[FIXED] How to customize the ratio of each subplot in a matplotlib figure?

Issue

import matplotlib.pyplot as plt
from matplotlib.gridspec import GridSpec


def format_axes(fig):
    for i, ax in enumerate(fig.axes):
        ax.text(0.5, 0.5, "ax%d" % (i+1), va="center", ha="center")
        ax.tick_params(labelbottom=False, labelleft=False)

fig = plt.figure(constrained_layout=True)

gs = GridSpec(2, 2, figure=fig)
ax1 = fig.add_subplot(gs\[0, 0\])
# identical to ax1 = plt.subplot(gs.new_subplotspec((0, 0), colspan=3))
ax2 = fig.add_subplot(gs\[0, 1\])
ax3 = fig.add_subplot(gs\[1, 1\])
ax4 = fig.add_subplot(gs\[1, 0\])
# ax5 = fig.add_subplot(gs\[-1, -2\])

fig.suptitle("GridSpec")
format_axes(fig)

plt.show()][1]][1]

As shown in the picture i want to extend ax4 into ax3 a little bit and ax3 should occupy the remaining space of the figure. The ax1 and ax2 should remain the same.

Solution

You have to use nested grid specs together with width_ratios parameter:

import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec


def format_axes(fig):
    for i, ax in enumerate(fig.axes):
        ax.text(0.5, 0.5, "ax%d" % (i + 1), va="center", ha="center")
        ax.tick_params(labelbottom=False, labelleft=False)


# gridspec inside gridspec
fig = plt.figure()

gs0 = gridspec.GridSpec(2, 1, figure=fig)

gs00 = gridspec.GridSpecFromSubplotSpec(1, 2, subplot_spec=gs0[0])
gs01 = gridspec.GridSpecFromSubplotSpec(1, 2, subplot_spec=gs0[1], width_ratios=[2, 1])

ax1 = fig.add_subplot(gs00[:, :-1])
ax2 = fig.add_subplot(gs00[:, -1])

ax3 = fig.add_subplot(gs01[:, :-1])
ax4 = fig.add_subplot(gs01[:, -1])

plt.suptitle("GridSpec Inside GridSpec")
format_axes(fig)

plt.show()

Answered By - bzu