the following program allow you to draw using your finger and great sample for opengl

实现无限循环滚动的UIScrollView，可以设置不同的滚动速度。自动滚动时，两列滚动视图的滚动速率是一样的。当用手指滚动某一列时，两列滚动视图的滚动速率是不同的 -Achieve infinite loop scrolling UIScrollView, you can set different scrolling speed. Automatic scroll, the two rows of rolling rate is the same view of the rolling.

ios图片马赛克处理，在图像上用手指滑动涂抹，所经过的区域形成马赛克效果。可以自定义马赛克效果粗细程度（即马赛克方块的大小），以及涂抹形成马赛克的范围。-ios image mosaic processing, slide your finger on the image smear, formed in the region through which a mosaic effect. You can customize the mosaic effect degree of thicknes