Hi everyone,
Bryan Tong Minh has been doing some great work on VipsScaler
extension, but there hasn't been a lot of recent chatter on the
mailing list about it. Since we're somewhat close to deploying
something on the cluster, it probably warrants at least an email.
First, some background. Currently, we use ImageMagick for scaling
images on Wikimedia websites. VIPS (
http://www.vips.ecs.soton.ac.uk/
) is an alternative image processing system that has a couple
advantages over ImageMagick for our purposes: 1) it's faster, and 2)
it's way more efficient with memory. The latter means that we can
allow for much larger images with VIPS than we can currently allow
using ImageMagick. For example, we currently disallow PNG images
greater than 12.5 MP.
Changing image scalers may introduce bugs, so we're proceeding
cautiously. We have a three step plan:
Step 1: Deploy VipsScaler extension, but only use it for PNGs over
12.5MP and/or TIFFs (which currently generate errors). Let this sit
in production a while, fixing any bugs we find with this
configuration.
Step 2: Deploy a comparison tool (to be written) that allows anyone to
rescale an image with VIPS, and compare it to the ImageMagick version.
Allow more time for testing and fixing.
Step 3: Switch to VIPS for everything
If you're interested in following progress, there's a couple places
you can look:
* VipsScaler tracking bug:
https://bugzilla.wikimedia.org/28135
* Follow changes in SVN:
https://www.mediawiki.org/wiki/Special:Code/MediaWiki?path=%2Ftrunk%2Fexten…
Step 1 could go out as early as next week, pending final review of the
extension. If anyone is interested in helping accelerate this, the
comparison tool in step 2 is only just started (it's the
SpecialVipsTest special page code), and Bryan is only working on it
when he has time (which isn't right now).
When we're ready to schedule this, we'll update the calendar here:
https://wikitech.wikimedia.org/view/Software_deployments
Rob