Hi,
I commited a fixto the axis contains methods, and now have working scroll
wheel zooming code. I still need to use transforms properly before it can
go into matplotlib, so for now I provide it only for demonstration
purposes.
- Paul
import math
import matplotlib
#matplotlib.use('WxAgg')
#matplotlib.use('TkAgg')
#matplotlib.use('GtkAgg')
import pylab
import matplotlib.colors as colors
def _rescale(lo,hi,step,pt=None,bal=None,scale='linear'):
"""
Rescale (lo,hi) by step, returning the new (lo,hi)
The scaling is centered on pt, with positive values of step
driving lo/hi away from pt and negative values pulling them in.
If bal is given instead of point, it is already in [0,1] coordinates.
This is a helper function for step-based zooming.
"""
# Convert values into the correct scale for a linear transformation
# TODO: use proper scale transformers
if scale=='log':
lo,hi = math.log10(lo),math.log10(hi)
if pt is not None: pt = math.log10(pt)
# Compute delta from axis range * %, or 1-% if percent is negative
if step > 0:
delta = float(hi-lo)*step/100
else:
delta = float(hi-lo)*step/(100-step)
# Add scale factor proportionally to the lo and hi values, preserving the
# point under the mouse
if bal is None:
bal = float(pt-lo)/(hi-lo)
lo = lo - bal*delta
hi = hi + (1-bal)*delta
# Convert transformed values back to the original scale
if scale=='log':
lo,hi = math.pow(10.,lo),math.pow(10.,hi)
return (lo,hi)
def onWheel(event):
"""
Process mouse wheel as zoom events
"""
ax = event.inaxes
# Older versions of matplotlib do not have event.step defined
try:
step = event.step
except:
if event.button == 'up':
step = 1
else:
step = -1
# Find colorbars attached to the canvas.
# FIXME Better way to tell if axes contains colorbar?
colorbars = getattr(event.canvas,'_colorbars',{})
# If in plot, use the xdata, ydata as the center point
# If not in plot, check if we are in a plot axis
if ax == None:
# Event not on plot: check if it happened in an axis
xdata,ydata = None,None
x,y = event.x,event.y
axes = event.canvas.figure.get_axes()
for ax in axes:
inx,_ = ax.xaxis.contains(event)
if inx:
xdata,_ = ax.transData.inverted().transform_point((x,y))
break
iny,_ = ax.yaxis.contains(event)
if iny:
_,ydata = ax.transData.inverted().transform_point((x,y))
break
else:
ax = None
else:
xdata,ydata = event.xdata,event.ydata
if ax in colorbars:
# Colorbar scrolling requires remapping the limits
# Note that xdata,ydata are in 0,1, and so are implicitly the
# balance point in the range of the data vlo,vhi
if colorbars[ax].orientation is 'vertical':
bal = ydata
else:
bal = xdata
# The scroll event may not have occurred in the right direction
if bal is not None:
mappable = colorbars[ax].mappable
if isinstance(mappable.norm,colors.LogNorm):
vscale = 'log'
else:
vscale = 'linear'
vlo,vhi = mappable.get_clim()
vlo,vhi = _rescale(vlo,vhi,step,bal=bal,scale=vscale)
mappable.set_clim(vlo,vhi)
event.canvas.draw_idle()
else:
# Axis scrolling requires remapping the axis limits
if xdata is not None:
lo,hi = ax.get_xlim()
lo,hi = _rescale(lo,hi,step,pt=xdata,scale=ax.get_xscale())
ax.set_xlim((lo,hi))
if ydata is not None:
lo,hi = ax.get_ylim()
lo,hi = _rescale(lo,hi,step,pt=ydata,scale=ax.get_yscale())
ax.set_ylim((lo,hi))
if xdata is not None or ydata is not None:
event.canvas.draw_idle()
def colorbar(*args,**kw):
cb = pylab.colorbar(*args,**kw)
canvas = pylab.gcf().canvas
if not hasattr(canvas,'_colorbars'):
canvas._colorbars = {}
canvas._colorbars[cb.ax] = cb
pylab.gcf().canvas.mpl_connect('scroll_event',onWheel)
pylab.subplot(211)
pylab.imshow([[1,2,3],[2,1,3]])
colorbar(orientation='horizontal')
pylab.subplot(212)
pylab.loglog([10,100,1000],[100,10,1000])
pylab.show()
-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
Matplotlib-devel mailing list
Matplotlib-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
