LEADTOOLS GDI/GDI+ (Leadtools.Drawing assembly)
LEAD Technologies, Inc

CreateGraphics Method

Example 





The source image.
Creates a GDI+ System.Drawing.Graphics object using this Leadtools.RasterImage as the display surface.
Syntax
public static RasterGraphics CreateGraphics( 
   RasterImage image
)
'Declaration
 
Public Shared Function CreateGraphics( _
   ByVal image As RasterImage _
) As RasterGraphics
'Usage
 
Dim image As RasterImage
Dim value As RasterGraphics
 
value = RasterImagePainter.CreateGraphics(image)
public static RasterGraphics CreateGraphics( 
   RasterImage image
)
 function Leadtools.Drawing.RasterImagePainter.CreateGraphics( 
   image 
)
public:
static RasterGraphics^ CreateGraphics( 
   RasterImage^ image
) 

Parameters

image
The source image.

Return Value

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

Example
 
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
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";
}
Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

See Also

Reference

RasterImagePainter Class
RasterImagePainter Members

 

 


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