渐变颜色的柱形条，可以设置开始、结束颜色，采用双缓冲技术实现，无任何闪烁问题，已在项目中应用。带源码及测试！-Cylindrical gradient color bar, you can set the start and end colors, using double buffering technology, without any flicker problems, has been applied in the project. With source code and test！