Port ability to pan layouts with middle mouse button depressed

python/gui/gui_auto.sip

@@ -285,6 +285,7 @@
 %Include layout/qgslayoutviewtoolselect.sip
 %Include layout/qgslayoutviewtooltemporarykeypan.sip
 %Include layout/qgslayoutviewtooltemporarykeyzoom.sip
+%Include layout/qgslayoutviewtooltemporarymousepan.sip
 %Include layout/qgslayoutviewtoolzoom.sip
 %Include locator/qgslocator.sip
 %Include locator/qgslocatorfilter.sip

python/gui/layout/qgslayoutviewtooltemporarymousepan.sip

@@ -0,0 +1,43 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutviewtooltemporarymousepan.h                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+class QgsLayoutViewToolTemporaryMousePan : QgsLayoutViewTool
+{
+%Docstring
+ Layout view tool for temporarily panning a layout while a mouse button is depressed.
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgslayoutviewtooltemporarymousepan.h"
+%End
+  public:
+
+    QgsLayoutViewToolTemporaryMousePan( QgsLayoutView *view /TransferThis/ );
+%Docstring
+ Constructor for QgsLayoutViewToolTemporaryMousePan.
+%End
+
+    virtual void layoutMoveEvent( QgsLayoutViewMouseEvent *event );
+
+    virtual void layoutReleaseEvent( QgsLayoutViewMouseEvent *event );
+
+    virtual void activate();
+
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutviewtooltemporarymousepan.h                  *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

src/gui/CMakeLists.txt

@@ -168,6 +168,7 @@ SET(QGIS_GUI_SRCS
   layout/qgslayoutviewtoolselect.cpp
   layout/qgslayoutviewtooltemporarykeypan.cpp
   layout/qgslayoutviewtooltemporarykeyzoom.cpp
+  layout/qgslayoutviewtooltemporarymousepan.cpp
   layout/qgslayoutviewtoolzoom.cpp
 
   locator/qgslocator.cpp
@@ -639,6 +640,7 @@ SET(QGIS_GUI_MOC_HDRS
   layout/qgslayoutviewtoolselect.h
   layout/qgslayoutviewtooltemporarykeypan.h
   layout/qgslayoutviewtooltemporarykeyzoom.h
+  layout/qgslayoutviewtooltemporarymousepan.h
   layout/qgslayoutviewtoolzoom.h
 
   locator/qgslocator.h

src/gui/layout/qgslayoutview.cpp

@@ -21,6 +21,7 @@
 #include "qgslayoutviewmouseevent.h"
 #include "qgslayoutviewtooltemporarykeypan.h"
 #include "qgslayoutviewtooltemporarykeyzoom.h"
+#include "qgslayoutviewtooltemporarymousepan.h"
 #include "qgssettings.h"
 #include "qgsrectangle.h"
 #include <memory>
@@ -36,6 +37,7 @@ QgsLayoutView::QgsLayoutView( QWidget *parent )
   viewport()->setMouseTracking( true );
 
   mSpacePanTool = new QgsLayoutViewToolTemporaryKeyPan( this );
+  mMidMouseButtonPanTool = new QgsLayoutViewToolTemporaryMousePan( this );
   mSpaceZoomTool = new QgsLayoutViewToolTemporaryKeyZoom( this );
 }
 
@@ -103,7 +105,22 @@ void QgsLayoutView::mousePressEvent( QMouseEvent *event )
   }
 
   if ( !mTool || !event->isAccepted() )
+  {
+    if ( event->button() == Qt::MidButton )
+    {
+      // Pan layout with middle mouse button
+      setTool( mMidMouseButtonPanTool );
+      event->accept();
+    }
+    else
+    {
+      QGraphicsView::mousePressEvent( event );
+    }
+  }
+  else
+  {
     QGraphicsView::mousePressEvent( event );
+  }
 }
 
 void QgsLayoutView::mouseReleaseEvent( QMouseEvent *event )

src/gui/layout/qgslayoutview.h

@@ -27,6 +27,7 @@ class QgsLayout;
 class QgsLayoutViewTool;
 class QgsLayoutViewToolTemporaryKeyPan;
 class QgsLayoutViewToolTemporaryKeyZoom;
+class QgsLayoutViewToolTemporaryMousePan;
 
 /**
  * \ingroup gui
@@ -125,6 +126,7 @@ class GUI_EXPORT QgsLayoutView: public QGraphicsView
     QPointer< QgsLayoutViewTool > mTool;
 
     QgsLayoutViewToolTemporaryKeyPan *mSpacePanTool = nullptr;
+    QgsLayoutViewToolTemporaryMousePan *mMidMouseButtonPanTool = nullptr;
     QgsLayoutViewToolTemporaryKeyZoom *mSpaceZoomTool = nullptr;
 
     QPoint mMouseCurrentXY;

src/gui/layout/qgslayoutviewtooltemporarymousepan.cpp

@@ -0,0 +1,47 @@
+/***************************************************************************
+                             qgslayoutviewtooltemporarymousepan.cpp
+                             --------------------------------------
+    Date                 : July 2017
+    Copyright            : (C) 2017 Nyall Dawson
+    Email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgslayoutviewtooltemporarymousepan.h"
+#include "qgslayoutviewmouseevent.h"
+#include "qgslayoutview.h"
+#include <QScrollBar>
+
+QgsLayoutViewToolTemporaryMousePan::QgsLayoutViewToolTemporaryMousePan( QgsLayoutView *view )
+  : QgsLayoutViewTool( view, tr( "Pan" ) )
+{
+  setCursor( Qt::ClosedHandCursor );
+}
+
+void QgsLayoutViewToolTemporaryMousePan::layoutMoveEvent( QgsLayoutViewMouseEvent *event )
+{
+  view()->horizontalScrollBar()->setValue( view()->horizontalScrollBar()->value() - ( event->x() - mLastMousePos.x() ) );
+  view()->verticalScrollBar()->setValue( view()->verticalScrollBar()->value() - ( event->y() - mLastMousePos.y() ) );
+  mLastMousePos = event->pos();
+}
+
+void QgsLayoutViewToolTemporaryMousePan::layoutReleaseEvent( QgsLayoutViewMouseEvent *event )
+{
+  if ( event->button() == Qt::MidButton )
+  {
+    view()->setTool( mPreviousViewTool );
+  }
+}
+
+void QgsLayoutViewToolTemporaryMousePan::activate()
+{
+  mLastMousePos = view()->mapFromGlobal( QCursor::pos() );
+  mPreviousViewTool = view()->tool();
+  QgsLayoutViewTool::activate();
+}

src/gui/layout/qgslayoutviewtooltemporarymousepan.h

@@ -0,0 +1,51 @@
+/***************************************************************************
+                             qgslayoutviewtooltemporarymousepan.h
+                             ------------------------------------
+    Date                 : July 2017
+    Copyright            : (C) 2017 Nyall Dawson
+    Email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSLAYOUTVIEWTOOLTEMPORARYMOUSEPAN_H
+#define QGSLAYOUTVIEWTOOLTEMPORARYMOUSEPAN_H
+
+#include "qgis.h"
+#include "qgis_gui.h"
+#include "qgslayoutviewtool.h"
+
+/**
+ * \ingroup gui
+ * Layout view tool for temporarily panning a layout while a mouse button is depressed.
+ * \since QGIS 3.0
+ */
+class GUI_EXPORT QgsLayoutViewToolTemporaryMousePan : public QgsLayoutViewTool
+{
+
+    Q_OBJECT
+
+  public:
+
+    /**
+     * Constructor for QgsLayoutViewToolTemporaryMousePan.
+     */
+    QgsLayoutViewToolTemporaryMousePan( QgsLayoutView *view SIP_TRANSFERTHIS );
+
+    void layoutMoveEvent( QgsLayoutViewMouseEvent *event ) override;
+    void layoutReleaseEvent( QgsLayoutViewMouseEvent *event ) override;
+    void activate() override;
+
+  private:
+
+    QPoint mLastMousePos;
+    QPointer< QgsLayoutViewTool > mPreviousViewTool;
+
+};
+
+#endif // QGSLAYOUTVIEWTOOLTEMPORARYMOUSEPAN_H