Fix #995. Add preliminary support for handling DPI changes.

nion/swift/Panel.py

@@ -78,6 +78,7 @@ def create_dock_widget(self, title: str, positions: typing.Sequence[str], positi
         self.dock_widget.on_size_changed = self.size_changed
         self.dock_widget.on_focus_changed = self.focus_changed
         self.dock_widget.on_ui_activity = self.document_controller._register_ui_activity
+        self.dock_widget.on_physical_dpi_changed = self.__physical_dpi_changed
 
     @property
     def document_controller(self) -> DocumentController.DocumentController:
@@ -117,6 +118,10 @@ def focus_changed(self, focused: bool) -> None:
         if focused:
             self.document_controller.request_refocus()
 
+    def __physical_dpi_changed(self, physical_dpi: float) -> None:
+        if self.dock_widget and self.dock_widget.widget:
+            self.dock_widget.widget.redraw()
+
     def __str__(self) -> str:
         return self.display_name
 

nion/swift/resources/changes.json

@@ -2,6 +2,10 @@
   {
     "version": "Unreleased",
     "notes": [
+      {
+        "issues": ["https://github.com/nion-software/nionswift/issues/995"],
+        "summary": "Fix crash when screen properties change. Also respond better to DPI changes."
+      },
       {
         "issues": ["https://github.com/nion-software/nionswift/issues/992"],
         "summary": "Add scroll bar to activity panel to prevent it growing beyond its available height."