How to retain Exif data with GDI+?

[Peter Redei]

When I save an JPEG image that has Exif parameters with GDI+ I loose the Exif data. Any idea how can we retain it in the saved image?

Regards,

Peter Redei

[Peter Redei]

Never mind

Never mind, I got it...

Peter Redei

[Dominic Sexton]

Hi Peter,

Can you share what the problem / solution was? It may be of use to others in the same situation

[Peter Redei]

Here is some code

Dominic,

I thought the solution was quite obvious and only I did not know it, so I did not submit any code. For you and for those to whom it is helpful...

$EncoderSaveFlag          = GUID$("{292266FC-AC40-47BF-8CFC-A85B89A655DE}")
%EncoderParameterValueTypeLong = 4 
%EncoderValueFlush                     = 20

TYPE EncoderParameter
   pGuid AS GUID             '  // GUID of the parameter
   NumberOfValues AS DWORD   '  // Number of the parameter values
   dwType AS DWORD           '  // Value type, like ValueTypeLONG  etc.
   Value AS DWORD            '  // A pointer to the parameter values
END TYPE
TYPE EncoderParameters
   Count AS DWORD                    ' // Number of parameters in this structure
   Parameter(0) AS EncoderParameter  ' // Parameter values - variable-length array
END TYPE 

DECLARE FUNCTION GDI_GdipSaveImageToFile(BYVAL lpImage AS DWORD, BYVAL flname AS STRING, BYREF clsidEncoder AS GUID, OPTIONAL BYREF EncoderParams AS EncoderParameters) AS LONG

FUNCTION GdipSaveImageToFile(BYVAL lpImage AS DWORD, BYVAL flname AS STRING, BYREF clsidEncoder AS GUID, OPTIONAL BYREF EncoderParams AS EncoderParameters) AS LONG
    LOCAL procAddr   AS DWORD
    LOCAL hRes       AS LONG
    LOCAL eps AS EncoderParameters
    LOCAL ep AS EncoderParameter
    LOCAL parameterValue AS DWORD


    eps.Count = 1
    ' // Initialize the one EncoderParameter object.
    eps.Parameter(0).pGuid = $EncoderSaveFlag
    eps.Parameter(0).dwType = %EncoderParameterValueTypeLong
    eps.Parameter(0).NumberOfValues = 1
    eps.Parameter(0).Value = VARPTR(parameterValue)
    parameterValue = %EncoderValueFlush

    IF hGdiLIB = 0 THEN
        FUNCTION = 0
    ELSE
        procAddr = GetProcAddress(hGdiLIB, "GdipSaveImageToFile")
        CALL DWORD procAddr USING GDI_GdipSaveImageToFile(lpImage, flname, clsidEncoder, eps) TO hRes
        FUNCTION = hRes
    END IF
END FUNCTION

My problem was that I passed %NULL instead of the eps structure.


Regards,


Peter Redei