Fix for disappearing MapQuickItems with tilted camera

This patch fixes a bug that makes MapQuickItem disappear when
the zoomLevel property is set, the camera is tilted and zoomed in
very close to the item, causing the coordinate of the map quick item
to end behind the camera.

Task-number: QTBUG-59397
Change-Id: Iae92204917729eb9daaf8592db318613bf57b966
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

1 files changed, 4 insertions, 12 deletions

diff --git a/src/location/maps/qgeoprojection.cpp b/src/location/maps/qgeoprojection.cpp
index 1a9981d3..81f3a947 100644
--- a/src/location/maps/qgeoprojection.cpp
+++ b/src/location/maps/qgeoprojection.cpp
@@ -258,11 +258,6 @@ QMatrix4x4 QGeoProjectionWebMercator::quickItemTransformation(const QGeoCoordina
     const QDoubleVector2D anchorScaled = QDoubleVector2D(anchorPoint.x(), anchorPoint.y()) * scale;
     const QDoubleVector2D anchorMercator = anchorScaled / mapWidth();
 
-    // Check for coord OOB, only coordinate is going to be projected to item position, so
-    // testing also coordAnchored might be superfluous
-    if (!isProjectable(coordWrapped))
-        return QMatrix4x4();
-
     const QDoubleVector2D coordAnchored = coordWrapped - anchorMercator;
     const QDoubleVector2D coordAnchoredScaled = coordAnchored * m_sideLength;
     QDoubleMatrix4x4 matTranslateScale;
@@ -272,21 +267,18 @@ QMatrix4x4 QGeoProjectionWebMercator::quickItemTransformation(const QGeoCoordina
                      (std::floor(zoomLevel) - std::floor(m_cameraData.zoomLevel())));
     matTranslateScale.scale(scale);
 
-    const QDoubleVector2D coordOnScreen = wrappedMapProjectionToItemPosition(coordWrapped);
-    QDoubleMatrix4x4 matTransformation;
-    matTransformation.translate(-coordOnScreen.x(), -coordOnScreen.y(), 0);
-    matTransformation *= m_quickItemTransformation;
-
     /*
-     *  The full transformation chain for quickItemTransformation() is:
+     *  The full transformation chain for quickItemTransformation() would be:
      *  matScreenShift * m_quickItemTransformation * matTranslate * matScale
      *  where:
      *  matScreenShift = translate(-coordOnScreen.x(), -coordOnScreen.y(), 0)
      *  matTranslate = translate(coordAnchoredScaled.x(), coordAnchoredScaled.y(), 0.0)
      *  matScale = scale(scale)
+     *
+     *  However, matScreenShift is removed, as setPosition(0,0) is used in place of setPositionOnScreen.
      */
 
-    return toMatrix4x4(matTransformation * matTranslateScale);
+    return toMatrix4x4(m_quickItemTransformation * matTranslateScale);
 }
 
 bool QGeoProjectionWebMercator::isProjectable(const QDoubleVector2D &wrappedProjection) const