|
3 | 3 | Interactive Adjustment of Colormap Range
|
4 | 4 | ========================================
|
5 | 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. |
| 6 | +Demonstration of how a colorbar can be used to interactively adjust the |
| 7 | +range of colormapping on an image. To use the interactive feature, you must |
| 8 | +be in either zoom mode (magnifying glass toolbar button) or |
| 9 | +pan mode (4-way arrow toolbar button) and click inside the colorbar. |
| 10 | +
|
| 11 | +When zooming, the bounding box of the zoom region defines the new vmin and |
| 12 | +vmax of the norm. Zooming using the right mouse button will expand the |
| 13 | +vmin and vmax proportionally to the selected region, in the same manner that |
| 14 | +one can zoom out on an axis. When panning, the vmin and vmax of the norm are |
| 15 | +both shifted according to the direction of movement. The |
| 16 | +Home/Back/Forward buttons can also be used to get back to a previous state. |
12 | 17 | """
|
13 |
| - |
14 |
| -importnumpyasnp |
15 | 18 | importmatplotlib.pyplotasplt
|
16 |
| -frommatplotlib.backend_basesimportMouseButton |
17 |
| - |
18 |
| -############################################################################### |
19 |
| -# Callback definitions |
20 |
| - |
21 |
| - |
22 |
| -defon_pick(event): |
23 |
| -adjust_colorbar(event.mouseevent) |
24 |
| - |
25 |
| - |
26 |
| -defon_move(mouseevent): |
27 |
| -ifmouseevent.inaxesiscolorbar.ax: |
28 |
| -adjust_colorbar(mouseevent) |
29 |
| - |
30 |
| - |
31 |
| -defadjust_colorbar(mouseevent): |
32 |
| -ifmouseevent.button==MouseButton.LEFT: |
33 |
| -colorbar.norm.vmax=max(mouseevent.ydata,colorbar.norm.vmin) |
34 |
| -elifmouseevent.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 |
| - |
| 19 | +importnumpyasnp |
42 | 20 |
|
43 |
| -############################################################################### |
44 |
| -# Generate figure with Axesimage and Colorbar |
| 21 | +t=np.linspace(0,2*np.pi,1024) |
| 22 | +data2d=np.sin(t)[:,np.newaxis]*np.cos(t)[np.newaxis, :] |
45 | 23 |
|
46 | 24 | 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.colormaps['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 |
| -assertcolorbar.normisaxesimage.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) |
| 25 | +im=ax.imshow(data2d) |
| 26 | +ax.set_title('Pan on the colorbar to shift the color mapping\n' |
| 27 | +'Zoom on the colorbar to scale the color mapping') |
84 | 28 |
|
85 |
| -############################################################################### |
86 |
| -# Display |
87 |
| -# |
88 |
| -# The colormap will now respond to left and right clicks in the Colorbar axes |
| 29 | +fig.colorbar(im,ax=ax,label='Interactive colorbar') |
89 | 30 |
|
90 | 31 | plt.show()
|