如何从 Matplotlib 散点图图形中获取 x y 坐标

Question

我的 GUI 中有一个 Widget 托管散点图。我设法包含了一个 pick event 但我无法通过单击只有 print('yahoo') 有效的图来获取 x y 坐标。我的代码基于以下文章：see link（部分：简单采摘示例）。如何通过单击散点图上的点来获取点的坐标（例如 x=20 和 y=50，这是我的五个点之一）？

前端代码：

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(595, 393)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.gridLayout = QtWidgets.QGridLayout(self.centralwidget)
        self.gridLayout.setObjectName("gridLayout")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setMaximumSize(QtCore.QSize(100, 16777215))
        self.pushButton.setObjectName("pushButton")
        self.gridLayout.addWidget(self.pushButton, 0, 0, 1, 1)
        self.widget = QtWidgets.QWidget(self.centralwidget)
        self.widget.setMinimumSize(QtCore.QSize(0, 200))
        self.widget.setStyleSheet("background-color: rgb(255, 255, 255);")
        self.widget.setObjectName("widget")
        self.gridLayout.addWidget(self.widget, 0, 1, 1, 1)
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 595, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

后端代码：

import sys
import matplotlib.pyplot as plt
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QMainWindow, QApplication, QWidget, QSizePolicy
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
from matplotlib.figure import Figure
from front_end import Ui_MainWindow


class Graph_init(FigureCanvas):

    def __init__(self, parent=None):

        fig = Figure()
        fig.patch.set_facecolor("None")
        self.axes = fig.add_subplot(111)
        self.compute_initial_figure()

        FigureCanvas.__init__(self, fig)
        self.setParent(parent)

        FigureCanvas.setSizePolicy(self, QSizePolicy.Expanding, QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)

        FigureCanvas.mpl_connect(self, 'pick_event', self.onclick)

    def onclick(self, event):
        print('yahoo')
        thisline = self.event.artist
        xdata = thisline.get_xdata()
        ydata = thisline.get_ydata()


class Graph_populate(Graph_init):

    def compute_initial_figure(self):

        x = [10,20,30,40,50]
        y = [100,50,150,200,75]
        size = [1000,2000,3000,5000,2000]

        self.axes.scatter(x,y,s=size,color='blue', picker=1)
        self.axes.patch.set_facecolor('None')


class GUI(QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super(GUI, self).__init__(parent)
        self.setupUi(self)
        self.sc = Graph_populate(self.widget)
        self.gridLayout.addWidget(self.sc, 0, 1, 1, 1)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    prog = GUI()
    prog.showMaximized()
    sys.exit(app.exec_())

谢谢

Answer 1

您正在绘制散点图。因此，您可以查看 pick_event_demo 的第三部分，其中处理了散点图。

想法是获取所选数据点的索引并将该索引处的数据取出以获得坐标。

def onclick(self, event):
    ind = event.ind[0]
    data = event.artist.get_offsets()
    xdata, ydata = data[ind,:]
    print ((xdata, ydata))

请注意，这些是数据点的坐标，而不是鼠标点击的坐标（我是这样理解这个问题的）。

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