Fix MeasureTool when DestinationCRS changes

Author: ahuarte47

src/app/qgsmeasuredialog.cpp

@@ -99,6 +99,7 @@ void QgsMeasureDialog::updateSettings()
   QgsDebugMsg( QString( "Area units: %1" ).arg( QgsUnitTypes::encodeUnit( mAreaUnits ) ) );
   QgsDebugMsg( QString( "Canvas units : %1" ).arg( QgsUnitTypes::encodeUnit( mCanvasUnits ) ) );
 
+  mTable->clear();
   mTotal = 0;
   updateUi();
 }

src/app/qgsmeasuretool.cpp

@@ -26,6 +26,7 @@
 #include "qgsmeasuredialog.h"
 #include "qgsmeasuretool.h"
 #include "qgscursors.h"
+#include "qgsmessagelog.h"
 
 #include <QMessageBox>
 #include <QMouseEvent>
@@ -46,6 +47,7 @@ QgsMeasureTool::QgsMeasureTool( QgsMapCanvas* canvas, bool measureArea )
   mDone = true;
   // Append point we will move
   mPoints.append( QgsPoint( 0, 0 ) );
+  mDestinationCrs = canvas->mapSettings().destinationCrs();
 
   mDialog = new QgsMeasureDialog( this );
   mDialog->setWindowFlags( mDialog->windowFlags() | Qt::Tool );
@@ -125,7 +127,47 @@ void QgsMeasureTool::updateSettings()
   mRubberBandPoints->setIcon( QgsRubberBand::ICON_CIRCLE );
   mRubberBandPoints->setIconSize( 10 );
   mRubberBandPoints->setColor( QColor( myRed, myGreen, myBlue, 150 ) );
+
+  // Reproject the points to the new destination CoordinateReferenceSystem
+  if ( mRubberBand->size() > 0 && mDestinationCrs != mCanvas->mapSettings().destinationCrs() )
+  {
+    QList<QgsPoint> points = mPoints;
+    bool lastDone = mDone;
+
+    mDialog->restart();
+    mDone = lastDone;
+    QgsCoordinateTransform ct( mDestinationCrs, mCanvas->mapSettings().destinationCrs() );
+
+    Q_FOREACH ( const QgsPoint& previousPoint, points )
+    {
+      try
+      {
+        QgsPoint point = ct.transform( previousPoint );
+
+        mPoints.append( point );
+        mRubberBand->addPoint( point, false );
+        mRubberBandPoints->addPoint( point, false );
+      }
+      catch ( QgsCsException &cse )
+      {
+        QgsMessageLog::logMessage( QString( "Transform error caught at the MeasureTool: %1" ).arg( cse.what() ) );
+      }
+    }
+
+    mRubberBand->updatePosition();
+    mRubberBand->update();
+    mRubberBandPoints->updatePosition();
+    mRubberBandPoints->update();
+  }
+  mDestinationCrs = mCanvas->mapSettings().destinationCrs();
+
   mDialog->updateSettings();
+
+  if ( !mDone && mRubberBand->size() > 0 )
+  {
+    mRubberBand->addPoint( mPoints.last() );
+    mDialog->addPoint( mPoints.last() );
+  }
 }
 
 //////////////////////////

src/app/qgsmeasuretool.h

@@ -98,6 +98,9 @@ class APP_EXPORT QgsMeasureTool : public QgsMapTool
     // project projection
     bool mWrongProjectProjection;
 
+    //! Destination CoordinateReferenceSystem used by the MapCanvas
+    QgsCoordinateReferenceSystem mDestinationCrs;
+
     //! Returns the snapped (map) coordinate
     //@param p (pixel) coordinate
     QgsPoint snapPoint( const QPoint& p );

tests/src/app/testqgsmeasuretool.cpp

@@ -24,6 +24,7 @@
 #include "qgsproject.h"
 #include "qgsmapcanvas.h"
 #include "qgsunittypes.h"
+#include "qgstestutils.h"
 
 /** \ingroup UnitTests
  * This is a unit test for the measure tool
@@ -113,7 +114,7 @@ void TestQgsMeasureTool::testLengthCalculation()
   QString measureString = dlg->editTotal->text();
   double measured = measureString.remove( ',' ).split( ' ' ).at( 0 ).toDouble();
   double expected = 26932.156;
-  QVERIFY( qgsDoubleNear( measured, expected, 0.001 ) );
+  QGSCOMPARENEAR( measured, expected, 0.001 );
 
   // change project length unit, check calculation respects unit
   QgsProject::instance()->writeEntry( "Measurement", "/DistanceUnits", QgsUnitTypes::encodeUnit( QGis::Feet ) );
@@ -130,7 +131,25 @@ void TestQgsMeasureTool::testLengthCalculation()
   measureString = dlg2->editTotal->text();
   measured = measureString.remove( ',' ).split( ' ' ).at( 0 ).toDouble();
   expected = 88360.0918635;
-  QVERIFY( qgsDoubleNear( measured, expected, 0.001 ) );
+  QGSCOMPARENEAR( measured, expected, 0.001 );
+
+  // check new CoordinateReferenceSystem, points must be reprojected to paint them successfully (issue #15182)
+  QgsCoordinateReferenceSystem srs2( 4326, QgsCoordinateReferenceSystem::EpsgCrsId );
+
+  QgsCoordinateTransform ct( srs, srs2 );
+
+  QgsPoint p0 = ct.transform( tool2->points()[0] );
+  QgsPoint p1 = ct.transform( tool2->points()[1] );
+
+  mCanvas->setDestinationCrs( srs2 );
+
+  QgsPoint n0 = tool2->points()[0];
+  QgsPoint n1 = tool2->points()[1];
+
+  QGSCOMPARENEAR( p0.x(), n0.x(), 0.001 );
+  QGSCOMPARENEAR( p0.y(), n0.y(), 0.001 );
+  QGSCOMPARENEAR( p1.x(), n1.x(), 0.001 );
+  QGSCOMPARENEAR( p1.y(), n1.y(), 0.001 );
 }
 
 void TestQgsMeasureTool::testAreaCalculation()
@@ -166,7 +185,7 @@ void TestQgsMeasureTool::testAreaCalculation()
   QString measureString = dlg->editTotal->text();
   double measured = measureString.remove( ',' ).split( ' ' ).at( 0 ).toDouble();
   double expected = 1009089817.0;
-  QVERIFY( qgsDoubleNear( measured, expected, 1.0 ) );
+  QGSCOMPARENEAR( measured, expected, 1.0 );
 
   // change project area unit, check calculation respects unit
   QgsProject::instance()->writeEntry( "Measurement", "/AreaUnits", QgsUnitTypes::encodeUnit( QgsUnitTypes::SquareMiles ) );
@@ -185,7 +204,7 @@ void TestQgsMeasureTool::testAreaCalculation()
   measureString = dlg2->editTotal->text();
   measured = measureString.remove( ',' ).split( ' ' ).at( 0 ).toDouble();
   expected = 389.6117565069;
-  QVERIFY( qgsDoubleNear( measured, expected, 0.001 ) );
+  QGSCOMPARENEAR( measured, expected, 0.001 );
 }
 
 QTEST_MAIN( TestQgsMeasureTool )