Author: jgerber
Description:
VipsScalar currently works by running a series of separate vips commands.
Looking at the source here:
makeCommands() will typically run something like:
unpack png file to a huge disc temp
vips im_png2vips huge.png t1.v
block shrink by large integer factor
vips im_shrink t1.v t2.v xx xx
bilinear resize to final exact dimensions
vips im_resize_linear t2.v t3.v xxxx yyyy
sharpen slightly to counteract softening effect of bilinear
vips im_convf t3.v t4.v sharpen_matrix
any 90-degree rotation required
vips im_rotxx t4.v final.jpg
Instead, it should simply run vipsthumbnail:
vipsthumbnail huge.png -o final.jpg --size required-output-size-in-pixels
--interpolator bicubic
This requires vips 7.32.2 or later which is not yet in Debian and must be built from source.
see https://bugzilla.wikimedia.org/show_bug.cgi?id=32721 for more detalis.
Version: master
Severity: normal