facet_pretty/
color.rs

1//! Color generation utilities for pretty-printing
2
3use core::hash::{Hash, Hasher};
4use std::hash::DefaultHasher;
5
6/// RGB color representation
7#[derive(Debug, Clone, Copy, PartialEq, Eq)]
8pub struct RGB {
9    /// Red component (0-255)
10    pub r: u8,
11    /// Green component (0-255)
12    pub g: u8,
13    /// Blue component (0-255)
14    pub b: u8,
15}
16
17impl RGB {
18    /// Create a new RGB color
19    pub fn new(r: u8, g: u8, b: u8) -> Self {
20        Self { r, g, b }
21    }
22
23    /// Write the RGB color as ANSI foreground color code to the formatter
24    pub fn write_fg<W: core::fmt::Write>(&self, f: &mut W) -> core::fmt::Result {
25        write!(f, "\x1b[38;2;{};{};{}m", self.r, self.g, self.b)
26    }
27
28    /// Write the RGB color as ANSI background color code to the formatter
29    pub fn write_bg<W: core::fmt::Write>(&self, f: &mut W) -> core::fmt::Result {
30        write!(f, "\x1b[48;2;{};{};{}m", self.r, self.g, self.b)
31    }
32}
33
34/// A color generator that produces unique colors based on a hash value
35pub struct ColorGenerator {
36    base_hue: f32,
37    saturation: f32,
38    lightness: f32,
39}
40
41impl Default for ColorGenerator {
42    fn default() -> Self {
43        Self {
44            base_hue: 210.0,
45            saturation: 0.7,
46            lightness: 0.6,
47        }
48    }
49}
50
51impl ColorGenerator {
52    /// Create a new color generator with default settings
53    pub fn new() -> Self {
54        Self::default()
55    }
56
57    /// Set the base hue (0-360)
58    pub fn with_base_hue(mut self, hue: f32) -> Self {
59        self.base_hue = hue;
60        self
61    }
62
63    /// Set the saturation (0.0-1.0)
64    pub fn with_saturation(mut self, saturation: f32) -> Self {
65        self.saturation = saturation.clamp(0.0, 1.0);
66        self
67    }
68
69    /// Set the lightness (0.0-1.0)
70    pub fn with_lightness(mut self, lightness: f32) -> Self {
71        self.lightness = lightness.clamp(0.0, 1.0);
72        self
73    }
74
75    /// Generate an RGB color based on a hash value
76    pub fn generate_color(&self, hash: u64) -> RGB {
77        // Use the hash to generate a hue offset
78        let hue_offset = (hash % 360) as f32;
79        let hue = (self.base_hue + hue_offset) % 360.0;
80
81        // Convert HSL to RGB
82        self.hsl_to_rgb(hue, self.saturation, self.lightness)
83    }
84
85    /// Generate an RGB color based on a hashable value
86    pub fn generate_color_for<T: Hash>(&self, value: &T) -> RGB {
87        let mut hasher = DefaultHasher::new();
88        value.hash(&mut hasher);
89        let hash = hasher.finish();
90        self.generate_color(hash)
91    }
92
93    /// Convert HSL color values to RGB
94    fn hsl_to_rgb(&self, h: f32, s: f32, l: f32) -> RGB {
95        let c = (1.0 - (2.0 * l - 1.0).abs()) * s;
96        let x = c * (1.0 - ((h / 60.0) % 2.0 - 1.0).abs());
97        let m = l - c / 2.0;
98
99        let (r, g, b) = match h as u32 {
100            0..=59 => (c, x, 0.0),
101            60..=119 => (x, c, 0.0),
102            120..=179 => (0.0, c, x),
103            180..=239 => (0.0, x, c),
104            240..=299 => (x, 0.0, c),
105            _ => (c, 0.0, x),
106        };
107
108        RGB::new(
109            ((r + m) * 255.0) as u8,
110            ((g + m) * 255.0) as u8,
111            ((b + m) * 255.0) as u8,
112        )
113    }
114}
115
116#[cfg(test)]
117mod tests {
118    use super::*;
119
120    #[test]
121    fn test_color_generator_default() {
122        let generator = ColorGenerator::default();
123        assert_eq!(generator.base_hue, 210.0);
124        assert_eq!(generator.saturation, 0.7);
125        assert_eq!(generator.lightness, 0.6);
126    }
127
128    #[test]
129    fn test_color_generator_with_methods() {
130        let generator = ColorGenerator::new()
131            .with_base_hue(180.0)
132            .with_saturation(0.5)
133            .with_lightness(0.7);
134
135        assert_eq!(generator.base_hue, 180.0);
136        assert_eq!(generator.saturation, 0.5);
137        assert_eq!(generator.lightness, 0.7);
138    }
139
140    #[test]
141    fn test_saturation_clamping() {
142        let generator = ColorGenerator::new().with_saturation(1.5);
143        assert_eq!(generator.saturation, 1.0);
144
145        let generator = ColorGenerator::new().with_saturation(-0.5);
146        assert_eq!(generator.saturation, 0.0);
147    }
148
149    #[test]
150    fn test_lightness_clamping() {
151        let generator = ColorGenerator::new().with_lightness(1.5);
152        assert_eq!(generator.lightness, 1.0);
153
154        let generator = ColorGenerator::new().with_lightness(-0.5);
155        assert_eq!(generator.lightness, 0.0);
156    }
157
158    #[test]
159    fn test_generate_color() {
160        let generator = ColorGenerator::default();
161
162        // Same hash should produce same color
163        let color1 = generator.generate_color(42);
164        let color2 = generator.generate_color(42);
165        assert_eq!(color1, color2);
166
167        // Different hashes should produce different colors
168        let color3 = generator.generate_color(100);
169        assert_ne!(color1, color3);
170    }
171
172    #[test]
173    fn test_generate_color_for() {
174        let generator = ColorGenerator::default();
175
176        // Same value should produce same color
177        let color1 = generator.generate_color_for(&"test");
178        let color2 = generator.generate_color_for(&"test");
179        assert_eq!(color1, color2);
180
181        // Different values should produce different colors
182        let color3 = generator.generate_color_for(&"other");
183        assert_ne!(color1, color3);
184    }
185}
facet_pretty/color.rs

facet_pretty/
color.rs
