Is it possible to continue editing a metafile which is stored in a variable

Question

I have created a metafile and drawn a few lines into it.
After that I stored the metafile in a variable.

Dim myImage as Metafile
.
.
System(0).Image = myImage

When I try to load the metafile again to extend it

myImage = System(0).Image
Dim gr as Graphics = Graphics.FromImage(myImage)

a System.OutOfMemoryException pops up

Answer 1

Hi @STL ,
You can consider saving Metafile as EMF, and then reload it.
Here's an example you can refer to.

    <DllImport("gdi32.dll")>  
    Private Shared Function CopyEnhMetaFile(ByVal hemfSrc As IntPtr, ByVal lpszFile As String) As IntPtr  
    End Function  
    <DllImport("gdi32.dll")>  
    Private Shared Sub DeleteEnhMetaFile(ByVal hemf As IntPtr)  
    End Sub  
  
    Public Function ReloadMetaFile(ByVal mf As Metafile, ByVal fileName As String) As Metafile  
  
        Dim iptrMetafileHandle As IntPtr = mf.GetHenhmetafile()  
        CopyEnhMetaFile(iptrMetafileHandle, fileName)  
        DeleteEnhMetaFile(iptrMetafileHandle)  
  
        Dim bm As Bitmap = New Bitmap(16, 16)  
        Using gr As Graphics = Graphics.FromImage(bm)  
            mf = New Metafile(fileName, gr.GetHdc())  
            gr.ReleaseHdc()  
        End Using  
  
        Return mf  
    End Function  

Use it:

        Dim myImage As Metafile = ...  
        Dim mf As Metafile = ReloadMetaFile(myImage, "EMF file path")  
        Dim gr As Graphics = Graphics.FromImage(mf)  
        ...  

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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