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| author | ivarlovlie <git@ivarlovlie.no> | 2022-09-20 09:24:27 +0200 |
|---|---|---|
| committer | ivarlovlie <git@ivarlovlie.no> | 2022-09-20 09:24:27 +0200 |
| commit | a9072370ca1eb9a5cce928b1d487db0f307edea6 (patch) | |
| tree | 59c3c23df930a8b5f888dc7813923abf4ceefed4 /apps/kit/src/lib/colors.ts | |
| parent | 56fa963a1d63cbe0bf28e29e717cceaa417c45c1 (diff) | |
| download | greatoffice-a9072370ca1eb9a5cce928b1d487db0f307edea6.tar.xz greatoffice-a9072370ca1eb9a5cce928b1d487db0f307edea6.zip | |
feat: Move old apps into it's own directory
Diffstat (limited to 'apps/kit/src/lib/colors.ts')
| -rw-r--r-- | apps/kit/src/lib/colors.ts | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/apps/kit/src/lib/colors.ts b/apps/kit/src/lib/colors.ts new file mode 100644 index 0000000..34c7992 --- /dev/null +++ b/apps/kit/src/lib/colors.ts @@ -0,0 +1,47 @@ +export function generate_random_hex_color(skip_contrast_check = false) { + let hex = __generate_random_hex_color(); + if (skip_contrast_check) return hex; + while ((__calculate_contrast_ratio("#ffffff", hex) < 4.5) || (__calculate_contrast_ratio("#000000", hex) < 4.5)) { + hex = __generate_random_hex_color(); + } + + return hex; +} + +// Largely copied from chroma js api +function __generate_random_hex_color(): string { + let code = "#"; + for (let i = 0; i < 6; i++) { + code += "0123456789abcdef".charAt(Math.floor(Math.random() * 16)); + } + return code; +} + +function __calculate_contrast_ratio(hex1: string, hex2: string): number { + const rgb1 = __hex_to_rgb(hex1); + const rgb2 = __hex_to_rgb(hex2); + const l1 = __get_luminance(rgb1[0], rgb1[1], rgb1[2]); + const l2 = __get_luminance(rgb2[0], rgb2[1], rgb2[2]); + const result = l1 > l2 ? (l1 + 0.05) / (l2 + 0.05) : (l2 + 0.05) / (l1 + 0.05); + return result; +} + +function __hex_to_rgb(hex: string): number[] { + if (!hex.match(/^#([A-Fa-f0-9]{6})$/)) return []; + if (hex[0] === "#") hex = hex.substring(1, hex.length); + return [parseInt(hex.substring(0, 2), 16), parseInt(hex.substring(2, 4), 16), parseInt(hex.substring(4, 6), 16)]; +} + +function __get_luminance(r: any, g: any, b: any) { + // relative luminance + // see http://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef + r = __luminance_x(r); + g = __luminance_x(g); + b = __luminance_x(b); + return 0.2126 * r + 0.7152 * g + 0.0722 * b; +} + +function __luminance_x(x: any) { + x /= 255; + return x <= 0.03928 ? x / 12.92 : Math.pow((x + 0.055) / 1.055, 2.4); +} |
