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CreateGraphics Method
See Also 



image
The source image.
image
The source image.
Creates a GDI+ System.Drawing.Graphics object using this Leadtools.RasterImage as the display surface.

Syntax

Visual Basic (Declaration) 
Public Shared Function CreateGraphics( _
   ByVal image As RasterImage _
) As RasterGraphics
Visual Basic (Usage)Copy Code
Dim image As RasterImage
Dim value As RasterGraphics
 
value = RasterImagePainter.CreateGraphics(image)
C# 
public static RasterGraphics CreateGraphics( 
   RasterImage image
)
C++/CLI 
public:
static RasterGraphics^ CreateGraphics( 
   RasterImage^ image
) 

Parameters

image
The source image.

Return Value

The GDI+ System.Drawing.Graphics object this method creates.

Example

This example draws an ellipse on a raster image.

Visual BasicCopy Code
Public Sub CreateGraphicsExample()
      Dim codecs As New RasterCodecs()
      Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"))

      Dim point1 As New LeadPoint(image.Width \ 8, image.Height \ 8)
      Dim point2 As New LeadPoint(image.Width \ 2, image.Height \ 2)

      ' Convert the coordinates if necessary.
      If image.ViewPerspective <> RasterViewPerspective.TopLeft Then
         point1 = image.PointToImage(RasterViewPerspective.TopLeft, point1)
         point2 = image.PointToImage(RasterViewPerspective.TopLeft, point2)
      End If

      ' Create the Graphics object
      Using rg As RasterGraphics = RasterImagePainter.CreateGraphics(image)
         rg.Graphics.DrawEllipse(New Pen(Color.White), point1.X, point1.Y, point2.X - point1.X, point2.Y - point1.Y)
      End Using

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Image1_CreateGraphics.bmp"), RasterImageFormat.Bmp, 0)

      image.Dispose()
      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
C#Copy Code
public void CreateGraphicsExample()
   {
      RasterCodecs codecs = new RasterCodecs();
      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"));

      LeadPoint point1 = new LeadPoint(image.Width / 8, image.Height / 8);
      LeadPoint point2 = new LeadPoint(image.Width / 2, image.Height / 2);

      // Convert the coordinates if necessary.
      if(image.ViewPerspective != RasterViewPerspective.TopLeft)
      {
         point1 = image.PointToImage(RasterViewPerspective.TopLeft, point1);
         point2 = image.PointToImage(RasterViewPerspective.TopLeft, point2);
      }

      // Create the Graphics object
      using(RasterGraphics rg = RasterImagePainter.CreateGraphics(image))
      {
         rg.Graphics.DrawEllipse(new Pen(Color.White), point1.X, point1.Y, point2.X - point1.X, point2.Y - point1.Y);
      }

      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Image1_CreateGraphics.bmp"), RasterImageFormat.Bmp, 0);

      image.Dispose();
      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

Remarks

This method allows you to create an infinite number of drawing capabilities such as paint, erase, color erase and brush, pen, spray gun, flood fill, color tube, text overlay, curve, line, rectangle, polygon, ellipse, freehand shapes, cut and paste, and more.

All GDI+ methods can be used to draw to the image using the returned System.Drawing.Graphics object. The graphics object must be disposed after using it.

If a region is defined for the image, GDI functions act only on the region, not on the entire image.

The GDI+ graphics supports only 1, 4, 8, 16 and 24 bit images. If you are using an image that has some other number of bits per pixel, you must use Leadtools.ImageProcessing.ColorResolutionCommand to change the image to a bits per pixel value supported by the DIB driver.

For more information refer to RasterImage and GDI/GDI+.

For more information, refer to Introduction to Image Processing With LEADTOOLS.

Requirements

Target Platforms: Silverlight 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)

See Also