[FEATURE] Colourblind preview modes now work on OSX (#4971)

* [FEATURE] Colourblind preview modes now work on OSX

* Enable colour picker widgets on Mac OS and colour preview modes in composer in Mac OS

src/app/composer/qgscomposer.cpp

@@ -326,16 +326,12 @@ QgsComposer::QgsComposer( QgsComposition *composition )
   QShortcut *ctrlEquals = new QShortcut( QKeySequence( QStringLiteral( "Ctrl+=" ) ), this );
   connect( ctrlEquals, &QShortcut::activated, mActionZoomIn, &QAction::trigger );
 
-#ifndef Q_OS_MAC
-  //disabled for OSX - see #10761
-  //also see http://qt-project.org/forums/viewthread/3630 QGraphicsEffects are not well supported on OSX
   QMenu *previewMenu = viewMenu->addMenu( QStringLiteral( "&Preview" ) );
   previewMenu->addAction( mActionPreviewModeOff );
   previewMenu->addAction( mActionPreviewModeGrayscale );
   previewMenu->addAction( mActionPreviewModeMono );
   previewMenu->addAction( mActionPreviewProtanope );
   previewMenu->addAction( mActionPreviewDeuteranope );
-#endif
 
   viewMenu->addSeparator();
   viewMenu->addAction( mActionZoomIn );

src/app/qgisapp.cpp

@@ -2244,14 +2244,6 @@ void QgisApp::createMenus()
     mSettingsMenu->insertSeparator( before );
   }
 
-
-#ifdef Q_OS_MAC
-  //disabled for OSX - see #10761
-  //also see http://qt-project.org/forums/viewthread/3630 QGraphicsEffects are not well supported on OSX
-  mMenuPreviewMode->menuAction()->setVisible( false );
-#endif
-
-
 #ifdef Q_OS_MAC
 
   // keep plugins from hijacking About and Preferences application menus

src/gui/qgscolorbutton.cpp

@@ -520,14 +520,13 @@ void QgsColorButton::prepareMenu()
   mMenu->addAction( pasteColorAction );
   connect( pasteColorAction, &QAction::triggered, this, &QgsColorButton::pasteColor );
 
-#ifndef Q_OS_MAC
   //disabled for OSX, as it is impossible to grab the mouse under OSX
   //see note for QWidget::grabMouse() re OSX Cocoa
   //http://qt-project.org/doc/qt-4.8/qwidget.html#grabMouse
   QAction *pickColorAction = new QAction( tr( "Pick color" ), this );
   mMenu->addAction( pickColorAction );
   connect( pickColorAction, &QAction::triggered, this, &QgsColorButton::activatePicker );
-#endif
+
   QAction *chooseColorAction = new QAction( tr( "Choose color..." ), this );
   mMenu->addAction( chooseColorAction );
   connect( chooseColorAction, &QAction::triggered, this, &QgsColorButton::showColorDialog );

src/gui/qgscompoundcolorwidget.cpp

@@ -201,13 +201,6 @@ QgsCompoundColorWidget::QgsCompoundColorWidget( QWidget *parent, const QColor &c
   int currentTab = settings.value( QStringLiteral( "Windows/ColorDialog/activeTab" ), 0 ).toInt();
   mTabWidget->setCurrentIndex( currentTab );
 
-#ifdef Q_OS_MAC
-  //disable color picker tab for OSX, as it is impossible to grab the mouse under OSX
-  //see note for QWidget::grabMouse() re OSX Cocoa
-  //http://qt-project.org/doc/qt-4.8/qwidget.html#grabMouse
-  mTabWidget->removeTab( 3 );
-#endif
-
   //setup connections
   connect( mColorBox, &QgsColorWidget::colorChanged, this, &QgsCompoundColorWidget::setColor );
   connect( mColorWheel, &QgsColorWidget::colorChanged, this, &QgsCompoundColorWidget::setColor );