Fix missing page shadows

Author: nyalldawson

python/core/layout/qgslayoutitempage.sip

@@ -91,8 +91,9 @@ will be set to true if string could be successfully interpreted as a
 page orientation.
 %End
 
-    virtual void attemptResize( const QgsLayoutSize &size, bool includesFrame = false );
+    virtual QRectF boundingRect() const;
 
+    virtual void attemptResize( const QgsLayoutSize &size, bool includesFrame = false );
 
     virtual QgsAbstractLayoutUndoCommand *createCommand( const QString &text, int id, QUndoCommand *parent = 0 ) /Factory/;
 

src/core/layout/qgslayoutitempage.cpp

@@ -32,10 +32,11 @@ QgsLayoutItemPage::QgsLayoutItemPage( QgsLayout *layout )
   setFlag( QGraphicsItem::ItemIsMovable, false );
   setZValue( QgsLayout::ZPage );
 
-  // use a hidden pen to specify the amount the page "bleeds" outside it's scene bounds,
-  // (it's a lot easier than reimplementing boundingRect() just to handle this)
-  QPen shadowPen( QBrush( Qt::transparent ), layout->pageCollection()->pageShadowWidth() * 2 );
-  setPen( shadowPen );
+  connect( this, &QgsLayoutItem::sizePositionChanged, this, [ = ]
+  {
+    mBoundingRect = QRectF();
+    prepareGeometryChange();
+  } );
 
   QFont font;
   QFontMetrics fm( font );
@@ -123,6 +124,17 @@ QgsLayoutItemPage::Orientation QgsLayoutItemPage::decodePageOrientation( const Q
   return Landscape;
 }
 
+QRectF QgsLayoutItemPage::boundingRect() const
+{
+  if ( mBoundingRect.isNull() )
+  {
+    double shadowWidth = mLayout->pageCollection()->pageShadowWidth();
+    mBoundingRect = rect();
+    mBoundingRect.adjust( 0, 0, shadowWidth, shadowWidth );
+  }
+  return mBoundingRect;
+}
+
 void QgsLayoutItemPage::attemptResize( const QgsLayoutSize &size, bool includesFrame )
 {
   QgsLayoutItem::attemptResize( size, includesFrame );

src/core/layout/qgslayoutitempage.h

@@ -121,8 +121,8 @@ class CORE_EXPORT QgsLayoutItemPage : public QgsLayoutItem
     */
     static QgsLayoutItemPage::Orientation decodePageOrientation( const QString &string, bool *ok SIP_OUT = nullptr );
 
+    QRectF boundingRect() const override;
     void attemptResize( const QgsLayoutSize &size, bool includesFrame = false ) override;
-
     QgsAbstractLayoutUndoCommand *createCommand( const QString &text, int id, QUndoCommand *parent = nullptr ) override SIP_FACTORY;
 
   public slots:
@@ -140,6 +140,7 @@ class CORE_EXPORT QgsLayoutItemPage : public QgsLayoutItem
     double mMaximumShadowWidth = -1;
 
     std::unique_ptr< QgsLayoutItemPageGrid > mGrid;
+    mutable QRectF mBoundingRect;
 
     friend class TestQgsLayoutPage;
 };