Fix MapQuickItem when zoomLevel is set

This patch fixes the behavior of MapQuickItem when the zoomLevel is
set, that is it makes behave the qquickitem as if it would be
on the map, instead of on the screen.

Change-Id: Ibb8a6000e2f6a37a68c32df001fc8565079a6f70
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

1 files changed, 36 insertions, 5 deletions

diff --git a/src/location/declarativemaps/qdeclarativegeomapquickitem.cpp b/src/location/declarativemaps/qdeclarativegeomapquickitem.cpp
index 4fab18cb..5a10f39f 100644
--- a/src/location/declarativemaps/qdeclarativegeomapquickitem.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomapquickitem.cpp
@@ -115,9 +115,25 @@ QT_BEGIN_NAMESPACE
     \image api-mapquickitem.png
 */
 
+QMapQuickItemMatrix4x4::QMapQuickItemMatrix4x4(QObject *parent) : QQuickTransform(parent) { }
+
+void QMapQuickItemMatrix4x4::setMatrix(const QMatrix4x4 &matrix)
+{
+    if (m_matrix == matrix)
+        return;
+    m_matrix = matrix;
+    update();
+}
+
+void QMapQuickItemMatrix4x4::applyTo(QMatrix4x4 *matrix) const
+{
+    *matrix *= m_matrix;
+}
+
+
 QDeclarativeGeoMapQuickItem::QDeclarativeGeoMapQuickItem(QQuickItem *parent)
 :   QDeclarativeGeoMapItemBase(parent), zoomLevel_(0.0),
-    mapAndSourceItemSet_(false), updatingGeometry_(false)
+    mapAndSourceItemSet_(false), updatingGeometry_(false), matrix_(nullptr)
 {
     setFlag(ItemHasContents, true);
     opacityContainer_ = new QQuickItem(this);
@@ -177,7 +193,13 @@ void QDeclarativeGeoMapQuickItem::geometryChanged(const QRectF &newGeometry, con
         return;
     }
 
-    QGeoCoordinate newCoordinate = map()->geoProjection().itemPositionToCoordinate(QDoubleVector2D(x(), y()) + (scaleFactor() * QDoubleVector2D(anchorPoint_)), false);
+    QGeoCoordinate newCoordinate;
+    // with zoomLevel set the anchorPoint has to be factored into the transformation to properly transform around it.
+    if (zoomLevel_ != 0.0)
+        newCoordinate = map()->geoProjection().itemPositionToCoordinate(QDoubleVector2D(x(), y()), false);
+    else
+        newCoordinate = map()->geoProjection().itemPositionToCoordinate(QDoubleVector2D(x(), y()) + QDoubleVector2D(anchorPoint_), false);
+
     if (newCoordinate.isValid())
         setCoordinate(newCoordinate);
 
@@ -337,11 +359,20 @@ void QDeclarativeGeoMapQuickItem::updatePolish()
 
     opacityContainer_->setOpacity(zoomLevelOpacity());
 
-    sourceItem_.data()->setScale(scaleFactor());
-    sourceItem_.data()->setPosition(QPointF(0,0));
     setWidth(sourceItem_.data()->width());
     setHeight(sourceItem_.data()->height());
-    setPositionOnMap(coordinate(), scaleFactor() * anchorPoint_);
+    if (zoomLevel_ != 0.0) { // zoom level initialized to 0.0. If it's different, it has been set explicitly.
+        if (!matrix_) {
+            matrix_ = new QMapQuickItemMatrix4x4(this);
+            matrix_->appendToItem(opacityContainer_);
+        }
+        matrix_->setMatrix(map()->geoProjection().quickItemTransformation(coordinate(), anchorPoint_, zoomLevel_));
+        setPositionOnMap(coordinate(), QPointF(0,0));
+    } else {
+        if (matrix_)
+            matrix_->setMatrix(QMatrix4x4());
+        setPositionOnMap(coordinate(), anchorPoint_);
+    }
 }
 
 /*!