[RESOLVED] How can I change by EMF byte array to jpeg file?

[fafalone]

Why would you go through StdPicture?

Public Sub EmfStreamToJpg(bEMF() As Byte, sSaveTo As String)
'this doesn't have to be EMF by the way, you could load any image type
'that GDI+ supports into the byte array without any other changes
Dim pStrm As IUnknown
Dim hEMF As Long

Set pStrm = pvStreamFromArray(VarPtr(bEMF(0)), UBound(bEMF) + 1)
Call GdipLoadImageFromStream(pStrm, hEMF)
If hEMF Then
   Call gdipImgToFileJPG(hEMF, sSaveTo)
   GdipDisposeImage hEMF
End If
End Sub
Public Function gdipImgToFileJPG(hImg As Long, sOut As String) As Long
Dim encoderCLSID As CLSIDG
Call GetEncoderClsid("image/jpeg", encoderCLSID) 'can also substitute any other supported codec, like image/png or image/bmp
GdipSaveImageToFile hImg, StrConv(sOut, vbUnicode), encoderCLSID, ByVal 0&
End Function

'
'generic support declares/funcs:

Public Type CLSIDG
   Data1 As Long
   Data2 As Integer
   Data3 As Integer
   Data4(0 To 7) As Byte
End Type
Public Type ImageCodecInfo
   ClassID As CLSIDG
   FormatID As CLSIDG
   CodecName As Long      ' String Pointer; const WCHAR*
   DllName As Long        ' String Pointer; const WCHAR*
   FormatDescription As Long ' String Pointer; const WCHAR*
   FilenameExtension As Long ' String Pointer; const WCHAR*
   MimeType As Long       ' String Pointer; const WCHAR*
   Flags As Long 'ImageCodecFlags   ' Should be a Long equivalent
   Version As Long
   SigCount As Long
   SigSize As Long
   SigPattern As Long      ' Byte Array Pointer; BYTE*
   SigMask As Long         ' Byte Array Pointer; BYTE*
End Type


Public Function GetEncoderClsid(strMimeType As String, ClassID As CLSIDG)
   Dim num As Long, SIZE As Long, i As Long
   Dim ICI() As ImageCodecInfo
   Dim Buffer() As Byte
   On Error GoTo e0
   GetEncoderClsid = -1 'Failure flag

   ' Get the encoder array size
   Call GdipGetImageEncodersSize(num, SIZE)
   If SIZE = 0 Then Exit Function ' Failed!

   ' Allocate room for the arrays dynamically
   ReDim ICI(1 To num) As ImageCodecInfo
   ReDim Buffer(1 To SIZE) As Byte

   ' Get the array and string data
   Call GdipGetImageEncoders(num, SIZE, Buffer(1))
   ' Copy the class headers
   Call CopyMemory(ICI(1), Buffer(1), (Len(ICI(1)) * num))

   ' Loop through all the codecs
   For i = 1 To num
      ' Must convert the pointer into a usable string
      If StrComp(PtrToStrW(ICI(i).MimeType), strMimeType, vbTextCompare) = 0 Then
         ClassID = ICI(i).ClassID   ' Save the class id
         GetEncoderClsid = i        ' return the index number for success
         Exit For
      End If
   Next
   ' Free the memory
   Erase ICI
   Erase Buffer
   Exit Function
e0:
   Debug.Print "GetEncoderCLSID.Error->" & Err.Description
End Function
Private Function PtrToStrW(ByVal lpsz As Long) As String
    Dim sOut As String
    Dim lLen As Long

    lLen = lstrlenW(lpsz)

    If (lLen > 0) Then
        sOut = StrConv(String$(lLen, vbNullChar), vbUnicode)
        Call CopyMemory(ByVal sOut, ByVal lpsz, lLen * 2)
        PtrToStrW = StrConv(sOut, vbFromUnicode)
    End If
End Function

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Note: If you're a fan of my typelib and/or want to do more advanced stuff with the IStream, you can simply replace IUnknown in EmfStreamToJpg and pvStreamFromArray with oleexp3.IStream to get a real IStream object.


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PS- I can't find much in the way of sample files or programs that can convert; but doesn't EMF+ store the image as PNG or JPEG? Wouldn't that then support transparency, which would be lost with a normal StdPicture object?