I think face detection gets us a great initial default on many important images, so I'm in favor of going forward with a server-side service that can set the initial position, which can then get used on desktop, mobile web, and mobile apps for display.


In general better more flexible cropping tools for image thumbnailing would be really interesting as well, though for now we can get away with client-side cropping based on the focal area as the apps do.

Perhaps adding a 'scenario' into the thumbnail identifier:

  320px-Foobar.jpg - normal image at 320px width
  96px-square-Foobar.jpg - square-cropped image at 96x96
  640px-landscape-Foobar.jpg - landscape-cropped "lead image style" at 640xsomething

which would pick out square or landscape crops based on the defined focal area (whether provided by the face detection service or manually set).

A couple possibilities for setting the data:
* stick it in WikiData somehow?
* or - use a parser function on the image description page that saves the coords to page props table

Using a parser function is relatively straightforward to implement, and a pretty UI could be made to set the coordinates without manually editing the {{#image-focalpoint:12,35}} or whatever. But something in the wikibase/wikidata world might be awesomer.

-- brion

On Tue, Feb 3, 2015 at 12:53 PM, Brian Gerstle <bgerstle@wikimedia.org> wrote:
In general, I just want an API that provides a way to get & set cropping of images in different scenarios.  As clever as it sounds to wrap some algo in a service, it won't cover all cropping cases (just faces at first) and will probably need a way for users to fine tune it anyway.

TL;DR; +1 but I think an image cropping & preference service is more valuable.

On Tue, Feb 3, 2015 at 3:38 PM, Brion Vibber <bvibber@wikimedia.org> wrote:
Happy thoughts. :D


Note that face detection alone doesn't work well for all images, so we should also have a way for images to override the focal point for cropping purposes. This could be implemented as parser functions that save page properties (thus giving them standard editing/versioning/audit trail) and give them a nice user-friendly UI for seeing/overriding the crop points.

-- brion

On Tue, Feb 3, 2015 at 12:20 PM, Greg Grossmeier <greg@wikimedia.org> wrote:

This was going to be my question during the dev summit: why *don't* we do this, and improve our detection over time (and retroactively) instead of relying on user's devices?

Which is a long way of saying: +1 :)

--
Sent from my phone, please excuse brevity.

On Feb 3, 2015 12:10 PM, "Max Semenik" <maxsem.wiki@gmail.com> wrote:
Problem: while apps have face detection available from iOS and Android for use in lead image positioning/cropping, mobile web doesn't have it, and even for apps detection is quite slow, resulting in battery drain and UX-problematic slowdown, especially on low-end Android devices.

With Dmitry's help, I discovered Android's face detection library sources ([1], separated out to a standalone library at [2]). This means that we can build a face detection service and supply its results to all users, be that apps, web or third parties.

Thoughts?

----

--
Best regards,
Max Semenik ([[User:MaxSem]])

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