code like
*ptr++ = *ptr++ = *ptr++ = color;
is wrong, because there is no guarantee that ptr will be incremented
_between_ the assignment operations. it can be incremented after all
assignment operations as well. Because of this both of these are valid
implementations for a compiler:
a. assign, increment, assign, increment, assign, increment
b. assign, assign, assign, increment by 3
In case b. only the first memory location of the 3 will be modified, being
assigned 3 times the same value, while the other 2 remain unchanged.
For example egcs-2.91.66 (and possibly gcc-2.95.x too) implement this in
the second way (like in case b.)
Also the order in which the assignement is made is undefined (left to right
or right to left).
this fixed the problem we had with greyscale jpegs showing up in red,
and possibly other problems related to pseudocolor and greyscale displays.
written in the libwraster.la file allowing automatic linking against
all the libs libwraster depends upon without specifing them again when
linking programs that use libwraster. -lwraster will be enough.
P.S. Please, that piece of code is perfectly valid, there's no need to
break it every month. There is nothing wrong with it, still it was
changed (and simultaneously broken) 4 or 5 times already.
That code use a smart trick to draw the multi diagonal gradient using
integer operations, that is perfectly valid and moreover is much faster
than the classical floating point calculation algorithm that was used
before, so there is no need to randomly 'fix' it every now and then.
If you don't understand how it works please ask.
