Convert Hex to RGBA

My fiddle - http://jsbin.com/pitu/1/edit

I wanted to try an easy hex to rgba conversion. Ever browser I've used renders colors using rgb as default so when using the farbtastic color picker I'm converting the hex value to rgb by grabbing the background color the hex value generates (as rgb by default = simple conversion)

I tried replacing the ) symbol to , 1), but that didn't work so I went to just see how converting rgb to rgba would work, and I'm still having trouble.

The jquery

$('.torgb').val($('#color').css('background-color'));
$('.torgba').val().replace(/rgb/g,"rgba");

The goal

EDIT:

TinyColor Is a great color manipulation js library that does everything I want here and more. I figure you guys may want to give it a try! - https://github.com/bgrins/TinyColor

Solution 1:

//If you write your own code, remember hex color shortcuts (eg., #fff, #000)

function hexToRgbA(hex){
    var c;
    if(/^#([A-Fa-f0-9]{3}){1,2}$/.test(hex)){
        c= hex.substring(1).split('');
        if(c.length== 3){
            c= [c[0], c[0], c[1], c[1], c[2], c[2]];
        }
        c= '0x'+c.join('');
        return 'rgba('+[(c>>16)&255, (c>>8)&255, c&255].join(',')+',1)';
    }
    throw new Error('Bad Hex');
}

hexToRgbA('#fbafff')

/*  returned value: (String)
rgba(251,175,255,1)
*/

Solution 2:

@ElDoRado1239 has the right idea, but there's also a cleaner way:

function hexToRGB(hex, alpha) {
    var r = parseInt(hex.slice(1, 3), 16),
        g = parseInt(hex.slice(3, 5), 16),
        b = parseInt(hex.slice(5, 7), 16);

    if (alpha) {
        return "rgba(" + r + ", " + g + ", " + b + ", " + alpha + ")";
    } else {
        return "rgb(" + r + ", " + g + ", " + b + ")";
    }
}

hexToRGB('#FF0000', 0.5);

Solution 3:

ES6 function for only handling 6 character hex with or without the '#':

const hex2rgba = (hex, alpha = 1) => {
  const [r, g, b] = hex.match(/\w\w/g).map(x => parseInt(x, 16));
  return `rgba(${r},${g},${b},${alpha})`;
};

Usage:

hex2rgba('#af087b', .5)   // returns: rgba(175,8,123,0.5)
hex2rgba('af087b', .5)    // returns: rgba(175,8,123,0.5)
hex2rgba('af087b')        // returns: rgba(175,8,123,1)

Solution 4:

Clean TypeScript version:

hexToRGB(hex: string, alpha: string) {

  const r = parseInt(hex.slice(1, 3), 16);
  const g = parseInt(hex.slice(3, 5), 16);
  const b = parseInt(hex.slice(5, 7), 16);

  if (alpha) {
    return `rgba(${r}, ${g}, ${b}, ${alpha})`;
  }

  return `rgb(${r}, ${g}, ${b})`;
}

Based on @AJFarkas's answer.