|
| 1 | +""" |
| 2 | +======================================== |
| 3 | +Interactive Adjustment of Colormap Range |
| 4 | +======================================== |
| 5 | +
|
| 6 | +Demonstration of using colorbar, picker, and event functionality to make an |
| 7 | +interactively adjustable colorbar widget. |
| 8 | +
|
| 9 | +Left clicks and drags inside the colorbar axes adjust the high range of the |
| 10 | +color scheme. Likewise, right clicks and drags adjust the low range. The |
| 11 | +connected AxesImage immediately updates to reflect the change. |
| 12 | +""" |
| 13 | + |
| 14 | +import numpy as np |
| 15 | +import matplotlib.pyplot as plt |
| 16 | +from matplotlib.backend_bases import MouseButton |
| 17 | + |
| 18 | +############################################################################### |
| 19 | +# Callback definitions |
| 20 | + |
| 21 | + |
| 22 | +def on_pick(event): |
| 23 | + adjust_colorbar(event.mouseevent) |
| 24 | + |
| 25 | + |
| 26 | +def on_move(mouseevent): |
| 27 | + if mouseevent.inaxes is colorbar.ax: |
| 28 | + adjust_colorbar(mouseevent) |
| 29 | + |
| 30 | + |
| 31 | +def adjust_colorbar(mouseevent): |
| 32 | + if mouseevent.button == MouseButton.LEFT: |
| 33 | + colorbar.norm.vmax = max(mouseevent.ydata, colorbar.norm.vmin) |
| 34 | + elif mouseevent.button == MouseButton.RIGHT: |
| 35 | + colorbar.norm.vmin = min(mouseevent.ydata, colorbar.norm.vmax) |
| 36 | + else: |
| 37 | + # discard all others |
| 38 | + return |
| 39 | + |
| 40 | + canvas.draw_idle() |
| 41 | + |
| 42 | + |
| 43 | +############################################################################### |
| 44 | +# Generate figure with Axesimage and Colorbar |
| 45 | + |
| 46 | +fig, ax = plt.subplots() |
| 47 | +canvas = fig.canvas |
| 48 | + |
| 49 | +delta = 0.1 |
| 50 | +x = np.arange(-3.0, 4.001, delta) |
| 51 | +y = np.arange(-4.0, 3.001, delta) |
| 52 | +X, Y = np.meshgrid(x, y) |
| 53 | +Z1 = np.exp(-X**2 - Y**2) |
| 54 | +Z2 = np.exp(-(X - 1)**2 - (Y - 1)**2) |
| 55 | +Z = (0.9*Z1 - 0.5*Z2) * 2 |
| 56 | + |
| 57 | +cmap = plt.get_cmap('viridis').with_extremes( |
| 58 | + over='xkcd:orange', under='xkcd:dark red') |
| 59 | +axesimage = plt.imshow(Z, cmap=cmap) |
| 60 | +colorbar = plt.colorbar(axesimage, ax=ax, use_gridspec=True) |
| 61 | + |
| 62 | +############################################################################### |
| 63 | +# Note that axesimage and colorbar share a Normalize object |
| 64 | +# so they will stay in sync |
| 65 | + |
| 66 | +assert colorbar.norm is axesimage.norm |
| 67 | +colorbar.norm.vmax = 1.5 |
| 68 | +axesimage.norm.vmin = -0.75 |
| 69 | + |
| 70 | +############################################################################### |
| 71 | +# Hook Colorbar up to canvas events |
| 72 | + |
| 73 | +# `set_navigate` helps you see what value you are about to set the range |
| 74 | +# to, and enables zoom and pan in the colorbar which can be helpful for |
| 75 | +# narrow or wide data ranges |
| 76 | +colorbar.ax.set_navigate(True) |
| 77 | + |
| 78 | +# React to all motion with left or right mouse buttons held |
| 79 | +canvas.mpl_connect("motion_notify_event", on_move) |
| 80 | + |
| 81 | +# React only to left and right clicks |
| 82 | +colorbar.ax.set_picker(True) |
| 83 | +canvas.mpl_connect("pick_event", on_pick) |
| 84 | + |
| 85 | +############################################################################### |
| 86 | +# Display |
| 87 | +# |
| 88 | +# The colormap will now respond to left and right clicks in the Colorbar axes |
| 89 | + |
| 90 | +plt.show() |
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