[Qt] Fix panning the map not updating the center property

platform/qt/include/qquickmapboxgl.hpp

@@ -51,7 +51,6 @@ public:
     void setZoomLevel(qreal zoomLevel);
     qreal zoomLevel() const;
 
-    void setCenter(const QGeoCoordinate &center);
     QGeoCoordinate center() const;
 
     QGeoServiceProvider::Error error() const;
@@ -104,6 +103,9 @@ signals:
     void styleChanged();
     void bearingChanged(qreal angle);
 
+public slots:
+    void setCenter(const QGeoCoordinate &center);
+
 private:
     qreal m_minimumZoomLevel = 0;
     qreal m_maximumZoomLevel = 20;

platform/qt/src/qquickmapboxglrenderer.cpp

@@ -42,7 +42,11 @@ void QQuickMapboxGLRenderer::render()
 void QQuickMapboxGLRenderer::synchronize(QQuickFramebufferObject *item)
 {
     if (!m_initialized) {
-        QObject::connect(m_map.data(), SIGNAL(needsRendering()), item, SLOT(update()));
+        auto qquickMapbox = static_cast<QQuickMapboxGL*>(item);
+
+        QObject::connect(m_map.data(), &QMapboxGL::needsRendering, qquickMapbox, &QQuickMapboxGL::update);
+        QObject::connect(this, &QQuickMapboxGLRenderer::centerChanged, qquickMapbox, &QQuickMapboxGL::setCenter);
+
         m_initialized = true;
     }
 
@@ -64,6 +68,7 @@ void QQuickMapboxGLRenderer::synchronize(QQuickFramebufferObject *item)
 
     if (syncStatus & QQuickMapboxGL::PanNeedsSync) {
         m_map->moveBy(quickMap->swapPan());
+        emit centerChanged(QGeoCoordinate(m_map->latitude(), m_map->longitude()));
     }
 
     if (syncStatus & QQuickMapboxGL::BearingNeedsSync) {

platform/qt/src/qquickmapboxglrenderer.hpp

@@ -1,15 +1,19 @@
 #ifndef QQUICKMAPBOXGLRENDERER_H
 #define QQUICKMAPBOXGLRENDERER_H
 
-#include <QScopedPointer>
+#include <QObject>
 #include <QQuickFramebufferObject>
+#include <QScopedPointer>
 
+class QGeoCoordinate;
+class QMapboxGL;
 class QOpenGLFramebufferObject;
 class QSize;
-class QMapboxGL;
 
-class QQuickMapboxGLRenderer : public QQuickFramebufferObject::Renderer
+class QQuickMapboxGLRenderer : public QObject, public QQuickFramebufferObject::Renderer
 {
+    Q_OBJECT
+
 public:
     QQuickMapboxGLRenderer();
     virtual ~QQuickMapboxGLRenderer();
@@ -19,6 +23,9 @@ public:
     virtual void render();
     virtual void synchronize(QQuickFramebufferObject *item);
 
+signals:
+    void centerChanged(const QGeoCoordinate &coordinate);
+
 private:
     bool m_initialized = false;