Set InfLineLabel on horizontal infinite line adjacent to y axis.

[JJ]

In the code below, I can't get the label to hug the y axis when the graph is resized. If the graph is resized smaller/larger, the label is truncated or additional space appears between the y axis and the label. Any ideas on how to position the label adjacent to the y axis for all graph sizes?

    import sys

    import numpy as np

    from PyQt5.QtWidgets import QApplication

    import pyqtgraph as pg

    app = QApplication(sys.argv)

    win = pg.GraphicsLayoutWidget(show=True, title="y = exp(x) with Movable Line")

    plot = win.addPlot(title="y = exp(x) with Movable Line")

    x = np.linspace(-2, 2, 1000)

    y = np.exp(x)

    plot.plot(x, y, pen='b')

    # Create a movable infinite horizontal line with a label that updates based on y-position

    h_line = pg.InfiniteLine(pos=1.0, angle=0, movable=True)

    plot.addItem(h_line)

    h_line.label = pg.InfLineLabel(h_line, text=f"y = {h_line.value():.2f}", position=0.05, color='r', fill=(255, 255, 255, 255))

    def update_label():

        h_line.label.setText(f"y = {h_line.value():.2f}")

    h_line.sigPositionChanged.connect(update_label)

    sys.exit(app.exec_())

[Patrick]

Hi JJ,

Try changing the initialisation parameters of the label to

h_line.label = pg.InfLineLabel(h_line, text=f"y = {h_line.value():.2f}", position=0.00, anchors=[(-0.1, 0), (-0.1, 1)], color='r', fill=(255, 255, 255, 255))

The "position" parameter is relative so needs to be zero so it doesn't expand, but the "anchors" parameter is what gives the fixed offset so the label doesn't get clipped by the y-axis.

Patrick