Wt

Animated fade transitions on WStackedWidgets can produce visible stuttering. This has been observed with Firefox 22 on Windows 7 and the git version of Wt (3.3.0-30-ga7f27d8). The issue also appears with Debian Wheezy/Iceweasel 17.0.7. I have not observed the problem with Safari (iPad, Windows, and Mac OS), or Chrome. The attached program will hopefully demonstrate the issue, though it seems somewhat timing sensitive.

A small patch is also attached which seems to improve the animation on Firefox. The patch has not been tested extensively.

As a note, it appears that Wt sends animateDisplay() instructions to the client prior to sending updates for the WContainerWidget/div that will be faded-in. On Firefox, if the "Loading" indicator gets displayed during an animation, it seems that a visible animation glitch can still result. The attached patch does not address this issue, and I mention the ordering concern on the off chance that it might be relevant.