用来检测画布色彩，调整颜色的深度，从而实现画布颜色的调整-Used to detect the canvas color, adjust the color depth, in order to achieve the adjustment of color on canvas

“whiteboard”应用程序允许用户绘制不同大小和颜色的几何形状。 可以在任何时间删除部分或全部几何形状图形。 绘制图形的大小和颜色的选择由设备的屏幕大小和该设备所支持的颜色深度决定。-This “virtual whiteboard” application allows the user to draw geometric shapes of various sizes and colors. All or part of a drawing can be era