I want to prepare a “portrait” A0 poster (841mm × 1189mm) placing different Artists (no Axes, but Rectangles and Texts) specifying their positions in mm from the top-left corner of the figure.

I have already figured out a possible procedure, e.g., if I want a rectangle, 40mm × 18mm, its top left corner positioned at (230mm, 190mm) from the top-left corner of the figure, I’d write

import matplotlib.pyplot as plt

fig = plt.figure(figsize(841/25.4, 25.4), layout='none')
fig.patches.append(plt.Rectangle((230, 190), 40, 18, transform=???))
# -------------------------------------------------------------///
fig.savefig('A0.pdf')

While I know that x_fig = x_mm/841 and y_fig = 1 - y_mm/1189I don’t know how to define a proper transform to have the coordinates specified the way I’d like them.

How can I define a proper transform?