Sven Köhler

Note: clang includes its own copy of stdarg.h as well!

stdarg.h is part of mingw-w64-headers as well as gcc

It is generally discouraged in C to cast pointers with small alignment requirements to pointers with bigger alignment requirements. To do so is generally considered a beginner's mistake. For that reason, it is generally recommended to properly align all data. Unaligned data (such as packed structs) can also decrease performance. There are compiler extensions to deal with unaligned access. Packed structs and GCC's aligned attribute can be used, for example. But that will not be portable, and still...

It is generally discouraged in C to cast pointers with small alignment requirements to pointers with bigger alignment requirements. To do so is generally considered a beginner's mistake. For that reason, it is generally recommended to properly align all data. Unaligned data (such as packed structs) can also decrease performance. There are compiler extensions to deal with unaligned access. Packed structs and GCC's aligned attribute can be used, for example. But that will not be portage, and still...

The bug described here was observed using the latest win32 build: http://downloads.sourceforge.net/xournal/xournal-0.4.8-win32.zip There does not seems to be a Windows build of 0.4.8.2016 available at the moment. That build is from 2014? In that case, updating poppler or cairo may fix the issue. I have yet to see whether the same problem exists on Linux (the arch linux xournal version linux should use the latest poppler/cairo). If the issue is present in all version, we might have to report a bug...

The bug described here was observed using the latest win32 build: http://downloads.sourceforge.net/xournal/xournal-0.4.8-win32.zip There does not seems to be a Windows build of 0.4.8.2016 available at the moment. The buildis from 2014? In that case, updating poppler or cairo may fix the issue. I have yet to see whether the same problem exists on Linux (the arch linux xournal version linux should use the latest poppler/cairo).

upon exporting a PDF, lines are thicker than in the original PDF

Disabling progressive backgrounds is an excellent workaround. Do you plan on implementing a "proper fix"? When transitioning from slide X to Y, a way to avoid the flashing is to continue to display slide X until rendering slide Y has finished.