Comment 6 for bug 1086446

There are a number of cross platform programs I use on OS X that use "scrolling" for zooming and don't have this problem (Google Earth, which is Qt based, and a number of Java programs come to mind). So it should be possible to get this to work better in Stellarium without doing a lot of extra work to support gestures and pinch zooming.

I'm not a programmer, I have minimal experience with Qt, and I'm not in a position to start hacking on Stellarium, so I apologize if the following comment is not helpful.

Looking at the Qt docs,

http://qt-project.org/doc/qt-5/QWheelEvent.html

I see this:

"There are two ways to read the wheel event delta: angleDelta() returns the delta in wheel degrees. This value is always provided. pixelDelta() returns the delta in screen pixels and is available on platforms that have high-resolution trackpads, such as Mac OS X."

Stellarium's behaviour *seems* like it uses low resolution values because I need to pull my fingers on the trackpad for quite a long distance before it responds at all to the scroll event, and when it does respond, it zooms a relatively large amount. The ideal behaviour would be to zoom continuously as I'm pulling my fingers over the touchpad, and allow zooming just a little bit.

Isn't the key to the solution using the high resolution value from the pixelDelta() member function (on OS X, as this might not be available on other platforms)?