Mixed subplot grid shapes

fig.add_subplot(nrows, ncols, index) positions purely from that call’s own (nrows, ncols) – nothing stops one figure from mixing shapes across calls, the classic “one wide panel over two narrow ones” layout: a (2, 1, 1) axes spans the top half, then two (2, 2, 3)/(2, 2, 4) axes split the bottom half into quarters. Every axes still tiles cleanly because both shapes divide the same margins the same way, but nothing here shares one consistent grid the way a single add_gridspec grid does – export formats that compose per-panel views into one grid (e.g. to_vega_lite()) fall back to exporting each axes as its own independent view instead of one combined layout.

tight_layout() assumes one shared grid shape too, so this figure skips it and relies on each axes’ own initial rect (every add_subplot call divides the same figure margins, so the panels still tile without gaps or overlap).

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import numpy as np
import plotpress

t = np.linspace(0, 10, 300)

fig = plotpress.Figure(figsize=(8, 6))
top = fig.add_subplot(2, 1, 1)
bottom_left = fig.add_subplot(2, 2, 3)
bottom_right = fig.add_subplot(2, 2, 4)

top.plot(t, np.sin(t) + 0.3 * np.sin(3 * t), color="#1f77b4")
top.set_title("add_subplot(2, 1, 1) -- a (2, 1) grid")

bottom_left.plot(t, np.cos(t), color="#d62728")
bottom_left.set_title("add_subplot(2, 2, 3) -- a (2, 2) grid")

bottom_right.scatter(t[::4], np.sin(t[::4]) * np.cos(t[::4]), s=8, color="#2ca02c")
bottom_right.set_title("add_subplot(2, 2, 4) -- a (2, 2) grid")

fig.suptitle("mixed grid shapes on one figure: (2, 1) top, (2, 2) bottom")