Fit bounds not fitting to provided points

[this-josh]

Describe the bug
I have a plot which I'd like to export as png so I'm using the _to_png feature. Ideally I'd like a zoom level of around 4.5 - my plot should cover from Madrid to St.Petersburg (roughly) - but I cannot provide this. When I provide bounds the image I get out doesn't seem to be obeying them.

I appreciate this is likely a function of dynamic window resizing, but exporting as png should be able to adhere to the provided bounds despite the png support being via selenium.

To Reproduce

import folium

m = folium.Map()

sw = [38, -3]
ne = [60, 31]
m.fit_bounds([sw, ne]) 

m.save("map.html")

import io
from PIL import Image

img_data = m._to_png(1)
img = Image.open(io.BytesIO(img_data))
img.save('map_plot.png')

Expected behavior
A png file contained within the provided bounds

Environment (please complete the following information):

• Browser [e.g. chrome, firefox] Chromium based
• Jupyter Notebook or html files? HTML and jupyer
• Python version (check it with import sys; print(sys.version_info)) 3.12.1
• folium version (check it with import folium; print(folium.__version__)) 0.15.1
• branca version (check it with import branca; print(branca.__version__)) 0.7.1

[hansthen]

I can at least confirm the issue.

[hansthen]

I created a small test program

import folium
from streamlit_folium import st_folium
import streamlit as st
from selenium import webdriver
import io
from PIL import Image
st.set_page_config(layout="wide")
options = webdriver.chrome.options.Options()
options.add_argument("--headless")
driver = webdriver.Chrome(options=options)

m = folium.Map(zoom_snap=0)

sw = [38, -3]
ne = [60, 31]

folium.Rectangle(
    bounds=[sw, ne],
).add_to(m)
m.fit_bounds([sw, ne])
m.save("map.html")

img_data = m._to_png(3, driver=driver)
img = Image.open(io.BytesIO(img_data))

left, right = st.columns(2)
with left:
    st_folium(m, width=800, height=800, returned_objects=[])

with right:
    st.image(img)

[hansthen]

The main issue seems to be the call to driver.fullscreen_window() in to_png. This is called after loading the page, which negates the set_bounds. This gives the following results

[hansthen]

If I make the driver.fullscreen_window() call before getting the image, it becomes a little better, however, the aspect ratio is still off.

[hansthen]

Replacing fullscreen_window() with set_window_size(1200,1200) makes it a little better.

However, here it seems fit_bounds is calculated differently when using the selenium webdriver. Probably this is because the set_window_size() also includes the chromium toolbar.

[this-josh]

Nice work @hansthen