I'm trying to create a color opposite of current color. I mean if current color is black, then I need to generate white.
Actually I have a text (the color of this text is dynamic, its color can be made at random). That text is into a div
and I need to set the opposite color of that text for the background-color
of div
. I would like that text be clear in the div
(color perspective).
The opposite color means: Dark / Bright
I have the current color of text and I can pass it to this function:
var TextColor = #F0F0F0; // for example (it is a bright color)
function create_opp_color(current color) {
// create opposite color according to current color
}
create_opp_color(TextColor); // this should be something like "#202020" (or a dark color)
Is there any idea to create create_opp_color()
function?
UPDATE: Production-ready code on GitHub.
This is how I'd do it:
function invertColor(hex) {
if (hex.indexOf('#') === 0) {
hex = hex.slice(1);
}
// convert 3-digit hex to 6-digits.
if (hex.length === 3) {
hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
}
if (hex.length !== 6) {
throw new Error('Invalid HEX color.');
}
// invert color components
var r = (255 - parseInt(hex.slice(0, 2), 16)).toString(16),
g = (255 - parseInt(hex.slice(2, 4), 16)).toString(16),
b = (255 - parseInt(hex.slice(4, 6), 16)).toString(16);
// pad each with zeros and return
return '#' + padZero(r) + padZero(g) + padZero(b);
}
function padZero(str, len) {
len = len || 2;
var zeros = new Array(len).join('0');
return (zeros + str).slice(-len);
}
Example Output:
Advanced Version:
This has a bw
option that will decide whether to invert to black or white; so you'll get more contrast which is generally better for the human eye.
function invertColor(hex, bw) {
if (hex.indexOf('#') === 0) {
hex = hex.slice(1);
}
// convert 3-digit hex to 6-digits.
if (hex.length === 3) {
hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
}
if (hex.length !== 6) {
throw new Error('Invalid HEX color.');
}
var r = parseInt(hex.slice(0, 2), 16),
g = parseInt(hex.slice(2, 4), 16),
b = parseInt(hex.slice(4, 6), 16);
if (bw) {
// https://stackoverflow.com/a/3943023/112731
return (r * 0.299 + g * 0.587 + b * 0.114) > 186
? '#000000'
: '#FFFFFF';
}
// invert color components
r = (255 - r).toString(16);
g = (255 - g).toString(16);
b = (255 - b).toString(16);
// pad each with zeros and return
return "#" + padZero(r) + padZero(g) + padZero(b);
}
Example Output: