qgslegend.h

一个非常好的GIS开源新版本

  /** called to read legend settings from project */
  void readProject(const QDomDocument &);
    
  /** called to write legend settings to project */
  void writeProject(QDomDocument &);

  /**Removes the current LegendLayer and all its LegendLayerFiles*/
  void legendLayerRemove();
  
  /**Toggle show in overview for current layer*/
  void legendLayerShowInOverview();

  /**Zooms to extent of the current legend layer (considers there may be several
  legend layer files*/
  void legendLayerZoom();

 /***Zooms so that the pixels of the raster layer occupies exactly one screen pixel.
     Only works on raster layers*/
  void legendLayerZoomNative();
  
  /**Show attribute table*/
  void legendLayerAttributeTable();

  /**Shows the property dialog of the first legend layer file in a legend layer*/
  void legendLayerShowProperties();
  
protected:

  /*!Event handler for mouse movements.
   * Mainly intended so handle cases where user is dragging and dropping
   * items into or out of groups, or is reordering layers.
   * @note Overrides method of the same name in the QListView class.
   * @return void
   */ 
  void mouseMoveEvent(QMouseEvent * e);

  /*!
   * Event handler for buton mouse presses.
   * Mainly intended so handle cases where user is dragging and dropping
   * items into or out of groups, or is reordering layers.
   * @note Overrides method of the same name in the QListView class.
   * @return void
   */ 
  void mousePressEvent(QMouseEvent * e);

  /*!
   * Event handler for mouse button releases.
   * Mainly intended so handle cases where user is dragging and dropping
   * items into or out of groups, or is reordering layers. Each sublass of
   * QgsLegendItem has an accept method that defines behaviour rules for
   * whether another QgsLegendItem child instance can be dropped onto it.
   * <h1>Behaviour rules for dropped legend items</h1>
   * <ul>
   * <li> Symbology groups, properies groups and layers groups can only be dropped
   * onto QgsLegendLayer nodes. </li> 
   * <li>Only QgsLegendGroup and QgsLegendLayer can be top level items in the view</li>
   * <li>Groups can be nested by dropping them into each other,</li>
   * <li>Each group can have one or more layers</li>
   * <li>Layers can be ordered by dragging them above or below another layer.</li>
   * <li>The order for QgsLegendSymbologyGroup, QgsLegendPropertyGroup and QgsLegendLayerGroup
   * is predefined to sort in that order.</li>
   * </ul>
   * @note Overrides method of the same name in the QListView class.
   * @return void
   */  
  void mouseReleaseEvent(QMouseEvent * e);
  void mouseDoubleClickEvent(QMouseEvent* e);

    /**Stores the necessary information about the position of an item in the hierarchy. Afterwards, 
this item may be moved back to the original position with resetToInitialPosition()*/
  void storeInitialPosition(QTreeWidgetItem* li);
  
  /**Moves an item back to the position where storeInitialPosition has been called*/
  void resetToInitialPosition(QTreeWidgetItem* li);

  /**Returns the legend layer to which a map layer gelongs*/
  QgsLegendLayer* findLegendLayer(const QString& layerKey);

  /**Checks mPixmapWidthValues and mPixmapHeightValues and sets a new icon size if necessary*/
  void adjustIconSize();

  /**Initialize pixmaps - called when QgsLegend is constructed */
  void initPixmaps();

  /**This function compares the layer order before a drag with the current layer ordering and triggers a canvas repaint if it has changed*/
  bool checkLayerOrderUpdate();

  private slots:

  /**Calls 'handleRightClickEvent' on the item*/
  void handleRightClickEvent(QTreeWidgetItem* item, const QPoint& position);
  /**Removes the current legend group*/
  void legendGroupRemove();
   /**Sets all listview items to open*/
  void expandAll();
  /**Sets all listview items to closed*/
  void collapseAll();
  /**Just for a test*/
  void handleItemChange(QTreeWidgetItem* item, int row);
  /** delegates current layer to map canvas */
  void handleCurrentItemChanged(QTreeWidgetItem* current, QTreeWidgetItem* previous);
  /**Calls openPersistentEditor for the current item*/
  void openEditor();
  /**Removes the current item and inserts it as a toplevel item at the end of the legend*/
  void makeToTopLevelItem();
  /**Show/ Hide the legend layer file groups*/
  void showLegendLayerFileGroups();
  
private:

   /*! Prevent the copying of QgsLegends
   * @todo See if this is really required - we may want multiple map, canvas and 
           legend support at some stage in the future.
   */
  QgsLegend( QgsLegend const & );

  /*!
   * Prevent the copying of QgsLegends
   * @todo See if this is really required - we may want multiple map, canvas and 
           legend support at some stage in the future.
   */
  QgsLegend & operator=( QgsLegend const & );

  /*!
   * Position of mouse when it is pressed at the start of a drag event.
   */
  QPoint mLastPressPos;

  /**True if the mouse is pressed*/
  bool mMousePressedFlag;

  /// keep track of the Item being dragged
  QTreeWidgetItem* mItemBeingMoved;

  /*!
   * Position in the list of the item being moved as it was at the start of a drag event.
   * An item at the top of the list will be 0 and each successive item below it
   * will be 1,2 3 etc... regardless of nesting level.
   */
  int mItemBeingMovedOrigPos;

  /**Information needed by 'storeInitialPosition' and 'resetToInitialPosition'*/
  enum HIERARCHY_POSITION_TYPE
    {
      FIRST_ITEM,
      FIRST_CHILD,
      YOUNGER_SIBLING
    };
  HIERARCHY_POSITION_TYPE mRestoreInformation;
  QTreeWidgetItem* mRestoreItem;

  bool mShowLegendLayerFiles;

  /**Stores the layer ordering before a mouse Move. After the move, this is used to
   decide if the mapcanvas really has to be refreshed*/
  std::deque<QString> mLayersPriorToMove;

  /**Action for the legendlayer right click menu*/
  QAction* mToggleEditingAction;

  /*!
   * A fuction sed to determin how far down in the list an item is (starting with one for the first Item.
   *If the item is not in the legend, -1 is returned
   * @see mItemBeingMovedOrigPos
   */
  int getItemPos(QTreeWidgetItem* item);

  /**Pointer to the main canvas. Used for requiring repaints in case of legend changes*/
  QgsMapCanvas* mMapCanvas;

  /**Map that keeps track of which checkboxes are in which check state. This is necessary because QTreeView does not emit 
     a signal for check state changes*/
  std::map<QTreeWidgetItem*, Qt::CheckState> mStateOfCheckBoxes;

  /**Stores the width values of the LegendSymbologyItem pixmaps. The purpose of this is that the legend may automatically change
   the global IconWidth when items are added or removed*/
  std::multiset<int> mPixmapWidthValues;

  /**Stores the width values of the LegendSymbologyItem pixmaps. The purpose of this is that the legend may automatically change
   the global IconWidth when items are added or removed*/
  std::multiset<int> mPixmapHeightValues;

  /**QgsLegend does not set the icon with/height to values lower than the minimum icon size*/
  QSize mMinimumIconSize;
  
  /** structure which holds pixmap which are used in legend */
  class QgsLegendPixmaps
  {
  public:
    //! Pixmap which is shown by default
    QPixmap mOriginalPixmap;
    
    //! Pixmap to show a bogus vertex was encoutnered in this layer (applies to vector layers only)
    QPixmap mProjectionErrorPixmap;

    //! Pixmap to show if this layer is represented in overview or now
    QPixmap mInOverviewPixmap;

    //! Pixmap to show it this layer has currently editing turned on
    QPixmap mEditablePixmap;

  } mPixmaps;

signals:
  void zOrderChanged(QgsLegend * lv);

  //! Emited whenever current (selected) layer changes
  //  the pointer to layer can be null if no layer is selected
  void currentLayerChanged ( QgsMapLayer * layer );
};
#endif