imageObj.getBytes fails for CAIRO/SVG output format

[panzel]

Under SWIG/C#, the MapServer 6.0.1 imageObj.GetBytes() method fails if the imagetype is 'svg' and the outputformat is specified by:

  OUTPUTFORMAT
    NAME "svg"
    DRIVER CAIRO/SVG
    MIMETYPE "image/svg+xml"
    IMAGEMODE RGB
    EXTENSION "svg"
  END

By comparison, it succeeds with imagetype 'png' with:

  OUTPUTFORMAT
    NAME "png"
    DRIVER AGG/PNG
    MIMETYPE "image/png"
    IMAGEMODE RGB
    EXTENSION "png"
    FORMATOPTION "GAMMA=0.75"
  END

The short-term work-around is to use imageObj.save, which works with 'svg'.

I've attached two map files (m11.map, m12.map) that show the png/svg cases, and a C# file (Program.cs) that reads a map file and creates an output file. When run with m12.map (the svg case), the output is:

Drawing map: 'MS' using imageObj.getBytes
GetBytes: getBytes: General error message. Failed to get image
 buffer;msSaveImageBuffer(): General error message. Unsupported image type

The C# code is copied almost intact from Tamas' ​http://mapserver.sourcearchive.com/documentation/5.2.0/getbytes_8cs-source.html. The original missed a "{0}" in the catch block's WriteLine statement.

This may be related to an older ticket: Ticket #3201, "GetBytes(), Write() on ImageObj results in error when parsing mapfile with AGG renderer in C# mapscript."