Flickering occurs when scrolling a GridView with UbuntuShapes

[Andrew Hayzen]

On Trusty Desktop running Intel GPU
$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

When I 'throw' the album page on music-app a high amount of flickering occurs [1].

Throw means if I click-drag and release the flickering occurs after the release of the mouse. Or if I use the two finger smooth scroll on a touchpad.

When changing the UbuntuShapes to Rectangles the flickering does not occur [2].

1 - https://docs.google.com/file/d/0B3XynHVKfrvMQTBOVFhMWUpva0U/edit
2 - https://code.launchpad.net/~andrew-hayzen/+junk/album-page-flicker-investigation

[Andrew Hayzen (ahayzen)]

I've just created an example of the issue here [1]. Note I had to add an Image to the UbuntuShape inside the GridView for the issue to occur.

1 - https://code.launchpad.net/~andrew-hayzen/+junk/test-gridview-ubuntushape

[Tim Peeters (tpeeters)]

I'm not sure if I would call it 'flickering'.. on my screen it is more like tearing, like different parts of the screen are updated not simultaneously.

[Loïc Molinari (loic.molinari)]

I've just tried the provided branch on my desktop and I don't see flickering. Is that still happening for you? We might have fixed that meanwhile, by making the UbuntuShape batchable by the QtQuick batched renderer.

[Andrew Hayzen (ahayzen)]

This appears to be fixed for me :)

However note i'm on utopic now where as this bug was reported on trusty, but it seems likely that the changes to the UbuntuShape have resolved the issue.

[Tim Peeters (tpeeters)]

I was testing inside a virtual machine, and even when I remove the UbuntuShape from the code, see http://pastebin.ubuntu.com/9095558/ I have the "flickering" . Also after removing the Rectangle from the pastebin code I still get the same effect.

So the UbuntuShape does not seem to affect this issue for me.

[Loïc Molinari (loic.molinari)]

Fixed then! Thanks.

[Andrew Hayzen (ahayzen)]

@Tim was that VM a trusty machine?

[Tim Peeters (tpeeters)]

When I last tested it in November, it was Utopic. The effect is not very strong/obvious though.

I don't remember when I first tested which version I was running, or if the issue was more obvious.