[рони]

Роман Андреевич,

let imageData = ctx.getImageData(0,0, cvs.width, cvs.height);
 let pix  = imageData.data;
  for (let i = 0, n = pix.length; i < n; i += 4) {
    if(pix[i] == 255 && pix[i + 1] == 255 && pix[i + 2] == 0) {
    pix[i]     = 228;
    pix[i + 1] = 60;
    pix[i + 2] = 30;
    }

  }