Note
Go to the endto download the full example code.
Trifinder Event Demo#
Example showing the use of a TriFinder object. As the mouse is moved over thetriangulation, the triangle under the cursor is highlighted and the index ofthe triangle is displayed in the plot title.
Note
This example exercises the interactive capabilities of Matplotlib, and thiswill not appear in the static documentation. Please run this code on yourmachine to see the interactivity.
You can copy and paste individual parts, or download the entire exampleusing the link at the bottom of the page.
importmatplotlib.pyplotaspltimportnumpyasnpfrommatplotlib.patchesimportPolygonfrommatplotlib.triimportTriangulationdefupdate_polygon(tri):iftri==-1:points=[0,0,0]else:points=triang.triangles[tri]xs=triang.x[points]ys=triang.y[points]polygon.set_xy(np.column_stack([xs,ys]))defon_mouse_move(event):ifevent.inaxesisNone:tri=-1else:tri=trifinder(event.xdata,event.ydata)update_polygon(tri)ax.set_title(f'In triangle{tri}')event.canvas.draw()# Create a Triangulation.n_angles=16n_radii=5min_radius=0.25radii=np.linspace(min_radius,0.95,n_radii)angles=np.linspace(0,2*np.pi,n_angles,endpoint=False)angles=np.repeat(angles[...,np.newaxis],n_radii,axis=1)angles[:,1::2]+=np.pi/n_anglesx=(radii*np.cos(angles)).flatten()y=(radii*np.sin(angles)).flatten()triang=Triangulation(x,y)triang.set_mask(np.hypot(x[triang.triangles].mean(axis=1),y[triang.triangles].mean(axis=1))<min_radius)# Use the triangulation's default TriFinder object.trifinder=triang.get_trifinder()# Setup plot and callbacks.fig,ax=plt.subplots(subplot_kw={'aspect':'equal'})ax.triplot(triang,'bo-')polygon=Polygon([[0,0],[0,0]],facecolor='y')# dummy data for (xs, ys)update_polygon(-1)ax.add_patch(polygon)fig.canvas.mpl_connect('motion_notify_event',on_mouse_move)plt.show()