参考: http://www.cnblogs.com/xujh/archive/2007/04/17/717433.html
使用 GraphicsPath -- 指定一系列的 Arc, Line
先补充下 Arc 的用法:
//... Graphics g = e.Graphics; int radius = 50; //圆角半径 Rectangle rectArc = new Rectangle(200, 200, 2*radius, 2*radius); // 弧度区域 g.DrawRectangle(Pens.Purple, rectArc); //显示区域边框 g.DrawArc(new Pen(Color.Red, 2), rectArc, 180, 90); // 绘制弧线 g.DrawArc(Pens.Blue, rectArc, 270, 90);
生成的效果:
由此可以推测出圆角矩形中的弧线与直线的关系:
所以最终代码为:
// 要实现 圆角化的 矩形 Rectangle rect = new Rectangle(180, 180, 200, 160); int cRadius = 15; // 圆角半径 // 指定图形路径, 有一系列 直线/曲线 组成 GraphicsPath myPath = new GraphicsPath(); myPath.StartFigure(); myPath.AddArc(new Rectangle(new Point(rect.X, rect.Y), new Size(2 * cRadius, 2 * cRadius)), 180, 90); myPath.AddLine(new Point(rect.X + cRadius, rect.Y), new Point(rect.Right - cRadius, rect.Y)); myPath.AddArc(new Rectangle(new Point(rect.Right - 2 * cRadius, rect.Y), new Size(2 * cRadius, 2 * cRadius)), 270, 90); myPath.AddLine(new Point(rect.Right, rect.Y + cRadius), new Point(rect.Right, rect.Bottom - cRadius)); myPath.AddArc(new Rectangle(new Point(rect.Right - 2 * cRadius, rect.Bottom - 2 * cRadius), new Size(2 * cRadius, 2 * cRadius)), 0, 90); myPath.AddLine(new Point(rect.Right - cRadius, rect.Bottom), new Point(rect.X + cRadius, rect.Bottom)); myPath.AddArc(new Rectangle(new Point(rect.X, rect.Bottom - 2 * cRadius), new Size(2 * cRadius, 2 * cRadius)), 90, 90); myPath.AddLine(new Point(rect.X, rect.Bottom - cRadius), new Point(rect.X, rect.Y + cRadius)); myPath.CloseFigure(); g.DrawPath(new Pen(Color.Red, 1), myPath);