File indexing completed on 2024-05-12 16:34:02

 /* This file is part of the KDE project
    Copyright (C) 2006 Martin Pfeiffer <hubipete@gmx.net> 
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
 */
 
 #ifndef FORMULARENDERER_H
 #define FORMULARENDERER_H
 
 #include <QPainter>
 #include "koformula_export.h"
 
 class AttributeManager;
 class BasicElement;
 
 /**
  * @short FormulaRenderer takes care of painting and layouting the elements
  *
  * FormulaRenderer follows the visitor pattern. It iterates through the element
  * tree and calls layout() or paint() methods to let the single elements layout
  * or paint itsselves. This more generic approach allows more efficient repainting
  * and relayouting.
  * The update() method is the most interesting of the class as it is used to update
  * the visuals when the formula tree has changed somehow. The method calls
  * layoutElement() and then paintElement(). The former is made to be efficient so it
  * layouts only as many parental elements as needed.
  * Using a central class for painting parts or the whole tree structure that makes
  * up a formula has several advantages. First it reduces a lot of code duplication.
  * Second it takes care of painting and layouting in the right order so that there
  * no need anymore for the single element classes to do so. Third we can control 
  * instance AttributeManager and destroying and constructing it often is not needed
  * anymore.
  *
  * @author Martin Pfeiffer <hubipete@gmx.net>
  */
 class KOFORMULA_EXPORT FormulaRenderer {
 public:
     /// The constructor
     FormulaRenderer();
 
     /// The destructor
     ~FormulaRenderer();
 
     /**
      * Paint an element and all its children
      * @param p The QPainter that should be used to paint the element
      * @param element The element to be painted
      * @param hints Whether to show the hints
      */
     void paintElement( QPainter& p, BasicElement* element, bool hints=false );
 
     /**
      * Layout an element and all its children
      * @param element The element to be layouted
      */
     void layoutElement( BasicElement* element );
 
     /**
      * Update an element after it has changed
      * @param p The QPainter that should be used to paint the element
      * @param element The element that has changed
      */
     void update( QPainter& p, BasicElement* element );
 
     /// Just for updating one elements layout after a change
     void updateElementLayout( BasicElement* element );
 
 private:
     qreal elementScaleFactor( BasicElement* element ) const;
 
     /// The attribute manager used for rendering and layouting
     AttributeManager* m_attributeManager;
 
     /// Used by update() to store the highest element in the tree that needs repaint
     BasicElement* m_dirtyElement;
 };
 
 #endif // FORMULARENDERER_H