From a71e95abcbbb7ce1ec01cc1e3e83e9d371239a6a Mon Sep 17 00:00:00 2001
From: g_j_m <g_j_m@c8812cc2-4d05-0410-92ff-de0c093fc19c>
Date: Mon, 24 Oct 2005 00:29:36 +0000
Subject: [PATCH] Fix a bug where the scale bar units weren't being correctly
 updated after a change in map units caused by turning on
 on-the-fly-reprojection.

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@4127 c8812cc2-4d05-0410-92ff-de0c093fc19c
---
 src/qgisapp.cpp              | 10 ++--------
 src/qgsmapcanvas.cpp         |  7 +++++++
 src/qgsmapcanvas.h           |  3 +++
 src/qgsprojectproperties.cpp |  1 +
 src/qgsprojectproperties.h   |  3 +++
 5 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/qgisapp.cpp b/src/qgisapp.cpp
index ae81fa394ca..10230b3f403 100644
--- a/src/qgisapp.cpp
+++ b/src/qgisapp.cpp
@@ -4698,6 +4698,7 @@ void QgisApp::projectProperties()
   QApplication::restoreOverrideCursor();
   //pass any refresg signals off to canvases
   connect (pp,SIGNAL(refresh()), mMapCanvas, SLOT(refresh()));
+  connect (pp,SIGNAL(mapUnitsChanged()), mMapCanvas, SLOT(mapUnitsChanged()));  
   connect (pp,SIGNAL(refresh()), mOverviewCanvas, SLOT(refresh()));
   
   bool wasProjected = pp->isProjected();
@@ -4705,20 +4706,13 @@ void QgisApp::projectProperties()
   // Display the modal dialog box.
   pp->exec();
 
-  // set the map units for the project if they have changed
-  if (mMapCanvas->mapUnits() != pp->mapUnits())
-  {
-    mMapCanvas->setMapUnits(pp->mapUnits());
-  }
-
   // If the canvas projection settings changed, we need to recalculate the extents in the
   // new coordinate system
   if(pp->isProjected() != wasProjected)
   {
     mMapCanvas->recalculateExtents();
   }
-  // Set the window title. No way to do a comparison like for the map
-  // units above, so redo it everytime.
+  // Set the window title.
   setTitleBarText_( *this );
   // delete the property sheet object
   delete pp;
diff --git a/src/qgsmapcanvas.cpp b/src/qgsmapcanvas.cpp
index 5d9dcc26656..abf39a951e7 100644
--- a/src/qgsmapcanvas.cpp
+++ b/src/qgsmapcanvas.cpp
@@ -955,6 +955,13 @@ bool QgsMapCanvas::projectionsEnabled()
   }
 }
 
+void QgsMapCanvas::mapUnitsChanged()
+{
+  // We assume that if the map units have changed, the changed value
+  // will be accessible from QgsProject.
+  setMapUnits(QgsProject::instance()->mapUnits());
+}
+
 void QgsMapCanvas::zoomToSelected()
 {
   QgsVectorLayer *lyr =
diff --git a/src/qgsmapcanvas.h b/src/qgsmapcanvas.h
index 60e34aed8d3..e2fb98650b6 100644
--- a/src/qgsmapcanvas.h
+++ b/src/qgsmapcanvas.h
@@ -259,6 +259,9 @@ public slots:
 
     /** A simple helper method to find out if on the fly projections are enabled or not */
     bool projectionsEnabled();
+
+    /** The map units may have changed, so cope with that */
+    void mapUnitsChanged();
     
 signals:
     /** Let the owner know how far we are with render operations */
diff --git a/src/qgsprojectproperties.cpp b/src/qgsprojectproperties.cpp
index f630a23736d..47909f6128c 100644
--- a/src/qgsprojectproperties.cpp
+++ b/src/qgsprojectproperties.cpp
@@ -228,6 +228,7 @@ void QgsProjectProperties::apply()
         QgsProject::instance()->mapUnits(srs.mapUnits());
     }
   }
+  emit mapUnitsChanged();
 
   // set the mouse display precision method and the
   // number of decimal places for the manual option
diff --git a/src/qgsprojectproperties.h b/src/qgsprojectproperties.h
index 12aafa64950..f5f5c090257 100644
--- a/src/qgsprojectproperties.h
+++ b/src/qgsprojectproperties.h
@@ -89,6 +89,9 @@ signals:
   void setDestSRSID(long theSRSID);   
   //! Signal used to inform listeners that the mouse display precision may have changed
   void displayPrecisionChanged();
+  //! Signal used to inform listeners that the map units may of
+  //changed (and that the new value can be found in QgsProject.
+  void mapUnitsChanged();
   //! let listening canvases know to refresh
   void refresh();
   //! notification of when on the fly projections are enabled / disabled