Skip to content

Instantly share code, notes, and snippets.

@leibovic
Created June 9, 2011 16:27
Show Gist options
  • Save leibovic/1017111 to your computer and use it in GitHub Desktop.
Save leibovic/1017111 to your computer and use it in GitHub Desktop.
Dominant Color
function getDominantColor(aImg) {
let canvas = document.createElement("canvas");
canvas.height = aImg.height;
canvas.width = aImg.width;
let context = canvas.getContext("2d");
context.drawImage(aImg, 0, 0);
// keep track of how many times a color appears in the image
let colorCount = {};
let maxCount = 0;
let dominantColor = "";
// data is an array of a series of 4 one-byte values representing the rgba values of each pixel
let data = context.getImageData(0, 0, aImg.height, aImg.width).data;
for (let i = 0; i < data.length; i += 4) {
// ignore transparent pixels
if (data[i+3] == 0)
continue;
let color = data[i] + "," + data[i+1] + "," + data[i+2];
// ignore white
if (color == "255,255,255")
continue;
colorCount[color] = colorCount[color] ? colorCount[color] + 1 : 1;
// keep track of the color that appears the most times
if (colorCount[color] > maxCount) {
maxCount = colorCount[color];
dominantColor = color;
}
}
let rgb = dominantColor.split(",");
return rgb;
}
@mathiasbynens
Copy link

@leibovic
Copy link
Author

Mardak wrote an add-on to help developers play around with this algorithm: http://ed.agadak.net/2011/06/restartless-dominant-color

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment