sysplot.plot_angle#

plot_angle(center, point1, point2, text, ax=None, size=75.0, unit='points', textposition='inside', color=None, text_kw=None, **kwargs)[source]#

Draw and label the angle between two vectors.

The angle is formed by the vectors center -> point1 and center -> point2. The visible arc is always circular in display space, and its diameter is controlled by size/unit.

This function is a thin wrapper around Matplotlib’s angle-annotation approach: https://matplotlib.org/stable/gallery/text_labels_and_annotations/angle_annotation.html

Note

Reversing point1 and point2 swaps the direction of the measured arc (useful to show the complementary/outer arc).

Parameters:

center (Sequence[float]) – Arc center (x, y) in data coordinates.
point1 (Sequence[float]) – First point (x, y) defining the first vector from center.
point2 (Sequence[float]) – Second point (x, y) defining the second vector from center.
text (str) – Label drawn near the arc (for example "$\\theta$").
ax (Axes | None) – Target axes. If None, uses matplotlib.pyplot.gca().
size (float) – Arc diameter in the unit specified by unit.
unit (Literal['points', 'pixels', 'axes width', 'axes height', 'axes min', 'axes max']) – Unit used for size. One of "points", "pixels", "axes width", "axes height", "axes min", or "axes max".
textposition (Literal['inside', 'outside', 'edge', 'legend']) – Label placement relative to the arc: "inside", "outside", "edge", or "legend". Use "legend" to hide on-plot text and use text as the legend label of the arc.
color – Shared default color for both the arc line and the text label. If omitted, both default to rcParams["text.color"]. In either case, kwargs["color"] overrides only the arc, and text_kw["color"] overrides only the text.
text_kw (dict | None) – Extra keyword arguments forwarded to the text annotation (e.g. fontsize, fontweight, color).
**kwargs – Additional keyword arguments forwarded to matplotlib.patches.Arc (e.g. linewidth, linestyle, alpha, zorder).

Return type: