Hello again,
as a paint file contains only a classic header and a standard bitmap(*) and as I needed to retrieve embedded bitmap's content and convert them in another fomat ( in fact, in ppm), ... Now concerning LibreOffice 4.2, it must recognize almost all paint files(**) and convert them in a text file which contains this bitmap(***) .
Previously, as libmwaw can only generate text files, the only solution was to convert the drawing files in text files. Now, as it begins to generate graphic and spreadsheet documents, in some near/far future, I plan to change the code to generate drawing files as graphic files: this is more natural and will probably be must better when some graphics shapes appear on many pages...
(*) which shares the same format as the bitmaps which can appear as embedded bitmap in a text document, drawing documents, ...
(**) excepted some bitmaps which have less then 16 colours, this is corrected in the lastest version of libmwaw but not in the current version of LibreOffice
(***) with a very small size, ie. a bitmap which needed to be enlarged by a factor ~10 and which need to be copied in some other graphic applications if you want to modify them