[Original notes written ~1997, copied from handwritten A4]

Protocols / Non visible changes
===============================

Filetype auto conversion 
  - On DataLoad of unknown type:
    SWI DataConvert_Convert
    => R0-> filename to convert
       R1-> List of types supported by preference
            -1 terminated
       R2 = Window handle
       R3 = Icon handle
       R4 = x position
       R5 = y position
    <= R0 = job handle
       or error if failed
    
    If error, ignore and return
    If window is closed / context vanishes, etc, call
    SWI DataConvert_Discard
    => R0 = job handle
    
    Jobs will be terminated on application quit.
  
  Alias$@ConvertType_XXX_XXX
    Should be set to the command to invoke the converter.
  Convert$Quality_XXX_XXX
    Should be set to a %age 'quality' the conversion uses,
    or the low quality followed by a space then the high
    quality (for example, JPEG->Sprite would probably have
    something like '60 100' to indicate that without
    dithering it's possible to lose a lot of data, but in
    high colour modes it's possible to get the image data
    to its most accurate degree.
    
  Message DataConvert_Convert
    +20 = flags:
            b0   delete source when done
            b1   convert in place
    +24 = filetype to convert to
    +28 = job handle
    +32...filename to convert
    
    "Can you convert this file please?"
    You should reply with DataConvert_Converting if you can.
  
  Message DataConvert_Converting
    +20 = flags:
            b0   conversion may take some time
    +24 = filetype
    +28 = job handle
    +32...filename
    
    "Ok, I'm working on it"
    Basically write the new flags field and reply with this.
    
  Message DataConvert_Complete
    +20 = Reason:
            0  Done, filename supplied
            1  Failed, error supplied
    +24 = job handle
    +28...filename or error message
    
    "I'm done now"
    
   Send this when you have completed the conversion.