.. _event_handling-path_editor: event_handling example code: path_editor.py =========================================== [`source code `_] :: import numpy as np import matplotlib.path as mpath import matplotlib.patches as mpatches import matplotlib.pyplot as plt Path = mpath.Path fig, ax = plt.subplots() pathdata = [ (Path.MOVETO, (1.58, -2.57)), (Path.CURVE4, (0.35, -1.1)), (Path.CURVE4, (-1.75, 2.0)), (Path.CURVE4, (0.375, 2.0)), (Path.LINETO, (0.85, 1.15)), (Path.CURVE4, (2.2, 3.2)), (Path.CURVE4, (3, 0.05)), (Path.CURVE4, (2.0, -0.5)), (Path.CLOSEPOLY, (1.58, -2.57)), ] codes, verts = zip(*pathdata) path = mpath.Path(verts, codes) patch = mpatches.PathPatch(path, facecolor='green', edgecolor='yellow', alpha=0.5) ax.add_patch(patch) class PathInteractor: """ An path editor. Key-bindings 't' toggle vertex markers on and off. When vertex markers are on, you can move them, delete them """ showverts = True epsilon = 5 # max pixel distance to count as a vertex hit def __init__(self, pathpatch): self.ax = pathpatch.axes canvas = self.ax.figure.canvas self.pathpatch = pathpatch self.pathpatch.set_animated(True) x, y = zip(*self.pathpatch.get_path().vertices) self.line, = ax.plot(x,y,marker='o', markerfacecolor='r', animated=True) self._ind = None # the active vert canvas.mpl_connect('draw_event', self.draw_callback) canvas.mpl_connect('button_press_event', self.button_press_callback) canvas.mpl_connect('key_press_event', self.key_press_callback) canvas.mpl_connect('button_release_event', self.button_release_callback) canvas.mpl_connect('motion_notify_event', self.motion_notify_callback) self.canvas = canvas def draw_callback(self, event): self.background = self.canvas.copy_from_bbox(self.ax.bbox) self.ax.draw_artist(self.pathpatch) self.ax.draw_artist(self.line) self.canvas.blit(self.ax.bbox) def pathpatch_changed(self, pathpatch): 'this method is called whenever the pathpatchgon object is called' # only copy the artist props to the line (except visibility) vis = self.line.get_visible() plt.Artist.update_from(self.line, pathpatch) self.line.set_visible(vis) # don't use the pathpatch visibility state def get_ind_under_point(self, event): 'get the index of the vertex under point if within epsilon tolerance' # display coords xy = np.asarray(self.pathpatch.get_path().vertices) xyt = self.pathpatch.get_transform().transform(xy) xt, yt = xyt[:, 0], xyt[:, 1] d = np.sqrt((xt-event.x)**2 + (yt-event.y)**2) ind = d.argmin() if d[ind]>=self.epsilon: ind = None return ind def button_press_callback(self, event): 'whenever a mouse button is pressed' if not self.showverts: return if event.inaxes==None: return if event.button != 1: return self._ind = self.get_ind_under_point(event) def button_release_callback(self, event): 'whenever a mouse button is released' if not self.showverts: return if event.button != 1: return self._ind = None def key_press_callback(self, event): 'whenever a key is pressed' if not event.inaxes: return if event.key=='t': self.showverts = not self.showverts self.line.set_visible(self.showverts) if not self.showverts: self._ind = None self.canvas.draw() def motion_notify_callback(self, event): 'on mouse movement' if not self.showverts: return if self._ind is None: return if event.inaxes is None: return if event.button != 1: return x,y = event.xdata, event.ydata vertices = self.pathpatch.get_path().vertices vertices[self._ind] = x,y self.line.set_data(zip(*vertices)) self.canvas.restore_region(self.background) self.ax.draw_artist(self.pathpatch) self.ax.draw_artist(self.line) self.canvas.blit(self.ax.bbox) interactor = PathInteractor(patch) ax.set_title('drag vertices to update path') ax.set_xlim(-3,4) ax.set_ylim(-3,4) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)