Image flickers when switching to/from fullscreen

[Arthur Mello]

With vivid-proposed on mako.

We have a Image component with PreserveAspectRatio set as fillMode filling all the Page. When the application is going fullscreen / non-fullscreen on device the Image flickers during the process. Hiding the header too seems to make the result worse. This is the scenario for gallery-app during media viewer.

On this branch [0] we have a sample app that seems to trigger the issue. Just tap the picture to go fullscreen / non-fullscreen.

[0] lp:~artmello/+junk/fullscreen_issue

[Arthur Mello (artmello)]

After some tests with sdk team, this does not seem to be an ui-toolkit issue. The problem still happens if we use only an Item and not the MainView/Page components. The sample code was updated to show that.

[Tim Peeters (tpeeters)]

It turns out that the flickering occurs even when the UITK is not used, so this is probably a bug for another project (I don't know which project, though).

[Arthur Mello (artmello)]

We did some more tests on this issue. It seems that even if the flickering does happen when we do not use any ubuntu-ui-toolkit it is worse when we have ManView/Page components. Especially when we hide/show the header during the process.

Here[0] there is a new branch that shows the problem. Talking with timp he mentioned that the header.visible property will be deprecated on version 1.3 of ubuntu-ui-toolkit , but during the tests the problem seems to still happen.

[0] lp:~artmello/+junk/fullscreen_issue_header

[Tim Peeters (tpeeters)]

May be related to this bug https://bugs.launchpad.net/tangxi/+bug/1417006

[Bill Filler (bfiller)]

This is not related to the https://bugs.launchpad.net/tangxi/+bug/1417006 I don't believe as that bug is arale specific and this issue can be observed on mako and krillin.

[Bill Filler (bfiller)]

also in our testing the flickering has nothing to do with an Image being displayed. The issue can be observed even with no image present, by toggling the window fullscreen and hiding/showing the header. The header clearly shows flicking and repainting issues in this scenario. Try the sample app here: lp:~artmello/+junk/fullscreen_issue_header

[Daniel van Vugt (vanvugt)]

Sounds like it could be one of the Mir on Android bugs:
   https://bugs.launchpad.net/mir/+bugs?field.tag=android

Although only bug 1441553 mentions "flicker". That's a relatively new bug and has been seen in a few different scenarios.

Other bugs in the above list may cause "stutter" but that's different and less likely to happen under Unity8 right now (we have built-in workarounds for most of them).

[Tim Peeters (tpeeters)]

Closing for UITK.

[Michał Sawicz (saviq)]

Syncing task from Mir.