Clipping with a Region

One of the properties of the Graphics class is the clip region. All drawing done by a given Graphics object is restricted to the clip region of that Graphics object. You can set the clip region by calling the SetClip method.

The following example constructs a path that consists of a single polygon. Then the code constructs a region, based on that path. The region is passed to the SetClip method of a Graphics object, and then two strings are drawn.

' Create a path that consists of a single polygon.
Dim polyPoints As Point() = { _
   New Point(10, 10), _
   New Point(150, 10), _
   New Point(100, 75), _
   New Point(100, 150)}
Dim path As New GraphicsPath()
path.AddPolygon(polyPoints)
      
' Construct a region based on the path.
Dim [region] As New [Region](path)
      
' Draw the outline of the region.
Dim pen As Pen = Pens.Black
e.Graphics.DrawPath(pen, path)
      
' Set the clipping region of the Graphics object.
e.Graphics.SetClip([region], CombineMode.Replace)
      
' Draw some clipped strings.
Dim fontFamily As New FontFamily("Arial")
Dim font As New Font( _
   fontFamily, _
   36, _
   FontStyle.Bold, _
   GraphicsUnit.Pixel)
Dim solidBrush As New SolidBrush(Color.FromArgb(255, 255, 0, 0))

e.Graphics.DrawString( _
   "A Clipping Region", _
   font, _
   solidBrush, _
   New PointF(15, 25))

e.Graphics.DrawString( _
   "A Clipping Region", _
   font, _
   solidBrush, _
   New PointF(15, 68))
[C#]
// Create a path that consists of a single polygon.
Point[] polyPoints = {
   new Point(10, 10),
   new Point(150, 10), 
   new Point(100, 75),
   new Point(100, 150)};
GraphicsPath path = new GraphicsPath();
path.AddPolygon(polyPoints);

// Construct a region based on the path.
Region region = new Region(path);

// Draw the outline of the region.
Pen pen = Pens.Black;
e.Graphics.DrawPath(pen, path);

// Set the clipping region of the Graphics object.
e.Graphics.SetClip(region, CombineMode.Replace);

// Draw some clipped strings.
FontFamily fontFamily = new FontFamily("Arial");
Font font = new Font(
   fontFamily,
   36, FontStyle.Bold,
   GraphicsUnit.Pixel);
SolidBrush solidBrush = new SolidBrush(Color.FromArgb(255, 255, 0, 0));

e.Graphics.DrawString(
   "A Clipping Region",
   font, solidBrush,
   new PointF(15, 25));

e.Graphics.DrawString(
   "A Clipping Region",
   font,
   solidBrush,
   new PointF(15, 68));

The following illustration shows the clipped strings.