highgui module: implemented QT and GTK mouse wheel callback support in linux

modules/highgui/src/window_QT.cpp

@@ -2629,8 +2629,18 @@ void DefaultViewPort::resizeEvent(QResizeEvent* evnt)
 
 void DefaultViewPort::wheelEvent(QWheelEvent* evnt)
 {
-    scaleView(evnt->delta() / 240.0, evnt->pos());
+    int delta = evnt->delta();
+    int cv_event = -1;
+    int flags = ((delta & 0xffff)<<16) | ((evnt->orientation() == Qt::Vertical) ? CV_EVENT_MOUSEWHEEL : CV_EVENT_MOUSEHWHEEL);
+    QPoint pt = evnt->pos();
+
+    icvmouseHandler(evnt, mouse_wheel, cv_event, flags);
+    icvmouseProcessing(QPoingF(pt), cv_event, flags);
+
+    scaleView(evnt->delta() / 240.0, pt);
     viewport()->update();
+
+    QWidget::mouseWheel(evnt);
 }
 
 

modules/highgui/src/window_QT.h

@@ -366,7 +366,7 @@ private slots:
 };
 
 
-enum type_mouse_event { mouse_up = 0, mouse_down = 1, mouse_dbclick = 2, mouse_move = 3 };
+enum type_mouse_event { mouse_up = 0, mouse_down = 1, mouse_dbclick = 2, mouse_move = 3, mouse_wheel = 3 };
 static const int tableMouseButtons[][3]={
     {CV_EVENT_LBUTTONUP, CV_EVENT_RBUTTONUP, CV_EVENT_MBUTTONUP},               //mouse_up
     {CV_EVENT_LBUTTONDOWN, CV_EVENT_RBUTTONDOWN, CV_EVENT_MBUTTONDOWN},         //mouse_down

modules/highgui/src/window_gtk.cpp

@@ -1066,6 +1066,8 @@ CV_IMPL int cvNamedWindow( const char* name, int flags )
                         G_CALLBACK(icvOnMouse), window );
     g_signal_connect( window->widget, "motion-notify-event",
                         G_CALLBACK(icvOnMouse), window );
+    g_signal_connect( window->widget, "scroll-event",
+                        G_CALLBACK(icvOnMouse), window );
     g_signal_connect( window->frame, "delete-event",
                         G_CALLBACK(icvOnClose), window );
 #if defined(GTK_VERSION3)
@@ -1076,7 +1078,7 @@ CV_IMPL int cvNamedWindow( const char* name, int flags )
                         G_CALLBACK(cvImageWidget_expose), window );
 #endif //GTK_VERSION3
 
-    gtk_widget_add_events (window->widget, GDK_BUTTON_RELEASE_MASK | GDK_BUTTON_PRESS_MASK | GDK_POINTER_MOTION_MASK) ;
+    gtk_widget_add_events (window->widget, GDK_BUTTON_RELEASE_MASK | GDK_BUTTON_PRESS_MASK | GDK_POINTER_MOTION_MASK | GDK_SCROLL_MASK) ;
 
     gtk_widget_show( window->frame );
     gtk_window_set_title( GTK_WINDOW(window->frame), name );
@@ -1947,6 +1949,13 @@ static gboolean icvOnMouse( GtkWidget *widget, GdkEvent *event, gpointer user_da
         }
         state = event_button->state;
     }
+    else if( event->type == GDK_SCROLL )
+    {
+        GdkEventButton* event_button = (GdkEventButton*)event;
+
+        cv_event = CV_EVENT_MOUSEWHEEL;
+        state = event_button->state;
+    }
 
     if( cv_event >= 0 ){
         // scale point if image is scaled
@@ -1973,7 +1982,23 @@ static gboolean icvOnMouse( GtkWidget *widget, GdkEvent *event, gpointer user_da
 //        if((unsigned)pt.x < (unsigned)(image_widget->original_image->width) &&
 //           (unsigned)pt.y < (unsigned)(image_widget->original_image->height) )
         {
-            int flags = (state & GDK_SHIFT_MASK ? CV_EVENT_FLAG_SHIFTKEY : 0) |
+            int flags = 0;
+            if (state & GDK_SCROLL_MASK) {
+                cv_event = CV_EVENT_MOUSEMOVE;
+                int orient = CV_EVENT_MOUSEWHEEL;
+                switch(event->scroll.direction) {
+                case GDK_SCROLL_RIGHT: orient = CV_EVENT_MOUSEHWHEEL;
+                case GDK_SCROLL_UP:    flags |= ((1 << 16) | orient);
+                    break;
+                case GDK_SCROLL_LEFT:  orient = CV_EVENT_MOUSEHWHEEL;
+                case GDK_SCROLL_DOWN:  flags |= ((-1 << 16) | orient);
+                    break;
+                case GDK_SCROLL_SMOOTH: // to prevent make warning; TODO
+                    ;
+                };
+            };
+            flags = flags |
+                (state & GDK_SHIFT_MASK ? CV_EVENT_FLAG_SHIFTKEY : 0) |
                 (state & GDK_CONTROL_MASK ? CV_EVENT_FLAG_CTRLKEY : 0) |
                 (state & (GDK_MOD1_MASK|GDK_MOD2_MASK) ? CV_EVENT_FLAG_ALTKEY : 0) |
                 (state & GDK_BUTTON1_MASK ? CV_EVENT_FLAG_LBUTTON : 0) |