中文说明：
使用抖动创建图像。使用抖动得到的图像看上去有更多的颜色数；不适用抖动得到的图像看上去颜色数少，大门空间分辨率要高些。
English Description：
Create an image using dithering. The image obtained by dithering appears to have more colors; The image obtained without dithering looks less color, and the spatial resolution of the gate should be higher