
    ///
    /// let p = Oklab32::new(0.25, 0.5, 1.0);
    /// assert_eq!(Oklab::l(p), Ch32::new(0.25));
    /// ```
    pub fn l<P>(p: P) -> P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get::<0>()
    }

    /// Get a mutable reference to the *L* component.
    ///
    /// # Example: Modify Oklab *L*
    /// ```
    /// use pix::chan::Ch32;
    /// use pix::oklab::{Oklab, Oklab32};
    ///
    /// let mut p = Oklab32::new(0.25, 0.5, 1.0);
    /// *Oklab::l_mut(&mut p) = Ch32::new(0.75);
    /// assert_eq!(Oklab::l(p), Ch32::new(0.75));
    /// ```
    pub fn l_mut<P>(p: &mut P) -> &mut P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get_mut::<0>()
    }

    /// Get the *a* component (green/red).
    ///
    /// # Example: Oklab *a*
    /// ```
    /// use pix::chan::Ch16;
    /// use pix::oklab::{Oklab, Oklab16};
    ///
    /// let p = Oklab16::new(0x2000, 0x1234, 0x8000);
    /// assert_eq!(Oklab::a(p), Ch16::new(0x1234));
    /// ```
    pub fn a<P>(p: P) -> P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get::<1>()
    }

    /// Get a mutable reference to the *a* component.
    ///
    /// # Example: Modify Oklab *a*
    /// ```
    /// use pix::chan::Ch16;
    /// use pix::oklab::{Oklab, Oklab16};
    ///
    /// let mut p = Oklab16::new(0x2000, 0x1234, 0x8000);
    /// *Oklab::a_mut(&mut p) = 0x4321.into();
    /// assert_eq!(Oklab::a(p), Ch16::new(0x4321));
    /// ```
    pub fn a_mut<P>(p: &mut P) -> &mut P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get_mut::<1>()
    }

    /// Get the *b* component (blue/yellow).
    ///
    /// # Example: Oklab *b*
    /// ```
    /// use pix::chan::Ch8;
    /// use pix::oklab::{Oklab, Oklab8};
    ///
    /// let p = Oklab8::new(0x93, 0x80, 0xA0);
    /// assert_eq!(Oklab::b(p), Ch8::new(0xA0));
    /// ```
    pub fn b<P>(p: P) -> P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get::<2>()
    }

    /// Get a mutable reference to the *b* component.
    ///
    /// # Example: Modify Oklab *b*
    /// ```
    /// use pix::chan::Ch8;
    /// use pix::oklab::{Oklab, Oklab8};
    ///
    /// let mut p = Oklab8::new(0x88, 0x77, 0x66);
    /// *Oklab::b_mut(&mut p) = 0x55.into();
    /// assert_eq!(Oklab::b(p), Ch8::new(0x55));
    /// ```
    pub fn b_mut<P>(p: &mut P) -> &mut P::Chan
    where
        P: Pixel<Model = Self>,
    {
        p.get_mut::<2>()
    }
}

impl ColorModel for Oklab {
    const CIRCULAR: Range<usize> = 0..0;
    const LINEAR: Range<usize> = 0..3;
    const ALPHA: usize = 3;

    /// Convert into *red*, *green*, *blue* and *alpha* components
    fn into_rgba<P>(p: P) -> PixRgba<P>
    where
        P: Pixel<Model = Self>,
    {
        let pl = Self::l(p).to_f32();
        let pa = Self::a(p).to_f32();
        let pb = Self::b(p).to_f32();

        let l_ = pl + 0.3963377774 * pa + 0.2158037573 * pb;
        let m_ = pl - 0.1055613458 * pa - 0.0638541728 * pb;
        let s_ = pl - 0.0894841775 * pa - 1.2914855480 * pb;

        let l = l_ * l_ * l_;
        let m = m_ * m_ * m_;
        let s = s_ * s_ * s_;

        let red = 4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s;
        let green = -1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s;
        let blue = -0.0041960863 * l - 0.7034186147 * m + 1.7076147010 * s;
        PixRgba::<P>::new(red, green, blue, p.alpha().to_f32())
    }

    /// Convert from *red*, *green*, *blue* and *alpha* components
    fn from_rgba<P>(rgba: PixRgba<P>) -> P
    where
        P: Pixel<Model = Self>,
    {
        let chan = rgba.channels();
        let red = chan[0].to_f32();
        let green = chan[1].to_f32();
        let blue = chan[2].to_f32();
        let alpha = chan[3];

        let l = 0.4122214708 * red + 0.5363325363 * green + 0.0514459929 * blue;
        let m = 0.2119034982 * red + 0.6806995451 * green + 0.1073969566 * blue;
        let s = 0.0883024619 * red + 0.2817188376 * green + 0.6299787005 * blue;

        let l_ = l.cbrt();
        let m_ = m.cbrt();
        let s_ = s.cbrt();

        let pl = 0.2104542553 * l_ + 0.7936177850 * m_ - 0.0040720468 * s_;
        let pa = 1.9779984951 * l_ - 2.4285922050 * m_ + 0.4505937099 * s_;
        let pb = 0.0259040371 * l_ + 0.7827717662 * m_ - 0.8086757660 * s_;

        P::from_channels(&[pl.into(), pa.into(), pb.into(), alpha])
    }
}

/// [Oklab](struct.Oklab.html) 8-bit opaque (no *alpha* channel)
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklab8 = Pix<3, Ch8, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 16-bit opaque (no *alpha* channel)
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklab16 = Pix<3, Ch16, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 32-bit opaque (no *alpha* channel)
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklab32 = Pix<3, Ch32, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 8-bit
/// [straight](../chan/struct.Straight.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba8 = Pix<4, Ch8, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 16-bit
/// [straight](../chan/struct.Straight.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba16 = Pix<4, Ch16, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 32-bit
/// [straight](../chan/struct.Straight.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba32 = Pix<4, Ch32, Oklab, Straight, Linear>;

/// [Oklab](struct.Oklab.html) 8-bit
/// [premultiplied](../chan/struct.Premultiplied.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba8p = Pix<4, Ch8, Oklab, Premultiplied, Linear>;

/// [Oklab](struct.Oklab.html) 16-bit
/// [premultiplied](../chan/struct.Premultiplied.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba16p = Pix<4, Ch16, Oklab, Premultiplied, Linear>;

/// [Oklab](struct.Oklab.html) 32-bit
/// [premultiplied](../chan/struct.Premultiplied.html) alpha
/// [linear](../chan/struct.Linear.html) gamma [pixel](../el/trait.Pixel.html)
/// format.
pub type Oklaba32p = Pix<4, Ch32, Oklab, Premultiplied, Linear>;

#[cfg(test)]
mod test {
    #[test]
    fn oklab_to_rgb() {
        // TODO
    }
}