Function pinch

pattern/canvas.js:3403–3414

(img, dx, dy, zoom)

}

function pinch(img, dx, dy, zoom) {
    /* Returns the image with a pinch distortion applied to it.
     *  - dx: horizontal offset (in pixels) of the effect.
     *  - dy: vertical offset (in pixels) of the effect.
     *  - zoom: the amount of bulge or pinch (-1.0-1.0):
     */
    var m1 = geometry.distance(0, 0, img.width, img.height);
    var m2 = Math.clamp(zoom || 0 * 0.75, -0.75, 0.75);
    return polar(img, dx, dy, function(d, a) { 
        return [d * Math.pow(m1/d, m2) * (1-m2), a]; 
    });
}

function splash(img, dx, dy, radius) {
    /* Returns the image with a light-tunnel distortion applied to it.