On Wed, Sep 29, 2010 at 4:44 AM, Alexander Dietz <alexanderdie...@googlemail.com> wrote:
> I would like to know how to find out the extend of the actual image in a > plot, in units of pixels. > As example I have attached a plot which is essentially empty. The lower left > corner is indicated by a red dot - what pixel position does this location > have? When opening this image in e.g. kview it is easy to find out that this > left corner of the actual plot corresponds to pixel (100,540). And so the > upper right corner (the yellow dot) is (720,60). > > But how do I find out these coordinates when generating such a plot with > matplotlib? Are there some variables of the axis or the actual plot that > contain these numbers? Take a look at the transformations tutorial. http://matplotlib.sourceforge.net/users/transforms_tutorial.html To convert from data -> pixel coordinates, use the axes transData transformation In [1]: ax = gca() In [2]: ax.transData.transform((0.5, 0.5)) Out[2]: array([ 333.125, 245. ]) You can also use mpl events to inspect the coordinates of the point under the mouse In [3]: fig = gcf() In [4]: def on_click(event): ...: print event.x, event.y ...: ...: In [5]: cid = fig.canvas.mpl_connect('button_press_event', on_click) In [6]: 188 166.0 300 227.0 384 292.0 In [7]: fig.canvas.mpl_disconnect(cid) See http://matplotlib.sourceforge.net/users/event_handling.html for more info. JDH ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
