Re: [matplotlib-devel] ginput: blocking call for mouse input

[Paul K. <pki...@ni...>]

On Tue, Feb 05, 2008 at 11:23:14PM +0100, Gael Varoquaux wrote:
> On Tue, Feb 05, 2008 at 04:11:59PM -0600, John Hunter wrote:
> > Also, my version of GaelInput has seemed to stop evolving. This
> > version has the option to draw lines between clicks, which I use a
> > lot. Also, the default timeout is 0 now, since you can always
> > right-click to abort.
> 
> You can still use this behavoir, using a timeout of zero, n = 0, and the
> middle click to end (I use right_click to cancel points). I am not sure
> what the default timeout should be. If you have strong opinions about it
> being 0, that's fine with me.
> 
> As far as n = 0 being the default, I think this is a bad idea. First of
> all, it break matlab-compatibility for no good reasons, second in most
> cases, IMHO, the naive programmer only wants one point, and puts some
> logics afterwards. He will not read the doc, and wont understand why his
> function is not returning after one click (so many people don't even know
> how to read docstring, I am not kidding).
> 
> As for the lines, having lines implies that there is a connection order
> in your points, which is not always the case. I suggest thus adding a
> optional (oof by default) keyword argument for this behavior.

In my applications I select multiple points from a particular line,
highlighting the point that will be selected as the mouse cursor moves.  
I put a text message on the plot explaining what to do which disappears 
when the selection is complete.

Some other useful cases are selecting an x-range, a y-range or a box,
with the appropriate shading for the selected region.

This is still in Tcl/Tk+BLT; I haven't moved it over to Python yet.

- Paul