Using barymetric center for poly triangulation

Previous commit used boundingBox center, which will not work on
some valid convex shapes. Barymetric center calculation should
work on all simple convex polygons.

Change-Id: I0915650c18a87ffcf7a2652ef57924894ae25833
Reviewed-by: David Laing <david.laing@nokia.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/imports/location/qdeclarativepolygonmapitem.cpp b/src/imports/location/qdeclarativepolygonmapitem.cpp
index f3f510fa..5c9be19c 100644
--- a/src/imports/location/qdeclarativepolygonmapitem.cpp
+++ b/src/imports/location/qdeclarativepolygonmapitem.cpp
@@ -300,11 +300,17 @@ void MapPolygonNode::update(const QColor& fillColor, const QPolygonF& shape,
 
     Vertex *vertices = (Vertex *)fill->vertexData();
 
-    vertices[fillVertexCount++].position = QVector2D(shape.boundingRect().center());
+    qreal xSum = 0, ySum = 0, count = 0;
+    // skip the center point for now, we'll fill it in afterwards
+    fillVertexCount++;
     for (int i = 0; i < shape.size(); ++i) {
+        xSum += shape.at(i).x();
+        ySum += shape.at(i).y();
+        count += 1.0;
         vertices[fillVertexCount++].position = QVector2D(shape.at(i));
     }
     vertices[fillVertexCount++].position = QVector2D(shape.at(0));
+    vertices[0].position = QVector2D(xSum / count, ySum / count);
 
     Q_ASSERT(fillVertexCount == fill->vertexCount());
     markDirty(DirtyGeometry);