在TC环境下实现的具有橡皮筋直线、圆、矩形等功能的模拟windows画板-In the TC environment to achieve a straight line with a rubber band, round, rectangular windows functions such as analog sketchpad

vc画图工具,实现橡皮筋效果，可以画椭圆、矩形。多边形等图形-vc drawing tools, to achieve a rubber band effect, you can draw ellipses, rectangles. Polygon graphics

橡皮筋绘制矩形，线，等不同形状，代码好用(Rubber band drawing rectangle, line, and other different shapes, code easy to use)