Function blur

pattern/canvas.js:3157–3165

(img, radius)

}

function blur(img, radius) {
    /* Applies a stack blur filter to the image and returns the blurred image.
     * - radius: the radius of the blur effect in pixels (0-175).
     */
    radius = (radius === undefined)? 10 : radius;
    radius = Math.min(radius, 175);
    var buffer = new OffscreenBuffer(img._img.width, img._img.height);
    return _stackblur(img, buffer, radius);
}

/*--- IMAGE FILTERS | ALPHA COMPOSITING ------------------------------------------------------------*/
// Based on: R. Dura, 2009, http://mouaif.wordpress.com/2009/01/05/photoshop-math-with-glsl-shaders/