generic.js

var generic_effect={}

generic_effect.apply_region_filter=function(in_imgData,out_imgData,window_width,window_height,
  pixel_form_region_rgba_filter) {

  var w=0;

  for (var y=0;y<out_imgData.height;y++)
    for (var x=0;x<out_imgData.width;x++) {
      w=((y*out_imgData.width)+x)<<2;
      new_rgba_pixel_val=pixel_form_region_rgba_filter(
          in_imgData,
          x-Math.round(window_width/2), y-Math.round(window_height/2),
          window_width, window_height);
      for (var i=0;i<4;i++) {
        out_imgData.data[w+i]=new_rgba_pixel_val[i];
      }
    }
}