Allow QgsScrollArea to maintain horizontal width of area for

child widgets, and apply scroll area to vertical contents only

Author: nyalldawson

python/gui/auto_generated/qgsscrollarea.sip.in

@@ -45,11 +45,23 @@ QScrollArea itself or its child viewport().
 %Docstring
 Returns ``True`` if a scroll recently occurred within
 the QScrollArea or its child viewport()
+%End
+
+    void setVerticalOnly( bool verticalOnly );
+%Docstring
+Sets whether the scroll area only applies vertical.
+
+If set to ``True``, then scroll area children will resize horizontally to match the width of
+the scroll area widget.
+
+.. versionadded:: 3.8
 %End
 
   protected:
     virtual void wheelEvent( QWheelEvent *event );
 
+    virtual void resizeEvent( QResizeEvent *event );
+
 
 };
 

src/gui/qgsscrollarea.cpp

@@ -34,6 +34,13 @@ void QgsScrollArea::wheelEvent( QWheelEvent *e )
   QScrollArea::wheelEvent( e );
 }
 
+void QgsScrollArea::resizeEvent( QResizeEvent *event )
+{
+  if ( mVerticalOnly && widget() )
+    widget()->setFixedWidth( event->size().width() );
+  QScrollArea::resizeEvent( event );
+}
+
 void QgsScrollArea::scrollOccurred()
 {
   mTimer.setSingleShot( true );
@@ -45,6 +52,16 @@ bool QgsScrollArea::hasScrolled() const
   return mTimer.isActive();
 }
 
+void QgsScrollArea::setVerticalOnly( bool verticalOnly )
+{
+  mVerticalOnly = verticalOnly;
+  if ( mVerticalOnly )
+    setHorizontalScrollBarPolicy( Qt::ScrollBarAlwaysOff );
+
+  if ( mVerticalOnly && widget() )
+    widget()->setFixedWidth( size().width() );
+}
+
 ///@cond PRIVATE
 
 ScrollAreaFilter::ScrollAreaFilter( QgsScrollArea *parent, QWidget *viewPort )

src/gui/qgsscrollarea.h

@@ -61,12 +61,25 @@ class GUI_EXPORT QgsScrollArea : public QScrollArea
      */
     bool hasScrolled() const;
 
+    /**
+     * Sets whether the scroll area only applies vertical.
+     *
+     * If set to TRUE, then scroll area children will resize horizontally to match the width of
+     * the scroll area widget.
+     *
+     * \since QGIS 3.8
+     */
+    void setVerticalOnly( bool verticalOnly );
+
   protected:
     void wheelEvent( QWheelEvent *event ) override;
+    void resizeEvent( QResizeEvent *event ) override;
 
   private:
     QTimer mTimer;
     ScrollAreaFilter *mFilter = nullptr;
+    bool mVerticalOnly = false;
+
 };
 
 #ifndef SIP_RUN