Bug summary
The navigation toolbar icons are rendered much larger than the toolbar when using Matplotlib 3.11.1 with PyQt5 on a macOS Retina display. The icons are therefore clipped.
The problem does not occur with Matplotlib 3.10.9 in the same Python environment. Only the Matplotlib version was changed for the comparison.
This may be related to the new DPI-aware _IconEngine used by the Qt backend in Matplotlib 3.11.
Code for reproduction
import platform
import sys
import matplotlib
from PyQt5 import QtCore, QtWidgets
matplotlib.use("Qt5Agg")
from matplotlib.backends.backend_qtagg import (
FigureCanvasQTAgg,
NavigationToolbar2QT,
)
from matplotlib.figure import Figure
app = QtWidgets.QApplication(sys.argv)
window = QtWidgets.QMainWindow()
window.setWindowTitle("Matplotlib Qt toolbar MWE")
figure = Figure()
canvas = FigureCanvasQTAgg(figure)
toolbar = NavigationToolbar2QT(canvas, window)
axes = figure.subplots()
axes.plot([1, 2, 3], [1, 4, 2], marker="o")
contents = QtWidgets.QWidget()
layout = QtWidgets.QVBoxLayout(contents)
layout.addWidget(toolbar)
layout.addWidget(canvas)
window.setCentralWidget(contents)
window.resize(900, 600)
window.show()
screen = app.primaryScreen()
print("Matplotlib:", matplotlib.__version__)
print("Backend:", matplotlib.get_backend())
print("Python:", sys.version.split()[0])
print("Architecture:", platform.machine())
print("macOS:", platform.mac_ver()[0])
print("PyQt:", QtCore.PYQT_VERSION_STR)
print("Qt runtime:", QtCore.qVersion())
print("Qt used to build PyQt:", QtCore.QT_VERSION_STR)
print("Device-pixel ratio:", screen.devicePixelRatio())
print("Logical DPI:", screen.logicalDotsPerInch())
print("Physical DPI:", screen.physicalDotsPerInch())
print("Toolbar icon size:", toolbar.iconSize())
raise SystemExit(app.exec())Actual outcome
With Matplotlib 3.11.1, the toolbar icons are approximately twice their intended linear size and are clipped by the toolbar.
The toolbar itself reports an icon size of 32 × 32.
Code output:
Python: 3.12.4
Architecture: arm64
macOS: 26.5.2
Matplotlib: 3.11.1
Backend: Qt5Agg
PyQt: 5.15.11
Qt runtime: 5.15.19
Qt used to build PyQt: 5.15.14
Screen device-pixel ratio: 2.0
Screen logical DPI: 72.0
Screen physical DPI: 127.5
Toolbar icon size: 32x32
Expected outcome
The icons should fit inside the toolbar, as they do with Matplotlib 3.10.9.
Code output:
Python: 3.12.4
Architecture: arm64
macOS: 26.5.2
Matplotlib: 3.10.9
Backend: Qt5Agg
PyQt: 5.15.11
Qt runtime: 5.15.19
Qt used to build PyQt: 5.15.14
Screen device-pixel ratio: 2.0
Screen logical DPI: 72.0
Screen physical DPI: 127.5
Toolbar icon size: 32x32
Additional information
The comparison was performed by installing Matplotlib 3.10.9 and 3.11.1 successively into the same virtual environment. Python, PyQt5, Qt, and the display configuration remained unchanged.
Operating system
macOS 26.5.2
Matplotlib Version
3.11.1
Matplotlib Backend
Qt5Agg
Python version
3.12.4
Jupyter version
No response
Installation
pip
Bug summary
The navigation toolbar icons are rendered much larger than the toolbar when using Matplotlib 3.11.1 with PyQt5 on a macOS Retina display. The icons are therefore clipped.
The problem does not occur with Matplotlib 3.10.9 in the same Python environment. Only the Matplotlib version was changed for the comparison.
This may be related to the new DPI-aware
_IconEngineused by the Qt backend in Matplotlib 3.11.Code for reproduction
Actual outcome
With Matplotlib 3.11.1, the toolbar icons are approximately twice their intended linear size and are clipped by the toolbar.
The toolbar itself reports an icon size of 32 × 32.
Code output:
Expected outcome
The icons should fit inside the toolbar, as they do with Matplotlib 3.10.9.
Code output:
Additional information
The comparison was performed by installing Matplotlib 3.10.9 and 3.11.1 successively into the same virtual environment. Python, PyQt5, Qt, and the display configuration remained unchanged.
Operating system
macOS 26.5.2
Matplotlib Version
3.11.1
Matplotlib Backend
Qt5Agg
Python version
3.12.4
Jupyter version
No response
Installation
pip