and replace old unused and poorly named FIND_ZIP. The new code prefers
pkgconfig and only falls back to manual detection if needed.
This also prioritizes detected zlib flags and includes to be preferred
over the ones that are added by pkgconfig for libpng, tifflib etc. which
would otherwise have caused the system default zlib to be used.
vips_resize() uses to just use nearest when upsizing, following standard
practice in repro. This is often unfortunate for image processing, where
small nearest upsizes will produce obvious aliasing.
It now picks a VipsInterpolate which corresponds (roughly) to the
selected VipsKernel and uses that with affine for any upsizing.
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.
oops, it was missing
also, change the return type from void to VImage. This makes chaining
possible, eg.:
VImage memory = im.write( Viameg::new_memory() );
when you write to a non-partial image, you create a sink ... so
vips_image_write() only needs to ref the input when writing to partials
this change makes it much easier to (for example) combine many images in
bounded space, see for example:
https://gist.github.com/jcupitt/c516325ebef7601b5da610af5619c9b2
- rename compression_level as deflate_level to match libgsf convention
- use libgsf enums for GSF_ZIP_STORED, etc.
- configure-time checks for zip64 and deflate-level
- off-topic: rename NEED_TYPE_INIT as HAVE_TYPE_INIT for consistency
