Function overlay

pattern/canvas.js:3313–3315

(img1, img2, dx, dy, alpha)

    return blend(SCREEN, img1, img2, dx, dy, alpha);
}
function overlay(img1, img2, dx, dy, alpha) {
    return blend(OVERLAY, img1, img2, dx, dy, alpha);
}
function hardlight(img1, img2, dx, dy, alpha) {
    return blend(HARDLIGHT, img1, img2, dx, dy, alpha);
}