[PATCH 1/1] kernel-shark: Use mouse wheel to scroll the graphs

["Yordan Karadzhov (VMware)" <y.karadz@gmail.com>]

The current zoom-in/zoom-out function of the mouse wheel will be
performed only when rolling the mouse wheel and simultaneously
pressing "Ctrl", while just rolling the wheel will move you up or
down in the scroll area of the graphs without zooming.

We want to introduce the change because zoom via Ctrl+ScrollWheel
is a binding familiar from the Web Browsers.

Suggested-by: FeRD (Frank Dana) <ferdnyc@gmail.com>
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 kernel-shark/src/KsGLWidget.cpp   | 3 ++-
 kernel-shark/src/KsTraceGraph.hpp | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel-shark/src/KsGLWidget.cpp b/kernel-shark/src/KsGLWidget.cpp
index 78ded33..404f0d0 100644
--- a/kernel-shark/src/KsGLWidget.cpp
+++ b/kernel-shark/src/KsGLWidget.cpp
@@ -266,7 +266,8 @@ void KsGLWidget::wheelEvent(QWheelEvent * event)
 {
 	int zoomFocus;
 
-	if (isEmpty())
+	if (QApplication::keyboardModifiers() != Qt::ControlModifier ||
+	    isEmpty())
 		return;
 
 	if (_mState->activeMarker()._isSet &&
diff --git a/kernel-shark/src/KsTraceGraph.hpp b/kernel-shark/src/KsTraceGraph.hpp
index 0eeef14..15ade42 100644
--- a/kernel-shark/src/KsTraceGraph.hpp
+++ b/kernel-shark/src/KsTraceGraph.hpp
@@ -28,7 +28,10 @@ public:
 	 * Reimplemented handler for mouse wheel events. All mouse wheel
 	 * events will be ignored.
 	 */
-	void wheelEvent(QWheelEvent *evt) {evt->ignore();}
+	void wheelEvent(QWheelEvent *evt) {
+		if (QApplication::keyboardModifiers() != Qt::ControlModifier)
+			QScrollArea::wheelEvent(evt);
+	}
 };
 
 /**
-- 
2.25.1