C#中Region、Exclude的用法小结

using System.Drawing;

// 1. 从矩形创建
Rectangle rect = new Rectangle(10, 10, 100, 100);
Region region1 = new Region(rect);

// 2. 从椭圆创建
GraphicsPath path = new GraphicsPath();
path.AddEllipse(20, 20, 80, 80);
Region region2 = new Region(path);

// 3. 从 GraphicsPath 创建复杂形状
GraphicsPath complexPath = new GraphicsPath();
complexPath.AddPolygon(new Point[] {
    new Point(0, 0),
    new Point(50, 100),
    new Point(100, 0)
});
Region region3 = new Region(complexPath);

public void Exclude(Rectangle rect);
public void Exclude(RectangleF rect);
public void Exclude(Region region);

// 创建一个大矩形区域
Region bigRegion = new Region(new Rectangle(0, 0, 200, 200));

// 创建一个小矩形区域（要排除的部分）
Rectangle hole = new Rectangle(50, 50, 100, 100);

// 从小区域中“挖掉”一个洞
bigRegion.Exclude(hole);

// 现在 bigRegion 是一个外框为 200x200，中间有 100x100 空洞的区域

this.Region = new Region(new Rectangle(0, 0, 300, 300));
this.Region.Exclude(new Rectangle(50, 50, 200, 200)); // 中间挖空

Graphics g = this.CreateGraphics();
Region updateRegion = g.Clip; // 获取当前裁剪区域
updateRegion.Exclude(someControl.Bounds); // 排除某个控件区域
g.Clip = updateRegion;
// 然后只绘制除该控件外的区域