JS function to calculate complementary colour?

Question

Does anybody know, off the top of your heads, a Javascript solution for calculating the complementary colour of a hex value?

There are a number of colour picking suites and palette generators on the web but I haven't seen any that actually calculate the colour dynamically using JS.

A detailed hint or a snippet would be very much appreciated.

score 68 · Accepted Answer · edited Sep 23 '19 at 15:40

Parsed through http://design.geckotribe.com/colorwheel/

    // Complement
    temprgb={ r: 0, g: 0xff, b: 0xff }; // Cyan
    temphsv=RGB2HSV(temprgb);
    temphsv.hue=HueShift(temphsv.hue,180.0);
    temprgb=HSV2RGB(temphsv);
    console.log(temprgb); // Complement is red (0xff, 0, 0)
    
    function RGB2HSV(rgb) {
     hsv = new Object();
     max=max3(rgb.r,rgb.g,rgb.b);
     dif=max-min3(rgb.r,rgb.g,rgb.b);
     hsv.saturation=(max==0.0)?0:(100*dif/max);
     if (hsv.saturation==0) hsv.hue=0;
      else if (rgb.r==max) hsv.hue=60.0*(rgb.g-rgb.b)/dif;
     else if (rgb.g==max) hsv.hue=120.0+60.0*(rgb.b-rgb.r)/dif;
     else if (rgb.b==max) hsv.hue=240.0+60.0*(rgb.r-rgb.g)/dif;
     if (hsv.hue<0.0) hsv.hue+=360.0;
     hsv.value=Math.round(max*100/255);
     hsv.hue=Math.round(hsv.hue);
     hsv.saturation=Math.round(hsv.saturation);
     return hsv;
    }
    
    // RGB2HSV and HSV2RGB are based on Color Match Remix [http://color.twysted.net/]
    // which is based on or copied from ColorMatch 5K [http://colormatch.dk/]
    function HSV2RGB(hsv) {
     var rgb=new Object();
     if (hsv.saturation==0) {
      rgb.r=rgb.g=rgb.b=Math.round(hsv.value*2.55);
     } else {
      hsv.hue/=60;
      hsv.saturation/=100;
      hsv.value/=100;
      i=Math.floor(hsv.hue);
      f=hsv.hue-i;
      p=hsv.value*(1-hsv.saturation);
      q=hsv.value*(1-hsv.saturation*f);
      t=hsv.value*(1-hsv.saturation*(1-f));
      switch(i) {
      case 0: rgb.r=hsv.value; rgb.g=t; rgb.b=p; break;
      case 1: rgb.r=q; rgb.g=hsv.value; rgb.b=p; break;
      case 2: rgb.r=p; rgb.g=hsv.value; rgb.b=t; break;
      case 3: rgb.r=p; rgb.g=q; rgb.b=hsv.value; break;
      case 4: rgb.r=t; rgb.g=p; rgb.b=hsv.value; break;
      default: rgb.r=hsv.value; rgb.g=p; rgb.b=q;
      }
      rgb.r=Math.round(rgb.r*255);
      rgb.g=Math.round(rgb.g*255);
      rgb.b=Math.round(rgb.b*255);
     }
     return rgb;
    }

    //Adding HueShift via Jacob (see comments)
    function HueShift(h,s) { 
        h+=s; while (h>=360.0) h-=360.0; while (h<0.0) h+=360.0; return h; 
    }
    
    //min max via Hairgami_Master (see comments)
    function min3(a,b,c) { 
        return (a<b)?((a<c)?a:c):((b<c)?b:c); 
    } 
    function max3(a,b,c) { 
        return (a>b)?((a>c)?a:c):((b>c)?b:c); 
    }

The magical HueShift(...) function is this: function HueShift(h,s) { h+=s; while (h>=360.0) h-=360.0; while (h<0.0) h+=360.0; return h; } — Jacob, Jan 04 '11 at 18:33
function min3(a,b,c) { return (ab)?((a>c)?a:c):((b>c)?b:c); } — Hairgami_Master, Dec 14 '11 at 15:26
Although this does do some awesome stuff, there is a massive amount of code missing. "HueShift"?. "See comments" you say? What comments? The lack of entirety has made this answer useless. — WebWanderer, Jun 11 '15 at 18:57
conditional branches are more expensive than modulus or Math.min/max. — geowar, Dec 10 '17 at 19:46
Hi, I tried your algorithm, with the following color `#00BCD4` which should look something like `{r: 0, g: 0xbc, b: 0xd4}` it should give me as complementary color this `# d41900` instead it gives me this `{ b: 0, g: 25, r: 212 }` this `#0019d4`. Could you give me a hand? — Paul, May 10 '21 at 14:53

Alex Flanagan · Answer 2 · 2017-08-15T02:50:37.203

38

I find that taking the bit-wise complement works well, and quickly.

var color = 0x320ae3;
var complement = 0xffffff ^ color;

I'm not sure if it's a perfect complement in the sense of "mixes together to form a 70% grey", however a 70% grey is "pure white" in terms of color timing in film. It occurred to me that XORing the RGB hex out of pure white might be a good first approximation. You could also try a darker grey to see how that works for you.

Again, this is a fast approximation and I make no guarantees that it'll be perfectly accurate.

See https://github.com/alfl/textful/blob/master/app.js#L38 for my implementation.

edited Aug 15 '17 at 02:50

answered Feb 21 '14 at 02:34

Alex Flanagan

557
4
9

10

This works nicely, except if you want the result to always be 6 characters long. I suggest `('000000' + (('0xffffff' ^ '0x320ae3').toString(16))).slice(-6);` – professormeowingtons Jun 02 '14 at 01:13
Buzzzz: (wrong) What would the opposite color of 0x7F7F7F be? 0x808080! That's not very "opposite". XOR with 0x808080 would be better (color distance then is always half) but still not "best". The HSL methods give best results. – geowar Dec 10 '17 at 19:37
Fair, if you xor grey out of grey you get a different grey. Call it a limit of the approach :D – Alex Flanagan Jan 12 '19 at 20:17

Edward · Answer 3 · 2016-06-06T16:29:51.210

None of the other functions here worked out the box, so I made this one.

It takes a hex value, converts it to HSL, shifts the hue 180 degrees and converts back to Hex

/* hexToComplimentary : Converts hex value to HSL, shifts
 * hue by 180 degrees and then converts hex, giving complimentary color
 * as a hex value
 * @param  [String] hex : hex value  
 * @return [String] : complimentary color as hex value
 */
function hexToComplimentary(hex){

    // Convert hex to rgb
    // Credit to Denis http://stackoverflow.com/a/36253499/4939630
    var rgb = 'rgb(' + (hex = hex.replace('#', '')).match(new RegExp('(.{' + hex.length/3 + '})', 'g')).map(function(l) { return parseInt(hex.length%2 ? l+l : l, 16); }).join(',') + ')';

    // Get array of RGB values
    rgb = rgb.replace(/[^\d,]/g, '').split(',');

    var r = rgb[0], g = rgb[1], b = rgb[2];

    // Convert RGB to HSL
    // Adapted from answer by 0x000f http://stackoverflow.com/a/34946092/4939630
    r /= 255.0;
    g /= 255.0;
    b /= 255.0;
    var max = Math.max(r, g, b);
    var min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2.0;

    if(max == min) {
        h = s = 0;  //achromatic
    } else {
        var d = max - min;
        s = (l > 0.5 ? d / (2.0 - max - min) : d / (max + min));

        if(max == r && g >= b) {
            h = 1.0472 * (g - b) / d ;
        } else if(max == r && g < b) {
            h = 1.0472 * (g - b) / d + 6.2832;
        } else if(max == g) {
            h = 1.0472 * (b - r) / d + 2.0944;
        } else if(max == b) {
            h = 1.0472 * (r - g) / d + 4.1888;
        }
    }

    h = h / 6.2832 * 360.0 + 0;

    // Shift hue to opposite side of wheel and convert to [0-1] value
    h+= 180;
    if (h > 360) { h -= 360; }
    h /= 360;

    // Convert h s and l values into r g and b values
    // Adapted from answer by Mohsen http://stackoverflow.com/a/9493060/4939630
    if(s === 0){
        r = g = b = l; // achromatic
    } else {
        var hue2rgb = function hue2rgb(p, q, t){
            if(t < 0) t += 1;
            if(t > 1) t -= 1;
            if(t < 1/6) return p + (q - p) * 6 * t;
            if(t < 1/2) return q;
            if(t < 2/3) return p + (q - p) * (2/3 - t) * 6;
            return p;
        };

        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;

        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    r = Math.round(r * 255);
    g = Math.round(g * 255); 
    b = Math.round(b * 255);

    // Convert r b and g values to hex
    rgb = b | (g << 8) | (r << 16); 
    return "#" + (0x1000000 | rgb).toString(16).substring(1);
}

This works great. How long did it take you to write this? I've been searching for something that does this for awhile and also encountered several 'out of the box' solutions that did not work. — AlexanderGriffin, Sep 16 '16 at 14:12
It took an hour or so - I just patched together some stackoverflow answers (credited in the code). — Edward, Sep 19 '16 at 12:31
@Edd: Hi, I tried your algorithm, with the following color `#00BCD4` it should give me as complementary color this `#d41900` instead it gives me this `#d41800`. Could you give me a hand? — Paul, May 10 '21 at 14:41
Works great! For anyone wanting a smaller difference, change h+= 180; to h+= 40; — Rasmus, Jul 16 '21 at 14:22
Produces values that align with this web tool. https://www.canva.com/colors/color-wheel — pistol-pete, Sep 14 '22 at 21:13

Stephen Turner · Answer 4 · 2018-06-21T09:56:40.910

9

Rather than reinventing the wheel, I found a library to work with colors.

Tiny Color

This is how you would implement some of the other answers using it.

color1 = tinycolor2('#f00').spin(180).toHexString(); // Hue Shift
color2 = tinycolor2("#f00").complement().toHexString(); // bitwise

edited Jun 21 '18 at 09:56

answered Jun 21 '18 at 09:51

Stephen Turner

7,125
4
51
68

score 3 · Answer 5 · answered May 06 '21 at 19:47

Hex and RGB complementry This is most correct and efficient way to get complementary hex color value

function complementryHexColor(hex){
    let r = hex.length == 4 ? parseInt(hex[1] + hex[1], 16) : parseInt(hex.slice(1, 3), 16);
    let g = hex.length == 4 ? parseInt(hex[2] + hex[2], 16) : parseInt(hex.slice(3, 5), 16);
    let b = hex.length == 4 ? parseInt(hex[3] + hex[3], 16) : parseInt(hex.slice(5), 16);
  
    [r, g, b] = complementryRGBColor(r, g, b);
    return '#' + (r < 16 ? '0' + r.toString(16) : r.toString(16)) + (g < 16 ? '0' + g.toString(16) : g.toString(16)) + (b < 16 ? '0' + b.toString(16) : b.toString(16));
}

function complementryRGBColor(r, g, b) {
    if (Math.max(r, g, b) == Math.min(r, g, b)) {
        return [255 - r, 255 - g, 255 - b];

    } else {
        r /= 255, g /= 255, b /= 255;
        var max = Math.max(r, g, b), min = Math.min(r, g, b);
        var h, s, l = (max + min) / 2;
        var d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
    
        switch (max) {
            case r: h = (g - b) / d + (g < b ? 6 : 0); break;
            case g: h = (b - r) / d + 2; break;
            case b: h = (r - g) / d + 4; break;
        }
    
        h = Math.round((h*60) + 180) % 360;
        h /= 360;
        
        function hue2rgb(p, q, t) {
            if (t < 0) t += 1;
            if (t > 1) t -= 1;
            if (t < 1/6) return p + (q - p) * 6 * t;
            if (t < 1/2) return q;
            if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
            return p;
        }
    
        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;
    
        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);

        return [Math.round(r*255), Math.round(g*255), Math.round(b*255)];
    }
}

score 2 · Answer 6 · edited Jun 20 '20 at 09:12

RGB Complimentary

function componentToHex(c) {
    var hex = c.toString(16);
    return hex.length == 1 ? "0" + hex : hex;
}


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;
}

function rgbComplimentary(r,g,b){

    var hex = "#" + componentToHex(r) + componentToHex(g) + componentToHex(b);
    var rgb = 'rgb(' + (hex = hex.replace('#', '')).match(new RegExp('(.{' + hex.length/3 + '})', 'g')).map(function(l) { return parseInt(hex.length%2 ? l+l : l, 16); }).join(',') + ')';

    // Get array of RGB values
    rgb = rgb.replace(/[^\d,]/g, '').split(',');

    var r = rgb[0]/255.0, g = rgb[1]/255.0, b = rgb[2]/255.0;

    var max = Math.max(r, g, b);
    var min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2.0;

    if(max == min) {
        h = s = 0;  //achromatic
    } else {
        var d = max - min;
        s = (l > 0.5 ? d / (2.0 - max - min) : d / (max + min));

        if(max == r && g >= b) {
            h = 1.0472 * (g - b) / d ;
        } else if(max == r && g < b) {
            h = 1.0472 * (g - b) / d + 6.2832;
        } else if(max == g) {
            h = 1.0472 * (b - r) / d + 2.0944;
        } else if(max == b) {
            h = 1.0472 * (r - g) / d + 4.1888;
        }
    }

    h = h / 6.2832 * 360.0 + 0;

    // Shift hue to opposite side of wheel and convert to [0-1] value
    h+= 180;
    if (h > 360) { h -= 360; }
    h /= 360;

    // Convert h s and l values into r g and b values
    // Adapted from answer by Mohsen http://stackoverflow.com/a/9493060/4939630
    if(s === 0){
        r = g = b = l; // achromatic
    } else {
        var hue2rgb = function hue2rgb(p, q, t){
            if(t < 0) t += 1;
            if(t > 1) t -= 1;
            if(t < 1/6) return p + (q - p) * 6 * t;
            if(t < 1/2) return q;
            if(t < 2/3) return p + (q - p) * (2/3 - t) * 6;
            return p;
        };

        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;

        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    r = Math.round(r * 255);
    g = Math.round(g * 255); 
    b = Math.round(b * 255);

    // Convert r b and g values to hex
    rgb = b | (g << 8) | (r << 16); 
    return hexToRgb("#" + (0x1000000 | rgb).toString(16).substring(1));

}


console.log(rgbComplimentary(242, 211, 215));

HEX Complimentary

function hexComplimentary(hex){

    var rgb = 'rgb(' + (hex = hex.replace('#', '')).match(new RegExp('(.{' + hex.length/3 + '})', 'g')).map(function(l) { return parseInt(hex.length%2 ? l+l : l, 16); }).join(',') + ')';

    // Get array of RGB values
    rgb = rgb.replace(/[^\d,]/g, '').split(',');

    var r = rgb[0]/255.0, g = rgb[1]/255.0, b = rgb[2]/255.0;

    var max = Math.max(r, g, b);
    var min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2.0;

    if(max == min) {
        h = s = 0;  //achromatic
    } else {
        var d = max - min;
        s = (l > 0.5 ? d / (2.0 - max - min) : d / (max + min));

        if(max == r && g >= b) {
            h = 1.0472 * (g - b) / d ;
        } else if(max == r && g < b) {
            h = 1.0472 * (g - b) / d + 6.2832;
        } else if(max == g) {
            h = 1.0472 * (b - r) / d + 2.0944;
        } else if(max == b) {
            h = 1.0472 * (r - g) / d + 4.1888;
        }
    }

    h = h / 6.2832 * 360.0 + 0;

    // Shift hue to opposite side of wheel and convert to [0-1] value
    h+= 180;
    if (h > 360) { h -= 360; }
    h /= 360;

    if(s === 0){
        r = g = b = l; // achromatic
    } else {
        var hue2rgb = function hue2rgb(p, q, t){
            if(t < 0) t += 1;
            if(t > 1) t -= 1;
            if(t < 1/6) return p + (q - p) * 6 * t;
            if(t < 1/2) return q;
            if(t < 2/3) return p + (q - p) * (2/3 - t) * 6;
            return p;
        };

        var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        var p = 2 * l - q;

        r = hue2rgb(p, q, h + 1/3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1/3);
    }

    r = Math.round(r * 255);
    g = Math.round(g * 255); 
    b = Math.round(b * 255);

    // Convert r b and g values to hex
    rgb = b | (g << 8) | (r << 16); 
    return "#" + (0x1000000 | rgb).toString(16).substring(1);
}


console.log(hexComplimentary("#ff5a5a"));

Source: Updated https://stackoverflow.com/a/37657940/6569224 answer

Hi, I tried your algorithm, with the following color `#00BCD4` it should give me as complementary color this `#d41900` instead it gives me this `#d41800`. Could you give me a hand? — Paul, May 10 '21 at 14:42

JS function to calculate complementary colour?

6 Answers6

RGB Complimentary

HEX Complimentary

Linked