Native Scrollers not working correctly in LC8 - Bug 17779

[hlowe]

I want to bring this LC bug to the group's attention so that you don't spend
hours (as I did) trying to track down the cause in your own code. This bug
was first reported in June 2016 by Louis, was confirmed as a bug, and is
still present in LC 8.1.0 -
http://quality.livecode.com/show_bug.cgi?id=17779

If acceleratedRendering is set to true then both iOS and Android native
scrollers (as reported by Louis) will not work correctly. The scrollers do
not respect the contentRect and instead draw outside the contentRect,
overwriting other screen areas. I have also found this bug results in some
object background fill colors being set to black. 

Setting acceleratedRendering to false fixes these issues. However, even if
acceleratedRendering is set to false, setting the compositorType of the
stack to "OpenGL" causes the bug to reappear. 

I encountered this bug when migrating an iOS iPad app that runs fine under
LC 6.7.11 and iOS 9.3 to LC 8.1.0 under iOS 9.3. Comparing my app (on the
iPad) with and without acceleratedRendering set to true demonstrates a
significant visual  delay when scrolling complex LC datagrids if
acceleratedRendering is turned off. I use Monte's excellent
mergDataGridScroller drop tool and it, as expected, is also impacted by the
bug as are the "roll your own" native scrollers that I have coded. 

The LC team have done an amazing job in delivering LC 8.1.0. No criticism is
intended. I just want to save you the many hours I spent trying to figure
out why my scrollers were no longer working as expected. 

Henry



--
View this message in context: http://runtime-revolution.278305.n4.nabble.com/Native-Scrollers-not-working-correctly-in-LC8-Bug-17779-tp4708480.html
Sent from the Revolution - User mailing list archive at Nabble.com.