.. _pylab_examples-ginput_manual_clabel:

pylab_examples example code: ginput_manual_clabel.py
====================================================

[`source code <ginput_manual_clabel.py>`_]

::

    #!/usr/bin/env python
    # -*- noplot -*-
    
    from __future__ import print_function
    """
    This provides examples of uses of interactive functions, such as ginput,
    waitforbuttonpress and manual clabel placement.
    
    This script must be run interactively using a backend that has a
    graphical user interface (for example, using GTKAgg backend, but not
    PS backend).
    
    See also ginput_demo.py
    """
    import time
    import matplotlib
    import numpy as np
    import matplotlib.cm as cm
    import matplotlib.mlab as mlab
    import matplotlib.pyplot as plt
    
    def tellme(s):
        print(s)
        plt.title(s,fontsize=16)
        plt.draw()
    
    ##################################################
    # Define a triangle by clicking three points
    ##################################################
    plt.clf()
    plt.axis([-1.,1.,-1.,1.])
    plt.setp(plt.gca(),autoscale_on=False)
    
    tellme('You will define a triangle, click to begin')
    
    plt.waitforbuttonpress()
    
    happy = False
    while not happy:
        pts = []
        while len(pts) < 3:
            tellme('Select 3 corners with mouse')
            pts = np.asarray( plt.ginput(3,timeout=-1) )
            if len(pts) < 3:
                tellme('Too few points, starting over')
                time.sleep(1) # Wait a second
    
        ph = plt.fill( pts[:,0], pts[:,1], 'r', lw=2 )
    
        tellme('Happy? Key click for yes, mouse click for no')
    
        happy = plt.waitforbuttonpress()
    
        # Get rid of fill
        if not happy:
            for p in ph: p.remove()
    
    ##################################################
    # Now contour according to distance from triangle
    # corners - just an example
    ##################################################
    
    # Define a nice function of distance from individual pts
    def f(x,y,pts):
        z = np.zeros_like(x)
        for p in pts:
            z = z + 1/(np.sqrt((x-p[0])**2+(y-p[1])**2))
        return 1/z
    
    X,Y = np.meshgrid( np.linspace(-1,1,51), np.linspace(-1,1,51) )
    Z = f(X,Y,pts)
    
    CS = plt.contour( X, Y, Z, 20 )
    
    tellme( 'Use mouse to select contour label locations, middle button to finish' )
    CL = plt.clabel( CS, manual=True )
    
    ##################################################
    # Now do a zoom
    ##################################################
    tellme( 'Now do a nested zoom, click to begin' )
    plt.waitforbuttonpress()
    
    happy = False
    while not happy:
        tellme( 'Select two corners of zoom, middle mouse button to finish' )
        pts = np.asarray( plt.ginput(2,timeout=-1) )
    
        happy = len(pts) < 2
        if happy: break
    
        pts = np.sort(pts,axis=0)
        plt.axis( pts.T.ravel() )
    
    tellme('All Done!')
    plt.show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)