TangIDE之贝赛尔曲线运动轨迹

var me = this;
var win = this.getWindow();
var sp = win.find("ui-sprite-general");
var factor = 0.01;

//贝塞尔的三个点{100, 100}, {20, 700}, {400, 20}

function updatePosition() {
    var value = factor;
    sp.x = (1 - value) * (1 - value) * 100 + 2 * value * (1 - value) * 20 + value * value * 400;
    sp.y = (1 - value) * (1 - value) * 100 + 2 * value * (1 - value) * 700 + value * value * 20;
    if(factor < 1) {
        setTimeout(updatePosition, 10);
    }
    factor += 0.03;
    var fp = win.dupChild("ui-foot-print-general", 0);
    fp.name = "ui-fp";
    fp.setPosition(sp.x, sp.y);
}
updatePosition();