diff options
Diffstat (limited to 'core')
| -rw-r--r-- | core/src/color.rs | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/core/src/color.rs b/core/src/color.rs index 4e79defb..d9271e83 100644 --- a/core/src/color.rs +++ b/core/src/color.rs @@ -1,5 +1,13 @@ use palette::rgb::{Srgb, Srgba}; +#[derive(Debug, thiserror::Error)] +/// Errors that can occur when constructing a [`Color`]. +pub enum ColorError { + #[error("The specified hex string is invalid. See supported formats.")] + /// The specified hex string is invalid. See supported formats. + InvalidHex, +} + /// A color in the `sRGB` color space. #[derive(Debug, Clone, Copy, PartialEq, Default)] pub struct Color { @@ -88,6 +96,52 @@ impl Color { } } + /// Creates a [`Color`] from a hex string. Supported formats are #rrggbb, #rrggbbaa, #rgb, + /// #rgba. The “#” is optional. Both uppercase and lowercase are supported. + pub fn from_hex(s: &str) -> Result<Color, ColorError> { + let hex = s.strip_prefix('#').unwrap_or(s); + let n_chars = hex.len(); + + let get_channel = |from: usize, to: usize| { + let num = usize::from_str_radix(&hex[from..=to], 16) + .map_err(|_| ColorError::InvalidHex)? + as f32 + / 255.0; + // If we only got half a byte (one letter), expand it into a full byte (two letters) + Ok(if from == to { num + num * 16.0 } else { num }) + }; + + if n_chars == 3 { + Ok(Color::from_rgb( + get_channel(0, 0)?, + get_channel(1, 1)?, + get_channel(2, 2)?, + )) + } else if n_chars == 6 { + Ok(Color::from_rgb( + get_channel(0, 1)?, + get_channel(2, 3)?, + get_channel(4, 5)?, + )) + } else if n_chars == 4 { + Ok(Color::from_rgba( + get_channel(0, 0)?, + get_channel(1, 1)?, + get_channel(2, 2)?, + get_channel(3, 3)?, + )) + } else if n_chars == 8 { + Ok(Color::from_rgba( + get_channel(0, 1)?, + get_channel(2, 3)?, + get_channel(4, 5)?, + get_channel(6, 7)?, + )) + } else { + Err(ColorError::InvalidHex) + } + } + /// Creates a [`Color`] from its linear RGBA components. pub fn from_linear_rgba(r: f32, g: f32, b: f32, a: f32) -> Self { // As described in: @@ -273,4 +327,19 @@ mod tests { assert_relative_eq!(result.b, 0.3); assert_relative_eq!(result.a, 1.0); } + + #[test] + fn from_hex() -> Result<(), ColorError> { + let tests = [ + ("#ff0000", [255, 0, 0, 255]), + ("00ff0080", [0, 255, 0, 128]), + ("#F80", [255, 136, 0, 255]), + ("#00f1", [0, 0, 255, 17]), + ]; + for (arg, expected) in tests { + assert_eq!(Color::from_hex(arg)?.into_rgba8(), expected); + } + assert!(Color::from_hex("invalid").is_err()); + Ok(()) + } } |