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CreateGraphics Method

Summary
Creates a GDI+ System.Drawing.Graphics object using this Leadtools.RasterImage as the display surface.
Syntax
C#
C++/CLI
Python
public static RasterGraphics CreateGraphics( 
   RasterImage image 
) 
public: 
static RasterGraphics^ CreateGraphics(  
   RasterImage^ image 
)  
def CreateGraphics(self,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+ and Introduction to Image Processing With LEADTOOLS.

Example

This example draws an ellipse on a raster image.

C#
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
 
 
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:\LEADTOOLS23\Resources\Images"; 
} 
Requirements

Target Platforms

Help Version 23.0.2024.2.29
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Leadtools.Drawing Assembly

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.