Workaround for Qt 5 regression causing custom colors in color chooser dialogs to not be remembered between calibre sessions

src/calibre/gui2/__init__.py

@@ -14,7 +14,7 @@ ORG_NAME = 'KovidsBrain'
 APP_UID  = 'libprs500'
 from calibre import prints
 from calibre.constants import (islinux, iswindows, isbsd, isfrozen, isosx,
-        plugins, config_dir, filesystem_encoding, DEBUG, isxp)
+        plugins, config_dir, filesystem_encoding, isxp)
 from calibre.utils.config import Config, ConfigProxy, dynamic, JSONConfig
 from calibre.ebooks.metadata import MetaInformation
 from calibre.utils.date import UNDEFINED_DATE
@@ -242,8 +242,7 @@ config = _config()
 # }}}
 
 QSettings.setPath(QSettings.IniFormat, QSettings.UserScope, config_dir)
-QSettings.setPath(QSettings.IniFormat, QSettings.SystemScope,
-        config_dir)
+QSettings.setPath(QSettings.IniFormat, QSettings.SystemScope, config_dir)
 QSettings.setDefaultFormat(QSettings.IniFormat)
 
 # Turn off DeprecationWarnings in windows GUI
@@ -876,7 +875,7 @@ def setup_gui_option_parser(parser):
 
 class Application(QApplication):
 
-    def __init__(self, args, force_calibre_style=False, override_program_name=None, headless=False):
+    def __init__(self, args, force_calibre_style=False, override_program_name=None, headless=False, color_prefs=gprefs):
         self.file_event_hook = None
         if override_program_name:
             args = [override_program_name] + args[1:]
@@ -916,6 +915,13 @@ class Application(QApplication):
         self._file_open_paths = []
         self._file_open_lock = RLock()
 
+        if not isosx:
+            # OS X uses a native color dialog that does not support custom
+            # colors
+            self.color_prefs = color_prefs
+            self.read_custom_colors()
+            self.lastWindowClosed.connect(self.save_custom_colors)
+
         if isxp:
             error_dialog(None, _('Windows XP not supported'), '<p>' + _(
                 'calibre versions newer than 2.0 do not run on Windows XP. This is'
@@ -1002,6 +1008,29 @@ class Application(QApplication):
         else:
             return QApplication.event(self, e)
 
+    @dynamic_property
+    def current_custom_colors(self):
+        from PyQt5.Qt import QColorDialog, QColor
+        def fget(self):
+            return [col.getRgb() for col in
+                    (QColorDialog.customColor(i) for i in xrange(QColorDialog.customCount()))]
+        def fset(self, colors):
+            num = min(len(colors), QColorDialog.customCount())
+            for i in xrange(num):
+                QColorDialog.setCustomColor(i, QColor(*colors[i]))
+        return property(fget=fget, fset=fset)
+
+    def read_custom_colors(self):
+        colors = self.color_prefs.get('custom_colors_for_color_dialog', None)
+        if colors is not None:
+            self.current_custom_colors = colors
+
+    def save_custom_colors(self):
+        # Qt 5 regression, it no longer saves custom colors
+        colors = self.current_custom_colors
+        if colors != self.color_prefs.get('custom_colors_for_color_dialog', None):
+            self.color_prefs.set('custom_colors_for_color_dialog', colors)
+
 _store_app = None
 
 class SanitizeLibraryPath(object):

src/calibre/gui2/tweak_book/main.py

@@ -47,13 +47,14 @@ def _run(args, notify=None):
     # errors during initialization of plugins that use the polish container
     # infrastructure.
     importlib.import_module('calibre.customize.ui')
+    from calibre.gui2.tweak_book import tprefs
     from calibre.gui2.tweak_book.ui import Main
 
     parser = option_parser()
     opts, args = parser.parse_args(args)
     decouple('edit-book-')
     override = 'calibre-edit-book' if islinux else None
-    app = Application(args, override_program_name=override)
+    app = Application(args, override_program_name=override, color_prefs=tprefs)
     app.load_builtin_fonts()
     app.setWindowIcon(QIcon(I('tweak.png')))
     Application.setOrganizationName(ORG_NAME)

src/calibre/gui2/viewer/main.py

@@ -993,7 +993,7 @@ def main(args=sys.argv):
     opts, args = parser.parse_args(args)
     open_at = float(opts.open_at.replace(',', '.')) if opts.open_at else None
     override = 'calibre-ebook-viewer' if islinux else None
-    app = Application(args, override_program_name=override)
+    app = Application(args, override_program_name=override, color_prefs=vprefs)
     app.load_builtin_fonts()
     app.setWindowIcon(QIcon(I('viewer.png')))
     QApplication.setOrganizationName(ORG_NAME)