OpenSceneGraph/include/osgWidget/StyleManager

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2008 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * 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 
 * OpenSceneGraph Public License for more details.
*/

// Code by: Jeremy Moles (cubicool) 2007-2008

#ifndef OSGWIDGET_STYLE_MANAGER
#define OSGWIDGET_STYLE_MANAGER

#include <map>
#include <osgDB/FieldReaderIterator>
#include <osgWidget/Box>
#include <osgWidget/Frame>
#include <osgWidget/Input>
#include <osgWidget/Canvas>

namespace osgWidget {

typedef osgDB::FieldReaderIterator& Reader;

class OSGWIDGET_EXPORT Style: public osg::Object
{
    public:
        META_Object(osgWidget, Style);

        // Class and contents...
        Style (const std::string& = "", const std::string& = "");
        Style (const Style&, const osg::CopyOp&);

        virtual bool applyStyle (Widget*, Reader);
        virtual bool applyStyle (Label*, Reader);
        virtual bool applyStyle (Input*, Reader);
        virtual bool applyStyle (Window*, Reader);
        virtual bool applyStyle (Window::EmbeddedWindow*, Reader);
        virtual bool applyStyle (Box*, Reader);
        virtual bool applyStyle (Frame::Corner*, Reader);
        virtual bool applyStyle (Frame::Border*, Reader);
        virtual bool applyStyle (Canvas*, Reader);



        void setStyle(const std::string& style) {
            _style = style;
        }

        std::string& getStyle() {
            return _style;
        }

        const std::string& getStyle() const {
            return _style;
        }

        static Widget::Layer                strToLayer     (const std::string&);
        static Widget::VerticalAlignment    strToVAlign    (const std::string&);
        static Widget::HorizontalAlignment  strToHAlign    (const std::string&);
        static Widget::CoordinateMode       strToCoordMode (const std::string&);
        static bool                         strToFill      (const std::string&);

    protected:

        std::string _style;

        bool _match(const char* seq, Reader r) {
            if(r.matchSequence(seq)) {
                ++r;

                return true;
            }

            return false;
        }
};

class OSGWIDGET_EXPORT StyleManager: public osg::Object
{
    public:
        typedef std::map<std::string, osg::ref_ptr<Style> > Styles;
        typedef Styles::iterator                            Iterator;
        typedef Styles::const_iterator                      ConstIterator;

        META_Object(osgWidget, StyleManager);

        StyleManager ();
        StyleManager (const StyleManager&, const osg::CopyOp&);

        bool addStyle(Style*);

        bool applyStyles(Widget* widget) {
            return _applyStyles(widget);
        }

        bool applyStyles(Window* window) {
            return _applyStyles(window);
        }

    private:
        Styles _styles;

        template<typename T>
        bool _applySpecificStyle(T* t, const std::string& style)
        {
            osgDB::FieldReaderIterator r;

            std::istringstream input(_styles[style]->getStyle());

            r.attach(&input);

            bool inc = false;

            while(!r.eof()) 
            {
                if(_styles[style]->applyStyle(t, r)) 
                    inc = true;
                else
                    r.advanceOverCurrentFieldOrBlock();
            }



            return inc;
        }

        template<typename T>
        bool _coerceAndApply(
            osg::Object*       obj,
            const std::string& style,
            const std::string& className
        ) {
            T* t = dynamic_cast<T*>(obj);

            if(!t) {
                warn()
                    << "An attempt was made to coerce Object [" << obj->getName()
                    << "] into a " << className << " but failed." << std::endl
                ;

                return 0;
            }

            return _applySpecificStyle(t, style);
        }


        bool _applyStyleToObject(osg::Object*, const std::string&);

        // 1. Check and see if the explicit FULL path is available.
        // 2. Check and see if each component working backward--minus the last--is available.
        // 3. Check to see if just the className() is available.
        template<typename T>
        bool _applyStyles(T* t)
        {
            if(!t)
            {
                warn()
                    << "Cannot call StyleManager::applyStyle with a NULL object."
                    << std::endl
                ;

                return false;
            }

            osg::Object* obj = dynamic_cast<osg::Object*>(t);

            if(!obj)
            {
                warn() 
                    << "Cannot coerce object into osg::Object in StyleManager:::applyStyle"
                    << std::endl
                ;

                return false;
            }

            std::string c = obj->className();

            // Case 3; there's no explicit Style set, so see if there's one for the class.
            if(t->getStyle().empty())
            {
                // Couldn't find the className, so we exit.
                if(_styles.find(c) == _styles.end()) return false;

                return _applyStyleToObject(obj, c);
            }

            // Case 1...
            if(_styles.find(t->getStyle()) != _styles.end()) return _applyStyleToObject(
                obj,
                t->getStyle()
            );

            return false;
        }

};

}

#endif