With this patch the non-default overscan color will be
blended into narrow border around the screen. The
screen area remains unchanged.
The implementation is conditional -- must have
C_OVERSCAN set to 1 in config.h. I've modified
configure.in but I have no means to test it -- please
test and let me know if that one is correct.
Overscan width and strength is controlled through
dosbox.conf or command line. In dosbox.conf use section
[render]. Set "overscan=<width>" to control how wide
the overscan border is going to be, "overscan=0" will
disable the border completely.
"overscanstrength=<value>" controls how much of
overscan color is going to be blended in with game
pixel color. Values 1 through 10 are accepted, 2
through 3 produce the best results, ymmv. Similarly,
command line can include "-overscan <width>" or
"-overscanstrength=<value>" to override these settings.
Overscan border works with all scalers in all modes.
There is practically no performance hit for having it
enabled but not drawn, slight performance hit when it's
drawn. Most games never bother with overscan so it
won't appear. Good test case: Crystal Caves -- the
overscan color is actually important gameplay element.
The patch is current with CVS as of 20050822 aroudn