forked from vikunja/frontend
22 lines
639 B
JavaScript
22 lines
639 B
JavaScript
export const colorIsDark = color => {
|
|
if (typeof color === 'undefined') {
|
|
return true // Defaults to dark
|
|
}
|
|
|
|
if (color === '#' || color === '') {
|
|
return true // Defaults to dark
|
|
}
|
|
|
|
if (color.substring(0, 1) !== '#') {
|
|
color = '#' + color
|
|
}
|
|
|
|
let rgb = parseInt(color.substring(1, 7), 16) // convert rrggbb to decimal
|
|
let r = (rgb >> 16) & 0xff // extract red
|
|
let g = (rgb >> 8) & 0xff // extract green
|
|
let b = (rgb >> 0) & 0xff // extract blue
|
|
|
|
// luma will be a value 0..255 where 0 indicates the darkest, and 255 the brightest
|
|
let luma = 0.2126 * r + 0.7152 * g + 0.0722 * b // per ITU-R BT.709
|
|
return luma > 128
|
|
} |