the new sequential mode readers for tiff/jpg/png were not working well
from the vips7 command-line: they either decompressed twice, or handed
over a sequential mode image
it should now work as well as it did pre-seq.
the vips7 loaders were a thin layer over the new VipsForeign system
however! VipsForeign does various "useful" things, like open via disc,
and this resulted in stuff like
vips im_jpeg2vips huge.jpg x.v
decompressing to a temp file before copying to x.v
im_jpeg2vips() and friends now call the low-level loaders directly and
avoid the extra mechanisms in VipsForeign
"nip2 huge.jpg" was loading twice as well, for the same reason
cli operations turn on seq mode automatically when they can
vips_operation_get_flags() added: lets you attach a set of flags to an
operation
flags for now are "nocache" (replacing the old nocache system) and "seqential"
if vips_object_set_argument_from_string() from string sees "seq" flag on the
object for which it is setting the arg, it enables sequential mode
all operations which can run sequentially have been tagged
the operation printer knows about flags and can display them
on end of an image loop, send a "minimise" signal down the pipeline
tilecache listens for this signal on its output and drops the cache
helps reduce ruby memuse
we had them as float before to make load/save easier, but that means we
need lots of hacks to make properties work correctly
instead, convert to/from float on read/write and have them as double
internally
good speedup for large tiffs
$ time ~/vips-7.26/bin/vips-7.26 vips im_copy wtc.tif x.v
real 0m12.728s
user 0m0.220s
sys 0m1.032s
$ time vips copy wtc.tif[sequential] x.v
real 0m4.328s
user 0m0.584s
sys 0m0.764s
new one was compiled with DEBUG, hence (partly) larger user time
John Cupitt