Hello,
Below is a MWE of a figure that includes two legends, one in two-column format and the other in one-column format. As written, the horizontal alignment between the two legends depends on details such as whether I generate the figure in a Jupyter notebook or with a script. I’ve experimented with transformations and have been unable to find a solution that robustly centers the legend keys of the single-column legend at the horizontal center of the two legend keys in the two-column legend. Any suggestions?
fig, ax = plt.subplots()
x = np.linspace(0, 1)
m = np.arange(1, 4)
lgnd_loc = (0.1, 0.1)
lbl = []
ln_pos = []
ln_neg = []
for k in m:
ln_pos += ax.plot(x, k * x)
ln_neg += ax.plot(x, -k * x)
lbl.append(f"m = {k:d}")
ln_zero = ax.plot(x, np.zeros_like(x), label=f"m = 0")
# Create first part of the legend
lgnd_2col = ax.legend(
title="Pos. Neg.",
alignment="left",
handles=[*zip(ln_pos, ln_neg)],
labels=lbl,
frameon=False,
fontsize="small",
handler_map={tuple: HandlerTuple(ndivide=None, pad=1.0)},
handlelength=6.0,
loc="lower left",
bbox_to_anchor=lgnd_loc,
borderpad=0,
)
# Add first part of legend as an artist to create second part
lgnd_2col_art = ax.add_artist(lgnd_2col)
# Create second part of the legend
lgnd_loc_new = (lgnd_loc[0] - ax.transAxes.inverted().transform((60, 0))[0], lgnd_loc[1])
lgnd_1col = ax.legend(
alignment="center",
handles=ln_zero,
ncols=1,
frameon=False,
fontsize="medium",
loc="upper left",
bbox_to_anchor=lgnd_loc_new,
borderpad=0,
)
plt.show()
