void translate(in float x, in float y);//移动
void rotate(in float angle);//旋转一个角度
void scale(in float x, in float y);//缩放
void drawImage(in nsIDOMElement image, in float a1, in float a2, in float a3可选, in float a4 可选, in float a5 可选, in float a6 可选, in float a7 可选, in float a8 可选);//绘制图形
