ChangeFromEmf(IntPtr,int,int) Method

Summary

Changes a Windows Enhanced Metafile (EMF) into a LEADTOOLS Leadtools.RasterImage object and, if successful, frees the Enhanced Metafile.

Syntax

C++

public static RasterImage ChangeFromEmf( 
   IntPtr hemf, 
   int width, 
   int height 
)

Public Overloads Shared Function ChangeFromEmf( _ 
   ByVal hemf As IntPtr, _ 
   ByVal width As Integer, _ 
   ByVal height As Integer _ 
) As RasterImage

public: 
static RasterImage^ ChangeFromEmf(  
   IntPtr hemf, 
   int width, 
   int height 
)

Parameters

hemf
Handle to the EMF to be changed.

width
Amount by which to scale the enhanced metafile's original width.

height
Amount by which to scale the enhanced metafile's original height.

Return Value

The newly created Leadtools.RasterImage object.

Remarks

Some metafiles do not have a background color, and hence, when the metafile is used to create a Leadtools.RasterImage object, the area not covered by the metafile objects will contain the default image background color (black). To create a raster image from a metafile like this with a specific background color, use ChangeFromEmf(hemf, width, height, backColor).

If this method is successful, hemf is freed.

The enhanced metafile can be loaded at the original dimension or scaled by using the width and height parameters.

If width == 0 and height == 0 - the enhanced metafile is loaded at the size present in the file.

If width == 0 and height > 0 - the enhanced metafile is stretched so that it has the height height (preserving the aspect ratio).

If width > 0 and height == 0 - the enhanced metafile is stretched so that it has the width width (preserving the aspect ratio).

If width > 0 and height > 0 - the enhanced metafile is stretched so that it has the width width and height height (the aspect ratio is ignored).

This method does not support signed images.

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

Example

This example loads a Leadtools.RasterImage, converts it to an EMF, then converts the EMF back to a Leadtools.RasterImage.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
 
public void ChangeFromEmfExample() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   IntPtr hemf; 
 
   // Load an image 
   using (RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 24, CodecsLoadByteOrder.BgrOrGray, 1, 1)) 
   { 
      // Change to EMF 
      hemf = RasterImageConverter.ChangeToEmf(image); 
   } 
 
   // Convert the EMF back to a RasterImage preserving the size 
   using (RasterImage image = RasterImageConverter.ChangeFromEmf(hemf, 0, 0)) 
   { 
      // Save it to disk 
      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Image1_ChangeToEmf.bmp"), RasterImageFormat.Bmp, 24); 
   } 
 
   // Clean up 
   codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub ChangeFromEmfExample() 
   Dim codecs As New RasterCodecs() 
 
   Dim hemf As IntPtr 
 
   ' Load an image 
   Using image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"), 24, CodecsLoadByteOrder.BgrOrGray, 1, 1) 
      ' Change to EMF 
      hemf = RasterImageConverter.ChangeToEmf(image) 
   End Using 
 
   ' Convert the EMF back to a RasterImage preserving the size 
   Using image As RasterImage = RasterImageConverter.ChangeFromEmf(hemf, 0, 0) 
      ' Save it to disk 
      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Image1_ChangeToEmf.bmp"), RasterImageFormat.Bmp, 24) 
   End Using 
 
   ' Clean up 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class