[Qt-interest] QWheelEvent (deltas)

[Joshua Grauman]

Thanks for the thoughts. I was figuring I would need to use software to 
adjust sensitivity. I guess my basic question boils down to wondering if 
there are any assumptions I can make. Most importantly, can I make any 
assumptions about the deltas? Where do these deltas come from, are they 
coded into the actual devices/drivers, or does Qt assign them for 
different devices? Are there any specs that specify that they must always 
be in multiples of 8, 120, etc. or can they be *any* value?

Thanks

Josh


> On 2010-12-02 Joshua Joshua Grauman wrote:
>
>> Hello all,
>>
>> I am implementing custom scrolling of a QTextEdit in my program and I
>> want it to work for all the different kinds of wheel events out there.
>
>> From the Qt docs: "Most mouse types work in steps of 15 degrees" which 
>> emphasis on MOST. That is it is almost certain that you will find other 
>> devices which return a different delta() than a multiple of 120. Or 
>> even if they send out a multiple of 120, that does not necessarily 
>> correspond "to 15 degrees of wheel motion".
>
> Qt doesn't offer you any API to query for a given device the 
> "sensitivity". So the best you can probably do is to adjust the 
> sensitivity "in software" (read: provide some settings and multiply the 
> received delta with some adjustment factor in your code).
>
> Cheers, Oliver
> --
> Oliver Knoll
> Dipl. Informatik-Ing. ETH
> COMIT AG - ++41 79 520 95 22
>
>
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