[Development] Exception to source compatibility: adding AA_CompressHighFrequencyEvents flag

[Shawn Rutledge]

> On 26 Apr 2016, at 14:56, Simon Hausmann <Simon.Hausmann at qt.io> wrote:
> 
> Hi,
> 
> The way you describe the problem sounds like it is specific to tablet events on X-Windows. In my opinion a solution to the problem applied to the 5.6 branch of Qt
> should also be limited to tablet events on X-Windows. Wouldn't it therefore be easiest to simply not do tablet event compression on X-Windows without any changes to the API?

I had that idea early on, but somebody warned me that the disadvantage is having to dig into the event too much just to decide.  This decision is preliminary, before really handling the event, so it needs to be quick.  But the compression code already spends a little time, and detecting whether it’s a tablet event isn’t much more work.  Maybe we will solve the problem that way then.

https://codereview.qt-project.org/#/c/157348/

> The day somebody really wants event compression for tablet events, we can consider introducing new API perhaps in a new minor release.

Yeah.  But we could still get https://codereview.qt-project.org/#/c/157011/ into 5.7, in case somebody wants to disable all event compression.