RE: gdk and vnc server/viewer at 16 bpp weirdness (solved)

[Vlad Harchev <hvv hippo ru>]

On Mon, 11 Sep 2000, Vlad Harchev wrote:

> On Mon, 11 Sep 2000, Vlad Harchev wrote:
> 
> > On Sun, 10 Sep 2000, Erik wrote:
> > 
> >  Hi,
> > 
> > > 
> > > On 10-Sep-2000 Vlad Harchev wrote:
> > > >  Hi,
> > > > 
> > > >  Have anybody used vnc server for X (running at 16 bpp, commandline option
> > > > '-depth 16') viewed with vncviewer (for any platform) running at 16 bpp too
> > > > (same commandline switch). I tried rather lot of combinations of vnc
> > > > server for X/(viewer,platform) and on all of them images that are displayed 
> > > > using gdk (probably using imlib, but I can be wrong) are displayed
> > > > totally incorrectly - some junk (looking like white noise + color) without
> > > > any
> > > > similarity to the original images. It's not a bug in vnc software since qt
> > > > and
> > > > motif apps look fine at showing pictures (netscape, kview). It seems there is
> > > > a nasty bug in gdk. More information: gcolorsel shows right colors, only
> > > > areas that were drawn by copying pixmap are broken (root window's image,
> > > > enlightnement's decorations, and (if pixmap theme is selected) every gtk 
> > > > widget. I've tried various versions of Xvnc (including most recent 3.3.3r1)
> > > > and vncviewer for X and Windows - both show the same. I used gtk-1.2.6 on
> > > > RH6.2 on x86.
> > > > 
> > > >  I've attached screenshot of gpanel. The current gtk theme is SatinBlack, so
> > > > everything should be dark shades of gray on the shot, but it looks like some
> > > > noise (though gradients are seen).
> > > > 
> > > >  Have anybody reported anything?
> > > >  
> > > >  Best regards,
> > > >   -Vlad
> > > 
> > > I've had no problems with vnc (16b or otherwise) doing gtk stuff. I've only
> > > used windows (95, 98, NT4, 2000) for clients, but I've used it on redhat(6.0?),
> > > debian, and fbsd without ill effects :/ Might want to check that you're using
> > > the same encoding on both sides?
> > 
> >[..] 
> >  So I cc'd to Raster.
> 
>  Whose email address is not valid.
> 
>  There is a year-old thread on gnome-list (with no useful content except a
> large screenshot) starting at 
> http://mail.gnome.org/pipermail/gnome-list/1999-October/033881.html
>  (screenshot is in next message).

 Hmm, I looked at the latest imlib - it's a bullshit. Red, green, blue masks
are hardcoded (the hardcoded values correspond to these masks on XFree for 
16 and 24 bit modes) (and replicated hunderd times by cutting and pasting)
accross rend.c - the module that renders images. 
 Alas, Xvnc at 16 bpp by default starts in the mode that is not compatible
with XFree (XFree's mode is RGB565, Xvnc's is BGR655), thus making all images
drawn using imlib to be screwed up. Fortunately, there is a switch for Xvnc
that allows to specify pixel format. Using that switch with pixel format
compatible with XFree at same depth solves the problem (since pixel format
corresponds to masks hardcoded into imlib). The correct full set of
switches for vncserver at 16 bpp is
  vncserver -pixelformat rgb565 -depth 16
 
 This could have been added to VNC FAQ..

 Best regards,
  -Vlad