轴 pyqtgraph 中的文本

Question

如何在 pyqtgraph 的垂直轴上添加文本（轴标签除外）。使用 TextItem 时，在 ViewBox 中添加文本而不是在 axesenter image description here

中

Answer 1

从你的描述中不是很清楚，你到底想要什么。我试图在一定程度上重现您在所附屏幕截图中所拥有的内容。只添加 TextItem 很容易，您可以使用 plot_widget.addItem(pg.TextItem()) 来完成。我假设您想将 TextItem 位置与当前绘制的数据连接起来。

我准备了扩展 PlotDataItem 的简短片段，并在右轴上跟随最后绘制的值 TextItem 进行了实时绘图。

示例代码如下：

import sys
from math import sin
from threading import Thread
from time import sleep

from PyQt5.QtCore import pyqtSignal, QPointF
from PyQt5.QtWidgets import QApplication
import pyqtgraph as pg


class MovingLabelPlot(pg.PlotDataItem):
    sig_new_data = pyqtSignal(list, list)
    data_label = None

    def __init__(self, parent, *args, **kargs):
        self.parent = parent
        super().__init__(*args, **kargs)
        # Connect sig_new_data to setData method
        self.sig_new_data.connect(self.setData)
        # Create our data_label
        self.data_label = pg.TextItem(color="white", fill="gray")
        self.data_label.plotted = False

    def setData(self, *args, **kargs):
        if self.data_label is not None:
            # Check if data_label was already plotted
            if not self.data_label.plotted:
                # Add data_label into scene
                self.scene().addItem(self.data_label)
                self.data_label.plotted = True
            # Get view box
            vb = self.getViewBox()
            # Map last x and y point from view to scene coordinates (pixels)
            scene_pos = vb.mapViewToScene(QPointF(args[0][-1], args[1][-1]))
            # Set label text
            self.data_label.setText(f"+  {round(args[1][-1], 5)}")
            label_rect = self.data_label.boundingRect()
            # Set position of the label to the right and mapped y position
            self.data_label.setPos(self.parent.width() - label_rect.width(),
                                   scene_pos.y() - label_rect.height() / 2)
        super().setData(*args, **kargs)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    running = True

    plot_widget = pg.PlotWidget()
    plot_curve = MovingLabelPlot(parent=plot_widget)
    plot_widget.showAxis('right')
    plot_widget.addItem(plot_curve)


    def update_data():
        """Generate sin signal and update plot"""
        x, y = [], []
        index = 0
        while running:
            x.append(index)
            y.append(sin(index * 0.025))
            plot_curve.sig_new_data.emit(y, x)
            index += 1
            sleep(0.01)


    # Start data generator
    Thread(target=update_data).start()
    plot_widget.show()
    app.exec()
    running = False

轴 pyqtgraph 中的文本

text in axes pyqtgraph

python

pyqtgraph