問題描述

我想實時跟蹤鼠標在 matplot 畫布上的位置.

I want to track the mouse's position over a matplot's canvas in real-time.

現在，我構建了一個繼承 Qwidget(像容器一樣)的 MplWidget，然后在它上面構建了一個畫布來顯示繪圖.但是，問題是我只能在除畫布區域之外的填充區域中跟蹤鼠標的位置.

For now, I built a MplWidget that inherits the Qwidget (act like a container), then built a canvas over it to show the plot. However, the problem is that I can only track the mouse's position in the padding area except for the canvas area.

由于我的畫布繼承了不是 QWidget 的 matplotlib.figure，因此它沒有 setMouseTracking() 屬性.這樣，如何解決這個問題?

Since my canvas inherits the matplotlib.figure that is not a QWidget, thus it doesn't have the setMouseTracking() attribute. In this way, how to resolve this issue?

我發現了一個非常有用的鏈接如何實時返回鼠標坐標?.然而，它也面臨同樣的問題.當鼠標在標簽(文本區域)上時，跟蹤功能似乎被中斷了.

I found a quite useful link How to return mouse coordinates in realtime?. However, it also suffers the same issue. When the mouse is over the label (text area), the tracking function seems to be interrupted.

我的這個類的代碼如下所示:

my code for this class shown here:

from PyQt5.QtWidgets import *

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas

from matplotlib.figure import Figure


class MplWidget(QWidget):

    def __init__(self, parent=None):
        # QWidget.__init__(self, parent)
        super(QWidget, self).__init__(parent)

        self.canvas = FigureCanvas(Figure())

        vertical_layout = QVBoxLayout()
        vertical_layout.addWidget(self.canvas)

        self.canvas.axes = self.canvas.figure.add_subplot(111)
        self.setLayout(vertical_layout)

        self.setMouseTracking(True)

    def mouseMoveEvent(self, e):
        text = "x: {0},  y: {1}".format(e.x(), e.y())
        print(text)
        super(MplWidget, self).mouseMoveEvent(e)

    def mousePressEvent(self, e):
        print('click!')

推薦答案

您已經注意到畫布不是由 Qt 而是由 matplotlib 處理的，因此解決方案是使用該庫提供的事件，如果您查看 文檔 你看到有以下事件:

As you have noticed the canvas is not handled by Qt but by matplotlib so the solution is to use the events provided by that library, if you review the docs you see that there are the following events:

事件名稱 類別和描述

'button_press_event'  MouseEvent - mouse button is pressed
'button_release_event'    MouseEvent - mouse button is released
'draw_event'  DrawEvent - canvas draw (but before screen update)
'key_press_event' KeyEvent - key is pressed
'key_release_event'   KeyEvent - key is released
'motion_notify_event' MouseEvent - mouse motion
'pick_event'  PickEvent - an object in the canvas is selected
'resize_event'    ResizeEvent - figure canvas is resized
'scroll_event'    MouseEvent - mouse scroll wheel is rolled
'figure_enter_event'  LocationEvent - mouse enters a new figure
'figure_leave_event'  LocationEvent - mouse leaves a figure
'axes_enter_event'    LocationEvent - mouse enters a new axes
'axes_leave_event'    LocationEvent - mouse leaves an axes

在您的情況下，您應該使用事件:

In your case you should use the events:

• button_press_event
• button_release_event
• motion_notify_event

例子:

from PyQt5 import QtWidgets

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure


class MplWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(MplWidget, self).__init__(parent)
        self.canvas = FigureCanvas(Figure())

        vertical_layout = QtWidgets.QVBoxLayout(self)
        vertical_layout.addWidget(self.canvas)

        self.canvas.axes = self.canvas.figure.add_subplot(111)

        self.canvas.mpl_connect("button_press_event", self.on_press)
        self.canvas.mpl_connect("button_release_event", self.on_release)
        self.canvas.mpl_connect("motion_notify_event", self.on_move)

    def on_press(self, event):
        print("press")
        print("event.xdata", event.xdata)
        print("event.ydata", event.ydata)
        print("event.inaxes", event.inaxes)
        print("x", event.x)
        print("y", event.y)

    def on_release(self, event):
        print("release:")
        print("event.xdata", event.xdata)
        print("event.ydata", event.ydata)
        print("event.inaxes", event.inaxes)
        print("x", event.x)
        print("y", event.y)

    def on_move(self, event):
        print("move")
        print("event.xdata", event.xdata)
        print("event.ydata", event.ydata)
        print("event.inaxes", event.inaxes)
        print("x", event.x)
        print("y", event.y)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = MplWidget()
    w.show()
    sys.exit(app.exec_())

這篇關于如何在 QWidget 中的 matplot 畫布上跟蹤鼠標?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！