vips_resize() used to do most of a downsize with vips_shrink() and the
final 200 - 300% with vips_reduce(). This was correct for lanczos2/3,
but not right for linear/cubic, which need more shrink and less
reduce to avoid aliasing.
This patch makes vips_resize() leave the final 100 - 200% to
vips_reduce() for linear/cubic, and leave everything to reduce for
nearest.
We were freeing pixel buffers on thread exit. This was convenient, but
meant that main thread buffers were not freed until program exit. As a
result, long-running programs which created main thread buffers would
slowly fill the operation cache with useless junk, forcing everything else out.
This change also frees pixel buffers on image close. This makes the
cache work much better in long-running programs, and can substantially
reduce memory use.
See https://github.com/jcupitt/libvips/issues/466
threads keep pixel buffers in thread-private storage, and free these
buffers on thread exit ... this means buffers created by the main thread will
only be freed on program exit!
if your program creates any main-thread buffers, these buffers will
eventually fill the operation cache and force everything else out,
making the cache useless
this patch explicitly frees main-thread pixel buffers on image close
when jpg compression is on, tiffsave now converts the input image for
jpg save ... previously, it would try to send a tiff-formatted image
(eg. perhaps with an alpha channel, or float data), which would fail
see https://github.com/jcupitt/libvips/issues/449
