Re: [Matplotlib-users] Reworked axis('scaled')

[Helge A. <he...@gm...>]

On 10/14/05, Mark Bakker <ma...@gm...> wrote:
>
> Hello all -
>
> I finally found time to fix the axis('scaled') feature.
> It is now consistent when zooming, as requested.
> In essence, it works the same as axis('equal'), but fixes the
> lower-left-hand corner rather than the center of the
> subplot. When using axis('scaled') the _autoscaleon is
> set to False, so that axis limits will be fixed when
> features are added to the figure. You can overwrite this
> by setting it the regular way (also works for axis('equal'))
> ax.set_autoscale_on(False).
>
> My last modification is a prototype implementation of
> zooming when two axes are linked. The idea behind this
> is that when an axis is 'equal' or 'scaled' and another
> axis is linked to this axis, that when you are zooming and
> changing the size of the subplot, then the size of the
> linkes axis should change accordingly. I use this when
> I am contouring 2D horizontal data and have a vertical
> cross-section linked to the x-axis of the horizontal plot.
> When I zoom in on the horizontal plot, the length of the
> linked axis now gets changes too! Works great, actually,
> but has been implemented for linked x-axis only for now.
> It works when zooming in the horizontal data (which
> has axis 'equal'), but not yet when zooming in the
> linked vertical cross-section. Still working on it.



Hi,
yes this is a step in the right direction! IMO it would also be nice with
functionality for
zooming in/out on single clicks with the left and right button, e.g.
something like the below for backend_bases.py: (hope it is not wrapped to
death...)

Helge


<pre>
...
def release_zoom(...):
...
# single click: 5 pixels is a threshold
if abs(x-lastx)<5 or abs(y-lasty)<5:

lastx, lasty =3D a.transData.inverse_xy_tup( (lastx, lasty) )
x, y =3D a.transData.inverse_xy_tup( (x, y) )
Xmin,Xmax=3Da.get_xlim()
Ymin,Ymax=3Da.get_ylim()

if self._button_pressed =3D=3D 1:

# zoom in by 20%, make point clicked center
dx=3D(Xmax-Xmin)*0.8*0.5
dy=3D(Ymax-Ymin)*0.8*0.5
a.set_xlim((x-dx, x+dx))
a.set_ylim((y-dy, y+dy))

elif self._button_pressed =3D=3D 3:

# zoom out by 20%, make point clicked center
dx=3D(Xmax-Xmin)*1.2*0.5
dy=3D(Ymax-Ymin)*1.2*0.5
a.set_xlim((x-dx, x+dx))
a.set_ylim((y-dy, y+dy))

self.draw()
self._xypress =3D None
self._button_pressed =3D=3D None

self.push_current()
self.release(event)
return

# zoom to rect
...
</pre>