How to convert colors in RGB format to hex format and vice versa?
For example, convert '#0080C0'
to (0, 128, 192)
.
Note: both versions of rgbToHex
expect integer values for r
, g
and b
, so you'll need to do your own rounding if you have non-integer values.
The following will do to the RGB to hex conversion and add any required zero padding:
function componentToHex(c) {
var hex = c.toString(16);
return hex.length == 1 ? "0" + hex : hex;
}
function rgbToHex(r, g, b) {
return "#" + componentToHex(r) + componentToHex(g) + componentToHex(b);
}
alert(rgbToHex(0, 51, 255)); // #0033ff
Converting the other way:
function hexToRgb(hex) {
var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
return result ? {
r: parseInt(result[1], 16),
g: parseInt(result[2], 16),
b: parseInt(result[3], 16)
} : null;
}
alert(hexToRgb("#0033ff").g); // "51";
Finally, an alternative version of rgbToHex()
, as discussed in @casablanca's answer and suggested in the comments by @cwolves:
function rgbToHex(r, g, b) {
return "#" + (1 << 24 | r << 16 | g << 8 | b).toString(16).slice(1);
}
alert(rgbToHex(0, 51, 255)); // #0033ff
Here's a version of hexToRgb()
that also parses a shorthand hex triplet such as "#03F":
function hexToRgb(hex) {
// Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
hex = hex.replace(shorthandRegex, function(m, r, g, b) {
return r + r + g + g + b + b;
});
var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
return result ? {
r: parseInt(result[1], 16),
g: parseInt(result[2], 16),
b: parseInt(result[3], 16)
} : null;
}
alert(hexToRgb("#0033ff").g); // "51";
alert(hexToRgb("#03f").g); // "51";