Added mouse wheel event logic to Qt TAS piano roll.

src/drivers/Qt/TasEditor/TasEditorWindow.cpp

@@ -3166,6 +3166,7 @@ QPianoRoll::QPianoRoll(QWidget *parent)
 	markerDragFrameNumber = 0;
 	markerDragCountdown = 0;
 	drawingStartTimestamp = 0;
+	wheelPixelCounter = 0;
 	headerItemUnderMouse = 0;
 	nextHeaderUpdateTime = 0;
 	mouse_x = mouse_y = -1;
@@ -3836,6 +3837,57 @@ void QPianoRoll::mouseMoveEvent(QMouseEvent * event)
 	updateDrag();
 }
 //----------------------------------------------------------------------------
+void QPianoRoll::wheelEvent(QWheelEvent *event)
+{
+	int ofs;
+
+	QPoint numPixels = event->pixelDelta();
+	QPoint numDegrees = event->angleDelta();
+
+	ofs = vbar->value();
+
+	if (!numPixels.isNull())
+	{
+		wheelPixelCounter -= numPixels.y();
+		//printf("numPixels: (%i,%i) \n", numPixels.x(), numPixels.y() );
+	}
+	else if (!numDegrees.isNull())
+	{
+		//QPoint numSteps = numDegrees / 15;
+		//printf("numSteps: (%i,%i) \n", numSteps.x(), numSteps.y() );
+		//printf("numDegrees: (%i,%i)  %i\n", numDegrees.x(), numDegrees.y(), pxLineSpacing );
+		wheelPixelCounter -= (pxLineSpacing * numDegrees.y()) / (15 * 8);
+	}
+	//printf("Wheel Event: %i\n", wheelPixelCounter);
+
+	if (wheelPixelCounter >= pxLineSpacing)
+	{
+		ofs += (wheelPixelCounter / pxLineSpacing);
+
+		if (ofs > maxLineOffset)
+		{
+			ofs = maxLineOffset;
+		}
+		vbar->setValue(ofs);
+
+		wheelPixelCounter = wheelPixelCounter % pxLineSpacing;
+	}
+	else if (wheelPixelCounter <= -pxLineSpacing)
+	{
+		ofs += (wheelPixelCounter / pxLineSpacing);
+
+		if (ofs < 0)
+		{
+			ofs = 0;
+		}
+		vbar->setValue(ofs);
+
+		wheelPixelCounter = wheelPixelCounter % pxLineSpacing;
+	}
+
+	event->accept();
+}
+//----------------------------------------------------------------------------
 void QPianoRoll::keyPressEvent(QKeyEvent *event)
 {
 	//printf("Key Press: 0x%x \n", event->key() );

src/drivers/Qt/TasEditor/TasEditorWindow.h

@@ -165,6 +165,7 @@ class QPianoRoll : public QWidget
 		void mouseReleaseEvent(QMouseEvent * event);
 		void mouseMoveEvent(QMouseEvent * event);
 		void mouseDoubleClickEvent(QMouseEvent * event);
+		void wheelEvent(QWheelEvent *event);
 		void keyPressEvent(QKeyEvent *event);
 		void keyReleaseEvent(QKeyEvent *event);
 		void focusInEvent(QFocusEvent *event);
@@ -224,6 +225,7 @@ class QPianoRoll : public QWidget
 		int markerDragFrameNumber;
 		int markerDragCountdown;
 		int drawingStartTimestamp;
+		int wheelPixelCounter;
 		int headerItemUnderMouse;
 		int nextHeaderUpdateTime;
 		int mouse_x;