[Question] Issue with MatplotlibChart and Specified xlim and ylim

[yuheiyta]

Question

I've encountered an issue while using MatplotlibChart in conjunction with setting xlim and ylim in a matplotlib.pyplot.figure object. It seems that the resultant plot extends beyond the specified x and y limits.
Any insights or solutions regarding this problem would be greatly appreciated. Thank you!

Code sample

import flet as ft
from flet import Page
from flet.matplotlib_chart import MatplotlibChart
import matplotlib
import matplotlib.pyplot as plt
import numpy as np

matplotlib.use("Agg")

def main(page: Page):
    
    fig = plt.figure()
    ax=fig.add_subplot()
    x=np.arange(0,100)
    y=x*2
    ax.plot(x,y)
    ax.set_xlim(10,)
    ax.set_ylim(30,)
    mplc = MatplotlibChart(figure=fig)

    page.add(mplc)
ft.app(target=main)

Error message

No response

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• I have searched for answers to my question both in the issues and in previous discussions.

[tehphilb]

From the Matplotlib docs:

plt.xlim(0,0) # Lower Limit, Upper Limit
plt.ylim(0,0) # Lower Limit, Upper Limit

Your example:

import flet as ft
from flet import Page
from flet.matplotlib_chart import MatplotlibChart
import matplotlib
import matplotlib.pyplot as plt
import numpy as np

matplotlib.use("Agg")

def main(page: Page):
    
    fig = plt.figure()
    ax=fig.add_subplot()
    x=np.arange(0,100)
    y=x*2
    ax.plot(x,y)
    ax.set_xlim(-10,)
    ax.set_ylim(-30,)
    mplc = MatplotlibChart(figure=fig)

    page.add(mplc)
ft.app(target=main)

[yuheiyta]

My point is that when showing with matplotlib, plots outside the range are hidden, whereas with MatplotlibChart the plots outside the range are still visible for some reason.

[tehphilb]

Now I got it.

It seems to be an issue with the clip_on attribute. https://matplotlib.org/3.2.2/api/_as_gen/matplotlib.axes.Axes.set_clip_on.html

Note that clip_on=True is actually the default behavior for the plotting functions in Matplotlib. It's seems possible that Flet, how it renders the Matplotlib charts, and the SVG representation may not respect this setting, so far.

[yuheiyta]

Thanks! I found some issues reported in matplotlib. Seemingly that this issue is not caused by matplotlib but svg handling part matplotlib/matplotlib#2423 (comment).