matplotlib 介绍之event 交互

上一篇文章粗略介绍了一下matplotlib的基本概念,见matplotlib 初步介绍

之所以写这篇,是记录一下自己对matplotlib中的event的event交互的学习及使用

下面就event交互来介绍我的真实使用情况
这里面的交互用到了两个,pick_eventkey_press_event,实现的功能是想要在线上面可以标注并设定区域,下面是标注类的代码和注释

class MarkState(object):

    def __init__(self):
        self.start = 0 # 区域的起始点
        self.end = 0 # 区域的结束点
        self.state = 0 # 区域的状态
        self.states = ['1', '2', '3']  # 接受的状态
        self.picked = [] # 当前选择的点
        self.vspans = [] # 垂直区域
        self.vlines = [] # 垂直线
        self.linedict = {} # 对应x轴坐标到vlines中的对应的index
        self.steps = [] # 各个步骤(用于撤销操作)
    
    def _reset(self): # 重置参数(重新画图)
        self.linedict.clear()
        self.vspans = []
        self.vlines = []
        self.picked = []
        self.steps = []

    def PointPick(self, event): # 画垂直线
        ind = event.ind # 这里注意一点,当途中点击的点比较密集时,可能一次点击会选中多个点,此时ind是list(ind是此时点击到的点的编号)
        if len(ind) > 1:
            ind = ind[int(len(ind)/2)] # 多个点选中时,取中间点
            # 或者像下面这样输出提示信息,让用户放大之后选
            # print('Please zoom in to pick') 
            # return 
        x_axis = int((event.artist.get_xdata())[ind]) # 取到点的x轴坐标
        # 记住不要在中文输入法pick操作,可能存在问题(例如会触发两次pick event)
        if x_axis in self.picked:  # pick已存在的点会触发消除操作
            self.picked.remove(x_axis)
            print('Remove point %d, picked: ' % x_axis, self.picked)
            self.vlines[self.linedict[x_axis]].remove()
            del self.vlines[self.linedict[x_axis]]
            del self.linedict[x_axis]
            plt.draw()
            return

        if len(self.picked) >= 2:
            print( 'Too many points picked, picked: ', self.picked)
            return

        self.picked.append(x_axis)
        print('Add point %d, picked: ' % x_axis, self.picked)
        ax_line = ax.axvline(x_axis, color = 'black')
        self.vlines.append(ax_line)
        self.linedict[x_axis] = len(self.vlines) - 1
        ele = {}
        ele['type'] = 'line'
        ele['ele'] = ax_line
        ele['value'] = x_axis
        self.steps.append(ele) # 记录这一步的操作,便于undo操作
        plt.draw()

    def StateSet(self, event): # 画垂直区域,key press event
        if event.key == '0': # 重新画图
            self._resetAx()
            plt.draw()
            print('Reset!')
            return
        if event.key == 'w': # 撤销上一步
            self._undo()
            plt.draw()
            print('Undo last step, picked:', self.picked)
            return
        if len(self.picked) < 2: # 不会出现大于2的情况
            print('Too less points selected, %d point(s) has been picked, picked' % len(self.picked), self.picked)
            return
        if event.key not in self.states: # 不在预设值的几个状态里面
            return
        self.state = event.key
        self.start = min(self.picked)
        self.end = max(self.picked)
        color = { # 不同状态垂直区域标注不同颜色
                '1': 'xkcd:light blue',
                '2': 'xkcd:light green',
                '3': 'xkcd:light purple',
                }
        span = ax.axvspan(self.start, self.end, facecolor = color[self.state], alpha=0.5) # alpha是透明度,0透明
        self.vspans.append(span)
        print(self.picked, 'is set to state %s' % self.state)
        ele = {}
        ele['type'] = 'span'
        ele['ele'] = span
        ele['start'] = self.start
        ele['end'] = self.end
        self.steps.append(ele)
        self.picked = [] # 画完垂直区域后将picker清空
        print('picked:', self.picked)
        # 重新画图
        plt.draw()

    def _resetAx(self):
        # for i in self.vspans:
        #     i.remove()
        # for i in self.vlines:
        #     i.remove()
        for i in self.steps:
            i['ele'].remove()
        self._reset()

    def _undo(self): # 撤销上一步
        if len(self.steps) == 0:
            print('no more operation')
            return
        self.steps[-1]['ele'].remove()
        if self.steps[-1]['type'] == 'line':
            if self.steps[-1]['value'] in self.picked:
                self.picked.remove(self.steps[-1]['value'])
        elif self.steps[-1]['type'] == 'span': #如果撤销的是区域,需要将该区域的start和end加入到picked中去
            self.picked = []
            self.picked.append(self.steps[-1]['start'])
            self.picked.append(self.steps[-1]['end'])
        del self.steps[-1]

可执行代码如下

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

fig, ax = plt.subplots()

class MarkState(object):

    def __init__(self):
        self.start = 0 # 区域的起始点
        self.end = 0 # 区域的结束点
        self.state = 0 # 区域的状态
        self.states = ['1', '2', '3']  # 接受的状态
        self.picked = [] # 当前选择的点
        self.vspans = [] # 垂直区域
        self.vlines = [] # 垂直线
        self.linedict = {} # 对应x轴坐标到vlines中的对应的index
        self.steps = [] # 各个步骤(用于撤销操作)
    
    def _reset(self): # 重置参数(重新画图)
        self.linedict.clear()
        self.vspans = []
        self.vlines = []
        self.picked = []
        self.steps = []

    def PointPick(self, event): # 画垂直线
        ind = event.ind # 这里注意一点,当途中点击的点比较密集时,可能一次点击会选中多个点,此时ind是list(ind是此时点击到的点的编号)
        if len(ind) > 1:
            ind = ind[int(len(ind)/2)] # 多个点选中时,取中间点
            # 或者像下面这样输出提示信息,让用户放大之后选
            # print('Please zoom in to pick') 
            # return 
        x_axis = int((event.artist.get_xdata())[ind]) # 取到点的x轴坐标
        # 记住不要在中文输入法pick操作,可能存在问题(例如会触发两次pick event)
        if x_axis in self.picked:  # pick已存在的点会触发消除操作
            self.picked.remove(x_axis)
            print('Remove point %d, picked: ' % x_axis, self.picked)
            self.vlines[self.linedict[x_axis]].remove()
            del self.vlines[self.linedict[x_axis]]
            del self.linedict[x_axis]
            plt.draw()
            return

        if len(self.picked) >= 2:
            print( 'Too many points picked, picked: ', self.picked)
            return

        self.picked.append(x_axis)
        print('Add point %d, picked: ' % x_axis, self.picked)
        ax_line = ax.axvline(x_axis, color = 'black')
        self.vlines.append(ax_line)
        self.linedict[x_axis] = len(self.vlines) - 1
        ele = {}
        ele['type'] = 'line'
        ele['ele'] = ax_line
        ele['value'] = x_axis
        self.steps.append(ele) # 记录这一步的操作,便于undo操作
        plt.draw()

    def StateSet(self, event): # 画垂直区域,key press event
        if event.key == '0': # 重新画图
            self._resetAx()
            plt.draw()
            print('Reset!')
            return
        if event.key == 'w': # 撤销上一步
            self._undo()
            plt.draw()
            print('Undo last step, picked:', self.picked)
            return
        if len(self.picked) < 2: # 不会出现大于2的情况
            print('Too less points selected, %d point(s) has been picked, picked' % len(self.picked), self.picked)
            return
        if event.key not in self.states: # 不在预设值的几个状态里面
            return
        self.state = event.key
        self.start = min(self.picked)
        self.end = max(self.picked)
        color = { # 不同状态垂直区域标注不同颜色
                '1': 'xkcd:light blue',
                '2': 'xkcd:light green',
                '3': 'xkcd:light purple',
                }
        span = ax.axvspan(self.start, self.end, facecolor = color[self.state], alpha=0.5) # alpha是透明度,0透明
        self.vspans.append(span)
        print(self.picked, 'is set to state %s' % self.state)
        ele = {}
        ele['type'] = 'span'
        ele['ele'] = span
        ele['start'] = self.start
        ele['end'] = self.end
        self.steps.append(ele)
        self.picked = []
        print('picked:', self.picked)
        # 重新画图
        plt.draw()

    def _resetAx(self):
        # for i in self.vspans:
        #     i.remove()
        # for i in self.vlines:
        #     i.remove()
        for i in self.steps:
            i['ele'].remove()
        self._reset()

    def _undo(self): # 撤销上一步
        if len(self.steps) == 0:
            print('no more operation')
            return
        self.steps[-1]['ele'].remove()
        if self.steps[-1]['type'] == 'line':
            if self.steps[-1]['value'] in self.picked:
                self.picked.remove(self.steps[-1]['value'])
        elif self.steps[-1]['type'] == 'span': #如果撤销的是区域,需要将该区域的start和end加入到picked中去
            self.picked = []
            self.picked.append(self.steps[-1]['start'])
            self.picked.append(self.steps[-1]['end'])
        del self.steps[-1]


if __name__ == '__main__':
    mark = MarkState()
    fig.canvas.mpl_connect('pick_event', mark.PointPick)

    fig.canvas.mpl_connect('key_press_event', mark.StateSet)

    df = pd.DataFrame(np.random.randint(0,6,(1,14)), index=['x'])

    # plot函数作图
    tension = list(df.loc['x'])

    data = list(range(14))

    ax.plot(data, tension, 'o', picker=5)  
    ax.plot(data, tension, color='red', linewidth=1)
    print(ax.lines)

    plt.show()  

实现效果如下

运行后生成
(某些原因图片无法上传,下次再传)

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