python - 正确使用 Matplotlib 的 pick 事件

Question

我相信我没有正确使用 Matplotlib 的选择事件。在下面的代码中，我创建了三个不相交的橙色圆盘，它们具有指定的半径和由 ID 号标识的位置。

我想单击-单击每个磁盘并向终端打印一条消息，标识磁盘、中心、半径和 ID。但是，每次我单击磁盘时，都会触发所有 磁盘的拾取事件。我哪里错了？

这是剧情

这是点击磁盘 1 的输出

这是代码。

from global_config import GC
import matplotlib as mpl
import matplotlib.pyplot as plt 
import numpy as np


class Disk:


    def __init__(self, center, radius, myid = None, figure=None, axes_object=None):
        """ 
        @ARGS
        CENTER : Tuple of floats
        RADIUS : Float
        """
        self.center = center
        self.radius = radius
        self.fig    = figure
        self.ax     = axes_object
        self.myid   = myid

    def onpick(self,event):
        print "You picked the disk ", self.myid, "  with Center: ", self.center, " and Radius:", self.radius


    def mpl_patch(self, diskcolor= 'orange' ):
        """ Return a Matplotlib patch of the object
        """
        mypatch =  mpl.patches.Circle( self.center, self.radius, facecolor = diskcolor, picker=1 )

        if self.fig != None:
            self.fig.canvas.mpl_connect('pick_event', self.onpick) # Activate the object's method

        return mypatch



def main():

    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.set_title('click on disks to print out a message')

    disk_list = []

    disk_list.append( Disk( (0,0), 1.0, 1, fig, ax   )   ) 
    ax.add_patch(disk_list[-1].mpl_patch() )

    disk_list.append( Disk( (3,3), 0.5, 2, fig, ax   )   )
    ax.add_patch(disk_list[-1].mpl_patch() )

    disk_list.append( Disk( (4,9), 2.5, 3, fig, ax   )   )
    ax.add_patch(disk_list[-1].mpl_patch() )


    ax.set_ylim(-2, 10);
    ax.set_xlim(-2, 10);

    plt.show()


if __name__ == "__main__":
    main()

Answer 1

有很多方法可以解决这个问题。我已经修改了您的代码以尝试显示两种可能的方式(因此它具有无关的代码，尽管您希望以哪种方式处理它)。

一般来说，我认为您只需附加一个 pick_event 处理程序，并且该处理程序需要确定哪个对象被击中。下面的代码以这种方式工作on_pick 函数捕获您的磁盘和补丁，然后返回一个函数来判断单击了哪个数字。

如果您想坚持附加多个 pick_event 处理程序，您可以通过调整 Disk.onpick 来实现，如下所示以确定 pick 事件是否相关到这个磁盘(每个磁盘都会得到每个选择事件)。您会注意到 Disk 类在 self.mypatch 中保存了它的补丁以使其工作。如果您想这样做，请放弃我对 main 所做的所有更改，并取消注释 Disk.mpl_patch 中的两行。

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


class Disk:


    def __init__(self, center, radius, myid = None, figure=None, axes_object=None):
        """ 
        @ARGS
        CENTER : Tuple of floats
        RADIUS : Float
        """
        self.center = center
        self.radius = radius
        self.fig    = figure
        self.ax     = axes_object
        self.myid   = myid
        self.mypatch = None


    def onpick(self,event):
        if event.artist == self.mypatch:
            print "You picked the disk ", self.myid, "  with Center: ", self.center, " and Radius:", self.radius


    def mpl_patch(self, diskcolor= 'orange' ):
        """ Return a Matplotlib patch of the object
        """
        self.mypatch = mpl.patches.Circle( self.center, self.radius, facecolor = diskcolor, picker=1 )

        #if self.fig != None:
            #self.fig.canvas.mpl_connect('pick_event', self.onpick) # Activate the object's method

        return self.mypatch

def on_pick(disks, patches):
    def pick_event(event):
        for i, artist in enumerate(patches):
            if event.artist == artist:
                disk = disks[i]
                print "You picked the disk ", disk.myid, "  with Center: ", disk.center, " and Radius:", disk.radius
    return pick_event


def main():

    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.set_title('click on disks to print out a message')

    disk_list = []
    patches = []

    disk_list.append( Disk( (0,0), 1.0, 1, fig, ax   )   ) 
    patches.append(disk_list[-1].mpl_patch())
    ax.add_patch(patches[-1])

    disk_list.append( Disk( (3,3), 0.5, 2, fig, ax   )   )
    patches.append(disk_list[-1].mpl_patch())
    ax.add_patch(patches[-1])

    disk_list.append( Disk( (4,9), 2.5, 3, fig, ax   )   )
    patches.append(disk_list[-1].mpl_patch()) 
    ax.add_patch(patches[-1])

    pick_handler = on_pick(disk_list, patches)

    fig.canvas.mpl_connect('pick_event', pick_handler) # Activate the object's method

    ax.set_ylim(-2, 10);
    ax.set_xlim(-2, 10);

    plt.show()


if __name__ == "__main__":
    main()