Add shell classes for layout view tools

Copy the same model as QgsMapCanvas uses, with separate
classes for individual interaction tools instead of keeping
all the logic in the QGraphicsView subclass (as is done
with composer)

python/gui/gui_auto.sip

@@ -276,6 +276,7 @@
 %Include layertree/qgslayertreeviewdefaultactions.sip
 %Include layout/qgslayoutdesignerinterface.sip
 %Include layout/qgslayoutview.sip
+%Include layout/qgslayoutviewtool.sip
 %Include locator/qgslocator.sip
 %Include locator/qgslocatorfilter.sip
 %Include locator/qgslocatorwidget.sip

python/gui/layout/qgslayoutview.sip

@@ -50,13 +50,42 @@ class QgsLayoutView: QGraphicsView
 .. seealso:: layoutSet()
 %End
 
+    QgsLayoutViewTool *tool();
+%Docstring
+ Returns the currently active tool for the view.
+.. seealso:: setTool()
+ :rtype: QgsLayoutViewTool
+%End
+
+    void setTool( QgsLayoutViewTool *tool );
+%Docstring
+ Sets the ``tool`` currently being used in the view.
+.. seealso:: unsetTool()
+.. seealso:: tool()
+%End
+
+    void unsetTool( QgsLayoutViewTool *tool );
+%Docstring
+ Unsets the current view tool, if it matches the specified ``tool``.
+
+ This is called from destructor of view tools to make sure
+ that the tool won't be used any more.
+ You don't have to call it manually, QgsLayoutViewTool takes care of it.
+%End
+
   signals:
 
     void layoutSet( QgsLayout *layout );
 %Docstring
  Emitted when a ``layout`` is set for the view.
 .. seealso:: currentLayout()
 .. seealso:: setCurrentLayout()
+%End
+
+    void toolSet( QgsLayoutViewTool *tool );
+%Docstring
+ Emitted when the current ``tool`` is changed.
+.. seealso:: setTool()
 %End
 
   protected:
@@ -68,6 +97,12 @@ class QgsLayoutView: QGraphicsView
 
     virtual void mouseDoubleClickEvent( QMouseEvent *event );
 
+    virtual void wheelEvent( QWheelEvent *event );
+
+    virtual void keyPressEvent( QKeyEvent *event );
+
+    virtual void keyReleaseEvent( QKeyEvent *event );
+
 
 };
 

python/gui/layout/qgslayoutviewtool.sip

@@ -0,0 +1,137 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutviewtool.h                                   *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsLayoutViewTool : QObject
+{
+%Docstring
+ Abstract base class for all layout view tools.
+ Layout view tools are user interactive tools for manipulating and adding items
+ to QgsLayoutView widgets.
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgslayoutviewtool.h"
+%End
+
+%ConvertToSubClassCode
+    if ( dynamic_cast<QgsMapToolZoom *>( sipCpp ) != NULL )
+      sipType = sipType_QgsMapToolZoom;
+    else
+      sipType = NULL;
+%End
+  public:
+
+    virtual ~QgsLayoutViewTool();
+
+    virtual void layoutMoveEvent( QMouseEvent *event );
+%Docstring
+ Mouse move event for overriding. Default implementation does nothing.
+%End
+
+    virtual void layoutDoubleClickEvent( QMouseEvent *event );
+%Docstring
+ Mouse double click event for overriding. Default implementation does nothing.
+%End
+
+    virtual void layoutPressEvent( QMouseEvent *event );
+%Docstring
+ Mouse press event for overriding. Default implementation does nothing.
+%End
+
+    virtual void layoutReleaseEvent( QMouseEvent *event );
+%Docstring
+ Mouse release event for overriding. Default implementation does nothing.
+%End
+
+    virtual void wheelEvent( QWheelEvent *event );
+%Docstring
+ Mouse wheel event for overriding. Default implementation does nothing.
+%End
+
+    virtual void keyPressEvent( QKeyEvent *event );
+%Docstring
+ Key press event for overriding. Default implementation does nothing.
+%End
+
+    virtual void keyReleaseEvent( QKeyEvent *event );
+%Docstring
+ Key release event for overriding. Default implementation does nothing.
+%End
+
+    void setAction( QAction *action );
+%Docstring
+ Associates an ``action`` with this tool. When the setLayoutTool
+ method of QgsLayoutView is called the action's state will be set to on.
+ Usually this will cause a toolbutton to appear pressed in and
+ the previously used toolbutton to pop out.
+.. seealso:: action()
+%End
+
+    QAction *action();
+%Docstring
+ Returns the action associated with the tool or None if no action is associated.
+.. seealso:: setAction()
+ :rtype: QAction
+%End
+
+    void setCursor( const QCursor &cursor );
+%Docstring
+ Sets a user defined ``cursor`` for use when the tool is active.
+%End
+
+    virtual void activate();
+%Docstring
+ Called when tool is set as the currently active layout tool.
+ Overridden implementations must take care to call the base class implementation.
+%End
+
+    virtual void deactivate();
+%Docstring
+ Called when tool is deactivated.
+ Overridden implementations must take care to call the base class implementation.
+%End
+
+    QString toolName() const;
+%Docstring
+ Returns a user-visible, translated name for the tool.
+ :rtype: str
+%End
+
+  signals:
+
+    void activated();
+%Docstring
+ Emitted when the tool is activated.
+%End
+
+    void deactivated();
+%Docstring
+ Emitted when the tool is deactivated.
+%End
+
+  protected:
+
+    QgsLayoutViewTool( QgsLayoutView *view /TransferThis/, const QString &name );
+%Docstring
+ Constructor for QgsLayoutViewTool, taking a layout ``view`` and
+ tool ``name`` as parameters.
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutviewtool.h                                   *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

src/app/layout/qgslayoutdesignerdialog.cpp

@@ -200,6 +200,10 @@ void QgsLayoutDesignerDialog::restoreWindowState()
 void QgsLayoutDesignerDialog::activateNewItemCreationTool( int type )
 {
   QgsLogger::debug( QStringLiteral( "creating new %1 item  " ).arg( QgsApplication::layoutItemRegistry()->itemMetadata( type )->visibleName() ) );
+  if ( mView )
+  {
+    //mView->setTool( QgsLayoutView::ToolAddItem );
+  }
 }
 
 

src/gui/CMakeLists.txt

@@ -159,6 +159,7 @@ SET(QGIS_GUI_SRCS
   layertree/qgslayertreeviewdefaultactions.cpp
 
   layout/qgslayoutview.cpp
+  layout/qgslayoutviewtool.cpp
 
   locator/qgslocator.cpp
   locator/qgslocatorfilter.cpp
@@ -623,6 +624,7 @@ SET(QGIS_GUI_MOC_HDRS
 
   layout/qgslayoutdesignerinterface.h
   layout/qgslayoutview.h
+  layout/qgslayoutviewtool.h
 
   locator/qgslocator.h
   locator/qgslocatorfilter.h

src/gui/layout/qgslayoutview.cpp

@@ -17,6 +17,7 @@
 
 #include "qgslayoutview.h"
 #include "qgslayout.h"
+#include "qgslayoutviewtool.h"
 
 QgsLayoutView::QgsLayoutView( QWidget *parent )
   : QGraphicsView( parent )
@@ -39,22 +40,91 @@ void QgsLayoutView::setCurrentLayout( QgsLayout *layout )
   emit layoutSet( layout );
 }
 
+QgsLayoutViewTool *QgsLayoutView::tool()
+{
+  return mTool;
+}
+
+void QgsLayoutView::setTool( QgsLayoutViewTool *tool )
+{
+  if ( !tool )
+    return;
+
+  if ( mTool )
+  {
+    mTool->deactivate();
+  }
+
+  // set new tool and activate it
+  mTool = tool;
+  mTool->activate();
+
+  emit toolSet( mTool );
+}
+
+void QgsLayoutView::unsetTool( QgsLayoutViewTool *tool )
+{
+  if ( mTool && mTool == tool )
+  {
+    mTool->deactivate();
+    mTool = nullptr;
+    emit toolSet( nullptr );
+    setCursor( Qt::ArrowCursor );
+  }
+}
+
 void QgsLayoutView::mousePressEvent( QMouseEvent *event )
 {
-  QGraphicsView::mousePressEvent( event );
+  if ( mTool )
+    mTool->layoutPressEvent( event );
+  else
+    QGraphicsView::mousePressEvent( event );
 }
 
 void QgsLayoutView::mouseReleaseEvent( QMouseEvent *event )
 {
-  QGraphicsView::mouseReleaseEvent( event );
+  if ( mTool )
+    mTool->layoutReleaseEvent( event );
+  else
+    QGraphicsView::mouseReleaseEvent( event );
 }
 
 void QgsLayoutView::mouseMoveEvent( QMouseEvent *event )
 {
-  QGraphicsView::mouseMoveEvent( event );
+  if ( mTool )
+    mTool->layoutMoveEvent( event );
+  else
+    QGraphicsView::mouseMoveEvent( event );
 }
 
 void QgsLayoutView::mouseDoubleClickEvent( QMouseEvent *event )
 {
-  QGraphicsView::mouseDoubleClickEvent( event );
+  if ( mTool )
+    mTool->layoutDoubleClickEvent( event );
+  else
+    QGraphicsView::mouseDoubleClickEvent( event );
+}
+
+void QgsLayoutView::wheelEvent( QWheelEvent *event )
+{
+  if ( mTool )
+    mTool->wheelEvent( event );
+  else
+    QGraphicsView::wheelEvent( event );
+}
+
+void QgsLayoutView::keyPressEvent( QKeyEvent *event )
+{
+  if ( mTool )
+    mTool->keyPressEvent( event );
+  else
+    QGraphicsView::keyPressEvent( event );
+}
+
+void QgsLayoutView::keyReleaseEvent( QKeyEvent *event )
+{
+  if ( mTool )
+    mTool->keyReleaseEvent( event );
+  else
+    QGraphicsView::keyReleaseEvent( event );
 }