Function rotate

libs/echarts/echarts.simple.js:2685–2702

* 旋转变换 * @param {Float32Array|Array. } out * @param {Float32Array|Array. } a * @param {number} rad

(out, a, rad)

 * @param {number} rad
 */
function rotate(out, a, rad) {
    var aa = a[0];
    var ac = a[2];
    var atx = a[4];
    var ab = a[1];
    var ad = a[3];
    var aty = a[5];
    var st = Math.sin(rad);
    var ct = Math.cos(rad);

    out[0] = aa * ct + ab * st;
    out[1] = -aa * st + ab * ct;
    out[2] = ac * ct + ad * st;
    out[3] = -ac * st + ct * ad;
    out[4] = ct * atx + st * aty;
    out[5] = ct * aty - st * atx;
    return out;
}

/**
 * 缩放变换