fig, ax = plt.subplots()

ax.plot([2, .5, -1], [1, .2, 1])

am = AngleMarker((.5, .2), (2, 1), (-1, 1), size=50, units="pixels", ax=ax,

text=r"$\theta$")

plt.show()

def testing(size=0.25, units="axes fraction", dpi=100, fs=(6.4, 5),

show=False):

fig, axes = plt.subplots(2, 2, sharex="col", sharey="row", dpi=dpi,

figsize=fs,

gridspec_kw=dict(width_ratios=[1, 3],

height_ratios=[3, 1]))

def plot_angle(ax, pos, vec1, vec2, acol="C0", **kwargs):

ax.plot([vec1[0], pos[0], vec2[0]], [vec1[1], pos[1], vec2[1]],

color=acol)

am = AngleMarker(pos, vec1, vec2, ax=ax, text=r"$\theta$", **kwargs)

tx = "figsize={}, dpi={}, arcsize={} {}".format(fs, dpi, size, units)

axes[0, 1].set_title(tx, loc="right", size=9)

kw = dict(size=size, units=units)

p = (.5, .2), (2, 0), (1, 1)

plot_angle(axes[0, 0], *p, **kw)

plot_angle(axes[0, 1], *p, **kw)

plot_angle(axes[1, 1], *p, **kw)

kw.update(acol="limegreen")

plot_angle(axes[0, 0], (1.2, 0), (1, -1), (1.3, -.8), **kw)

plot_angle(axes[1, 1], (0.2, 1), (0, 0), (.3, .2), **kw)

plot_angle(axes[0, 1], (0.2, 0), (0, -1), (.3, -.8), **kw)

kw.update(acol="crimson")

plot_angle(axes[1, 0], (1, .5), (1, 1), (2, .5), **kw)

fig.tight_layout()

fig.savefig(tx.replace("=", "_") + ".png")

fig.savefig(tx.replace("=", "_") + ".pdf")

if show:

plt.show()

s = [(0.25, "axes min"), (0.25, "axes max"),

(0.25, "axes width"), (0.25, "axes height"),

(100, "pixels"), (72, "points")]

d = [72, 144]

f = [(6.4, 5), (12.8, 10)]

import itertools

for (size, unit), dpi, fs in itertools.product(s, d, f):

testing(size=size, units=unit, dpi=dpi, fs=fs)