X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=pv%2Fview%2Fviewport.cpp;h=d9be32c996ee142b44603d1c9097a9bcde93295a;hb=08d9c3caec0a3ad1c624af685f948e17b91d278a;hp=2dfdddc1448bddecd8653918c63204ca63dd266c;hpb=18ca62d26394f2ffe6e993ff02cd64958b2cee1b;p=pulseview.git

diff --git a/pv/view/viewport.cpp b/pv/view/viewport.cpp
index 2dfdddc1..d9be32c9 100644
--- a/pv/view/viewport.cpp
+++ b/pv/view/viewport.cpp
@@ -82,7 +82,8 @@ void Viewport::drag()
 
 void Viewport::drag_by(const QPoint &delta)
 {
-	if (isnan(drag_offset_))
+	// Use std::isnan() instead of isnan(), the latter can cause issues.
+	if (std::isnan(drag_offset_))
 		return;
 
 	view_.set_scale_offset(view_.scale(), drag_offset_ -
@@ -194,18 +195,27 @@ void Viewport::mouseDoubleClickEvent(QMouseEvent *event)
 		view_.zoom(-2.0, event->x());
 }
 
-void Viewport::wheelEvent(QWheelEvent *event)
+void Viewport::wheelEvent(QWheelEvent *e)
 {
-	assert(event);
-
-	if (event->orientation() == Qt::Vertical) {
-		// Vertical scrolling is interpreted as zooming in/out
-		view_.zoom(event->delta() / 120, event->x());
-	} else if (event->orientation() == Qt::Horizontal) {
+	assert(e);
+
+	if (e->orientation() == Qt::Vertical)
+	{
+		if (e->modifiers() & Qt::ControlModifier) {
+			// Vertical scrolling with the control key pressed
+			// is intrepretted as vertical scrolling
+			view_.set_v_offset(-view_.owner_visual_v_offset() -
+				(e->delta() * height()) / (8 * 120));
+		} else {
+			// Vertical scrolling is interpreted as zooming in/out
+			view_.zoom(e->delta() / 120, e->x());
+		}
+	}
+	else if (e->orientation() == Qt::Horizontal)
+	{
 		// Horizontal scrolling is interpreted as moving left/right
 		view_.set_scale_offset(view_.scale(),
-				       event->delta() * view_.scale()
-				       + view_.offset());
+			e->delta() * view_.scale() + view_.offset());
 	}
 }