thumbnails are not being cached by gallery

[Bill Filler]

The gallery app is not using the QML cache to store thumbnails. They are being reloaded each time they are needed which causes slowness and the spinners to be shown. We set the imageSource on the qml side to path + Date.now() to make sure changes to the files on disk are updated, but this could be optimized.

Instead we should monitor file modifications and only invalidate the cache for that file if possible.

[Arthur Mello (artmello)]

We are still not using the QML cache to store thumbnails, but we are not able to see the slowness and the spinners anymore (at least after all the thumbnails are generated). Probably this was fixed with some change on thumbnail image provider.

[Sebastien Bacher (seb128)]

On the current rtm image (r142) I can see the spinners for like 15 seconds every time the gallery application is restarted, that's really a suboptimal user experience

[Sebastien Bacher (seb128)]

Some update, the weird behaviour was due to a file confusing the thumbnailer. One way to trigger it is to record a 1 second video with the camera application (click record and then click stop directly). When thumbnailing of one file fails it seem the gallery is acting weird, like if it was wipping the whole cache and trying to regenerate it every time

[Michi Henning (michihenning)]

I strongly recommend to not use an additional caching layer in the gallery app. The right thing to do is to ask the (new) thumbnailer for a thumbnail when you need it. If the cache is hot, it'll be returned to you in around 1-1.5 msec on a Nexus 4. Given that, extra caching on top of that just wastes resources.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.