OpenSceneGraph/src/osgText/FTVectoriser.h

#ifndef        __FTVectoriser__
#define        __FTVectoriser__

#include "FTGL.h"

#include <osg/Referenced>

#include <vector>

#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H

#include "FTGlyph.h"



using namespace std;

/**
 * ftPoint class is a basic 3 dimensional point for holding outline font
 * point data.
 *
 * @see    FTOutlineGlyph
 * @see    FTPolyGlyph
 *
 */
class FTGL_EXPORT ftPoint
{
    public:
        /**
         * Default constructor. Point is set to zero.
         */
        ftPoint()
        : x(0), y(0), z(0)
        {}
        
        /**
         * Constructor.
         *
         * @param X
         * @param Y
         * @param Z
         */
        ftPoint( const float X, const float Y, const float Z)
        : x(X), y(Y), z(Z)
        {}
        
        /**
         * Operator == Tests for eqaulity
         *
         * @param a
         * @param b
         * @return
         */
        friend bool operator == ( const ftPoint &a, const ftPoint &b) 
        {
            return((a.x == b.x) && (a.y == b.y) && (a.z == b.z));
        }

        /**
         * Operator != Tests for non equality
         *
         * @param a
         * @param b
         * @return
         */
        friend bool operator != ( const ftPoint &a, const ftPoint &b) 
        {
            return((a.x != b.x) || (a.y != b.y) || (a.z != b.z));
        }
        
        /**
         * The point data
         */
        float x, y, z; // FIXME make private
        
    private:
};


/**
 * FTContour class is a container of points that describe an outline
 * point data.
 *
 * @see    FTOutlineGlyph
 * @see    FTPolyGlyph
 * @see    ftPoint
 *
 */
class FTGL_EXPORT FTContour
{
    public:
        /**
         * Default constructor
         */
        FTContour();

        /**
         *    Destructor
         */
        ~FTContour();
    
        /**
         * Add a point to the end of this contour.
         *
         * Doesn't add the point if it's already on the end or the start
         * of the contour. The Z component is always 0
         *
         * @param x    The X component of the point
         * @param y The Y component of the point
         */
        void AddPoint( const float x, const float y);
        
        /**
         * How many points define this contour
         *
         * @return the number of points in this contour
         */
        int size() const { return pointList.size();}

        /**
         *    The list of points in this contour
         */
        vector< ftPoint> pointList;
        
    private:
        /**
        * A 'max' number of points that this contour holds. Note however it
        * can hold more than this number. It is just used to reserve space
        * in the <vector>
        */
        const unsigned int kMAXPOINTS;
};


/**
 * FTVectoriser class is a helper class that converts font outlines into
 * point data. It includes a bezier curve evaluator
 *
 * @see    FTOutlineGlyph
 * @see    FTPolyGlyph
 * @see    FTContour
 * @see    ftPoint
 *
 */
class FTGL_EXPORT FTVectoriser : public osg::Referenced
{
    public:
        /**
         * Constructor
         *
         * @param glyph The freetype glyph to be processed
         */
        FTVectoriser( FT_Glyph glyph);

        /**
         *    Destructor
         */
        virtual ~FTVectoriser();

        /**
         * Process the freetype outline data into contours of points
         *
         * @return <code>true</code> on success
         */
        bool Process();

        /**
         * Copy the outline data into a block of <code>doubles</code>
         * @param d
         */
        void MakeOutline( double* d);

        /**
         * Get the total count of points in this outline
         *
         * @return the number of points
         */
        int points();

        /**
         * Get the count of contours in this outline
         *
         * @return the number of contours
         */
        int contours() const { return contourList.size();}

        /**
         * Get the nuber of points in a contour in this outline
         *
         * @param c        The contour index
         * @return        the number of points in contour[c]
         */
        int contourSize( int c) const { return contourList[c]->size();}

        /**
         * Get the flag for the tesselation rule for this outline
         *
         * @return The contour flag
         */
        int ContourFlag() const { return contourFlag;}
        
    private:
        /**
         * Process a conic ( second order bezier curve)
         *
         * @param index    The index of the current point in the point list.
         * @param first    The index into the pointlist of the first point in
         *                the contour that the current point is part of.
         * @param last    The index into the pointlist of the last point in
         *                the contour that the current point is part of.
         * @return         the number of control points processed
         */
        int Conic( const int index, const int first, const int last);

        /**
         * Process a cubic ( third order) bezier curve
         *
         * @param index    The index of the current point in the point list.
         * @param first    The index into the pointlist of the first point in
         *                the contour that the current point is part of.
         * @param last    The index into the pointlist of the last point in
         *                the contour that the current point is part of.
         * @return         the number of control points processed
         */
        int Cubic( const int index, const int first, const int last);

        /**
         * @param a
         * @param b
         */
        void deCasteljau( const float t, const int n);

        /**
         * @param a
         */
        void evaluateCurve( const int n);

        /**
         * The list of contours in this outline
         */
        vector< const FTContour*> contourList;
            
        /**
         * A temporary FTContour
         */
        FTContour* contour;

        /**
        * A flag indicating the tesselation rule for this outline
         */
        int contourFlag;

        /**
         * A Freetype outline
         */
        FT_Outline ftOutline;
        
        /**
         */
         // Magic numbers -- #define MAX_DEG 4
        float bValues[4][4][2];    //3D array storing values of de Casteljau algorithm.
        float ctrlPtArray[4][2]; // Magic numbers
        
        /**
         */
        const float kBSTEPSIZE;

};


#endif    //    __FTVectoriser__