向容器中设置背景色为桌面颜色；设置颜色，并绘制矩形、圆角矩形、椭圆，并且将其显示出来；，并填充矩形、圆角矩形、椭圆（设置颜色）；设置字体，并显示文本信息。-containers to set the background color of the desktop color Set the color, and drawing rectangle, rounded corner rectangles, ovals, and to demonstrate , and filled rectan