Expose 'change colors' through dbus interface

Summary:
This exposes the Okular's functionality of changing the document's colors
through its d-bus interface. This is mainly useful for scripting Okular to
switch to a 'day mode' or 'night mode'.

[Example] Switching themes of two applications with one hotkey:

{F5905771}

Reviewers: #okular, aacid

Reviewed By: #okular, aacid

Subscribers: okular-devel

Tags: #okular

Differential Revision: https://phabricator.kde.org/D13471

part.cpp

@@ -2848,6 +2848,15 @@ void Part::slotPreferences()
     dialog->show();
 }
 
+void Part::slotToggleChangeColors()
+{
+  m_pageView->slotToggleChangeColors();
+}
+
+void Part::slotSetChangeColors(bool active)
+{
+  m_pageView->slotSetChangeColors(active);
+}
 
 void Part::slotAnnotationPreferences()
 {

part.h

@@ -163,6 +163,8 @@ class OKULARPART_EXPORT Part : public KParts::ReadWritePart, public Okular::Docu
         Q_SCRIPTABLE void slotGotoFirst();
         Q_SCRIPTABLE void slotGotoLast();
         Q_SCRIPTABLE void slotTogglePresentation();
+        Q_SCRIPTABLE void slotToggleChangeColors();
+        Q_SCRIPTABLE void slotSetChangeColors(bool active);
         Q_SCRIPTABLE Q_NOREPLY void reload();
         Q_SCRIPTABLE Q_NOREPLY void enableStartWithPrint();
         Q_SCRIPTABLE Q_NOREPLY void enableExitAfterPrint();

ui/pageview.cpp

@@ -5498,13 +5498,18 @@ void PageView::slotProcessRenditionAction( const Okular::RenditionAction *action
     };
 }
 
-void PageView::slotToggleChangeColors()
+void PageView::slotSetChangeColors(bool active)
 {
-    Okular::SettingsCore::setChangeColors( !Okular::SettingsCore::changeColors() );
+    Okular::SettingsCore::setChangeColors(active);
     Okular::Settings::self()->save();
     viewport()->update();
 }
 
+void PageView::slotToggleChangeColors()
+{
+    slotSetChangeColors( !Okular::SettingsCore::changeColors() );
+}
+
 void PageView::slotFitWindowToPage()
 {
     PageViewItem currentPageItem = nullptr;

ui/pageview.h

@@ -124,6 +124,9 @@ Q_OBJECT
         void openAnnotationWindow( Okular::Annotation *annotation, int pageNumber );
         void reloadForms();
 
+        void slotToggleChangeColors();
+        void slotSetChangeColors(bool active);
+
     Q_SIGNALS:
         void rightClick( const Okular::Page *, const QPoint & );
         void mouseBackButtonClick();
@@ -269,7 +272,6 @@ Q_OBJECT
         void slotAnnotationWindowDestroyed( QObject *window );
         void slotProcessMovieAction( const Okular::MovieAction *action );
         void slotProcessRenditionAction( const Okular::RenditionAction *action );
-        void slotToggleChangeColors();
         void slotFitWindowToPage();
 };