matplotlib:修补补丁的位置(或:圆圈的set_xy)

Question

受此示例的启发,我正在尝试编写一个小的matplotlib程序,该程序允许用户动态地在散点图中拖放数据点.与使用条形图(因此允许拖动矩形)的示例相比,我的目标是与其他补丁实现相同,例如圆形(任何与矩形相比更具散射图兼容性的补丁) ).但是我仍然坚持更新我的补丁的位置.虽然a Rectangle提供了一个功能,但set_xy我找不到直接模拟Cirlce或Ellipse.获得圆的位置对于矩形也不那么简单,但是可以通过获得边界框来实现.现在缺少的部分是找到一种方法来更新补丁的位置.任何关于如何实现这一点的提示都会很棒!当前最小的工作示例如下所示:

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches

class DraggablePatch:

  def __init__(self, patch):
    self.patch = patch
    self.storedPosition = None
    self.connect()

  def getPosOfPatch(self, marker):
    ext = marker.get_extents().get_points()
    x0 = ext[0,0]
    y0 = ext[0,1]
    x1 = ext[1,0]
    y1 = ext[1,1]
    return 0.5*(x0+x1), 0.5*(y0+y1)

  def connect(self):
    'connect to all the events we need'
    self.cidpress  = self.patch.figure.canvas.mpl_connect('button_press_event',  self.onPress)
    self.cidmotion = self.patch.figure.canvas.mpl_connect('motion_notify_event', self.onMove)

  def onPress(self, event):
    'on button press we will see if the mouse is over us and store some data'
    contains, attrd = self.patch.contains(event)
    if contains:
      self.storedPosition = self.getPosOfPatch(self.patch), event.xdata, event.ydata

  def onMove(self, event):
    'how to update an circle?!'
    contains, attrd = self.patch.contains(event)
    if contains and self.storedPosition is not None:
      oldPos, oldEventXData, oldEventYData = self.storedPosition
      dx = event.xdata - oldEventXData
      dy = event.ydata - oldEventYData
      newX = oldPos[0] + dx
      newY = oldPos[1] + dy
      print "now I would like to move my patch to", newX, newY


def myPatch(x,y): 
  return patches.Circle((x,y), radius=.05, alpha=0.5)

N = 10
x = np.random.random(N)
y = np.random.random(N)
patches = [myPatch(x[i], y[i]) for i in range(N)]

fig = plt.figure()
ax = fig.add_subplot(111)
drs = []
for patch in patches:
  ax.add_patch(patch)
  dr = DraggablePatch(patch)
  drs.append(dr)

plt.show()

Answer 1

它有点恼人,它不一致,但更新圆的位置,设置circ.center = new_x, new_y.

作为一个简单的(不可拖动的)示例:

import matplotlib.pyplot as plt
from matplotlib.patches import Circle

class InteractiveCircle(object):
    def __init__(self):
        self.fig, self.ax = plt.subplots()
        self.ax.axis('equal')

        self.circ = Circle((0.5, 0.5), 0.1)
        self.ax.add_artist(self.circ)
        self.ax.set_title('Click to move the circle')

        self.fig.canvas.mpl_connect('button_press_event', self.on_click)

    def on_click(self, event):
        if event.inaxes is None:
            return
        self.circ.center = event.xdata, event.ydata
        self.fig.canvas.draw()

    def show(self):
        plt.show()


InteractiveCircle().show()