Aspect ratio SizeHint and fullscreen

[Billy Biggs <vektor dumbterm net>]

  I am the author of a video application which can view content in the
following modes: 4:3 windowed, 4:3 fullsrceen, 16:9 windowed, and 16:9
fullscreen.  When fullscreen, we fill the largest window available to
properly fit our content.

  We were experimenting with trying to use WM size hints to have the
window manager resize us nicely when in windowed mode.  We discovered a
metacity bug [1], but in disucssing this, we think we found something in
need of a new spec.

  Should window managers ignore aspect ratio hints if the application is
in a fullscreen state, or should there be a more explicit protocol?  The
problem is that when viewing 16:9 content on a 4:3 screen, you want the
black bars on top and bottom in fullscreen, but in windowed mode, you
want the window manager to only allow resizing which maintains the
aspect ratio.

  Thoughts?
  -Billy

  [1] http://bugzilla.gnome.org/show_bug.cgi?id=112241