Re: mouse zoom centred on mouse position.

[Petr M. <mi...@ph...>]

> On Sat, Jun 23, 2012 at 11:23 PM, Petr Mikulik wrote:
> > I have revised the mouse wheel zooming, see patch:
> > https://sourceforge.net/tracker/?func=detail&aid=3537423&group_id=2055&atid=302055
> 
> However (the following comments are all unrelated to your specific
> change), if revising the mouse, I would be very very very grateful if
> functions would be modified in such a way that it would be possible to
> specify the amount of zoom/scroll, not only large discrete steps.

I have tested the changes with an USB mouse attached to my notebook.
But it seems you write only about touchpads?

(I don't like touchpads. It's a hardware thing that goes worse and worse :-) 
That one I have in my Asus notebook is horrible - it is large and flat 
(without edges) but not centered with respect to F and J keys on the 
keyboard so that typing by 10 fingers makes strange things. Hm, yes, 
sometimes I use it ... but I find hitting Arrow or Pg keys much faster for 
scrolling.)

> generate one single scrolling event for one pixel. Usually one gets
> 2-5 steps with very very tiny movement. Last time when I tested, a
> single swipe from left to right moved me from default (-10,10) to
> somewhere around 2000. With a single movement!!! In a native mac
> application that would correspond to a movement across the width of

Does it mean that touchpad and mouse have very different sensitivity on Mac?

> So it would be very helpful to have not just
>     zoom_around_mouse('+');
> but rather something like
>     zoom_around_mouse(1.134);

Or a global variable mouse_sensitivity?

> And related to your change: on Mac it is natural to use scrolling for
> actually scrolling, since there are other events on trackpad which
> allow zooming in (they work the same as maps on smart phones, using
> two fingers and sliding them closer together or further apart).
> Redefining the meaning of scrolling means a slightly unnatural
> experience for mac users, but for the sake of all other more
> widespread OS-es and hardware and for the sake of consistency of
> gnuplot across platforms, it should be acceptable to use key
> combinations that make sense elsewhere.
> 
> However ... if you redefine the meaning of scrolling event, then
> please provide drag-and-drop to move around the graph.

So it seems you want different mapping for events generated by touchpads and 
trackpoints than events for mouses, because, by chance, the mouse wheel 
up/down events useful for zooming correspond to y-sliding touchpad while 
x-sliding and double-finger gestures on touchpad have no mouse equivalents.

Is it possible to know the input device sending the event?

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PM