Description

DietBru

opened on Oct 29, 2017

Issue body actions

Hello,
when making a plot with two differently scaled y-axes by following this example, the second scale becomes incorrect after using the zoom tool (see example below). Interestingly, reading the ylim values (see example below) yields in the expected results. Using ax.set_ylim() and using the paning tool do not show this behavior.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.set(title="Two y-scales", ylabel="x / m")
# right ax:
axr = ax.twinx()
axr.set_ylabel("x / cm")


def track_yax(ax_):
    """Syncronize second y-axis with first axis. """
    y1, y2 = ax.get_ylim()
    axr.set_ylim(100*y1, y2*100)
    # axr.figure.canvas.draw() # does not make a difference
    yr1, yr2 = axr.get_ylim()
    print(f"Lower: {y1:+.5g} -> {yr1:+.5g}\t Upper: {y2:+.5g} -> {yr2:+.5g}")


# automatically update ylim of ax2 when ylim of ax1 changes.
ax.callbacks.connect("ylim_changed", track_yax)


# Do the plotting:
ax.plot([0, 5, 2, 4, 1], 'o-')
ax.grid(True)

plt.show()

Matplotlib version

• Operating system: Debian 4.13.4-2 (Sid) x86_64 GNU/Linux
• Matplotlib version: 2.1.0.post484.dev0+g883096231 (git master)
• Matplotlib backend: Qt5Agg
• Python version: Python 3.6.3 on Anaconda 5.0.1

Activity

1. tacaswell

   added this to the This milestone has been deleted milestone on Oct 29, 2017
2. tacaswell commented on Oct 29, 2017

   

   tacaswell

   on Oct 29, 2017

   Member

   More actions

   I have a vauge memory of there being related issue that zoom was not going through the normal code path.

   Maybe related to #2790
3. github-actions commented on Apr 23, 2023

   

   github-actionsBot

   on Apr 23, 2023

   More actions

   This issue has been marked "inactive" because it has been 365 days since the last comment. If this issue is still present in recent Matplotlib releases, or the feature request is still wanted, please leave a comment and this label will be removed. If there are no updates in another 30 days, this issue will be automatically closed, but you are free to re-open or create a new issue if needed. We value issue reports, and this procedure is meant to help us resurface and prioritize issues that have not been addressed yet, not make them disappear. Thanks for your help!
4. github-actions

   added

   status: inactiveMarked by the “Stale” Github ActionMarked by the “Stale” Github Action

   on Apr 23, 2023
5. jklymak commented on Apr 23, 2023

   

   jklymak

   on Apr 23, 2023

   Member

   More actions

   https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.secondary_yaxis.html is meant for this situation. I'm going to close this, despite the original codepath being problematic.
6. jklymak

   closed this as not plannedon Apr 23, 2023
7. jklymak

   removed

   status: inactiveMarked by the “Stale” Github ActionMarked by the “Stale” Github Action

   on Apr 23, 2023
8. QuLogic

   removed this from the future releases milestone on Apr 25, 2023

Issue actions