This class is used to define an arbitrary region on a 2D surface.

This is a resource-based entity (unlike the Rectangle and Point value types), and therefore requires careful lifetime management. You should Dispose() the object when you are finished with it to release the resources back to the system.

At its simplest, you can construct a Region from a Rectangle or RectangleF. More complex regions can be constructed from a System.Drawing.Drawing2D.GraphicsPath. For interop with the Win32 HRGN, you can use GetHrgn() and FromHrgn().

You can then manipulate the region in a variety of ways, including logical operations with another Region, System.Drawing.Drawing2D.GraphicsPath, or Rectangle / RectangleF. It can also be made to represent no area at all with the MakeEmpty() method, or the whole of the infinite plane with MakeInfinite(). You can create the Complement() (the area of the supplied object that does not intersect with the Region), Intersect() two regions, create Union() of two regions (the combined areas of both), and Xor() two regions (which is equivalent to the Union( )—Intersect()).

You can also provide a Matrix and Transform() the region, or simply Translate() it. This is not an ambient transformation like the ones provided for a Pen or Graphics surface—it actually manipulates the underlying System.Drawing.Drawing2D.RegionData.

There is an Equals() method, which determines whether two Region objects would be equivalent on a given Graphics surface, and you can determine whether a Point or any portion of a Rectangle (expressed in a variety of ways) will intersect with the region on a particular Graphics surface.

public sealed class Region : MarshalByRefObject : IDisposable {
// Public Constructors
   public Region();
   public Region(System.Drawing.Drawing2D.GraphicsPath path);
   public Region(Rectangle rect);
   public Region(RectangleF rect);
   public Region(System.Drawing.Drawing2D.RegionData rgnData);
// Public Static Methods
   public static Region FromHrgn(IntPtr hrgn);
// Public Instance Methods
   public Region Clone();
   public void Complement(System.Drawing.Drawing2D.GraphicsPath path);
   public void Complement(Rectangle rect);
   public void Complement(RectangleF rect);
   public void Complement(Region region);
   public void Dispose();  // implements IDisposable
   public bool Equals(Region region, Graphics g);
   public void Exclude(System.Drawing.Drawing2D.GraphicsPath path);
   public void Exclude(Rectangle rect);
   public void Exclude(RectangleF rect);
   public void Exclude(Region region);
   public RectangleF GetBounds(Graphics g);
   public IntPtr GetHrgn(Graphics g);
   public RegionData GetRegionData();
   public RectangleF[ ] GetRegionScans(System.Drawing.Drawing2D.Matrix matrix);
   public void Intersect(System.Drawing.Drawing2D.GraphicsPath path);
   public void Intersect(Rectangle rect);
   public void Intersect(RectangleF rect);
   public void Intersect(Region region);
   public bool IsEmpty(Graphics g);
   public bool IsInfinite(Graphics g);
   public bool IsVisible(int x, int y, Graphics g);
   public bool IsVisible(int x, int y, int width, int height);
   public bool IsVisible(int x, int y, int width, int height, Graphics g);
   public bool IsVisible(Point point);
   public bool IsVisible(PointF point);
   public bool IsVisible(PointF point, Graphics g);
   public bool IsVisible(Point point, Graphics g);
   public bool IsVisible(Rectangle rect);
   public bool IsVisible(RectangleF rect);
   public bool IsVisible(RectangleF rect, Graphics g);
   public bool IsVisible(Rectangle rect, Graphics g);
   public bool IsVisible(float x, float y);
   public bool IsVisible(float x, float y, Graphics g);
   public bool IsVisible(float x, float y, float width, float height);
   public bool IsVisible(float x, float y, float width, float height, Graphics g);
   public void MakeEmpty();
   public void MakeInfinite();
   public void Transform(System.Drawing.Drawing2D.Matrix matrix);
   public void Translate(int dx, int dy);
   public void Translate(float dx, float dy);
   public void Union(System.Drawing.Drawing2D.GraphicsPath path);
   public void Union(Rectangle rect);
   public void Union(RectangleF rect);
   public void Union(Region region);
   public void Xor(System.Drawing.Drawing2D.GraphicsPath path);
   public void Xor(Rectangle rect);
   public void Xor(RectangleF rect);
   public void Xor(Region region);
// Protected Instance Methods
   protected override void Finalize();  // overrides object
}

Hierarchy

System.Object System.MarshalByRefObject Region(System.IDisposable)

Returned By

Graphics.{Clip, MeasureCharacterRanges()}, System.Windows.Forms.Control.Region

Passed To

Graphics.{Clip, ExcludeClip(), FillRegion(), IntersectClip(), SetClip()}, System.Windows.Forms.Control.{Invalidate(), Region}