Updated to latest main branch

changes/2155.bugfix.rst

@@ -0,0 +1 @@
+DPI scaling on Windows is now improved and related bugs are fixed.

examples/window/window/app.py

@@ -19,10 +19,16 @@ def do_right(self, widget, **kwargs):
  self.main_window.position = (2000, 500)
 
  def do_left_current_screen(self, widget, **kwargs):
- self.main_window.screen_position = (0, 100)
+ self.main_window.screen_position = (
+ self.main_window.screen.origin[0],
+ self.main_window.screen_position[1],
+ )
 
  def do_right_current_screen(self, widget, **kwargs):
- self.main_window.screen_position = (1080, 100)
+ self.main_window.screen_position = (
+ self.main_window.screen.size[0] - self.main_window.size[0],
+ self.main_window.screen_position[1],
+ )
 
  def do_small(self, widget, **kwargs):
  self.main_window.size = (400, 300)

iOS/tests_backend/probe.py

@@ -1,7 +1,7 @@
 import asyncio
 
 import toga
-from toga_iOS.libs import NSRunLoop, UIScreen
+from toga_iOS.libs import NSRunLoop
 
 
 class BaseProbe:
@@ -21,5 +21,5 @@ async def redraw(self, message=None, delay=0):
 
  def assert_image_size(self, image_size, size, screen):
  # Retina displays render images at a higher resolution than their reported size.
- scale = int(UIScreen.mainScreen.scale)
+ scale = int(screen._impl.native.scale)
  assert image_size == (size[0] * scale, size[1] * scale)

testbed/tests/app/test_desktop.py

@@ -6,6 +6,7 @@
 from toga.colors import CORNFLOWERBLUE, FIREBRICK, REBECCAPURPLE
 from toga.style.pack import Pack
 
+from ..widgets.probe import get_probe
 from ..window.test_window import window_probe
 
 ####################################################################################
@@ -357,6 +358,102 @@ async def test_current_window(app, app_probe, main_window):
  window3.close()
 
 
+@pytest.mark.skipif(
+ toga.platform.current_platform != "windows", reason="This test is Windows specific"
+)
+async def test_system_dpi_change(
+ monkeypatch, app, app_probe, main_window, main_window_probe
+):
+ # Store original window content
+ main_window_content_original = main_window.content
+
+ from toga_winforms.libs import shcore
+
+ GetScaleFactorForMonitor_original = getattr(shcore, "GetScaleFactorForMonitor")
+
+ def set_mock_dpi_scale(value):
+ def GetScaleFactorForMonitor_mock(hMonitor, pScale):
+ pScale.value = int(value * 100)
+
+ monkeypatch.setattr(
+ "toga_winforms.libs.shcore.GetScaleFactorForMonitor",
+ GetScaleFactorForMonitor_mock,
+ )
+
+ dpi_change_events = [
+ app._impl.winforms_DisplaySettingsChanged,
+ main_window._impl.winforms_LocationChanged,
+ main_window._impl.winforms_Resize,
+ ]
+ for flex_direction in ("row", "column"):
+ main_window.content = toga.Box(
+ style=Pack(direction=flex_direction),
+ children=[
+ toga.Box(style=Pack(flex=1)),
+ toga.Button(text="hello"),
+ toga.Label(text="toga"),
+ toga.Button(text="world"),
+ toga.Box(style=Pack(flex=1)),
+ ],
+ )
+ widget_dimension_to_compare = "width" if flex_direction == "row" else "height"
+ await main_window_probe.redraw(
+ "\nMain Window is ready for testing DPI scaling with "
+ f"window content flex direction set to: {flex_direction}"
+ )
+ for dpi_change_event in dpi_change_events:
+ print(
+ f"\nRunning DPI change event: {dpi_change_event.__func__.__qualname__}"
+ )
+
+ # Set initial DPI scale value
+ set_mock_dpi_scale(1.0)
+ dpi_change_events[0](None, None)
+ await main_window_probe.redraw(
+ "Setting initial DPI scale value to 1.0 before starting DPI scale testing"
+ )
+
+ for pScale_value_mock in (1.25, 1.5, 1.75, 2.0):
+ # Store original widget dimension
+ original_widget_dimension = dict()
+ for widget in main_window.content.children:
+ widget_probe = get_probe(widget)
+ original_widget_dimension[widget] = getattr(
+ widget_probe, widget_dimension_to_compare
+ )
+
+ set_mock_dpi_scale(pScale_value_mock)
+ # Trigger DPI change event
+ dpi_change_event(None, None)
+ await main_window_probe.redraw(
+ f"Triggering DPI change event for testing scaling at {pScale_value_mock} scale"
+ )
+
+ # Check Widget size DPI scaling
+ for widget in main_window.content.children:
+ if isinstance(widget, toga.Box):
+ # Dimension of spacer boxes should decrease when dpi scale increases
+ getattr(
+ get_probe(widget), widget_dimension_to_compare
+ ) < original_widget_dimension[widget]
+ else:
+ # Dimension of other widgets should increase when dpi scale increases
+ getattr(
+ get_probe(widget), widget_dimension_to_compare
+ ) > original_widget_dimension[widget]
+
+ # Restore original state
+ monkeypatch.setattr(
+ "toga_winforms.libs.shcore.GetScaleFactorForMonitor",
+ GetScaleFactorForMonitor_original,
+ )
+ dpi_change_events[0](None, None)
+ main_window.content.window = None
+ main_window.content = main_window_content_original
+ main_window.show()
+ await main_window_probe.redraw("\nRestoring original state of Main Window")
+
+
 async def test_session_based_app(
  monkeypatch,
  app,

winforms/src/toga_winforms/__init__.py

@@ -2,6 +2,11 @@
 
 import toga
 
+from .libs.user32 import (
+ DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2,
+ SetProcessDpiAwarenessContext,
+)
+
 # Add a reference to the Winforms assembly
 clr.AddReference("System.Windows.Forms")
 
@@ -16,4 +21,17 @@
  "WindowsBase, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
 )
 
+# Enable DPI awareness. This must be done before calling any other UI-related code
+# (https://learn.microsoft.com/en-us/dotnet/desktop/winforms/high-dpi-support-in-windows-forms).
+import System.Windows.Forms as WinForms # noqa: E402
+
+WinForms.Application.EnableVisualStyles()
+WinForms.Application.SetCompatibleTextRenderingDefault(False)
+
+if SetProcessDpiAwarenessContext is not None:
+ if not SetProcessDpiAwarenessContext(
+ DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2
+ ): # pragma: no cover
+ print("WARNING: Failed to set the DPI Awareness mode for the app.")
+
 __version__ = toga._package_version(__file__, __name__)

winforms/src/toga_winforms/app.py

@@ -2,10 +2,10 @@
 import re
 import sys
 import threading
-from ctypes import windll
 
 import System.Windows.Forms as WinForms
-from System import Environment, Threading
+from Microsoft.Win32 import SystemEvents
+from System import Threading
 from System.Media import SystemSounds
 from System.Net import SecurityProtocolType, ServicePointManager
 from System.Windows.Threading import Dispatcher
@@ -79,32 +79,10 @@ def create(self):
  self.app_context = WinForms.ApplicationContext()
  self.app_dispatcher = Dispatcher.CurrentDispatcher
 
- # Check the version of windows and make sure we are setting the DPI mode
- # with the most up to date API
- # Windows Versioning Check Sources : https://www.lifewire.com/windows-version-numbers-2625171
- # and https://docs.microsoft.com/en-us/windows/release-information/
- win_version = Environment.OSVersion.Version
- if win_version.Major >= 6: # Checks for Windows Vista or later
- # Represents Windows 8.1 up to Windows 10 before Build 1703 which should use
- # SetProcessDpiAwareness(True)
- if (win_version.Major == 6 and win_version.Minor == 3) or (
- win_version.Major == 10 and win_version.Build < 15063
- ): # pragma: no cover
- windll.shcore.SetProcessDpiAwareness(True)
- print(
- "WARNING: Your Windows version doesn't support DPI-independent rendering. "
- "We recommend you upgrade to at least Windows 10 Build 1703."
- )
- # Represents Windows 10 Build 1703 and beyond which should use
- # SetProcessDpiAwarenessContext(-2)
- elif win_version.Major == 10 and win_version.Build >= 15063:
- windll.user32.SetProcessDpiAwarenessContext(-2)
- # Any other version of windows should use SetProcessDPIAware()
- else: # pragma: no cover
- windll.user32.SetProcessDPIAware()
-
- self.native.EnableVisualStyles()
- self.native.SetCompatibleTextRenderingDefault(False)
+ # Register the DisplaySettingsChanged event handler
+ SystemEvents.DisplaySettingsChanged += WeakrefCallable(
+ self.winforms_DisplaySettingsChanged
+ )
 
  # Ensure that TLS1.2 and TLS1.3 are enabled for HTTPS connections.
  # For some reason, some Windows installs have these protocols
@@ -129,6 +107,14 @@ def create(self):
  # Call user code to populate the main window
  self.interface._startup()
 
+ ######################################################################
+ # Native event handlers
+ ######################################################################
+
+ def winforms_DisplaySettingsChanged(self, sender, event):
+ for window in self.interface.windows:
+ window._impl.update_dpi()
+
  ######################################################################
  # Commands and menus
  ######################################################################

winforms/src/toga_winforms/container.py

@@ -6,14 +6,23 @@
 
 class Container(Scalable):
  def __init__(self, native_parent):
- self.init_scale(native_parent)
  self.native_parent = native_parent
  self.native_width = self.native_height = 0
  self.content = None
 
  self.native_content = WinForms.Panel()
  native_parent.Controls.Add(self.native_content)
 
+ self.native_content.CreateGraphics().Dispose()
+
+ @property
+ def dpi_scale(self):
+ window = self.content.interface.window
+ if window:
+ return window._impl.dpi_scale
+ else:
+ return 1
+
  @property
  def width(self):
  return self.scale_out(self.native_width)

winforms/src/toga_winforms/dialogs.py

@@ -6,11 +6,10 @@
  ContentAlignment,
  Font as WinFont,
  FontFamily,
- FontStyle,
- SystemFonts,
 )
 from System.Windows.Forms import DialogResult, MessageBoxButtons, MessageBoxIcon
 
+from .libs.user32 import DPI_AWARENESS_CONTEXT_UNAWARE, SetThreadDpiAwarenessContext
 from .libs.wrapper import WeakrefCallable
 
 
@@ -98,6 +97,24 @@ class StackTraceDialog(BaseDialog):
  def __init__(self, title, message, content, retry):
  super().__init__()
 
+ # This dialog uses a fixed layout, so we create it as DPI-unaware so it will be
+ # scaled by the system. "When a window is created, its DPI awareness is defined
+ # as the DPI awareness of the calling thread at that time."
+ # (https://learn.microsoft.com/en-us/windows/win32/hidpi/high-dpi-improvements-for-desktop-applications).
+ self.prev_dpi_context = None
+ if SetThreadDpiAwarenessContext is not None: # pragma: no branch
+ self.prev_dpi_context = SetThreadDpiAwarenessContext(
+ DPI_AWARENESS_CONTEXT_UNAWARE
+ )
+ if not self.prev_dpi_context: # pragma: no cover
+ print("WARNING: Failed to set DPI Awareness for StackTraceDialog")
+
+ # Changing the DPI awareness re-scales all pre-existing Font objects, including
+ # the system fonts.
+ font_size = 8.25
+ message_font = WinFont(FontFamily.GenericSansSerif, font_size)
+ monospace_font = WinFont(FontFamily.GenericMonospace, font_size)
+
  self.native = WinForms.Form()
  self.native.MinimizeBox = False
  self.native.FormBorderStyle = self.native.FormBorderStyle.FixedSingle
@@ -114,22 +131,18 @@ def __init__(self, title, message, content, retry):
  textLabel.Width = 520
  textLabel.Alignment = ContentAlignment.MiddleCenter
  textLabel.Text = message
-
+ textLabel.Font = message_font
  self.native.Controls.Add(textLabel)
 
  # A scrolling text box for the stack trace.
  trace = WinForms.RichTextBox()
  trace.Left = 10
- trace.Top = 30
+ trace.Top = 35
  trace.Width = 504
- trace.Height = 210
+ trace.Height = 205
  trace.Multiline = True
  trace.ReadOnly = True
- trace.Font = WinFont(
- FontFamily.GenericMonospace,
- float(SystemFonts.DefaultFont.Size),
- FontStyle.Regular,
- )
+ trace.Font = monospace_font
  trace.Text = content
 
  self.native.Controls.Add(trace)
@@ -141,6 +154,7 @@ def __init__(self, title, message, content, retry):
  retry.Top = 250
  retry.Width = 100
  retry.Text = "&Retry"
+ retry.Font = message_font
  retry.Click += WeakrefCallable(self.winforms_Click_retry)
 
  self.native.Controls.Add(retry)
@@ -150,6 +164,7 @@ def __init__(self, title, message, content, retry):
  quit.Top = 250
  quit.Width = 100
  quit.Text = "&Quit"
+ quit.Font = message_font
  quit.Click += WeakrefCallable(self.winforms_Click_quit)
 
  self.native.Controls.Add(quit)
@@ -159,6 +174,7 @@ def __init__(self, title, message, content, retry):
  accept.Top = 250
  accept.Width = 100
  accept.Text = "&OK"
+ accept.Font = message_font
  accept.Click += WeakrefCallable(self.winforms_Click_accept)
 
  self.native.Controls.Add(accept)
@@ -173,6 +189,18 @@ def winforms_FormClosing(self, sender, event):
  # event will be triggered.
  if not self.future.done():
  event.Cancel = True # pragma: no cover
+ else:
+ # Reverting the DPI awareness at the end of __init__ would cause the window
+ # to be DPI-aware, presumably because the window isn't actually "created"
+ # until we call ShowDialog.
+ #
+ # This cleanup doesn't make any difference to the dialogs example, because
+ # "When the window procedure for a window is called [e.g. when clicking a
+ # button], the thread is automatically switched to the DPI awareness context
+ # that was in use when the window was created." However, other apps may do
+ # things outside of the context of a window event.
+ if self.prev_dpi_context: # pragma: no branch
+ SetThreadDpiAwarenessContext(self.prev_dpi_context)
 
  def winforms_Click_quit(self, sender, event):
  self.future.set_result(False)

winforms/src/toga_winforms/libs/shcore.py

@@ -0,0 +1,5 @@
+from ctypes import HRESULT, POINTER, windll, wintypes
+
+GetScaleFactorForMonitor = windll.shcore.GetScaleFactorForMonitor
+GetScaleFactorForMonitor.restype = HRESULT
+GetScaleFactorForMonitor.argtypes = [wintypes.HMONITOR, POINTER(wintypes.UINT)]