Changes the resolution of an existing Windows Enhanced Metafile (EMF).
public static IntPtr UpdateMetaFileResolution(
IntPtr emfHandle,
int xResolution,
int yResolution
)
Public Shared Function UpdateMetaFileResolution( _
ByVal emfHandle As IntPtr, _
ByVal xResolution As Integer, _
ByVal yResolution As Integer _
) As IntPtr
public:
static IntPtr UpdateMetaFileResolution(
IntPtr emfHandle,
int xResolution,
int yResolution
)
emfHandle
Handle to the source EMF
xResolution
New horizontal resolution
yResolution
New vertical resolution
A handle to the modified Windows Enhanced Metafile (EMF).
This method is especially helpful in case you use the CreateEnhMetaFile Windows API when generating the EMF handle. For example, requirement is to create an EMF with 8.5 by 11 inches at 300 DPI. With CreateEnhMetaFile, the resolution of the generated EMF is the same as the resolution of the reference HDC. Since it is impractical to find an HDC with resolution equal to the desired one, you can use UpdateMetaFileResolution to accomplish this. Here is an example:
const int resolution = 300;
// Calculate the width in pixels:
int widthInPixels = (int)(8.5 * resolution);
int heightInPixels = (int)(11.0 * resolution);
Win32.RECT rc = new Win32.RECT();
rc.left = 0;
rc.top = 0;
rc.right = widthInPixels;
rc.bottom = heightInPixels;
IntPtr hdc = Win32.CreateEnhMetaFile(IntPtr.Zero, IntPtr.Zero, rc, IntPtr.Zero);
IntPtr hEmfTemp = Win32.CloseEnhMetaFile(hdc);
// hEmfTemp has the same resolution as the screen, change it to the desired one
IntPtr hEmf;
hEmf = DocumentWriter.UpdateMetaFileResolution(hEmfTemp, resolution, resolution);
Win32.DeleteEnhMetaFile(hEmfTemp);
// hEmf now is 8.5 by 11 at 300
If xResolution or yResolution is 0, then the original resolution of the EMF handle will be used. If either xResolution or yResolution is equal to -1, then the aspect ratio for original EMF handle will be maintained and the positive value for either xResolution or yResolution will be used as the resolution (DPI) value for the modified emf handle.
Note that xResolution and yResolution cannot be both less than zero.
This example will load an Enhanced Metafile from disk and then change its resolution to 200 by 200 dots per inch.
using Leadtools;
using Leadtools.Codecs;
using Leadtools.Forms.DocumentWriters;
using Leadtools.Forms.Ocr;
private static void ShowMetaFileDimension(IntPtr hemf)
{
// Use System.Drawing.Imaging.Metafile to load the EMF and get its information
using (var metafile = new System.Drawing.Imaging.Metafile(hemf, false))
{
Console.WriteLine("Size: {0} by {1} pixels", metafile.Width, metafile.Height);
Console.WriteLine("Resolution: {0} by {1} pixels/inch", metafile.HorizontalResolution, metafile.VerticalResolution);
}
}
//// Windows API
[DllImport("gdi32")]
private extern static IntPtr GetEnhMetaFile(string lpszMetaFile);
[DllImport("gdi32")]
private extern static int DeleteEnhMetaFile(IntPtr hemf);
public void ChangeMetaFileResolutionExample()
{
// Load the original meta file
var hemf = GetEnhMetaFile(Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.emf"));
// Show the dimension
Console.WriteLine("Original EMF dimension:");
ShowMetaFileDimension(hemf);
// Change the resolution to be 200 by 200 dots/inch
var hemfDest = DocumentWriter.UpdateMetaFileResolution(hemf, 200, 200);
// No need for the original handle anymore
DeleteEnhMetaFile(hemf);
Console.WriteLine("New EMF dimension:");
ShowMetaFileDimension(hemfDest);
DeleteEnhMetaFile(hemfDest);
}
static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.DocumentWriters
Imports Leadtools.Forms.Ocr
Private Shared Sub ShowMetaFileDimension(hemf As IntPtr)
' Use System.Drawing.Imaging.Metafile to load the EMF and get its information
Using metafile As New System.Drawing.Imaging.Metafile(hemf, False)
Console.WriteLine("Size: {0} by {1} pixels", metafile.Width, metafile.Height)
Console.WriteLine("Resolution: {0} by {1} pixels/inch", metafile.HorizontalResolution, metafile.VerticalResolution)
End Using
End Sub
'''/ Windows API
<DllImport("gdi32")>
Private Shared Function GetEnhMetaFile(lpszMetaFile As String) As IntPtr
End Function
<DllImport("gdi32")>
Private Shared Function DeleteEnhMetaFile(hemf As IntPtr) As Integer
End Function
Public Sub ChangeMetaFileResolutionExample()
' Load the original meta file
Dim hemf As IntPtr = GetEnhMetaFile(Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.emf"))
' Show the dimension
Console.WriteLine("Original EMF dimension:")
ShowMetaFileDimension(hemf)
' Change the resolution to be 200 by 200 dots/inch
Dim hemfDest As IntPtr = DocumentWriter.UpdateMetaFileResolution(hemf, 200, 200)
' No need for the original handle anymore
DeleteEnhMetaFile(hemf)
Console.WriteLine("New EMF dimension:")
ShowMetaFileDimension(hemfDest)
DeleteEnhMetaFile(hemfDest)
End Sub
Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
Programming with LEADTOOLS Document Writers
Raster .NET | C API | C++ Class Library | JavaScript HTML5
Document .NET | C API | C++ Class Library | JavaScript HTML5
Medical .NET | C API | C++ Class Library | JavaScript HTML5
Medical Web Viewer .NET
Your email has been sent to support! Someone should be in touch! If your matter is urgent please come back into chat.
Chat Hours:
Monday - Friday, 8:30am to 6pm ET
Thank you for your feedback!
Please fill out the form again to start a new chat.
All agents are currently offline.
Chat Hours:
Monday - Friday
8:30AM - 6PM EST
To contact us please fill out this form and we will contact you via email.