Skip to content

fix(color-generator): contrast color calculation #3274

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
sean-perkins merged 2 commits into from
Nov 30, 2023
Merged

fix(color-generator): contrast color calculation #3274

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0a01974
fix(color-generator): contrast color calculation
sean-perkins Nov 30, 2023
b0ef2d4
refactor: apply types and code style
sean-perkins Nov 30, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
29 changes: 27 additions & 2 deletions src/components/page/theming/_utils/color.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,28 @@ const rgbToYIQ = ({ r, g, b }: RGB): number => {
return (r * 299 + g * 587 + b * 114) / 1000;
};

const RED = 0.2126;
const GREEN = 0.7152;
const BLUE = 0.0722;
const GAMMA = 2.4;

const luminance = ({ r, g, b }: RGB) => {
const a = [r, g, b].map((v) => {
v /= 255;
return v <= 0.03928 ? v / 12.92 : Math.pow((v + 0.055) / 1.055, GAMMA);
});
return a[0] * RED + a[1] * GREEN + a[2] * BLUE;
};

// Original source: https://stackoverflow.com/a/9733420
const contrast = (rgb1: RGB, rgb2: RGB) => {
const lum1 = luminance(rgb1);
const lum2 = luminance(rgb2);
const brightest = Math.max(lum1, lum2);
const darkest = Math.min(lum1, lum2);
return (brightest + 0.05) / (darkest + 0.05);
};

export class Color {
readonly hex: string;
readonly hsl: HSL;
Expand Down Expand Up @@ -176,8 +198,11 @@ export class Color {
return /(^#[0-9a-fA-F]+)/.test(value.trim());
}

contrast(threshold = 128): Color {
return new Color(this.yiq >= threshold ? '#000' : '#fff');
contrast(): Color {
const blackContrastRatio = contrast(this.rgb, { r: 0, g: 0, b: 0 });
const whiteContrastRatio = contrast(this.rgb, { r: 255, g: 255, b: 255 });

return new Color(blackContrastRatio >= whiteContrastRatio ? '#000' : '#fff');
}

mix(from: string | RGB | HSL | Color, amount = 0.5): Color {
Expand Down