[tracer] Added reprojection of layers

qgis · Jan 8, 2016 · 12705b7 · 12705b7
1 parent 9a6ffc4
commit 12705b7
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Showing 3 changed files with 99 additions and 17 deletions.
diff --git a/src/core/qgstracer.cpp b/src/core/qgstracer.cpp
@@ -450,9 +450,17 @@ void extract_linework( QgsGeometry* g, QgsMultiPolyline& mpl )
 // -------------
 
 
-QgsTracer::QgsTracer( QList<QgsVectorLayer*> layers )
-  : mGraph(0)
+QgsTracer::QgsTracer()
+    : mGraph( 0 )
 {
+}
+
+
+void QgsTracer::initGraph()
+{
+  if ( mGraph )
+    return; // already initialized
+
   QgsFeature f;
   QgsMultiPolyline mpl;
 
@@ -463,13 +471,29 @@ QgsTracer::QgsTracer( QList<QgsVectorLayer*> layers )
   QTime t1, t2, t2a, t3;
 
   t1.start();
-  foreach ( QgsVectorLayer* vl, layers )
+  foreach ( QgsVectorLayer* vl, mLayers )
   {
+    QgsCoordinateTransform ct( vl->crs(), mCRS );
+
     QgsFeatureIterator fi = vl->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ) );
     while ( fi.nextFeature( f ) )
     {
-      if ( f.geometry() )
-        extract_linework( f.geometry(), mpl );
+      if ( !f.geometry() )
+        continue;
+
+      if ( !ct.isShortCircuited() )
+      {
+        try
+        {
+          f.geometry()->transform( ct );
+        }
+        catch ( QgsCsException& )
+        {
+          continue; // ignore if the transform failed
+        }
+      }
+
+      extract_linework( f.geometry(), mpl );
     }
   }
   int timeExtract = t1.elapsed();
@@ -509,12 +533,47 @@ QgsTracer::QgsTracer( QList<QgsVectorLayer*> layers )
 }
 
 QgsTracer::~QgsTracer()
+{
+  invalidateGraph();
+}
+
+void QgsTracer::setLayers( const QList<QgsVectorLayer*>& layers )
+{
+  if ( mLayers == layers )
+    return;
+
+  mLayers = layers;
+  invalidateGraph();
+}
+
+void QgsTracer::setDestinationCrs( const QgsCoordinateReferenceSystem& crs )
+{
+  if ( mCRS == crs )
+    return;
+
+  mCRS = crs;
+  invalidateGraph();
+}
+
+void QgsTracer::init()
+{
+  if ( mGraph )
+    return;
+
+  initGraph();
+}
+
+
+void QgsTracer::invalidateGraph()
 {
   delete mGraph;
+  mGraph = 0;
 }
 
-QgsPolyline QgsTracer::findShortestPath( const QgsPoint& p1, const QgsPoint& p2 )
+QVector<QgsPoint> QgsTracer::findShortestPath( const QgsPoint& p1, const QgsPoint& p2 )
 {
+  init();  // does nothing if the graph exists already
+
   QTime t;
   t.start();
   int v1 = point_in_graph( *mGraph, p1 );

diff --git a/src/core/qgstracer.h b/src/core/qgstracer.h
@@ -22,7 +22,7 @@ class QgsVectorLayer;
 #include <QVector>
 
 #include "qgspoint.h"
-
+#include "qgscoordinatereferencesystem.h"
 
 struct QgsTracerGraph;
 
@@ -37,18 +37,42 @@ class CORE_EXPORT QgsTracer : public QObject
 {
     Q_OBJECT
   public:
-    QgsTracer( QList<QgsVectorLayer*> layers );
+    QgsTracer();
     ~QgsTracer();
 
+    //! Get layers used for tracing
+    QList<QgsVectorLayer*> layers() const { return mLayers; }
+    //! Set layers used for tracing
+    void setLayers( const QList<QgsVectorLayer*>& layers );
+
+    //! Get CRS used for tracing
+    QgsCoordinateReferenceSystem destinationCrs() const { return mCRS; }
+    //! Set CRS used for tracing
+    void setDestinationCrs( const QgsCoordinateReferenceSystem& crs );
+
+    //! Build the internal data structures. This may take some time
+    //! depending on how big the input layers are. It is not necessary
+    //! to call this method explicitly - it will be called by findShortestPath()
+    //! if necessary.
+    void init();
+
     //! Given two points, find the shortest path and return points on the way.
     //! If the points are not located on existing vertices or edges,
     //! search will fail and return empty array. The search will also fail
     //! if the two points are not connected.
     QVector<QgsPoint> findShortestPath( const QgsPoint& p1, const QgsPoint& p2 );
 
+  private:
+    void initGraph();
+    void invalidateGraph();
+
   private:
     //! Graph data structure for path searching
     QgsTracerGraph* mGraph;
+    //! Input layers for the graph building
+    QList<QgsVectorLayer*> mLayers;
+    //! Destination CRS in which graph is built and tracing done
+    QgsCoordinateReferenceSystem mCRS;
 };
 
 

diff --git a/tests/src/core/testqgstracer.cpp b/tests/src/core/testqgstracer.cpp
@@ -94,11 +94,10 @@ void TestQgsTracer::testSimple()
    * 0,0  +--+  10,0
    */
 
-  QList<QgsVectorLayer*> layers;
   QgsVectorLayer* vl = make_layer( wkts );
-  layers << vl;
 
-  QgsTracer tracer( layers );
+  QgsTracer tracer;
+  tracer.setLayers( QList<QgsVectorLayer*>() << vl );
 
   QgsPolyline points1 = tracer.findShortestPath( QgsPoint( 0, 0 ), QgsPoint( 20, 10 ) );
   QCOMPARE( points1.count(), 3 );
@@ -142,11 +141,11 @@ void TestQgsTracer::testPolygon()
   QStringList wkts;
   wkts << "POLYGON((0 0, 0 10, 20 10, 10 0, 0 0))";
 
-  QList<QgsVectorLayer*> layers;
   QgsVectorLayer* vl = make_layer( wkts );
-  layers << vl;
 
-  QgsTracer tracer( layers );
+  QgsTracer tracer;
+  tracer.setLayers( QList<QgsVectorLayer*>() << vl );
+
   QgsPolyline points = tracer.findShortestPath( QgsPoint( 1, 0 ), QgsPoint( 0, 1 ) );
   QCOMPARE( points.count(), 3 );
   QCOMPARE( points[0], QgsPoint( 1, 0 ) );
@@ -169,11 +168,11 @@ void TestQgsTracer::testButterfly()
    *  0,0
    */
 
-  QList<QgsVectorLayer*> layers;
   QgsVectorLayer* vl = make_layer( wkts );
-  layers << vl;
 
-  QgsTracer tracer( layers );
+  QgsTracer tracer;
+  tracer.setLayers( QList<QgsVectorLayer*>() << vl );
+
   QgsPolyline points = tracer.findShortestPath( QgsPoint( 0, 0 ), QgsPoint( 10, 0 ) );
 
   QCOMPARE( points.count(), 3 );