.. _event_handling-viewlims: event_handling example code: viewlims.py ======================================== [`source code `_] :: # Creates two identical panels. Zooming in on the right panel will show # a rectangle in the first panel, denoting the zoomed region. import numpy as np import matplotlib.pyplot as plt from matplotlib.patches import Rectangle # We just subclass Rectangle so that it can be called with an Axes # instance, causing the rectangle to update its shape to match the # bounds of the Axes class UpdatingRect(Rectangle): def __call__(self, ax): self.set_bounds(*ax.viewLim.bounds) ax.figure.canvas.draw_idle() # A class that will regenerate a fractal set as we zoom in, so that you # can actually see the increasing detail. A box in the left panel will show # the area to which we are zoomed. class MandlebrotDisplay(object): def __init__(self, h=500, w=500, niter=50, radius=2., power=2): self.height = h self.width = w self.niter = niter self.radius = radius self.power = power def __call__(self, xstart, xend, ystart, yend): self.x = np.linspace(xstart, xend, self.width) self.y = np.linspace(ystart, yend, self.height).reshape(-1, 1) c = self.x + 1.0j * self.y threshold_time = np.zeros((self.height, self.width)) z = np.zeros(threshold_time.shape, dtype=np.complex) mask = np.ones(threshold_time.shape, dtype=np.bool) for i in range(self.niter): z[mask] = z[mask]**self.power + c[mask] mask = (np.abs(z) < self.radius) threshold_time += mask return threshold_time def ax_update(self, ax): ax.set_autoscale_on(False) # Otherwise, infinite loop # Get the number of points from the number of pixels in the window dims = ax.axesPatch.get_window_extent().bounds self.width = int(dims[2] + 0.5) self.height = int(dims[2] + 0.5) # Get the range for the new area xstart, ystart, xdelta, ydelta = ax.viewLim.bounds xend = xstart + xdelta yend = ystart + ydelta # Update the image object with our new data and extent im = ax.images[-1] im.set_data(self.__call__(xstart, xend, ystart, yend)) im.set_extent((xstart, xend, ystart, yend)) ax.figure.canvas.draw_idle() md = MandlebrotDisplay() Z = md(-2., 0.5, -1.25, 1.25) fig1, (ax1, ax2) = plt.subplots(1, 2) ax1.imshow(Z, origin='lower', extent=(md.x.min(), md.x.max(), md.y.min(), md.y.max())) ax2.imshow(Z, origin='lower', extent=(md.x.min(), md.x.max(), md.y.min(), md.y.max())) rect = UpdatingRect([0, 0], 0, 0, facecolor='None', edgecolor='black') rect.set_bounds(*ax2.viewLim.bounds) ax1.add_patch(rect) # Connect for changing the view limits ax2.callbacks.connect('xlim_changed', rect) ax2.callbacks.connect('ylim_changed', rect) ax2.callbacks.connect('xlim_changed', md.ax_update) ax2.callbacks.connect('ylim_changed', md.ax_update) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)