Only set Tk scaling-on-map for Windows systems

QuLogic · QuLogic · commit f1f8094b7aed · 2022-04-26T15:45:36.000-04:00
On Windows, the DPI that Tk sees is 96 for regular screens and some
multiple of that for HiDPI screens. On Linux, the DPI is the true DPI
(or at least what the display server tells it is true), and doesn't have
anything to do with HiDPI. On macOS, the DPI appears closer to 72 by
default.
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -175,7 +175,8 @@ def __init__(self, figure=None, master=None):
             master=self._tkcanvas, width=w, height=h)
         self._tkcanvas.create_image(w//2, h//2, image=self._tkphoto)
         self._tkcanvas.bind("<Configure>", self.resize)
-        self._tkcanvas.bind("<Map>", self._update_device_pixel_ratio)
+        if sys.platform == 'win32':
+            self._tkcanvas.bind("<Map>", self._update_device_pixel_ratio)
         self._tkcanvas.bind("<Key>", self.key_press)
         self._tkcanvas.bind("<Motion>", self.motion_notify_event)
         self._tkcanvas.bind("<Enter>", self.enter_notify_event)
@@ -212,7 +213,7 @@ def filter_destroy(event):
         self._rubberband_rect = None
 
     def _update_device_pixel_ratio(self, event=None):
-        # Tk gives scaling with respect to 72 DPI, but most (all?) screens are
+        # Tk gives scaling with respect to 72 DPI, but Windows screens are
         # scaled vs 96 dpi, and pixel ratio settings are given in whole
         # percentages, so round to 2 digits.
         ratio = round(self._tkcanvas.tk.call('tk', 'scaling') / (96 / 72), 2)
