Move the coordinate <-> item position conversion to QGeoProjection

This patch simplifies the QGeoMap API removing all the API
necessary to convert to and from screen.
This is now demanded to a specific QGeoProjection class, that will
be independent of the map, except for using the same Geo projection
(currently only WebMercator, or EPSG:3857, although we use a sphere
instead of an ellipsoid, i believe)

The benefits are
- This relieves subclasses of QGeoMap from implementing a
GeoProjection API, especially since QtLocation currently supports
only WebMercator, and reimplementations would have to anyway
produce the same results as the inbuilt one.

- This avoids the several indirection steps previously necessary
to perform a map projection (qgeotiledmap -> private->mapscene->
private). Since these operation are quite frequent one per
map item coordinate at every redraw, shortening the indirection
chain is beneficial

- It simplifies the highly complex QGeoTiledMapScene, separating
all the logic that is not needed to draw the scene, but only
to perform geo coordinate <-> screen coordinate conversion

Change-Id: I9e3ca5280166f2d6430a32deb44c030d02d9d4e1
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/imports/location/qdeclarativepolygonmapitem.cpp b/src/imports/location/qdeclarativepolygonmapitem.cpp
index ee603f8c..0e11db79 100644
--- a/src/imports/location/qdeclarativepolygonmapitem.cpp
+++ b/src/imports/location/qdeclarativepolygonmapitem.cpp
@@ -157,7 +157,7 @@ void QGeoMapPolygonGeometry::updateSourcePoints(const QGeoMap &map,
 
     double unwrapBelowX = 0;
     if (preserveGeometry_ )
-        unwrapBelowX = map.coordinateToItemPosition(geoLeftBound_, false).x();
+        unwrapBelowX = map.geoProjection().coordinateToItemPosition(geoLeftBound_, false).x();
 
     for (int i = 0; i < path.size(); ++i) {
         const QGeoCoordinate &coord = path.at(i);
@@ -165,7 +165,7 @@ void QGeoMapPolygonGeometry::updateSourcePoints(const QGeoMap &map,
         if (!coord.isValid())
             continue;
 
-        QDoubleVector2D point = map.coordinateToItemPosition(coord, false);
+        QDoubleVector2D point = map.geoProjection().coordinateToItemPosition(coord, false);
 
         // We can get NaN if the map isn't set up correctly, or the projection
         // is faulty -- probably best thing to do is abort
@@ -213,7 +213,7 @@ void QGeoMapPolygonGeometry::updateScreenPoints(const QGeoMap &map)
         return;
     }
 
-    QDoubleVector2D origin = map.coordinateToItemPosition(srcOrigin_, false);
+    QDoubleVector2D origin = map.geoProjection().coordinateToItemPosition(srcOrigin_, false);
 
     // Create the viewport rect in the same coordinate system
     // as the actual points
@@ -613,7 +613,7 @@ void QDeclarativePolygonMapItem::geometryChanged(const QRectF &newGeometry, cons
     }
 
     QDoubleVector2D newPoint = QDoubleVector2D(x(),y()) + QDoubleVector2D(geometry_.firstPointOffset());
-    QGeoCoordinate newCoordinate = map()->itemPositionToCoordinate(newPoint, false);
+    QGeoCoordinate newCoordinate = map()->geoProjection().itemPositionToCoordinate(newPoint, false);
     if (newCoordinate.isValid()) {
         double firstLongitude = path_.at(0).longitude();
         double firstLatitude = path_.at(0).latitude();