From c39183f97e98a3cc59c716e2e68121eaf64d3fe8 Mon Sep 17 00:00:00 2001
From: John Wiggins <jwiggins@users.noreply.github.com>
Date: Fri, 26 Feb 2021 11:58:07 +0100
Subject: [PATCH] Don't mess up the component bounds in HiDPI mode (#635)

---
 enable/abstract_window.py             |  9 ++++++---
 enable/tests/test_component_editor.py | 19 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/enable/abstract_window.py b/enable/abstract_window.py
index 693226a13..6599f26d4 100644
--- a/enable/abstract_window.py
+++ b/enable/abstract_window.py
@@ -220,16 +220,19 @@ def _component_changed(self, old, new):
         size = self._get_control_size()
         if (size is not None) and hasattr(self.component, "bounds"):
             new.on_trait_change(self.component_bounds_changed, "bounds")
+            pix_scale = self.base_pixel_scale
             if getattr(self.component, "fit_window", False):
                 self.component.outer_position = [0, 0]
-                self.component.outer_bounds = list(size)
+                self.component.outer_bounds = [
+                    size[0] / pix_scale, size[1] / pix_scale
+                ]
             elif hasattr(self.component, "resizable"):
                 if "h" in self.component.resizable:
                     self.component.outer_x = 0
-                    self.component.outer_width = size[0]
+                    self.component.outer_width = size[0] / pix_scale
                 if "v" in self.component.resizable:
                     self.component.outer_y = 0
-                    self.component.outer_height = size[1]
+                    self.component.outer_height = size[1] / pix_scale
         self._update_region = None
         self.redraw()
 
diff --git a/enable/tests/test_component_editor.py b/enable/tests/test_component_editor.py
index 7b27e2c9b..2ee2ed8bb 100644
--- a/enable/tests/test_component_editor.py
+++ b/enable/tests/test_component_editor.py
@@ -11,10 +11,11 @@
 """
 import unittest
 
-from enable.component_editor import ComponentEditor
 from traits.api import Any, HasTraits
 from traitsui.api import Item, View
 
+from enable.component import Component
+from enable.component_editor import ComponentEditor
 from enable.tests._testing import get_dialog_size, skip_if_null
 
 ITEM_WIDTH, ITEM_HEIGHT = 700, 200
@@ -72,3 +73,19 @@ def test_initial_component_with_item_size(self):
 
         self.assertGreater(size[0], ITEM_WIDTH - 1)
         self.assertGreater(size[1], ITEM_HEIGHT - 1)
+
+    @skip_if_null
+    def test_component_hidpi_size_stability(self):
+        # Issue #634: HiDPI doubles size of components when a component is
+        # replaced
+        dialog = _ComponentDialogWithSize(thing=Component())
+        dialog.edit_traits()
+
+        initial_bounds = dialog.thing.bounds
+        # Force the window into HiDPI mode
+        dialog.thing.window.base_pixel_scale = 2.0
+
+        dialog.thing = Component()
+        new_bounds = dialog.thing.bounds
+
+        self.assertListEqual(initial_bounds, new_bounds)