/// <summary>
/// 根据普通矩形得到圆角矩形的路径
/// </summary>
/// <param name="rectangle">原始矩形</param>
/// <param name="r">半径</param>
/// <returns>图形路径</returns>
private static GraphicsPath GetRoundRectangle(Rectangle rectangle, int r, roundStyle rs)
{
int l = 2 * r;
// 把圆角矩形分成八段直线、弧的组合，依次加到路径中
GraphicsPath gp = new GraphicsPath();
switch (rs)
{
case roundStyle.left:
gp.AddLine(new Point(rectangle.Right - r, rectangle.Bottom), new Point(rectangle.X + r, rectangle.Bottom));
gp.AddArc(new Rectangle(rectangle.X, rectangle.Bottom - l, l, l), 90F, 90F);
gp.AddLine(new Point(rectangle.X, rectangle.Bottom - r), new Point(rectangle.X, rectangle.Y + r));
gp.AddArc(new Rectangle(rectangle.X, rectangle.Y, l, l), 180F, 90F);
gp.AddLine(new Point(rectangle.X + r, rectangle.Y), new Point(rectangle.Right - r, rectangle.Y));
gp.AddArc(new Rectangle(rectangle.Right - l, rectangle.Y, l, l), 270F, 90F);
gp.AddLine(new Point(rectangle.Right, rectangle.Y + r), new Point(rectangle.Right, rectangle.Bottom - r));
gp.AddArc(new Rectangle(rectangle.Right - l, rectangle.Bottom - l, l, l), 0F, 90F);
break;
case roundStyle.right:
gp.AddLine(new Point(rectangle.Right - r, rectangle.Bottom), new Point(rectangle.X + r, rectangle.Bottom));
gp.AddArc(new Rectangle(rectangle.X, rectangle.Bottom - l, l, l), 90F, 90F);
gp.AddLine(new Point(rectangle.X, rectangle.Bottom - r), new Point(rectangle.X, rectangle.Y + r));
gp.AddArc(new Rectangle(rectangle.X, rectangle.Y, l, l), 180F, 90F);
gp.AddLine(new Point(rectangle.X + r, rectangle.Y), new Point(rectangle.Right - r, rectangle.Y));
gp.AddArc(new Rectangle(rectangle.Right - l, rectangle.Y, l, l), 270F, 90F);
gp.AddLine(new Point(rectangle.Right, rectangle.Y + r), new Point(rectangle.Right, rectangle.Bottom - r));
gp.AddArc(new Rectangle(rectangle.Right - l, rectangle.Bottom - l, l, l), 0F, 90F);
break;
}
return(gp);
}
/// <summary>
/// C# GDI+ 绘制圆角实心矩形
/// </summary>
/// <param name="g">Graphics 对象</param>
/// <param name="rectangle">要填充的矩形</param>
/// <param name="backColor">填充背景色</param>
/// <param name="r">圆角半径</param>
public static void FillRoundRectangle(Graphics g, Rectangle rectangle, Color backColor, int r, roundStyle rs)
{
rectangle = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - 1, rectangle.Height - 1);
Brush b = new SolidBrush(backColor);
g.FillPath(b, GetRoundRectangle(rectangle, r, rs));
}
