[GtkUI] Add a way to change themes

Currently, the only way to change the themes is by manually set a value
in the command line or set it as env variable.

Closes: https://dev.deluge-torrent.org/ticket/3536
Closes: https://github.com/deluge-torrent/deluge/pull/392

4 files changed, 101 insertions, 5 deletions

diff --git a/deluge/ui/gtk3/glade/preferences_dialog.ui b/deluge/ui/gtk3/glade/preferences_dialog.ui
index aa1531d75..44bcafe4c 100644
--- a/deluge/ui/gtk3/glade/preferences_dialog.ui
+++ b/deluge/ui/gtk3/glade/preferences_dialog.ui
@@ -430,6 +430,77 @@
                               </packing>
                             </child>
                             <child>
+                              <object class="GtkFrame" id="frame_theme">
+                                <property name="visible">True</property>
+                                <property name="can_focus">False</property>
+                                <property name="label_xalign">0</property>
+                                <property name="shadow_type">none</property>
+                                <child>
+                                  <object class="GtkAlignment" id="alignment_theme">
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">False</property>
+                                    <property name="top_padding">3</property>
+                                    <property name="left_padding">10</property>
+                                    <child>
+                                      <object class="GtkBox" id="hbox_theme">
+                                        <property name="visible">True</property>
+                                        <property name="can_focus">False</property>
+                                        <child>
+                                          <object class="GtkRadioButton" id="radio_theme_light">
+                                            <property name="label" translatable="yes">Light</property>
+                                            <property name="visible">True</property>
+                                            <property name="can_focus">True</property>
+                                            <property name="receives_default">False</property>
+                                            <property name="tooltip_text" translatable="yes">The light theme</property>
+                                            <property name="active">True</property>
+                                            <property name="draw_indicator">True</property>
+                                          </object>
+                                          <packing>
+                                            <property name="expand">False</property>
+                                            <property name="fill">True</property>
+                                            <property name="position">0</property>
+                                          </packing>
+                                        </child>
+                                        <child>
+                                          <object class="GtkRadioButton" id="radio_theme_dark">
+                                            <property name="label" translatable="yes">Dark</property>
+                                            <property name="visible">True</property>
+                                            <property name="can_focus">True</property>
+                                            <property name="receives_default">False</property>
+                                            <property name="tooltip_text" translatable="yes">The dark theme</property>
+                                            <property name="draw_indicator">True</property>
+                                            <property name="group">radio_theme_light</property>
+                                          </object>
+                                          <packing>
+                                            <property name="expand">False</property>
+                                            <property name="fill">True</property>
+                                            <property name="padding">7</property>
+                                            <property name="position">1</property>
+                                          </packing>
+                                        </child>
+                                      </object>
+                                    </child>
+                                  </object>
+                                </child>
+                                <child type="label">
+                                  <object class="GtkLabel" id="label_theme">
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">False</property>
+                                    <property name="label" translatable="yes">Theme</property>
+                                    <attributes>
+                                      <attribute name="weight" value="bold"/>
+                                    </attributes>
+                                  </object>
+                                </child>
+                              </object>
+                              <packing>
+                                <property name="expand">False</property>
+                                <property name="fill">False</property>
+                                <property name="padding">5</property>
+                                <property name="position">1</property>
+                              </packing>
+                            </child>
+                            <child>
                               <object class="GtkFrame" id="frame29">
                                 <property name="visible">True</property>
                                 <property name="can_focus">False</property>
@@ -736,7 +807,7 @@ and daemon (does not apply in Standalone mode).</property>
                                 <property name="expand">False</property>
                                 <property name="fill">False</property>
                                 <property name="padding">5</property>
-                                <property name="position">1</property>
+                                <property name="position">2</property>
                               </packing>
                             </child>
                             <child>
@@ -964,7 +1035,7 @@ and daemon (does not apply in Standalone mode).</property>
                                 <property name="expand">False</property>
                                 <property name="fill">True</property>
                                 <property name="padding">5</property>
-                                <property name="position">2</property>
+                                <property name="position">3</property>
                               </packing>
                             </child>
                             <child>
@@ -1024,7 +1095,7 @@ and daemon (does not apply in Standalone mode).</property>
                                 <property name="expand">False</property>
                                 <property name="fill">False</property>
                                 <property name="padding">5</property>
-                                <property name="position">3</property>
+                                <property name="position">4</property>
                               </packing>
                             </child>
                             <child>
@@ -1101,7 +1172,7 @@ and daemon (does not apply in Standalone mode).</property>
                               <packing>
                                 <property name="expand">False</property>
                                 <property name="fill">True</property>
-                                <property name="position">4</property>
+                                <property name="position">5</property>
                               </packing>
                             </child>
                           </object>
diff --git a/deluge/ui/gtk3/gtkui.py b/deluge/ui/gtk3/gtkui.py
index 434d1b82b..0fbb5b773 100644
--- a/deluge/ui/gtk3/gtkui.py
+++ b/deluge/ui/gtk3/gtkui.py
@@ -84,6 +84,7 @@ except ImportError:
 
 DEFAULT_PREFS = {
     'standalone': True,
+    'dark_theme': False,
     'interactive_add': True,
     'focus_add_dialog': True,
     'enable_system_tray': True,
diff --git a/deluge/ui/gtk3/mainwindow.py b/deluge/ui/gtk3/mainwindow.py
index e1e3bb342..84956f2cd 100644
--- a/deluge/ui/gtk3/mainwindow.py
+++ b/deluge/ui/gtk3/mainwindow.py
@@ -72,6 +72,12 @@ class MainWindow(component.Component):
         self.config = ConfigManager('gtk3ui.conf')
         self.main_builder = Gtk.Builder()
 
+        # Set theme
+        Gtk.Settings.get_default().set_property(
+            'gtk-application-prefer-dark-theme',
+            self.config['dark_theme'],
+        )
+
         # Patch this GtkBuilder to avoid connecting signals from elsewhere
         #
         # Think about splitting up  mainwindow gtkbuilder file into the necessary parts
diff --git a/deluge/ui/gtk3/preferences.py b/deluge/ui/gtk3/preferences.py
index a024a5958..cf303d75a 100644
--- a/deluge/ui/gtk3/preferences.py
+++ b/deluge/ui/gtk3/preferences.py
@@ -13,7 +13,7 @@ from hashlib import sha1 as sha
 from urllib.parse import urlparse
 
 from gi import require_version
-from gi.repository import Gtk
+from gi.repository import GObject, Gtk
 from gi.repository.Gdk import Color
 
 import deluge.common
@@ -171,6 +171,14 @@ class Preferences(component.Component):
         # Radio buttons to choose between systray and appindicator
         self.builder.get_object('alignment_tray_type').set_visible(appindicator)
 
+        # Initialize a binding for dark theme
+        Gtk.Settings.get_default().bind_property(
+            'gtk-application-prefer-dark-theme',
+            self.builder.get_object('radio_theme_dark'),
+            'active',
+            GObject.BindingFlags.BIDIRECTIONAL | GObject.BindingFlags.SYNC_CREATE,
+        )
+
         from .gtkui import DEFAULT_PREFS
 
         self.COLOR_DEFAULTS = {}
@@ -557,6 +565,9 @@ class Preferences(component.Component):
         self.builder.get_object('radio_thinclient').set_active(
             not self.gtkui_config['standalone']
         )
+        self.builder.get_object('radio_theme_dark').set_active(
+            self.gtkui_config['dark_theme']
+        )
         self.builder.get_object('chk_show_rate_in_title').set_active(
             self.gtkui_config['show_rate_in_title']
         )
@@ -741,6 +752,9 @@ class Preferences(component.Component):
         ).get_active()
 
         # Interface tab #
+        new_gtkui_config['dark_theme'] = self.builder.get_object(
+            'radio_theme_dark'
+        ).get_active()
         new_gtkui_config['enable_system_tray'] = self.builder.get_object(
             'chk_use_tray'
         ).get_active()
@@ -1074,6 +1088,10 @@ class Preferences(component.Component):
 
     def on_button_cancel_clicked(self, data):
         log.debug('on_button_cancel_clicked')
+        Gtk.Settings.get_default().set_property(
+            'gtk-application-prefer-dark-theme',
+            self.gtkui_config['dark_theme'],
+        )
         self.hide()
         return True