Export (0) Print
Expand All
Expand Minimize

Graphics::DrawImage Method (Image, Rectangle, Int32, Int32, Int32, Int32, GraphicsUnit, ImageAttributes, Graphics::DrawImageAbort)

Draws the specified portion of the specified Image at the specified location and with the specified size.

Namespace:  System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

public:
void DrawImage(
	Image^ image, 
	Rectangle destRect, 
	int srcX, 
	int srcY, 
	int srcWidth, 
	int srcHeight, 
	GraphicsUnit srcUnit, 
	ImageAttributes^ imageAttr, 
	Graphics::DrawImageAbort^ callback
)

Parameters

image
Type: System.Drawing::Image

Image to draw.

destRect
Type: System.Drawing::Rectangle

Rectangle structure that specifies the location and size of the drawn image. The image is scaled to fit the rectangle.

srcX
Type: System::Int32

The x-coordinate of the upper-left corner of the portion of the source image to draw.

srcY
Type: System::Int32

The y-coordinate of the upper-left corner of the portion of the source image to draw.

srcWidth
Type: System::Int32

Width of the portion of the source image to draw.

srcHeight
Type: System::Int32

Height of the portion of the source image to draw.

srcUnit
Type: System.Drawing::GraphicsUnit

Member of the GraphicsUnit enumeration that specifies the units of measure used to determine the source rectangle.

imageAttr
Type: System.Drawing.Imaging::ImageAttributes

ImageAttributes that specifies recoloring and gamma information for image.

callback
Type: System.Drawing::Graphics::DrawImageAbort

Graphics::DrawImageAbort delegate that specifies a method to call during the drawing of the image. This method is called frequently to check whether to stop execution of the DrawImage method according to application-determined criteria.

ExceptionCondition
ArgumentNullException

image is nullptr.

The srcX, srcY, srcWidth, and srcHeight parameters specify a rectangular portion, of the image object to draw. The rectangle is relative to the upper-left corner of the source image. This portion is scaled to fit inside the rectangle specified by the destRect object.

This overload with the callback parameter provides the means to stop the drawing of an image once it starts according to criteria determined by the application. For example, an application could start drawing a large image and the user might scroll the image off the screen, in which case the application could stop the drawing.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e, which is a parameter of the Paint event handler. The code first defines a callback method for the Graphics::DrawImageAbort delegate; the definition is simplistic and merely tests to see whether the DrawImage method calls it with a null callBackData parameter. The main body of the example performs the following actions:

  • Creates an instance of the Graphics::DrawImageAbort callback method.

  • Creates an image from a JPEG file SampImag.jpg in the folder of the example.

  • Creates points that define a destination rectangle in which to draw the image.

  • Creates a source rectangle to select the portion of the image to draw.

  • Sets the graphics drawing unit to pixel.

  • Draws the original image to the screen.

  • Creates an additional destination rectangle in which to draw an adjusted image.

  • Creates and sets the attributes of the adjusted image to have a larger-than-usual gamma value.

  • Draws the adjusted image to the screen.

For the original, unadjusted destination rectangle, the position locates the image on the screen, and the size of the source rectangle and the size and shape of the destination rectangle determines the scaling of the drawn image.

Because this example uses an overload that does not pass a callBackData parameter, the Graphics::DrawImageAbort callback returns true, which causes the DrawImage method to end, and the exception-handling code included in the example prints out the exception text rather than drawing the image.

   // Define DrawImageAbort callback method. 
private:
   bool DrawImageCallback5( IntPtr callBackData )
   {
      // Test for call that passes callBackData parameter. 
      if ( callBackData == IntPtr::Zero )
      {
         // If no callBackData passed, abort DrawImage method. 
         return true;
      }
      else
      {
         // If callBackData passed, continue DrawImage method. 
         return false;
      }
   }

private:
   void DrawImageRect4IntAtrribAbort( PaintEventArgs^ e )
   {
      // Create callback method.
      Graphics::DrawImageAbort^ imageCallback = gcnew Graphics::DrawImageAbort( this, &Form1::DrawImageCallback5 );

      // Create image.
      Image^ newImage = Image::FromFile( "SampImag.jpg" );

      // Create rectangle for displaying original image.
      Rectangle destRect1 = Rectangle(100,25,450,150);

      // Create coordinates of rectangle for source image. 
      int x = 50;
      int y = 50;
      int width = 150;
      int height = 150;
      GraphicsUnit units = GraphicsUnit::Pixel;

      // Draw original image to screen.
      e->Graphics->DrawImage( newImage, destRect1, x, y, width, height, units );

      // Create rectangle for adjusted image.
      Rectangle destRect2 = Rectangle(100,175,450,150);

      // Create image attributes and set large gamma.
      ImageAttributes^ imageAttr = gcnew ImageAttributes;
      imageAttr->SetGamma( 4.0F );
      try
      {
         // Draw adjusted image to screen.
         e->Graphics->DrawImage( newImage, destRect2, x, y, width, height, units, imageAttr, imageCallback );
      }
      catch ( Exception^ ex ) 
      {
         e->Graphics->DrawString( ex->ToString(), gcnew System::Drawing::Font( "Arial",8 ), Brushes::Black, PointF(0,0) );
      }
   }

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Show:
© 2014 Microsoft