refs #883, added functions for fade in/out

src/blackgui/guiutility.cpp

@@ -29,8 +29,11 @@
 #include <QTabWidget>
 #include <QThreadStorage>
 #include <QWidget>
+#include <QTimer>
 #include <Qt>
 #include <QtGlobal>
+#include <QGraphicsOpacityEffect>
+#include <QPropertyAnimation>
 
 using namespace BlackMisc;
 
@@ -345,4 +348,33 @@ namespace BlackGui
     {
         return QApplication::topLevelWidgets().contains(widget);
     }
+
+    QGraphicsOpacityEffect *CGuiUtility::fadeInWidget(int durationMs, QWidget *widget, double startValue, double endValue)
+    {
+        // http://stackoverflow.com/questions/19087822/how-to-make-qt-widgets-fade-in-or-fade-out#
+        Q_ASSERT(widget);
+        QGraphicsOpacityEffect *effect = new QGraphicsOpacityEffect(widget);
+        widget->setGraphicsEffect(effect);
+        QPropertyAnimation *a = new QPropertyAnimation(effect, "opacity");
+        a->setDuration(durationMs);
+        a->setStartValue(startValue);
+        a->setEndValue(endValue);
+        a->setEasingCurve(QEasingCurve::InBack);
+        a->start(QPropertyAnimation::DeleteWhenStopped);
+        return effect;
+    }
+
+    QGraphicsOpacityEffect *CGuiUtility::fadeOutWidget(int durationMs, QWidget *widget, double startValue, double endValue)
+    {
+        Q_ASSERT(widget);
+        QGraphicsOpacityEffect *effect = new QGraphicsOpacityEffect(widget);
+        widget->setGraphicsEffect(effect);
+        QPropertyAnimation *a = new QPropertyAnimation(effect, "opacity");
+        a->setDuration(durationMs);
+        a->setStartValue(startValue);
+        a->setEndValue(endValue);
+        a->setEasingCurve(QEasingCurve::OutBack);
+        a->start(QPropertyAnimation::DeleteWhenStopped);
+        return effect;
+    }
 } // ns

src/blackgui/guiutility.h

@@ -27,6 +27,7 @@ class QLayout;
 class QMimeData;
 class QTabWidget;
 class QWidget;
+class QGraphicsOpacityEffect;
 
 namespace BlackGui
 {
@@ -106,6 +107,12 @@ namespace BlackGui
         //! Is top level widget?
         static bool isTopLevelWidget(QWidget *widget);
 
+        //! Fade in a widget
+        static QGraphicsOpacityEffect *fadeInWidget(int durationMs, QWidget *widget, double startValue = 0.0, double endValue = 1.0);
+
+        //! Fade out a widget
+        static QGraphicsOpacityEffect *fadeOutWidget(int durationMs, QWidget *widget, double startValue = 1.0, double endValue = 0.0);
+
     private:
         //! Constructor, use static methods only
         CGuiUtility() {}