drawImage 方法
实现
void drawImage(/*CanvasImageSource*/ image, num sx_OR_x, num sy_OR_y,
[num? sw_OR_width,
num? height_OR_sh,
num? dx,
num? dy,
num? dw,
num? dh]) native;
void drawImage(/*CanvasImageSource*/ image, num sx_OR_x, num sy_OR_y,
[num? sw_OR_width,
num? height_OR_sh,
num? dx,
num? dy,
num? dw,
num? dh]) native;