Unix VM

Ian Piumarta ian.piumarta at inria.fr
Tue Jun 11 05:03:06 UTC 2002


David,

> Ian -- On my RedHat 7.0 system, when I maximize the squeak window, it
> falls about 4 pixels short of reaching all the way to the right of the
> display. That is, the window reaches all the way to the top, left and
> bottom of the screen, but leaves a 4 pixel gap on the right.

It's to protect you from core dumps when using the X shared memory
extensions.  Whenever possible the Display bitmap is copied to the screen
using XPutImage, but when `-xshm' is in use it's copied using
XShmPutImage.  The latter cannot cope with scanlines that are padded to
less than 4 bytes (Xlib deposits little core crottes all over the place).  
Hence the horizontal grid being set to 4.  It's probably not necessary
when `-xshm' isn't being used (or could be reduced to 32/bpp pixels
instead of being fixed at 4).  I'll see about making it conditional on
something along those lines.

Does this happen when you use "fullscreen on" from the world menu too?  
(It shouldn't, since in that case your screen is almost certainly a
multiple of 4 pixels wide.)

Ian




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