matplotlib-devel Mailing List for matplotlib

Hi John and the matplotlib people,

John Hunter wrote:
>>>>>> "Charlie" == Charlie Moad <cw...@gm...> writes:
> 
>     Charlie>      At what point should we push another minor release
>     Charlie> for py2.5? or should we at all?  I am able to compile and
>     Charlie> run the latest in svn on all 3 major platforms.  The only
>     Charlie> missing component is pygtk for windows.  0.87.5 is not
>     Charlie> py2.5 compatible in many ways.  Just thought I would
>     Charlie> throw it out there.
> 
> I've CCd Cedric Gustin, who maintains pygtk for win32.  Cedric, do you
> plan to push out a python2.5 version in the near future?  If so, we
> can hold up the mpl release which uses some pygtk extension code in
> building.  If not, we can go ahead with the release w/o gtk support,
> since this is not a common backend on windows.

Yes, pygtk binaries for python 2.5 will be available this week. I just
need a few more days as I'm also working on binaries for
pygtk-2.10/pygobject-2.12/pycairo-1.2.

Or, if you want, I can give you early access to pygtk binaries for
python 2.5 for testing purpose with matplotlib ? Just tell me if you
need pygtk-2.10 or 2.8 ?

Cedric

* Short Story :
I want to create my custom navigation bar with my custom zoom behavior:
My first step is zooming by pressing +/- keys to zoom in and zoom out 
while pointing the mouse to the "zoom's center".
I the long run I want a zooming and panning behavior interact smoothly 
with images (similar to photoshop's):
- Zooming with the left button to zoom in the right button to zoom out.
- Zooming with the mouse wheel.
- Other interactions ...

But I am stuck :-(

* Question :
My question is how do you "magnify" the image after change the axes ?
(with
self.axes.set_xlim((x1, x2))
self.axes.set_ylim((y1, y2))
)

* Long story:
First, I wanted to understand how the zoom worked. So I traced the zoom 
functionality from the NavigationToolbar2Wx to the following method:
- backend._bases.NavigationToolbar2.drag_pan
 From what I understand, this is where the magic bar happens?

Now I wrote a dirty method ( see OnKeyPress below ) where I drive the 
zoom by changing the xmin,xmax,ymin,ymax when I press any key instead of 
the default mouse dragging behavior.

When I zoom out:
xmin,xmax = Xmin + 50, Xmax - 50
ymin,ymax = Ymin + 50, Ymax – 50
it works find. The image becomes smaller.

But, when I zoom in as below
xmin,xmax = Xmin - 50, Xmax + 50
ymin,ymax = Ymin - 50, Ymax + 50
the image just get cropped but not magnified. I other words
self.axes.set_xlim and self.axes.set_ylim do not make the "data pixels 
bigger" (as happends in the correct zoom funcionality), they just stay 
the same size. The image becomes smaller and smaller instead of keeping 
the same size with les "data pixels into it"…

def OnKeyPress(self, event):
if not event.inaxes: return
x, y = self.axes.transData.inverse_xy_tup( (event.x, event.y))
Xmin,Xmax=self.axes.get_xlim()
Ymin,Ymax=self.axes.get_ylim()

# Dirty hack to understand how zoom works
xmin,xmax = Xmin - 50, Xmax + 50
ymin,ymax = Ymin - 50, Ymax + 50

if self.axes.get_xscale()=='log':
alpha=log(Xmax/Xmin)/log(xmax/xmin)
x1=pow(Xmin/xmin,alpha)*Xmin
x2=pow(Xmax/xmin,alpha)*Xmin
else:
alpha=(Xmax-Xmin)/(xmax-xmin)
x1=alpha*(Xmin-xmin)+Xmin
x2=alpha*(Xmax-xmin)+Xmin
if self.axes.get_yscale()=='log':
alpha=log(Ymax/Ymin)/log(ymax/ymin)
y1=pow(Ymin/ymin,alpha)*Ymin
y2=pow(Ymax/ymin,alpha)*Ymin
else:
alpha=(Ymax-Ymin)/(ymax-ymin)
y1=alpha*(Ymin-ymin)+Ymin
y2=alpha*(Ymax-ymin)+Ymin


self.axes.set_xlim((x1, x2))
self.axes.set_ylim((y1, y2))

self.canvas.draw()

Any help would be welcomed!

Daniel.