C89 provided only double-precision mathematical functions (sin() etc),
and so despite using single-precision elsewhere, those are what Puzzles
has traditionally used. C99 introduced single-precision equivalents
(sinf() etc), and I hope it's been long enough that we can safely use
them. Maybe they'll even be faster.
Rather than directly use the single-precision functions, though, we use
the magic macros from <tgmath.h> that automatically choose the precision
of mathematical functions based on their arguments. This has the
advantage that we only need to change which header we include, and thus
that we can switch back again if some platform has trouble with the new
header.
This adds the ability to turn off hat-test's normal scaling of the
bounding box to fit on an A4 page, which I intended for printing test
patches (but never actually found a need to print one). The --unscaled
mode seems more useful if you're planning to turn the output into an
image, e.g. to use as a desktop background.
Also added --clip, which generates a rectangle completely covered in
hats (i.e. shows any hat that overlaps the output rectangle at all),
as opposed to the normal mode which omits any hat that doesn't fit
_entirely_ in the output rectangle (more similar to what Loopy wants).
Actually generating a desktop background by this method is still a bit
fiddly to get right, but it's better than before.
I noticed while hacking on hat-test recently that it's quite awkward
to be compiling a test main() program that lives in a source file also
built into the Puzzles support library, because every modification to
main() also triggers a rebuild of the library, and thence of all the
actual puzzles. So it's better if such a test main() has its own
source file.
In order to make hat-test work standalone, I've had to move a lot of
hat.c's internal declarations out into a second header file. This also
means making a bunch of internal functions global, which means they're
also in the namespace of programs other than hat-test, which means in
turn that they should have names with less implicit context.