Disable support for canvas rotation by default

Rotation support can be enabled at runtime exporting the
QGIS_ENABLE_CANVAS_ROTATION variable (set to any value)

Author: Sandro Santilli

src/app/qgisapp.cpp

@@ -1750,38 +1750,40 @@ void QgisApp::createStatusBar()
   statusBar()->addPermanentWidget( mScaleEdit, 0 );
   connect( mScaleEdit, SIGNAL( scaleChanged() ), this, SLOT( userScale() ) );
 
-  // add a widget to show/set current rotation
-  mRotationLabel = new QLabel( QString(), statusBar() );
-  mRotationLabel->setObjectName( "mRotationLabel" );
-  mRotationLabel->setFont( myFont );
-  mRotationLabel->setMinimumWidth( 10 );
-  mRotationLabel->setMaximumHeight( 20 );
-  mRotationLabel->setMargin( 3 );
-  mRotationLabel->setAlignment( Qt::AlignCenter );
-  mRotationLabel->setFrameStyle( QFrame::NoFrame );
-  mRotationLabel->setText( tr( "Rotation:" ) );
-  mRotationLabel->setToolTip( tr( "Current clockwise map rotation in degrees" ) );
-  statusBar()->addPermanentWidget( mRotationLabel, 0 );
-
-  mRotationEdit = new QgsDoubleSpinBox( statusBar() );
-  mRotationEdit->setObjectName( "mRotationEdit" );
-  mRotationEdit->setClearValue( 0.0 );
-  mRotationEdit->setKeyboardTracking( false );
-  mRotationEdit->setMaximumWidth( 120 );
-  mRotationEdit->setDecimals( 1 );
-  mRotationEdit->setMaximumHeight( 20 );
-  mRotationEdit->setRange( -180.0, 180.0 );
-  mRotationEdit->setWrapping( true );
-  mRotationEdit->setSingleStep( 5.0 );
-  mRotationEdit->setFont( myFont );
-  mRotationEdit->setWhatsThis( tr( "Shows the current map clockwise rotation "
-                                   "in degrees. It also allows editing to set "
-                                   "the rotation" ) );
-  mRotationEdit->setToolTip( tr( "Current clockwise map rotation in degrees" ) );
-  statusBar()->addPermanentWidget( mRotationEdit, 0 );
-  connect( mRotationEdit, SIGNAL( valueChanged( double ) ), this, SLOT( userRotation() ) );
-
-  showRotation();
+  if ( getenv( "QGIS_ENABLE_CANVAS_ROTATION" ) ) {
+    // add a widget to show/set current rotation
+    mRotationLabel = new QLabel( QString(), statusBar() );
+    mRotationLabel->setObjectName( "mRotationLabel" );
+    mRotationLabel->setFont( myFont );
+    mRotationLabel->setMinimumWidth( 10 );
+    mRotationLabel->setMaximumHeight( 20 );
+    mRotationLabel->setMargin( 3 );
+    mRotationLabel->setAlignment( Qt::AlignCenter );
+    mRotationLabel->setFrameStyle( QFrame::NoFrame );
+    mRotationLabel->setText( tr( "Rotation:" ) );
+    mRotationLabel->setToolTip( tr( "Current clockwise map rotation in degrees" ) );
+    statusBar()->addPermanentWidget( mRotationLabel, 0 );
+
+    mRotationEdit = new QgsDoubleSpinBox( statusBar() );
+    mRotationEdit->setObjectName( "mRotationEdit" );
+    mRotationEdit->setClearValue( 0.0 );
+    mRotationEdit->setKeyboardTracking( false );
+    mRotationEdit->setMaximumWidth( 120 );
+    mRotationEdit->setDecimals( 1 );
+    mRotationEdit->setMaximumHeight( 20 );
+    mRotationEdit->setRange( -180.0, 180.0 );
+    mRotationEdit->setWrapping( true );
+    mRotationEdit->setSingleStep( 5.0 );
+    mRotationEdit->setFont( myFont );
+    mRotationEdit->setWhatsThis( tr( "Shows the current map clockwise rotation "
+                                     "in degrees. It also allows editing to set "
+                                     "the rotation" ) );
+    mRotationEdit->setToolTip( tr( "Current clockwise map rotation in degrees" ) );
+    statusBar()->addPermanentWidget( mRotationEdit, 0 );
+    connect( mRotationEdit, SIGNAL( valueChanged( double ) ), this, SLOT( userRotation() ) );
+
+    showRotation();
+  }
 
 
   // render suppression status bar widget

src/gui/qgsmapcanvas.cpp

@@ -899,6 +899,8 @@ double QgsMapCanvas::rotation() const
 
 void QgsMapCanvas::setRotation( double degrees )
 {
+  if ( ! getenv( "QGIS_ENABLE_CANVAS_ROTATION" ) ) return;
+
   double current = rotation();
 
   if ( degrees == current )