A stab at improving the measurement system. Added a new selector in Options for converting the result, and grayed out the layer units when OTFP is on. Should fix #1219, I hope.

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@11340 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: homann

src/app/qgisapp.cpp

@@ -5435,7 +5435,9 @@ void QgisApp::projectProperties()
   QApplication::restoreOverrideCursor();
 
   //pass any refresg signals off to canvases
-  //connect (pp,SIGNAL(refresh()), mMapCanvas, SLOT(refresh()));
+  // Line below was commented out by wonder three years ago (r4949).
+  // It is needed to refresh scale bar after changing display units.
+  connect (pp,SIGNAL(refresh()), mMapCanvas, SLOT(refresh()));
 
   QgsMapRenderer* myRender = mMapCanvas->mapRenderer();
   bool wasProjected = myRender->hasCrsTransformEnabled();

src/app/qgsmeasuredialog.cpp

@@ -18,6 +18,7 @@
 #include "qgsmeasuredialog.h"
 #include "qgsmeasuretool.h"
 
+#include "qgslogger.h"
 #include "qgscontexthelp.h"
 #include "qgsdistancearea.h"
 #include "qgsmapcanvas.h"
@@ -89,16 +90,22 @@ void QgsMeasureDialog::mouseMove( QgsPoint &point )
     QList<QgsPoint> tmpPoints = mTool->points();
     tmpPoints.append( point );
     double area = mTool->canvas()->mapRenderer()->distanceArea()->measurePolygon( tmpPoints );
+    QGis::UnitType myDisplayUnits;
+    // Ignore units
+    convertMeasurement( area, myDisplayUnits, true );
     editTotal->setText( formatArea( area ) );
   }
   else if ( !mMeasureArea && mTool->points().size() > 0 )
   {
     QgsPoint p1( mTool->points().last() ), p2( point );
 
     double d = mTool->canvas()->mapRenderer()->distanceArea()->measureLine( p1, p2 );
+    editTotal->setText( formatDistance( mTotal + d ) );
+    QGis::UnitType myDisplayUnits;
+    // Ignore units
+    convertMeasurement( d, myDisplayUnits, false );
     QTreeWidgetItem *item = mTable->topLevelItem( mTable->topLevelItemCount() - 1 );
     item->setText( 0, QLocale::system().toString( d, 'f', 2 ) );
-    editTotal->setText( formatDistance( mTotal + d ) );
   }
 }
 
@@ -108,6 +115,9 @@ void QgsMeasureDialog::addPoint( QgsPoint &point )
   if ( mMeasureArea && numPoints > 2 )
   {
     double area = mTool->canvas()->mapRenderer()->distanceArea()->measurePolygon( mTool->points() );
+    QGis::UnitType myDisplayUnits;
+    // Ignore units
+    convertMeasurement( area, myDisplayUnits, true );
     editTotal->setText( formatArea( area ) );
   }
   else if ( !mMeasureArea && numPoints > 1 )
@@ -121,6 +131,10 @@ void QgsMeasureDialog::addPoint( QgsPoint &point )
     mTotal += d;
     editTotal->setText( formatDistance( mTotal ) );
 
+    QGis::UnitType myDisplayUnits;
+    // Ignore units
+    convertMeasurement( d, myDisplayUnits, false );
+
     QTreeWidgetItem *item = mTable->topLevelItem( mTable->topLevelItemCount() - 1 );
     item->setText( 0, QLocale::system().toString( d, 'f', 2 ) );
 
@@ -173,24 +187,26 @@ void QgsMeasureDialog::on_btnHelp_clicked()
 
 QString QgsMeasureDialog::formatDistance( double distance )
 {
-  QString txt;
-  QString unitLabel;
-
-  QGis::UnitType myMapUnits = mTool->canvas()->mapUnits();
-  return QgsDistanceArea::textUnit( distance, 2, myMapUnits, false );
+  QGis::UnitType myDisplayUnits;
+  convertMeasurement( distance, myDisplayUnits, false );
+  return QgsDistanceArea::textUnit( distance, 2, myDisplayUnits, false );
 }
 
 QString QgsMeasureDialog::formatArea( double area )
 {
-  QGis::UnitType myMapUnits = mTool->canvas()->mapUnits();
-  return QgsDistanceArea::textUnit( area, 2, myMapUnits, true );
+  QGis::UnitType myDisplayUnits;
+  convertMeasurement( area, myDisplayUnits, true );
+  return QgsDistanceArea::textUnit( area, 2, myDisplayUnits, true );
 }
 
 void QgsMeasureDialog::updateUi()
 {
+  double dummy = 1.0;
+  QGis::UnitType myDisplayUnits;
+  // The dummy distance is ignored 
+  convertMeasurement( dummy, myDisplayUnits, false );
 
-  QGis::UnitType myMapUnits = mTool->canvas()->mapUnits();
-  switch ( myMapUnits )
+  switch ( myDisplayUnits )
   {
     case QGis::Meters:
       mTable->setHeaderLabels( QStringList( tr( "Segments (in meters)" ) ) );
@@ -218,3 +234,43 @@ void QgsMeasureDialog::updateUi()
 
 }
 
+void QgsMeasureDialog::convertMeasurement(double &measure, QGis::UnitType &u, bool isArea)
+{
+  // Helper for converting between meters and feet
+  // The parameter &u is out only...
+  
+  QGis::UnitType myUnits = mTool->canvas()->mapUnits();
+  if ( myUnits == QGis::Degrees &&
+       mTool->canvas()->mapRenderer()->distanceArea()->ellipsoid() != "NONE" &&
+       mTool->canvas()->mapRenderer()->distanceArea()->hasCrsTransformEnabled() )
+  {
+    // Measuring on an ellipsoid returns meters
+    myUnits = QGis::Meters;
+  }
+
+  // Get the units for display
+  QSettings settings;
+  QString myDisplayUnitsTxt = settings.value( "/qgis/measure/displayunits", "meters").toString();
+
+  // Only convert between meters and feet
+  if ( myUnits == QGis::Meters && myDisplayUnitsTxt == "feet" )
+  {
+    measure /= 0.3048;
+    if ( isArea )
+    {
+      measure /= 0.3048;
+    }
+    myUnits = QGis::Feet;
+  }
+  if ( myUnits == QGis::Feet && myDisplayUnitsTxt == "meters" )
+  {
+    measure *= 0.3048 * 0.3048;
+    if ( isArea )
+    {
+      measure *= 0.3048;
+    }
+    myUnits = QGis::Meters;
+  }
+  
+  u = myUnits;
+}

src/app/qgsmeasuredialog.h

@@ -20,6 +20,7 @@
 #include "ui_qgsmeasurebase.h"
 
 #include "qgspoint.h"
+#include "qgsdistancearea.h"
 
 class QCloseEvent;
 class QgsMeasureTool;
@@ -72,6 +73,9 @@ class QgsMeasureDialog : public QDialog, private Ui::QgsMeasureBase
     //! shows/hides table, shows correct units
     void updateUi();
 
+    //! Converts the measurement, depending on settings in options and current transformation
+    void convertMeasurement(double &measure, QGis::UnitType &u, bool isArea);
+
     double mTotal;
 
     //! Help context id

src/app/qgsoptions.cpp

@@ -113,6 +113,17 @@ QgsOptions::QgsOptions( QWidget *parent, Qt::WFlags fl ) :
   getEllipsoidList();
   QString myEllipsoidId = settings.value( "/qgis/measure/ellipsoid", "WGS84" ).toString();
   cmbEllipsoid->setItemText( cmbEllipsoid->currentIndex(), getEllipsoidName( myEllipsoidId ) );
+
+  // Set the units for measuring
+  QString myUnitsTxt = settings.value( "/qgis/measure/displayunits", "meters").toString();
+  if ( myUnitsTxt == "feet" )
+  {
+    radFeet->setChecked( true );
+  } else {
+    radMeters->setChecked( true );
+  }
+  
+
   // add the themes to the combo box on the option dialog
   QDir myThemeDir( QgsApplication::pkgDataPath() + "/themes/" );
   myThemeDir.setFilter( QDir::Dirs );
@@ -402,6 +413,15 @@ void QgsOptions::saveOptions()
 
   settings.setValue( "/qgis/measure/ellipsoid", getEllipsoidAcronym( cmbEllipsoid->currentText() ) );
 
+  if ( radFeet->isChecked() )
+  {
+    settings.setValue( "/qgis/measure/displayunits", "feet" );
+  }
+  else
+  {
+    settings.setValue( "/qgis/measure/displayunits", "meters" );
+  }
+  settings.setValue( "/qgis/measure/ellipsoid", getEllipsoidAcronym( cmbEllipsoid->currentText() ) );
   //set the colour for selections
   QColor myColor = pbnSelectionColour->color();
   settings.setValue( "/qgis/default_selection_color_red", myColor.red() );

src/app/qgsprojectproperties.cpp

@@ -58,6 +58,7 @@ QgsProjectProperties::QgsProjectProperties( QgsMapCanvas* mapCanvas, QWidget *pa
   //see if the user wants on the fly projection enabled
   bool myProjectionEnabled = myRender->hasCrsTransformEnabled();
   cbxProjectionEnabled->setChecked( myProjectionEnabled );
+  btnGrpMapUnits->setEnabled( !myProjectionEnabled );
 
   long myCRSID = myRender->destinationSrs().srsid();
   QgsDebugMsg( "Read project CRSID: " + QString::number( myCRSID ) );
@@ -430,3 +431,9 @@ void QgsProjectProperties::on_mSnappingOptionsPushButton_clicked()
     d.layerSettings( mSnappingLayerSettings );
   }
 }
+
+void QgsProjectProperties::on_cbxProjectionEnabled_stateChanged(int state)
+{
+  btnGrpMapUnits->setEnabled( state == Qt::Unchecked );
+}
+

src/app/qgsprojectproperties.h

@@ -93,6 +93,9 @@ class QgsProjectProperties : public QDialog, private Ui::QgsProjectPropertiesBas
      */
     void on_mSnappingOptionsPushButton_clicked();
 
+    void on_cbxProjectionEnabled_stateChanged(int state);
+
+
   signals:
     //! Signal used to inform listeners that the mouse display precision may have changed
     void displayPrecisionChanged();

src/ui/qgsoptionsbase.ui

@@ -476,6 +476,27 @@
             </property>
            </widget>
           </item>
+          <item row="2" column="0">
+           <widget class="QLabel" name="textLabel1_8">
+            <property name="text">
+             <string>Display units (if applicable)</string>
+            </property>
+           </widget>
+          </item>
+          <item row="2" column="1">
+           <widget class="QRadioButton" name="radMeters">
+            <property name="text">
+             <string>Meters</string>
+            </property>
+           </widget>
+          </item>
+          <item row="2" column="2">
+           <widget class="QRadioButton" name="radFeet">
+            <property name="text">
+             <string>Feet</string>
+            </property>
+           </widget>
+          </item>
          </layout>
         </widget>
        </item>

src/ui/qgsprojectpropertiesbase.ui

@@ -139,7 +139,7 @@
        <item row="1" column="0">
         <widget class="QGroupBox" name="btnGrpMapUnits">
          <property name="title">
-          <string>Map units</string>
+          <string>Layer units (only used when CRS transformation is disabled)</string>
          </property>
          <layout class="QHBoxLayout">
           <property name="margin">