Multiplot fails if it is the first plot in the script

When a script has a multiplotas it's very first plot, the plot produced it's a regular plot, the second plot overwrites the first one withouth any error indication:

Let's use this small example:

import numpy as np
import gnuplotlib as gp
th = np.linspace(0, 2*np.pi, 100)
x1 = np.cos(th)
y1 = np.sin(th)
x2 = 2*np.cos(th)
y2 = 3*np.sin(th)

gp.plot(
    ((
        x1,
        y1,
        dict(
            legend = "Circle",
            _with = "linespoints dt 4 pt 4",
        )),
     dict(
         title="Circle",
         xlabel="X",
         ylabel="Y",
     )),
    ((
        x2,
        y2,
        dict(
            legend = "Ellipse",
            _with = "linespoints dt 4 pt 4",
        )),
     dict(title="Ellipse",
         xlabel="X",
         ylabel="Y",
     )),
    _wait=True,
    square=True,
    multiplot="layout 2,1"
)

This produces the following output:

As we see, the Ellipse plot has overwritten the Circle plot, totally ignoring the multiplot argument. No warnings, no errors. Just silently ignores the option.

However, if we add a regular plot before the multiplot:

import numpy as np
import gnuplotlib as gp
th = np.linspace(0, 2*np.pi, 100)
x1 = np.cos(th)
y1 = np.sin(th)
x2 = 2*np.cos(th)
y2 = 3*np.sin(th)
# Dummy plot so multiplot doesn't fail
gp.plot(
    np.sin(th),
    np.cos(th),
    _wait=True,
)

gp.plot(
    ((
        x1,
        y1,
        dict(
            legend = "Circle",
            _with = "linespoints dt 4 pt 4",
        )),
     dict(
         title="Circle",
         xlabel="X",
         ylabel="Y",
     )),
    ((
        x2,
        y2,
        dict(
            legend = "Ellipse",
            _with = "linespoints dt 4 pt 4",
        )),
     dict(title="Ellipse",
         xlabel="X",
         ylabel="Y",
     )),
    _wait=True,
    square=True,
    multiplot="layout 2,1"
)

We get the desired output

One curious effect is that this only works if _wait=True is provided in the Dummy Plot

Commencez par exécuter les deux reproductions Python de l’issue et suivez la gestion des plots et du multiplot dans le projet. Comparez le cas du premier plot avec le cas précédé par un plot factice et _wait=True. Le travail est terminé lorsqu’un script dont le premier plot utilise multiplot="layout 2,1" rend les deux plots sans nécessiter de plot factice ni écraser silencieusement le premier.