[composer] Allow item rotation from -360->360

Fix #12696

Author: nyalldawson

src/app/composer/qgscomposeritemwidget.cpp

@@ -150,6 +150,8 @@ QgsComposerItemWidget::QgsComposerItemWidget( QWidget *parent, QgsComposerItem *
 
   setupUi( this );
 
+  mItemRotationSpinBox->setClearValue( 0 );
+
   //make button exclusive
   QButtonGroup *buttonGroup = new QButtonGroup( this );
   buttonGroup->addButton( mUpperLeftCheckBox );

src/core/composer/qgscomposeritem.cpp

@@ -1009,13 +1009,10 @@ double QgsComposerItem::rectHandlerBorderTolerance() const
 
 void QgsComposerItem::setItemRotation( const double r, const bool adjustPosition )
 {
-  if ( r >= 360 )
+  mItemRotation = r;
+  if ( mItemRotation >= 360.0 || mItemRotation <= -360.0 )
   {
-    mItemRotation = ( static_cast< int >( r ) ) % 360;
-  }
-  else
-  {
-    mItemRotation = r;
+    mItemRotation = fmod( mItemRotation, 360.0 );
   }
 
   QgsExpressionContext context = createExpressionContext();

src/core/composer/qgscomposeritem.h

@@ -427,13 +427,13 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
      */
     bool positionLock() const { return mItemPositionLocked; }
 
-    /** Returns the current rotation for the composer item.
-     * \returns rotation for composer item
+    /**
+     * Returns the current rotation for the composer item, in degrees clockwise.
      * \param valueType controls whether the returned value is the user specified rotation,
      * or the current evaluated rotation (which may be affected by data driven rotation
      * settings).
      * \since QGIS 2.1
-     * \see setItemRotation
+     * \see setItemRotation()
      */
     double itemRotation( const QgsComposerObject::PropertyValueType valueType = QgsComposerObject::EvaluatedValue ) const;
 
@@ -555,14 +555,15 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
 
   public slots:
 
-    /** Sets the item rotation
-     * \param r item rotation in degrees
+    /**
+     * Sets the item \a rotation, in degrees clockwise.
+     * \param rotation item rotation in degrees
      * \param adjustPosition set to true if item should be shifted so that rotation occurs
      * around item center. If false, rotation occurs around item origin
      * \since QGIS 2.1
      * \see itemRotation
      */
-    virtual void setItemRotation( const double r, const bool adjustPosition = false );
+    virtual void setItemRotation( const double rotation, const bool adjustPosition = false );
 
     void repaint() override;
 

src/ui/composer/qgscomposeritemwidgetbase.ui

@@ -374,6 +374,9 @@
           <property name="suffix">
            <string> °</string>
           </property>
+          <property name="minimum">
+           <double>-360.000000000000000</double>
+          </property>
           <property name="maximum">
            <double>360.000000000000000</double>
           </property>