Help viewer: Add option for scroll wheel zooming

Fixes: QTCREATORBUG-14154
Change-Id: Ia6c4aedb78954614477f0228ba82c4dc476a2525
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: David Schulz <david.schulz@qt.io>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/plugins/help/helpviewer.cpp b/src/plugins/help/helpviewer.cpp
index 1c40bbd111..d667c3b26c 100644
--- a/src/plugins/help/helpviewer.cpp
+++ b/src/plugins/help/helpviewer.cpp
@@ -91,6 +91,16 @@ HelpViewer::~HelpViewer()
     restoreOverrideCursor();
 }
 
+void HelpViewer::setScrollWheelZoomingEnabled(bool enabled)
+{
+    m_scrollWheelZoomingEnabled = enabled;
+}
+
+bool HelpViewer::isScrollWheelZoomingEnabled() const
+{
+    return m_scrollWheelZoomingEnabled;
+}
+
 void HelpViewer::setActionVisible(Action action, bool visible)
 {
     if (visible)
@@ -162,6 +172,16 @@ void HelpViewer::home()
     setSource(LocalHelpManager::homePage());
 }
 
+void HelpViewer::wheelEvent(QWheelEvent *event)
+{
+    if (m_scrollWheelZoomingEnabled && event->modifiers() == Qt::ControlModifier) {
+        event->accept();
+        event->delta() > 0 ? scaleUp() : scaleDown();
+    } else {
+        QWidget::wheelEvent(event);
+    }
+}
+
 void HelpViewer::slotLoadStarted()
 {
     ++m_loadOverrideStack;