路径编辑器

跨GUI共享事件。

此示例演示了使用Matplotlib事件处理与画布上的对象进行交互和修改对象的跨GUI应用程序。

路径编辑器示例

  1. import numpy as np
  2. import matplotlib.path as mpath
  3. import matplotlib.patches as mpatches
  4. import matplotlib.pyplot as plt
  6. Path = mpath.Path
  8. fig, ax = plt.subplots()
  10. pathdata = [
  11.     (Path.MOVETO, (1.58, -2.57)),
  12.     (Path.CURVE4, (0.35, -1.1)),
  13.     (Path.CURVE4, (-1.75, 2.0)),
  14.     (Path.CURVE4, (0.375, 2.0)),
  15.     (Path.LINETO, (0.85, 1.15)),
  16.     (Path.CURVE4, (2.2, 3.2)),
  17.     (Path.CURVE4, (3, 0.05)),
  18.     (Path.CURVE4, (2.0, -0.5)),
  19.     (Path.CLOSEPOLY, (1.58, -2.57)),
  20.     ]
  22. codes, verts = zip(*pathdata)
  23. path = mpath.Path(verts, codes)
  24. patch = mpatches.PathPatch(path, facecolor='green', edgecolor='yellow', alpha=0.5)
  25. ax.add_patch(patch)
  28. class PathInteractor(object):
  29.     """
  30.     An path editor.
  32.     Key-bindings
  34.       't' toggle vertex markers on and off.  When vertex markers are on,
  35.           you can move them, delete them
  38.     """
  40.     showverts = True
  41.     epsilon = 5  # max pixel distance to count as a vertex hit
  43.     def __init__(self, pathpatch):
  45.         self.ax = pathpatch.axes
  46.         canvas = self.ax.figure.canvas
  47.         self.pathpatch = pathpatch
  48.         self.pathpatch.set_animated(True)
  50.         x, y = zip(*self.pathpatch.get_path().vertices)
  52.         self.line, = ax.plot(x, y, marker='o', markerfacecolor='r', animated=True)
  54.         self._ind = None  # the active vert
  56.         canvas.mpl_connect('draw_event', self.draw_callback)
  57.         canvas.mpl_connect('button_press_event', self.button_press_callback)
  58.         canvas.mpl_connect('key_press_event', self.key_press_callback)
  59.         canvas.mpl_connect('button_release_event', self.button_release_callback)
  60.         canvas.mpl_connect('motion_notify_event', self.motion_notify_callback)
  61.         self.canvas = canvas
  63.     def draw_callback(self, event):
  64.         self.background = self.canvas.copy_from_bbox(self.ax.bbox)
  65.         self.ax.draw_artist(self.pathpatch)
  66.         self.ax.draw_artist(self.line)
  67.         self.canvas.blit(self.ax.bbox)
  69.     def pathpatch_changed(self, pathpatch):
  70.         'this method is called whenever the pathpatchgon object is called'
  71.         # only copy the artist props to the line (except visibility)
  72.         vis = self.line.get_visible()
  73.         plt.Artist.update_from(self.line, pathpatch)
  74.         self.line.set_visible(vis)  # don't use the pathpatch visibility state
  76.     def get_ind_under_point(self, event):
  77.         'get the index of the vertex under point if within epsilon tolerance'
  79.         # display coords
  80.         xy = np.asarray(self.pathpatch.get_path().vertices)
  81.         xyt = self.pathpatch.get_transform().transform(xy)
  82.         xt, yt = xyt[:, 0], xyt[:, 1]
  83.         d = np.sqrt((xt - event.x)**2 + (yt - event.y)**2)
  84.         ind = d.argmin()
  86.         if d[ind] >= self.epsilon:
  87.             ind = None
  89.         return ind
  91.     def button_press_callback(self, event):
  92.         'whenever a mouse button is pressed'
  93.         if not self.showverts:
  94.             return
  95.         if event.inaxes is None:
  96.             return
  97.         if event.button != 1:
  98.             return
  99.         self._ind = self.get_ind_under_point(event)
  101.     def button_release_callback(self, event):
  102.         'whenever a mouse button is released'
  103.         if not self.showverts:
  104.             return
  105.         if event.button != 1:
  106.             return
  107.         self._ind = None
  109.     def key_press_callback(self, event):
  110.         'whenever a key is pressed'
  111.         if not event.inaxes:
  112.             return
  113.         if event.key == 't':
  114.             self.showverts = not self.showverts
  115.             self.line.set_visible(self.showverts)
  116.             if not self.showverts:
  117.                 self._ind = None
  119.         self.canvas.draw()
  121.     def motion_notify_callback(self, event):
  122.         'on mouse movement'
  123.         if not self.showverts:
  124.             return
  125.         if self._ind is None:
  126.             return
  127.         if event.inaxes is None:
  128.             return
  129.         if event.button != 1:
  130.             return
  131.         x, y = event.xdata, event.ydata
  133.         vertices = self.pathpatch.get_path().vertices
  135.         vertices[self._ind] = x, y
  136.         self.line.set_data(zip(*vertices))
  138.         self.canvas.restore_region(self.background)
  139.         self.ax.draw_artist(self.pathpatch)
  140.         self.ax.draw_artist(self.line)
  141.         self.canvas.blit(self.ax.bbox)
  144. interactor = PathInteractor(patch)
  145. ax.set_title('drag vertices to update path')
  146. ax.set_xlim(-3, 4)
  147. ax.set_ylim(-3, 4)
  149. plt.show()

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