[tracer] Fix reprojection, limit tracing graph to visible extent

qgis · Jan 11, 2016 · 33ea60d · 33ea60d
1 parent bf8571d
commit 33ea60d
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Showing 6 changed files with 105 additions and 7 deletions.
diff --git a/src/core/qgstracer.cpp b/src/core/qgstracer.cpp
@@ -250,14 +250,14 @@ QVector<QgsPoint> shortest_path( const QgsTracerGraph& g, int v1, int v2 )
 }
 
 
-int point2vertex( const QgsTracerGraph& g, const QgsPoint& pt )
+int point2vertex( const QgsTracerGraph& g, const QgsPoint& pt, double epsilon = 1e-6 )
 {
   // TODO: use spatial index
 
   for ( int i = 0; i < g.v.count(); ++i )
   {
     const QgsTracerGraph::V& v = g.v.at( i );
-    if ( v.pt == pt )
+    if ( v.pt == pt || ( fabs( v.pt.x() - pt.x() ) < epsilon && fabs( v.pt.y() - pt.y() ) < epsilon ) )
       return i;
   }
 
@@ -472,7 +472,12 @@ void QgsTracer::initGraph()
   {
     QgsCoordinateTransform ct( vl->crs(), mCRS );
 
-    QgsFeatureIterator fi = vl->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( QgsAttributeList() ) );
+    QgsFeatureRequest request;
+    request.setSubsetOfAttributes( QgsAttributeList() );
+    if ( !mExtent.isEmpty() )
+      request.setFilterRect( ct.transformBoundingBox( mExtent, QgsCoordinateTransform::ReverseTransform ) );
+
+    QgsFeatureIterator fi = vl->getFeatures( request );
     while ( fi.nextFeature( f ) )
     {
       if ( !f.geometry() )
@@ -567,6 +572,15 @@ void QgsTracer::setDestinationCrs( const QgsCoordinateReferenceSystem& crs )
   invalidateGraph();
 }
 
+void QgsTracer::setExtent( const QgsRectangle& extent )
+{
+  if ( mExtent == extent )
+    return;
+
+  mExtent = extent;
+  invalidateGraph();
+}
+
 void QgsTracer::init()
 {
   if ( mGraph )

diff --git a/src/core/qgstracer.h b/src/core/qgstracer.h
@@ -24,6 +24,7 @@ class QgsVectorLayer;
 #include "qgscoordinatereferencesystem.h"
 #include "qgsfeature.h"
 #include "qgspoint.h"
+#include "qgsrectangle.h"
 
 struct QgsTracerGraph;
 
@@ -51,6 +52,11 @@ class CORE_EXPORT QgsTracer : public QObject
     //! Set CRS used for tracing
     void setDestinationCrs( const QgsCoordinateReferenceSystem& crs );
 
+    //! Get extent to which graph's features will be limited (empty extent means no limit)
+    QgsRectangle extent() const { return mExtent; }
+    //! Set extent to which graph's features will be limited (empty extent means no limit)
+    void setExtent( const QgsRectangle& extent );
+
     //! 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()
@@ -82,6 +88,8 @@ class CORE_EXPORT QgsTracer : public QObject
     QList<QgsVectorLayer*> mLayers;
     //! Destination CRS in which graph is built and tracing done
     QgsCoordinateReferenceSystem mCRS;
+    //! Extent for graph building (empty extent means no limit)
+    QgsRectangle mExtent;
 };
 
 

diff --git a/src/gui/qgsmapcanvastracer.cpp b/src/gui/qgsmapcanvastracer.cpp
@@ -17,6 +17,7 @@ QgsMapCanvasTracer::QgsMapCanvasTracer( QgsMapCanvas* canvas )
 
   connect( canvas, SIGNAL( destinationCrsChanged() ), this, SLOT( updateSettings() ) );
   connect( canvas, SIGNAL( layersChanged() ), this, SLOT( updateSettings() ) );
+  connect( canvas, SIGNAL( extentsChanged() ), this, SLOT( updateSettings() ) );
   // TODO: watch for snapping changes
 
   mActionEnableTracing = new QAction( QIcon( QgsApplication::getThemeIcon( "/mActionTracing.png" ) ), tr( "Enable Tracing" ), this );
@@ -48,4 +49,5 @@ void QgsMapCanvasTracer::updateSettings()
   setLayers( layers );
 
   setDestinationCrs( mCanvas->mapSettings().destinationCrs() );
+  setExtent( mCanvas->extent() );
 }
diff --git a/src/gui/qgsmaptoolcapture.cpp b/src/gui/qgsmaptoolcapture.cpp
@@ -143,20 +143,40 @@ bool QgsMapToolCapture::tracingEnabled()
 }
 
 
+QgsPoint QgsMapToolCapture::tracingStartPoint()
+{
+  try
+  {
+    QgsMapLayer* layer = mCanvas->currentLayer();
+    if ( !layer )
+      return QgsPoint();
+    QgsPointV2 v = mCaptureCurve.endPoint();
+    return toMapCoordinates( layer, QgsPoint( v.x(), v.y() ) );
+  }
+  catch ( QgsCsException & )
+  {
+    QgsDebugMsg( "transformation to layer coordinate failed" );
+    return QgsPoint();
+  }
+}
+
+
 void QgsMapToolCapture::tracingMouseMove( QgsMapMouseEvent* e )
 {
   if ( !e->isSnapped() )
     return;
 
-  QgsPointV2 v = mCaptureCurve.endPoint();
+  QgsPoint pt0 = tracingStartPoint();
+  if ( pt0 == QgsPoint() )
+    return;
 
   QgsMapCanvasTracer* tracer = QgsMapCanvasTracer::tracerForCanvas( mCanvas );
   if ( !tracer )
     return;  // this should not happen!
 
   mTempRubberBand->reset( mCaptureMode == CapturePolygon ? QGis::Polygon : QGis::Line );
 
-  QVector<QgsPoint> points = tracer->findShortestPath( QgsPoint( v.x(), v.y() ), e->mapPoint() );
+  QVector<QgsPoint> points = tracer->findShortestPath( pt0, e->mapPoint() );
   if ( points.isEmpty() )
     return;
 
@@ -190,9 +210,11 @@ bool QgsMapToolCapture::tracingAddVertex( const QgsPoint& point )
     return res;
   }
 
-  QgsPointV2 v = mCaptureCurve.endPoint();
+  QgsPoint pt0 = tracingStartPoint();
+  if ( pt0 == QgsPoint() )
+    return false;
 
-  QVector<QgsPoint> points = tracer->findShortestPath( QgsPoint( v.x(), v.y() ), point );
+  QVector<QgsPoint> points = tracer->findShortestPath( pt0, point );
   if ( points.isEmpty() )
     return false; // ignore the vertex - can't find path to the end point!
 

diff --git a/src/gui/qgsmaptoolcapture.h b/src/gui/qgsmaptoolcapture.h
@@ -143,6 +143,8 @@ class GUI_EXPORT QgsMapToolCapture : public QgsMapToolAdvancedDigitizing
   private:
     //! whether tracing has been requested by the user
     bool tracingEnabled();
+    //! first point that will be used as a start of the trace
+    QgsPoint tracingStartPoint();
     //! handle of mouse movement when tracing enabled and capturing has started
     void tracingMouseMove( QgsMapMouseEvent* e );
     //! handle of addition of clicked point (with the rest of the trace) when tracing enabled

diff --git a/tests/src/core/testqgstracer.cpp b/tests/src/core/testqgstracer.cpp
@@ -32,6 +32,8 @@ class TestQgsTracer : public QObject
     void testPolygon();
     void testButterfly();
     void testLayerUpdates();
+    void testExtent();
+    void testReprojection();
 
   private:
 
@@ -268,6 +270,54 @@ void TestQgsTracer::testLayerUpdates()
   delete vl;
 }
 
+void TestQgsTracer::testExtent()
+{
+  // check whether the tracer correctly handles the extent limitation
+
+  // same shape as in testSimple()
+  QStringList wkts;
+  wkts  << "LINESTRING(0 0, 0 10)"
+  << "LINESTRING(0 0, 10 0)"
+  << "LINESTRING(0 10, 20 10)"
+  << "LINESTRING(10 0, 20 10)";
+
+  QgsVectorLayer* vl = make_layer( wkts );
+
+  QgsTracer tracer;
+  tracer.setLayers( QList<QgsVectorLayer*>() << vl );
+  tracer.setExtent( QgsRectangle( 0, 0, 5, 5 ) );
+  tracer.init();
+
+  QgsPolyline points1 = tracer.findShortestPath( QgsPoint( 0, 0 ), QgsPoint( 10, 0 ) );
+  QCOMPARE( points1.count(), 2 );
+  QCOMPARE( points1[0], QgsPoint( 0, 0 ) );
+  QCOMPARE( points1[1], QgsPoint( 10, 0 ) );
+
+  QgsPolyline points2 = tracer.findShortestPath( QgsPoint( 0, 0 ), QgsPoint( 20, 10 ) );
+  QCOMPARE( points2.count(), 0 );
+}
+
+void TestQgsTracer::testReprojection()
+{
+  QStringList wkts;
+  wkts  << "LINESTRING(1 0, 2 0)";
+
+  QgsVectorLayer* vl = make_layer( wkts );
+
+  QgsCoordinateReferenceSystem dstCrs( "EPSG:3857" );
+  QgsCoordinateTransform ct( QgsCoordinateReferenceSystem( "EPSG:4326" ), dstCrs );
+  QgsPoint p1 = ct.transform( QgsPoint( 1, 0 ) );
+  QgsPoint p2 = ct.transform( QgsPoint( 2, 0 ) );
+
+  QgsTracer tracer;
+  tracer.setLayers( QList<QgsVectorLayer*>() << vl );
+  tracer.setDestinationCrs( dstCrs );
+  tracer.init();
+
+  QgsPolyline points1 = tracer.findShortestPath( p1, p2 );
+  QCOMPARE( points1.count(), 2 );
+}
+
 
 QTEST_MAIN( TestQgsTracer )
 #include "testqgstracer.moc"