Filtering Photos

Here is the code that makes it work:

ocean.onload = function(){
  ctx.drawImage(ocean, W/2 - 325, H/2 - 250, 640 ,480);
  
  var myImg = ctx.getImageData(W/2 - 235, H/2 - 250, 640, 481);
  
  for (var i = 0; i < myImg.data.length; i += 4)
  {
  myImg.data[i] += 25;
  myImg.data[i + 1] -= 200;
  myImg.data[i + 2] -= 200;
  myImg.data[i + 3] = 255;
  } 
  ctx.putImageData(myImg, W/2 - 325, H/2 - 250);
}
        

Go ahead and play with the values and see how it changes. The amount you set will be added or subtracted from the normal value

Red Value
Green Value
Blue Value
Alpha Value
Black and whtie	Inverted