kvui: fix ZeroDivisionError on windows after monitor reset by setting fixed DPI

kvui.py

@@ -57,8 +57,29 @@ for classobj in SoundLoader._classes:
     # .extensions(), which e.g. in audio_sdl2.pyx then calls a function called "mix_init()"
     classobj.extensions()
 
-from kivymd.uix.divider import MDDivider
 from kivy.core.window import Window
+
+if sys.platform == "win32":
+    from kivy.core.window.window_sdl2 import WindowSDL, _WindowsSysDPIWatch
+
+    # The process is deliberately DPI-unaware (see above), so Windows scales the whole window for us. Kivy's dynamic
+    # DPI handling conflicts with that after a display reconnects: it can briefly use a zero density and then enter a
+    # resize/layout loop. Keep Kivy's coordinate system at the fixed 96 DPI that a DPI-unaware process expects.
+    def _set_fixed_windows_density(self: WindowSDL):
+        self._density = 1.
+        self.dpi = 96.
+
+    def _ignore_windows_dpi_changes(self: _WindowsSysDPIWatch):
+        pass
+
+    WindowSDL._update_density_and_dpi = _set_fixed_windows_density
+    Window._update_density_and_dpi()
+    if Window._win_dpi_watch is not None:
+        Window._win_dpi_watch.stop()
+        Window._win_dpi_watch = None
+    _WindowsSysDPIWatch.start = _ignore_windows_dpi_changes
+
+from kivymd.uix.divider import MDDivider
 from kivy.core.clipboard import Clipboard
 from kivy.core.text.markup import MarkupLabel
 from kivy.core.image import ImageLoader, ImageLoaderBase, ImageData