.. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_event_handling_path_editor.py: =========== Path Editor =========== Sharing events across GUIs. This example demonstrates a cross-GUI application using Matplotlib event handling to interact with and modify objects on the canvas. .. image:: /gallery/event_handling/images/sphx_glr_path_editor_001.png :alt: drag vertices to update path :class: sphx-glr-single-img .. code-block:: default import numpy as np from matplotlib.backend_bases import MouseButton from matplotlib.path import Path from matplotlib.patches import PathPatch import matplotlib.pyplot as plt 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 = Path(verts, codes) patch = PathPatch( path, facecolor='green', edgecolor='yellow', alpha=0.5) ax.add_patch(patch) class PathInteractor: """ An path editor. Press 't' to toggle vertex markers on and off. When vertex markers are on, they can be dragged with the mouse. """ 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 vertex canvas.mpl_connect('draw_event', self.on_draw) canvas.mpl_connect('button_press_event', self.on_button_press) canvas.mpl_connect('key_press_event', self.on_key_press) canvas.mpl_connect('button_release_event', self.on_button_release) canvas.mpl_connect('motion_notify_event', self.on_mouse_move) self.canvas = canvas def get_ind_under_point(self, event): """ Return the index of the point closest to the event position or *None* if no point is within ``self.epsilon`` to the event position. """ # 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 on_draw(self, event): """Callback for draws.""" 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 on_button_press(self, event): """Callback for mouse button presses.""" if (event.inaxes is None or event.button != MouseButton.LEFT or not self.showverts): return self._ind = self.get_ind_under_point(event) def on_button_release(self, event): """Callback for mouse button releases.""" if (event.button != MouseButton.LEFT or not self.showverts): return self._ind = None def on_key_press(self, event): """Callback for key presses.""" 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 on_mouse_move(self, event): """Callback for mouse movements.""" if (self._ind is None or event.inaxes is None or event.button != MouseButton.LEFT or not self.showverts): return vertices = self.pathpatch.get_path().vertices vertices[self._ind] = event.xdata, event.ydata 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() .. _sphx_glr_download_gallery_event_handling_path_editor.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: path_editor.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: path_editor.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_