Update color mode handling for dark/light theme

Author: PierreRaybaut

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog #
 
+## Version 3.5.4 ##
+
+In this release, test coverage is 74%.
+
+🛠️ Bug fixes:
+
+* Improved dark/light mode theme update:
+  * The theme mode may be changed during the application lifetime
+  * Added methods `update_color_mode` on `CodeEditor` and `ConsoleBaseWidget` widgets
+
 ## Version 3.5.3 ##
 
 In this release, test coverage is 74%.

guidata/__init__.py

@@ -8,7 +8,7 @@
 and application development tools for Qt.
 """
 
-__version__ = "3.5.3"
+__version__ = "3.5.4"
 
 
 # Dear (Debian, RPM, ...) package makers, please feel free to customize the
@@ -30,7 +30,9 @@ def qapplication():
     if not app:
         app = QApplication([])
         install_translator(app)
-        set_color_mode(app)
+        from guidata import qthelpers
+
+        qthelpers.set_color_mode()
     return app
 
 
@@ -53,39 +55,3 @@ def install_translator(qapp):
                 break
     if QT_TRANSLATOR is not None:
         qapp.installTranslator(QT_TRANSLATOR)
-
-
-def set_color_mode(app):
-    """Set color mode (dark or light), depending on OS setting"""
-    from qtpy.QtCore import Qt
-    from qtpy.QtGui import QColor, QPalette
-    from qtpy.QtWidgets import QStyleFactory
-
-    from guidata import qthelpers
-
-    if qthelpers.is_dark_mode():
-        app.setStyle(QStyleFactory.create("Fusion"))
-        dark_palette = QPalette()
-        dark_color = QColor(50, 50, 50)
-        disabled_color = QColor(127, 127, 127)
-        dpsc = dark_palette.setColor
-        dpsc(QPalette.Window, dark_color)
-        dpsc(QPalette.WindowText, Qt.white)
-        dpsc(QPalette.Base, QColor(31, 31, 31))
-        dpsc(QPalette.AlternateBase, dark_color)
-        dpsc(QPalette.ToolTipBase, Qt.white)
-        dpsc(QPalette.ToolTipText, Qt.white)
-        dpsc(QPalette.Text, Qt.white)
-        dpsc(QPalette.Disabled, QPalette.Text, disabled_color)
-        dpsc(QPalette.Button, dark_color)
-        dpsc(QPalette.ButtonText, Qt.white)
-        dpsc(QPalette.Disabled, QPalette.ButtonText, disabled_color)
-        dpsc(QPalette.BrightText, Qt.red)
-        dpsc(QPalette.Link, QColor(42, 130, 218))
-        dpsc(QPalette.Highlight, QColor(42, 130, 218))
-        dpsc(QPalette.HighlightedText, Qt.black)
-        dpsc(QPalette.Disabled, QPalette.HighlightedText, disabled_color)
-        app.setPalette(dark_palette)
-        app.setStyleSheet(
-            "QToolTip { color: #ffffff; background-color: #2a82da; border: 1px solid white; }"
-        )

guidata/qthelpers.py

@@ -77,6 +77,23 @@
     from collections.abc import Callable
 
 
+def set_dark_mode(state: bool) -> None:
+    """Set dark mode for Qt application
+
+    Args:
+        state (bool): True to enable dark mode
+    """
+    if state:
+        os.environ["QT_COLOR_MODE"] = "dark"
+    else:
+        os.environ["QT_COLOR_MODE"] = "light"
+    set_color_mode()
+
+    # Iterate over all top-level widgets:
+    for widget in QW.QApplication.instance().topLevelWidgets():
+        win32_fix_title_bar_background(widget)
+
+
 def is_dark_mode() -> bool:
     """Return True if current color mode is dark mode
 
@@ -89,13 +106,60 @@ def is_dark_mode() -> bool:
         return darkdetect.isDark()
 
 
+DEFAULT_STYLES = None
+
+
+def set_color_mode():
+    """Set color mode (dark or light), depending on OS setting or on the
+    `QT_LIGHT_COLOR_MODE` environment variable."""
+    global DEFAULT_STYLES
+
+    app = QW.QApplication.instance()
+
+    if DEFAULT_STYLES is None:
+        # Store default palette to be able to restore it:
+        DEFAULT_STYLES = app.style().objectName(), app.palette(), app.styleSheet()
+
+    if is_dark_mode():
+        app.setStyle(QW.QStyleFactory.create("Fusion"))
+        dark_palette = QG.QPalette()
+        dark_color = QG.QColor(50, 50, 50)
+        disabled_color = QG.QColor(127, 127, 127)
+        dpsc = dark_palette.setColor
+        dpsc(QG.QPalette.Window, dark_color)
+        dpsc(QG.QPalette.WindowText, QC.Qt.white)
+        dpsc(QG.QPalette.Base, QG.QColor(31, 31, 31))
+        dpsc(QG.QPalette.AlternateBase, dark_color)
+        dpsc(QG.QPalette.ToolTipBase, QC.Qt.white)
+        dpsc(QG.QPalette.ToolTipText, QC.Qt.white)
+        dpsc(QG.QPalette.Text, QC.Qt.white)
+        dpsc(QG.QPalette.Disabled, QG.QPalette.Text, disabled_color)
+        dpsc(QG.QPalette.Button, dark_color)
+        dpsc(QG.QPalette.ButtonText, QC.Qt.white)
+        dpsc(QG.QPalette.Disabled, QG.QPalette.ButtonText, disabled_color)
+        dpsc(QG.QPalette.BrightText, QC.Qt.red)
+        dpsc(QG.QPalette.Link, QG.QColor(42, 130, 218))
+        dpsc(QG.QPalette.Highlight, QG.QColor(42, 130, 218))
+        dpsc(QG.QPalette.HighlightedText, QC.Qt.black)
+        dpsc(QG.QPalette.Disabled, QG.QPalette.HighlightedText, disabled_color)
+        app.setPalette(dark_palette)
+        app.setStyleSheet(
+            "QToolTip { color: #ffffff; background-color: #2a82da; border: 1px solid white; }"
+        )
+    elif DEFAULT_STYLES is not None:
+        style, palette, stylesheet = DEFAULT_STYLES
+        app.setStyle(QW.QStyleFactory.create(style))
+        app.setPalette(palette)
+        app.setStyleSheet(stylesheet)
+
+
 def win32_fix_title_bar_background(widget: QW.QWidget) -> None:
     """Fix window title bar background for Windows 10+ dark theme
 
     Args:
         widget (QW.QWidget): Widget to fix
     """
-    if os.name != "nt" or not is_dark_mode() or sys.maxsize == 2**31 - 1:
+    if os.name != "nt" or sys.maxsize == 2**31 - 1:
         return
 
     import ctypes
@@ -117,10 +181,18 @@ class WINDOWCOMPOSITIONATTRIBDATA(ctypes.Structure):
         ]
 
     accent = ACCENTPOLICY()
-    accent.AccentState = 1  # Default window Blur #ACCENT_ENABLE_BLURBEHIND
+    if is_dark_mode():
+        accent.AccentState = 1  # Default window Blur #ACCENT_ENABLE_BLURBEHIND
+    else:
+        # TODO: find a way to restore the default behavior
+        pass
 
     data = WINDOWCOMPOSITIONATTRIBDATA()
-    data.Attribute = 26  # WCA_USEDARKMODECOLORS
+    if is_dark_mode():
+        data.Attribute = 26  # WCA_USEDARKMODECOLORS
+    else:
+        # TODO: find a way to restore the default behavior
+        pass
     data.SizeOfData = ctypes.sizeof(accent)
     data.Data = ctypes.cast(ctypes.pointer(accent), ctypes.POINTER(ctypes.c_int))
 

guidata/widgets/codeeditor.py

@@ -130,13 +130,11 @@ def __init__(
     ) -> None:
         QPlainTextEdit.__init__(self, parent)
 
-        win32_fix_title_bar_background(self)
-
         self.visible_blocks = []
         self.highlighter = None
         self.normal_color = None
         self.sideareas_color = None
-        self.linenumbers_color = QColor(Qt.lightGray if is_dark_mode() else Qt.darkGray)
+        self.linenumbers_color = None
 
         # Line number area management
         self.linenumbers_margin = True
@@ -171,6 +169,20 @@ def __init__(
         self.setFocusPolicy(Qt.StrongFocus)
         self.setup(language=language, font=font, columns=columns, rows=rows)
 
+        self.update_color_mode()
+
+    def update_color_mode(self) -> None:
+        """Update color mode according to the current theme"""
+        win32_fix_title_bar_background(self)
+        suffix = "dark" if is_dark_mode() else "light"
+        color_scheme = CONF.get("color_schemes", "default/" + suffix)
+        self.highlighter.set_color_scheme(color_scheme)
+        self.highlighter.rehighlight()
+        self.linenumbers_color = QColor(Qt.lightGray if is_dark_mode() else Qt.darkGray)
+        self.normal_color = self.highlighter.get_foreground_color()
+        self.sideareas_color = self.highlighter.get_sideareas_color()
+        self.linenumberarea.update()
+
     def text_has_changed(self) -> None:
         """Text has changed: restart the timer to emit SIG_EDIT_STOPPED after a delay"""
         if self.timer.isActive():

guidata/widgets/console/base.py

@@ -11,7 +11,6 @@
 # pylint: disable=R0911
 # pylint: disable=R0201
 
-
 import os
 import re
 import sys
@@ -42,6 +41,7 @@
 
 from guidata.config import CONF
 from guidata.configtools import get_font, get_icon
+from guidata.qthelpers import is_dark_mode
 from guidata.widgets.console.calltip import CallTipWidget
 from guidata.widgets.console.mixins import BaseEditMixin
 from guidata.widgets.console.terminal import ANSIEscapeCodeHandler
@@ -367,8 +367,9 @@ def set_palette(self, background, foreground):
         background color and caret (text cursor) color
         """
         palette = QPalette()
-        palette.setColor(QPalette.Base, background)
+        # palette.setColor(QPalette.Base, background)
         palette.setColor(QPalette.Text, foreground)
+        palette.setColor(QPalette.Background, background)
         self.setPalette(palette)
 
         # Set the right background color when changing color schemes
@@ -1528,6 +1529,11 @@ def __init__(self, parent=None):
         self.set_pythonshell_font()
         self.setMouseTracking(True)
 
+    def update_color_mode(self):
+        """Update color mode according to the current theme"""
+        light_background = not is_dark_mode()
+        self.set_light_background(light_background)
+
     def set_light_background(self, state):
         """
 
@@ -1540,7 +1546,7 @@ def set_light_background(self, state):
             )
         else:
             self.set_palette(
-                background=QColor(Qt.black), foreground=QColor(Qt.lightGray)
+                background=QColor(50, 50, 50), foreground=QColor(Qt.lightGray)
             )
         self.ansi_handler.set_light_background(state)
         self.set_pythonshell_font()
@@ -1624,7 +1630,7 @@ def append_text_to_shell(self, text, error, prompt):
     def set_pythonshell_font(self, font=None):
         """Python Shell only"""
         if font is None:
-            font = QFont()
+            font = self.font()
         for style in self.font_styles:
             style.apply_style(
                 font=font,