Re: mouse pan and zoom

[Ethan M. <merritt@u.washington.edu>]

On Friday 17 July 2009, Ethan Merritt wrote:
> On Friday 17 July 2009, James R. Van Zandt wrote:
> > 
> > I've just checked in code to do "pan and zoom" with the mouse wheel.
> 
> First thoughts:
> 
> It works nicely here in x11, but doesn't do anything at all in wxt or
> in the new canvas or qt terminals.  I understand that extra javascript
> would be needed for the canvas,  but what is needed in order to support
> this for other interactive terminal types?

  OK. I figured out how to add a wxt handler for mouse wheel events.

  I'll punt on qt and hope that Jérôme Lodewyck will take care of it.

  What about the windows terminal - can someone confirm whether that
  is recognizing pan and zoom using the same conventions as x11?

	Ethan 



> 
> Wouldn't it be logical to apply this in 3D also?
> 
> It does not immediately strike me as useful to save the settings on the
> zoom stack.  Unlike a click-and-drag zoom operation, the inverse is easy
> to achieve by reversing the direction of the mouse wheel.
> 
> 
> > These commands work like Acroread or Gimp:
> > 
> >  - control-wheel-up zooms in toward the center of the plot
> >  - control-wheel-down  reverses the above
> > 
> >  - wheel-up move the viewpoint up (increases both ymin and ymax by ten
> >    percent of the plot range)
> > 
> >  - wheel-down moves the viewpoint down
> > 
> >  - shift-wheel-up moves the viewpoint left (decreases both xmin and xmax
> >    by ten percent of the plot range)
> > 
> >  - shift-wheel-down moves the viewpoint right
> > 
> > 
> > I implemented these just for completeness:
> > 
> >  - shift-control-wheel-up zooms in only the X axis
> >  - shift-control-wheel-down zooms out only the X axis
> > 
> > 
> > These work for linear or log axes.
> > 
> > A simple plot for testing, with or without log axes:
> > 
> > set parametric; plot sin(t)+1.02,cos(t)+1.02
> > 
> > (If zero is not currently on an axis, you can use "L" to toggle
> > logscale along that axis.)
> > 
> > 
> > I'll be glad to add documentation, but first I'll see what changes
> > people want.  E.g.:
> > 
> >  - Are the pan and zoom steps reasonable?  Should they be user-tunable?
> >  - Do you have a better idea for shift-control-wheel?
> >  - Each of these commands is added to the zoom stack, so they can be
> > undone individually.  That was easy to implement, but do we want that?
> > Does "u" recover all that memory?  Should we suggest that the user
> > type "u" occasionally?
> > 
> >         - Jim Van Zandt
> > 
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