Python terminal time-series plots

terminal_plots.py

"""
-- Use example in ROS2 terminal:
self.get_logger().info(f"X: {plot_bipolar(self.kf.x[3])}, Y: {plot_bipolar(self.kf.x[4])}, Z: {plot_bipolar(self.kf.x[5])}")

-- Output:
[INFO] [1740172663.636000550]: X: |..........|@.........|, Y: |..........|..........|, Z: |..........|..........|
[INFO] [1740172663.685122760]: X: |..........|@@........|, Y: |..........|@.........|, Z: |..........|..........|
[INFO] [1740172663.735189229]: X: |..........|@@........|, Y: |..........|@.........|, Z: |..........|@.........|
[INFO] [1740172663.785187161]: X: |..........|@.........|, Y: |..........|@@........|, Z: |..........|@@........|
[INFO] [1740172663.836043554]: X: |..........|..........|, Y: |..........|@@........|, Z: |..........|@@........|
[INFO] [1740172663.885599439]: X: |........@@|..........|, Y: |..........|@@@.......|, Z: |..........|@.........|
[INFO] [1740172663.936368587]: X: |.......@@@|..........|, Y: |..........|@@@.......|, Z: |..........|..........|
[INFO] [1740172664.036233326]: X: |.......@@@|..........|, Y: |..........|@@@.......|, Z: |.........@|..........|
[INFO] [1740172664.085884790]: X: |.......@@@|..........|, Y: |..........|@@@.......|, Z: |.......@@@|..........|
[INFO] [1740172664.135952420]: X: |.........@|..........|, Y: |..........|@@@.......|, Z: |.......@@@|..........|
[INFO] [1740172664.185436597]: X: |..........|..........|, Y: |..........|@@@@......|, Z: |.......@@@|..........|
[INFO] [1740172664.235322967]: X: |..........|@@........|, Y: |..........|@@@@......|, Z: |........@@|..........|
[INFO] [1740172664.284865093]: X: |..........|@@@.......|, Y: |..........|@@@@@.....|, Z: |..........|..........|
[INFO] [1740172664.335568914]: X: |..........|@@@@......|, Y: |..........|@@@@@@....|, Z: |..........|..........|
[INFO] [1740172664.384939519]: X: |..........|@@@@......|, Y: |..........|@@@@@@....|, Z: |..........|@.........|
[INFO] [1740172664.435073784]: X: |..........|@@@.......|, Y: |..........|@@@@@@@...|, Z: |..........|@@........|
[INFO] [1740172664.484868278]: X: |..........|@@........|, Y: |..........|@@@@@@@...|, Z: |..........|@@@.......|
[INFO] [1740172664.534943600]: X: |..........|@.........|, Y: |..........|@@@@@@@@..|, Z: |..........|@@........|
[INFO] [1740172664.584550877]: X: |..........|..........|, Y: |..........|@@@@@@@@..|, Z: |..........|@.........|
[INFO] [1740172664.635254544]: X: |..........|..........|, Y: |..........|@@@@@@@@@.|, Z: |..........|..........|
[INFO] [1740172664.685434040]: X: |..........|..........|, Y: |..........|@@@@@@@@@.|, Z: |.........@|..........|
[INFO] [1740172664.735551564]: X: |..........|..........|, Y: |..........|@@@@@@@@@.|, Z: |........@@|..........|
[INFO] [1740172664.786323921]: X: |..........|@@........|, Y: |..........|@@@@@@@@@.|, Z: |.......@@@|..........|
[INFO] [1740172664.835487208]: X: |..........|@@@@......|, Y: |..........|@@@@@@@@@@|, Z: |.......@@@|..........|
[INFO] [1740172664.885027330]: X: |..........|@@@@@.....|, Y: |..........|@@@@@@@@@@|, Z: |........@@|..........|
[INFO] [1740172664.935182178]: X: |..........|@@@@@@@...|, Y: |..........|@@@@@@@@@@|, Z: |..........|..........|

        ...etc...
"""

def plot_bipolar(val: float, max: float = 1.0, width: int = 20) -> str:
    """
    Plot a number as a horizontal bar centered at zero.
    Useful when logging fast moving time series data in a terminal
    that would be hard to read as floating point numbers

    Example for val = 0.4:
        |..........|@@@@......|
    Example for val = -0.4:
        |......@@@@|..........|
    """
    half_w = width // 2
    n_filled = int(min(abs(val),max) / max * half_w)
    l = '@' * n_filled if val < 0.0 else ''
    r = '@' * n_filled if val > 0.0 else ''

    return f"|{l:.>{half_w}}{"|"}{r:.<{half_w}}|"

def plot_positive(val: float, max: float = 1.0, width: int = 20) -> str:
    """
    Plot a number on a scale from 0 to max as a simple bar.
    Useful when logging fast moving time series data in a terminal
    that would be hard to read as floating point numbers

    Example for val = 0.4
        |@@@@@@@@............|
    """
    n_filled = int(min(val,max) / max * width)
    r = '@' * n_filled
    return f"|{r:.<{width}}|"