1/*
2 * Copyright (c) 2023.
3 *
4 * This software is free software;
5 *
6 * You can redistribute it or modify it under terms of the MIT, Apache License or Zlib license
7 */
8
9//! Image Colorspace information and manipulation utilities.
10
11/// All possible image colorspaces
12/// Some of them aren't yet supported exist here.
13#[allow(clippy::upper_case_acronyms)]
14#[derive(Copy, Clone, Debug, Eq, PartialEq)]
15#[non_exhaustive]
16pub enum ColorSpace {
17 /// Red, Green , Blue
18 RGB,
19 /// Red, Green, Blue, Alpha
20 RGBA,
21 /// YUV colorspace
22 YCbCr,
23 /// Grayscale colorspace
24 Luma,
25 /// Grayscale with alpha colorspace
26 LumaA,
27 YCCK,
28 /// Cyan , Magenta, Yellow, Black
29 CMYK,
30 /// Blue, Green, Red
31 BGR,
32 /// Blue, Green, Red, Alpha
33 BGRA,
34 /// The colorspace is unknown
35 Unknown,
36 /// Alpha Red Green Blue
37 ARGB,
38 /// Hue,Saturation,Lightness
39 /// Conversion from RGB to HSL and back matches that of Python [colorsys](https://docs.python.org/3/library/colorsys.html) module
40 /// Color type is expected to be in floating point
41 HSL,
42 /// Hue, Saturation,Value
43 ///
44 /// Conversion from RGB to HSV and back matches that of Python [colorsys](https://docs.python.org/3/library/colorsys.html) module
45 /// Color type is expected to be in floating point
46 HSV
47}
48
49impl ColorSpace {
50 /// Number of color channels present for a certain colorspace
51 ///
52 /// E.g. RGB returns 3 since it contains R,G and B colors to make up a pixel
53 pub const fn num_components(&self) -> usize {
54 match self {
55 Self::RGB | Self::YCbCr | Self::BGR | Self::HSV | Self::HSL => 3,
56 Self::RGBA | Self::YCCK | Self::CMYK | Self::BGRA | Self::ARGB => 4,
57 Self::Luma => 1,
58 Self::LumaA => 2,
59 Self::Unknown => 0
60 }
61 }
62
63 pub const fn has_alpha(&self) -> bool {
64 matches!(self, Self::RGBA | Self::LumaA | Self::BGRA | Self::ARGB)
65 }
66
67 pub const fn is_grayscale(&self) -> bool {
68 matches!(self, Self::LumaA | Self::Luma)
69 }
70
71 /// Returns the position of the alpha pixel in a pixel
72 ///
73 ///
74 /// That is for an array of color components say `[0,1,2,3]` if the image has an alpha channel
75 /// and is in RGBA format, this will return `Some(3)`, indicating alpha is found in the third index
76 /// but if the image is in `ARGB` format, it will return `Some(0)` indicating alpha is found in
77 /// index 0
78 ///
79 /// If an image doesn't have an alpha channel returns `None`
80 ///
81 pub const fn alpha_position(&self) -> Option<usize> {
82 match self {
83 ColorSpace::RGBA => Some(3),
84 ColorSpace::LumaA => Some(1),
85 ColorSpace::BGRA => Some(3),
86 ColorSpace::ARGB => Some(0),
87 _ => None
88 }
89 }
90}
91
92/// Encapsulates all colorspaces supported by
93/// the library
94pub static ALL_COLORSPACES: [ColorSpace; 12] = [
95 ColorSpace::RGB,
96 ColorSpace::RGBA,
97 ColorSpace::LumaA,
98 ColorSpace::Luma,
99 ColorSpace::CMYK,
100 ColorSpace::BGRA,
101 ColorSpace::BGR,
102 ColorSpace::YCCK,
103 ColorSpace::YCbCr,
104 ColorSpace::ARGB,
105 ColorSpace::HSL,
106 ColorSpace::HSV
107];
108
109/// Color characteristics
110///
111/// Gives more information about values in a certain
112/// colorspace
113#[allow(non_camel_case_types)]
114#[derive(Copy, Clone, Debug, PartialEq)]
115pub enum ColorCharacteristics {
116 /// Normal default gamma setting
117 /// The float contains gamma present
118 ///
119 /// The default gamma value is 2.2 but for
120 /// decoders that allow specifying gamma values,e.g PNG,
121 /// the gamma value becomes the specified value by the decoder
122 sRGB,
123 /// Linear transfer characteristics
124 /// The image is in linear colorspace
125 Linear
126}
127