Allow to tilt/rotate the map using the scroll wheel

This patch allows to rotate the map by using the scroll wheel in
combination with the Shift key, and to tilt the map in combination
with the Control key.

[ChangeLog][QtLocation][MapGestureArea] Added rotation and tilt
scrollwheel actions.

Change-Id: I1cfdad7615258e75506802ac4f4e71413b71b8ce
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

1 files changed, 22 insertions, 9 deletions

diff --git a/src/location/declarativemaps/qquickgeomapgesturearea.cpp b/src/location/declarativemaps/qquickgeomapgesturearea.cpp
index 6931c774..39fd2397 100644
--- a/src/location/declarativemaps/qquickgeomapgesturearea.cpp
+++ b/src/location/declarativemaps/qquickgeomapgesturearea.cpp
@@ -243,6 +243,8 @@ QT_BEGIN_NAMESPACE
     MapGestureArea objects are used as part of a Map, to provide for panning,
     flicking and pinch-to-zoom gesture used on touch displays, as well as two finger rotation
     and two finger parallel vertical sliding to tilt the map.
+    On platforms supporting \l QWheelEvent, using the scroll wheel alone, or in combination with
+    key modifiers Shift or Control will also zoom, rotate or tilt the map, respectively.
 
     A MapGestureArea is automatically created with a new Map and available with
     the \l{Map::gesture}{gesture} property. This is the only way
@@ -939,15 +941,26 @@ void QQuickGeoMapGestureArea::handleWheelEvent(QWheelEvent *event)
     const QGeoCoordinate &wheelGeoPos = m_map->geoProjection().itemPositionToCoordinate(QDoubleVector2D(event->posF()), false);
     const QPointF &preZoomPoint = event->posF();
 
-    const double zoomLevelDelta = event->angleDelta().y() * qreal(0.001);
-    // Gesture area should always honor maxZL, but Map might not.
-    m_declarativeMap->setZoomLevel(qMin<qreal>(m_declarativeMap->zoomLevel() + zoomLevelDelta, maximumZoomLevel()),
-                                   false);
-    const QPointF &postZoomPoint = m_map->geoProjection().coordinateToItemPosition(wheelGeoPos, false).toPointF();
-
-    if (preZoomPoint != postZoomPoint) // need to re-anchor the wheel geoPos to the event position
-          m_declarativeMap->setCenter(m_map->geoProjection().anchorCoordinateToPoint(wheelGeoPos, preZoomPoint));
-
+    // Not using AltModifier as, for some reason, it causes angleDelta to be 0
+    if (event->modifiers() & Qt::ShiftModifier && rotationEnabled()) {
+        // First set bearing
+        const double bearingDelta = event->angleDelta().y() * qreal(0.05);
+        m_declarativeMap->setBearing(m_declarativeMap->bearing() + bearingDelta);
+        // then reanchor
+        m_declarativeMap->setCenter(m_map->geoProjection().anchorCoordinateToPoint(wheelGeoPos, preZoomPoint));
+    } else if (event->modifiers() & Qt::ControlModifier && tiltEnabled()) {
+        const double tiltDelta = event->angleDelta().y() * qreal(0.05);
+        m_declarativeMap->setTilt(m_declarativeMap->tilt() + tiltDelta);
+    } else if (pinchEnabled()) {
+        const double zoomLevelDelta = event->angleDelta().y() * qreal(0.001);
+        // Gesture area should always honor maxZL, but Map might not.
+        m_declarativeMap->setZoomLevel(qMin<qreal>(m_declarativeMap->zoomLevel() + zoomLevelDelta, maximumZoomLevel()),
+                                       false);
+        const QPointF &postZoomPoint = m_map->geoProjection().coordinateToItemPosition(wheelGeoPos, false).toPointF();
+
+        if (preZoomPoint != postZoomPoint) // need to re-anchor the wheel geoPos to the event position
+              m_declarativeMap->setCenter(m_map->geoProjection().anchorCoordinateToPoint(wheelGeoPos, preZoomPoint));
+    }
     event->accept();
 }
 #endif