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#!/usr/bin/env python
"""
This example shows how to use matplotlib to provide a data cursor. It
uses matplotlib to draw the cursor and may be a slow since this
requires redrawing the figure with every mouse move.
Faster cursoring is possible using native GUI drawing, as in
wxcursor_demo.py
"""
from pylab import *
class Cursor:
def __init__(self, ax):
self.ax = ax
self.lx, = ax.plot( (0,0), (0,0), 'k-' ) # the horiz line
self.ly, = ax.plot( (0,0), (0,0), 'k-' ) # the vert line
# text location in axes coords
self.txt = ax.text( 0.7, 0.9, '', transform=ax.transAxes)
def mouse_move(self, event):
if not event.inaxes: return
ax = event.inaxes
minx, maxx = ax.get_xlim()
miny, maxy = ax.get_ylim()
x, y = event.xdata, event.ydata
# update the line positions
self.lx.set_data( (minx, maxx), (y, y) )
self.ly.set_data( (x, x), (miny, maxy) )
self.txt.set_text( 'x=%1.2f, y=%1.2f'%(x,y) )
draw()
class SnaptoCursor:
"""
Like Cursor but the crosshair snaps to the nearest x,y point
For simplicity, I'm assuming x is sorted
"""
def __init__(self, ax, x, y):
self.ax = ax
self.lx, = ax.plot( (0,0), (0,0), 'k-' ) # the horiz line
self.ly, = ax.plot( (0,0), (0,0), 'k-' ) # the vert line
self.x = x
self.y = y
# text location in axes coords
self.txt = ax.text( 0.7, 0.9, '', transform=ax.transAxes)
def mouse_move(self, event):
if not event.inaxes: return
ax = event.inaxes
minx, maxx = ax.get_xlim()
miny, maxy = ax.get_ylim()
x, y = event.xdata, event.ydata
indx = searchsorted(self.x, [x])[0]
x = self.x[indx]
y = self.y[indx]
# update the line positions
self.lx.set_data( (minx, maxx), (y, y) )
self.ly.set_data( (x, x), (miny, maxy) )
self.txt.set_text( 'x=%1.2f, y=%1.2f'%(x,y) )
print 'x=%1.2f, y=%1.2f'%(x,y)
draw()
t = arange(0.0, 1.0, 0.01)
s = sin(2*2*pi*t)
ax = subplot(111)
cursor = Cursor(ax)
#cursor = SnaptoCursor(ax, t, s)
connect('motion_notify_event', cursor.mouse_move)
ax.plot(t, s, 'o')
axis([0,1,-1,1])
show()
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