---

OGLFT.h

// -*- c++ -*-
/*
 * OGLFT: A library for drawing text with OpenGL using the FreeType library
 * Copyright (C) 2002 lignum Computing, Inc. <oglft@lignumcomputing.com>
 * $Id: OGLFT.h,v 1.14 2003/10/01 14:21:34 allen Exp $
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#ifndef OGLFT_H
#define OGLFT_H

#include <cmath>
#include <map>
#include <list>
#include <vector>
#ifdef HAVE_MPATROL
#include <mpdebug.h>
#endif
#include <GL/gl.h>
#include <GL/glu.h>

#ifndef OGLFT_NO_SOLID
#include <GL/gle.h>
#endif

#ifndef OGLFT_NO_QT
#include <qstring.h>
#include <qcolor.h>
#endif

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


namespace OGLFT {

  enum Coordinates {
    X, 
    Y, 
    Z, 
    W  
  };

  enum ColorSpace {
    R, 
    G, 
    B, 
    A, 
  };

  typedef void (*GLUTessCallback)();


  class Library {
  public:
    static FT_Library& instance ( void );

  protected:
    Library ( void );
    ~Library( void );

  private:
    static Library library;
    static FT_Library library_;
  };

  struct Advance {
    float dx_;  
    float dy_;  

    Advance ( float dx = 0, float dy = 0 ) : dx_( dx ), dy_( dy )
    {}

    Advance ( FT_Vector v )
    {
      dx_ = v.x / 64.;
      dy_ = v.y / 64.;
    }

    Advance& operator+= ( const FT_Vector v )
    {
      dx_ += v.x / 64.;
      dy_ += v.y / 64.;
      return *this;
    }
  };

  struct BBox {
    float x_min_;     
    float y_min_;     
    float x_max_;     
    float y_max_;     
    Advance advance_; 

    BBox () : x_min_( 0 ), y_min_( 0 ), x_max_( 0 ), y_max_( 0 )
    {}

    BBox ( FT_BBox ft_bbox )
    {
      x_min_ = ft_bbox.xMin / 64.;
      y_min_ = ft_bbox.yMin / 64.;
      x_max_ = ft_bbox.xMax / 64.;
      y_max_ = ft_bbox.yMax / 64.;
    }

    BBox& operator*= ( double k )
    {
      x_min_ *= k;
      y_min_ *= k;
      x_max_ *= k;
      y_max_ *= k;
      advance_.dx_ *= k;
      advance_.dy_ *= k;

      return *this;
    }

    BBox& operator+= ( const BBox& b )
    {
      float new_value;

      new_value = b.x_min_ + advance_.dx_;
      if ( new_value < x_min_ ) x_min_ = new_value;

      new_value = b.y_min_ + advance_.dy_;
      if ( new_value < y_min_ ) y_min_ = new_value;

      new_value = b.x_max_ + advance_.dx_;
      if ( new_value > x_max_ ) x_max_ = new_value;

      new_value = b.y_max_ + advance_.dy_;
      if ( new_value > y_max_ ) y_max_ = new_value;

      advance_.dx_ += b.advance_.dx_;
      advance_.dy_ += b.advance_.dy_;

      return *this;
    }
  };

  class ColorTess {
  public:
    virtual GLfloat* color ( GLdouble* p ) = 0;
  };

  class TextureTess {
  public:
    virtual GLfloat* texCoord ( GLdouble* p ) = 0;
  };

  typedef std::vector<GLuint> DisplayLists;

  typedef DisplayLists::const_iterator DLCI;

  typedef DisplayLists::iterator DLI;


  class Face {
  public:
    enum HorizontalJustification {
      LEFT,   
      ORIGIN, 
      CENTER, 
      RIGHT   
    };

    enum VerticalJustification {
      BOTTOM,   
      BASELINE, 
      MIDDLE,   
      TOP       
    };

    enum GlyphCompileMode {
      COMPILE,    
      IMMEDIATE   
    };

  private:
    struct FaceData {
      FT_Face face_;
      bool free_on_exit_;
      FaceData ( FT_Face face, bool free_on_exit = true )
        : face_( face ), free_on_exit_( free_on_exit )
      {}
    };
  protected:
    std::vector< FaceData > faces_;

    bool valid_;

    enum GlyphCompileMode compile_mode_;

    float point_size_;

    FT_UInt resolution_;

    bool advance_;

    GLfloat foreground_color_[4];

    GLfloat background_color_[4];

    enum HorizontalJustification horizontal_justification_;
    
    enum VerticalJustification vertical_justification_;

    GLfloat string_rotation_;

    FT_UInt rotation_reference_glyph_;

    FT_Face rotation_reference_face_;

    GLfloat rotation_offset_y_;

    typedef std::map< FT_UInt, GLuint > GlyphDLists;

    typedef GlyphDLists::const_iterator GDLCI;

    typedef GlyphDLists::iterator GDLI;

    GlyphDLists glyph_dlists_;

    DisplayLists character_display_lists_;

  public:
    Face ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );

    Face ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    virtual ~Face ( void );

    bool isValid ( void ) const { return valid_; }

    bool addAuxiliaryFace ( const char* filename );

    bool addAuxiliaryFace ( FT_Face face );

    void setCompileMode ( enum GlyphCompileMode compile_mode )
    {
      compile_mode_ = compile_mode;
    }

    enum GlyphCompileMode compileMode ( void ) const { return compile_mode_; }

    void setPointSize ( float point_size );
      
    float pointSize ( void ) { return point_size_; }

    void setResolution ( FT_UInt resolution );
      
    FT_UInt resolution ( void ) { return resolution_; }

    void setAdvance ( bool advance ) { advance_ = advance; }

    bool advance ( void ) const { return advance_; }

    void setForegroundColor ( GLfloat red = 0.0,
                              GLfloat green = 0.0,
                              GLfloat blue = 0.0,
                              GLfloat alpha = 1.0 );

    void setForegroundColor ( const GLfloat foreground_color[4] );
#ifndef OGLFT_NO_QT

    void setForegroundColor ( const QRgb foreground_color );
#endif /* OGLFT_NO_QT */

    GLfloat foregroundRed ( void ) const { return foreground_color_[R]; }
    GLfloat foregroundGreen ( void ) const { return foreground_color_[G]; }
    GLfloat foregroundBlue ( void ) const { return foreground_color_[B]; }
    GLfloat foregroundAlpha ( void ) const { return foreground_color_[A]; }

    void setBackgroundColor ( GLfloat red = 1.0,
                              GLfloat green = 1.0,
                              GLfloat blue = 1.0,
                              GLfloat alpha = 0.0 );

    void setBackgroundColor ( const GLfloat background_color[4] );
#ifndef OGLFT_NO_QT

    void setBackgroundColor ( const QRgb background_color );
#endif /* OGLFT_NO_QT */

    GLfloat backgroundRed ( void ) const { return background_color_[R]; }
    GLfloat backgroundGreen ( void ) const { return background_color_[G]; }
    GLfloat backgroundBlue ( void ) const { return background_color_[B]; }
    GLfloat backgroundAlpha ( void ) const { return background_color_[A]; }

    virtual void setCharacterRotationZ ( GLfloat character_rotation_z ) = 0;

    virtual GLfloat characterRotationZ ( void ) const = 0;

    void setCharacterRotationReference ( unsigned char c );

    void setStringRotation ( GLfloat string_rotation );

    GLfloat stringRotation ( void ) const { return string_rotation_; }

    void setHorizontalJustification ( enum HorizontalJustification
                                      horizontal_justification )
    {
      horizontal_justification_ = horizontal_justification;
    }

    enum HorizontalJustification horizontalJustification ( void ) const
    { return horizontal_justification_; }

    void setVerticalJustification ( enum VerticalJustification
                                    vertical_justification )
    {
      vertical_justification_ = vertical_justification;
    }

    enum VerticalJustification verticaljustification ( void )
      const { return vertical_justification_; }

    void setCharacterDisplayLists ( const DisplayLists& character_display_lists )
    {
      character_display_lists_ = character_display_lists;
    }

    DisplayLists& characterDisplayLists ( void )
    { return character_display_lists_; }

    virtual double height ( void ) const = 0;

    virtual BBox measure ( unsigned char c ) = 0;
#ifndef OGLFT_NO_QT

    virtual BBox measure ( QChar c ) = 0;
#endif /* OGLFT_NO_QT */

    virtual BBox measure ( const char* s );
    virtual BBox measureRaw ( const char* s );
#ifndef OGLFT_NO_QT

    virtual BBox measure ( const QString& s );
    virtual BBox measure ( const QString& format, double number );
    virtual BBox measureRaw ( const QString& s );
#endif /* OGLFT_NO_QT */

    GLuint compile ( const char* s );
#ifndef OGLFT_NO_QT

    GLuint compile ( const QString& s );
#endif /* OGLFT_NO_QT */

    GLuint compile ( unsigned char c );
#ifndef OGLFT_NO_QT

    GLuint compile ( const QChar c );
#endif /* OGLFT_NO_QT */

    void draw ( const char* s );
#ifndef OGLFT_NO_QT

    void draw ( const QString& s );
#endif /* OGLFT_NO_QT */

    void draw ( unsigned char c );

#ifndef OGLFT_NO_QT

    void draw ( const QChar c );
#endif /* OGLFT_NO_QT */

    void draw ( GLfloat x, GLfloat y, unsigned char c );
    void draw ( GLfloat x, GLfloat y, GLfloat z, unsigned char c );
#ifndef OGLFT_NO_QT

    void draw ( GLfloat x, GLfloat y, QChar c );
    void draw ( GLfloat x, GLfloat y, GLfloat z, QChar c );
#endif /* OGLFT_NO_QT */

    void draw ( GLfloat x, GLfloat y, const char* s );
    void draw ( GLfloat x, GLfloat y, GLfloat z, const char* s );
#ifndef OGLFT_NO_QT

    void draw ( GLfloat x, GLfloat y, const QString& s );
    void draw ( GLfloat x, GLfloat y, GLfloat z, const QString& s );
    void draw ( GLfloat x, GLfloat y, const QString& format, double number );
    void draw ( GLfloat x, GLfloat y, GLfloat z, const QString& format,
                double number );
#endif /* OGLFT_NO_QT */

    int ascender ( void ) { return faces_.front().face_->ascender; }

    int descender ( void ) { return faces_.front().face_->descender; }

  protected:
    // The various styles override these routines

    virtual GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index ) = 0;

    virtual void renderGlyph ( FT_Face face, FT_UInt glyph_index ) = 0;

    virtual void setCharSize ( void ) = 0;

    virtual void clearCaches ( void ) = 0;

    virtual void setRotationOffset ( void ) = 0;

  private:
    void init ( void );
    BBox measure_nominal ( const char* s );
#ifndef OGLFT_NO_QT
    BBox measure_nominal ( const QString& s );
    QString format_number ( const QString& format, double number );
#endif /* OGLFT_NO_QT */
  };


  class Polygonal : public Face {
  protected:
    struct {
      bool active_;
      GLfloat x_, y_, z_;
    } character_rotation_;

    unsigned int tessellation_steps_;

    double delta_, delta2_, delta3_;

    double vector_scale_;

    FT_Outline_Funcs interface_;

    static const unsigned int DEFAULT_TESSELLATION_STEPS = 4;

    struct VertexInfo {
      double v_[3]; 




      ColorTess* color_tess_;

      TextureTess* texture_tess_;

      VertexInfo ( ColorTess* color_tess = 0, TextureTess* texture_tess = 0 )
        : color_tess_( color_tess ), texture_tess_( texture_tess )
      {
        v_[X] = v_[Y] = v_[Z] = 0.;
      }

      VertexInfo ( FT_Vector* ft_v, ColorTess* color_tess = 0,
                   TextureTess* texture_tess = 0 )
        : color_tess_( color_tess ), texture_tess_( texture_tess )
      {
        v_[X] = (double)( ft_v->x / 64 ) + (double)( ft_v->x % 64 ) / 64.;
        v_[Y] = (double)( ft_v->y / 64 ) + (double)( ft_v->y % 64 ) / 64.;
        v_[Z] = 0.;
      }

      VertexInfo ( double p[2], ColorTess* color_tess = 0,
                   TextureTess* texture_tess = 0 )
        : color_tess_( color_tess ), texture_tess_( texture_tess )
      {
        v_[X] = p[X];
        v_[Y] = p[Y];
        v_[Z] = 0.;
      }

      VertexInfo ( double x, double y, ColorTess* color_tess = 0,
                   TextureTess* texture_tess = 0 )
        : color_tess_( color_tess ), texture_tess_( texture_tess )
      {
        v_[X] = x;
        v_[Y] = y;
        v_[Z] = 0.;
      }

      void normalize ( void )
      {
        double length = sqrt( v_[X] * v_[X] + v_[Y] * v_[Y] + v_[Z] * v_[Z] );
        v_[X] /= length;
        v_[Y] /= length;
        v_[Z] /= length;
      }
    };

    VertexInfo last_vertex_;

    typedef std::list< VertexInfo* > VertexInfoList;

    typedef VertexInfoList::const_iterator VILCI;

    typedef VertexInfoList::iterator VILI;

    VertexInfoList vertices_;

    bool contour_open_;

    ColorTess* color_tess_;

    TextureTess* texture_tess_;

  public:
    Polygonal ( const char* filename, float point_size = 12,
                FT_UInt resolution = 100 );

    Polygonal ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    virtual ~Polygonal ( void );

    void setTessellationSteps ( unsigned int tessellation_steps );

    unsigned int tessellationSteps ( void ) const { return tessellation_steps_; }

    void setCharacterRotationX ( GLfloat character_rotation_x );

    void setCharacterRotationY ( GLfloat character_rotation_y );

    void setCharacterRotationZ ( GLfloat character_rotation_z );

    GLfloat characterRotationX ( void ) const { return character_rotation_.x_; }

    GLfloat characterRotationY ( void ) const { return character_rotation_.y_; }

    GLfloat characterRotationZ ( void ) const { return character_rotation_.z_; }

    void setColorTess ( ColorTess* color_tess );
    ColorTess* colorTess ( void ) const { return color_tess_; }
    void setTextureTess ( TextureTess* texture_tess );
    TextureTess* textureTess ( void ) const { return texture_tess_; }

    double height ( void ) const;

    BBox measure ( unsigned char c );
#ifndef OGLFT_NO_QT

    BBox measure ( const QChar c );
#endif /* OGLFT_NO_QT */

    BBox measure ( const char* s ) { return Face::measure( s ); }
#ifndef OGLFT_NO_QT

    BBox measure ( const QString& format, double number )
    { return Face::measure( format, number ); }
#endif /* OGLFT_NO_QT */

  private:
    void init ( void );
    void setCharSize ( void );
    void setRotationOffset ( void );
    GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
  protected:
    void clearCaches ( void );
  };


  class Outline : public Polygonal {
  public:
    Outline ( const char* filename, float point_size = 12,
              FT_UInt resolution = 100 );
    Outline ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    ~Outline ( void );
  private:
    void init ( void );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    static int moveToCallback ( FT_Vector* to, Outline* outline );
    static int lineToCallback ( FT_Vector* to, Outline* outline );
    static int conicToCallback ( FT_Vector* control, FT_Vector* to, Outline* outline );
    static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
                                 FT_Vector* to, Outline* outline );
  };


  class Filled : public Polygonal {
    GLUtesselator* tess_obj_;

    VertexInfoList extra_vertices_;

  protected:
    GLfloat depth_offset_;

  public:
    Filled ( const char* filename, float point_size = 12,
             FT_UInt resolution = 100 );
    Filled ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
    virtual ~Filled ( void );

    VertexInfoList& extraVertices ( void ) { return extra_vertices_; }

  protected:
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
  private:
    void init ( void );
    static int moveToCallback ( FT_Vector* to, Filled* filled );
    static int lineToCallback ( FT_Vector* to, Filled* filled );
    static int conicToCallback ( FT_Vector* control, FT_Vector* to, Filled* filled);
    static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
                                 FT_Vector* to, Filled* filled );
    static void vertexCallback ( VertexInfo* vertex );
    static void beginCallback ( GLenum which );
    static void endCallback ( void );
    static void combineCallback ( GLdouble coords[3], void* vertex_data[4],
                                  GLfloat weight[4], void** out_data,
                                  Filled* filled );
    static void errorCallback ( GLenum error_code );
  };

#ifndef OGLFT_NO_SOLID


  class Solid : public Filled {
  private:

    FT_Outline_Funcs interface_;

    static const unsigned int N_POLYLINE_PTS = 4;

    struct glePoint2D {
      double p_[2];
      glePoint2D ( double p[2] ) { p_[X] = p[X]; p_[Y] = p[Y]; }
      glePoint2D ( double x, double y ) { p_[X] = x; p_[Y] = y; }
      glePoint2D ( const VertexInfo& v ) { p_[X] = v.v_[X]; p_[Y] = v.v_[Y]; }
    };

    struct {
      double depth_;
      struct {
        int x_, y_;
      } normal_sign_;
      std::vector< glePoint2D > contour_;
      std::vector< glePoint2D > contour_normals_;
      gleDouble up_[3];
      int n_polyline_pts_;
      gleDouble point_array_[N_POLYLINE_PTS][3];
    } extrusion_;

  public:
    Solid ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );

    Solid ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    ~Solid ( void );
    void setDepth ( double depth );
      
    double depth ( void ) const { return extrusion_.depth_; }

  private:
    // It would be nice if C/C++ had real matrix notation (like Perl!)
    void assign ( gleDouble a[3], double x, double y, double z )
    {
      a[X] = x;
      a[Y] = y;
      a[Z] = z;
    }

    void init ( void );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    static int moveToCallback ( FT_Vector* to, Solid* solid );
    static int lineToCallback ( FT_Vector* to, Solid* solid );
    static int conicToCallback ( FT_Vector* control, FT_Vector* to, Solid* solid );
    static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
                                 FT_Vector* to, Solid* solid );
  };
#endif /* OGLFT_NO_SOLID */

  class Raster : public Face {
  protected:
    GLfloat character_rotation_z_;
  public:
    Raster ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );
    Raster ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
    virtual ~Raster ( void );
    void setCharacterRotationZ ( GLfloat character_rotation_z );
    GLfloat characterRotationZ ( void ) const { return character_rotation_z_; }

    double height ( void ) const;

    BBox measure ( unsigned char c );
#ifndef OGLFT_NO_QT

    BBox measure ( const QChar c );
#endif /* OGLFT_NO_QT */

    BBox measure ( const char* s ) { return Face::measure( s ); }
#ifndef OGLFT_NO_QT

    BBox measure ( const QString& format, double number )
    { return Face::measure( format, number ); }
#endif /* OGLFT_NO_QT */

  private:
    void init ( void );
    GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
    void setCharSize ( void );
    void setRotationOffset ( void );
    void clearCaches ( void );
  };


  class Monochrome : public Raster {
  public:
    Monochrome ( const char* filename, float point_size = 12,
                 FT_UInt resolution = 100 );
    Monochrome ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
    ~Monochrome ( void );
  private:
    GLubyte* invertBitmap ( const FT_Bitmap& bitmap );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
  };


  class Grayscale : public Raster {
  public:
    Grayscale ( const char* filename, float point_size = 12,
                FT_UInt resolution = 100 );
    Grayscale ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
    ~Grayscale ( void );
  private:
    GLubyte* invertPixmap ( const FT_Bitmap& bitmap );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
  };


  class Translucent : public Raster {
  public:
    Translucent ( const char* filename, float point_size = 12,
                  FT_UInt resolution = 100 );
    Translucent ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    ~Translucent ( void );

  private:
    GLubyte* invertPixmapWithAlpha ( const FT_Bitmap& bitmap );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
  };

  class Texture : public Face {
  protected:
    struct {
      bool active_; 

      GLfloat x_,   
        y_,         
        z_;         
    } character_rotation_;

    struct TextureInfo {
      GLuint texture_name_;  
      FT_Int left_bearing_,  
        bottom_bearing_;     
      int width_,            
        height_;             
      GLfloat texture_s_,    

        texture_t_;          

      FT_Vector advance_;    
    };

    typedef std::map< FT_UInt, TextureInfo > GlyphTexObjs;

    typedef GlyphTexObjs::const_iterator GTOCI;

    typedef GlyphTexObjs::iterator GTOI;

    GlyphTexObjs glyph_texobjs_;

  public:
    Texture ( const char* filename, float point_size = 12,
              FT_UInt resolution = 100 );

    Texture ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );

    virtual ~Texture ( void );
    void setCharacterRotationX ( GLfloat character_rotation_x );

    void setCharacterRotationY ( GLfloat character_rotation_y );

    void setCharacterRotationZ ( GLfloat character_rotation_z );

    GLfloat characterRotationX ( void ) const { return character_rotation_.x_; }

    GLfloat characterRotationY ( void ) const { return character_rotation_.y_; }

    GLfloat characterRotationZ ( void ) const { return character_rotation_.z_; }

    double height ( void ) const;

    BBox measure ( unsigned char c );
#ifndef OGLFT_NO_QT

    BBox measure ( const QChar c );
#endif /* OGLFT_NO_QT */

    BBox measure ( const char* s ) { return Face::measure( s ); }
#ifndef OGLFT_NO_QT

    BBox measure ( const QString& format, double number )
    { return Face::measure( format, number ); }
#endif /* OGLFT_NO_QT */

  protected:
    unsigned int nearestPowerCeil ( unsigned int a );
    virtual void bindTexture ( FT_Face face, FT_UInt glyph_index ) = 0;

  private:
    void init ( void );
    void setCharSize ( void );
    void setRotationOffset ( void );
    GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
    void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    void clearCaches ( void );
  };


  class MonochromeTexture : public Texture {
  public:
    MonochromeTexture ( const char* filename, float point_size = 12,
                        FT_UInt resolution = 100 );
    MonochromeTexture ( FT_Face face, float point_size = 12,
                        FT_UInt resolution = 100 );
    ~MonochromeTexture ( void );
  private:
    GLubyte* invertBitmap ( const FT_Bitmap& bitmap, int* width, int* height );
    void bindTexture ( FT_Face face, FT_UInt glyph_index );
  };


  class GrayscaleTexture : public Texture {
  public:
    GrayscaleTexture ( const char* filename, float point_size = 12,
                       FT_UInt resolution = 100 );
    GrayscaleTexture ( FT_Face face, float point_size = 12,
                       FT_UInt resolution = 100 );
    ~GrayscaleTexture ( void );
  private:
    GLubyte* invertPixmap ( const FT_Bitmap& bitmap, int* width, int* height );
    void bindTexture ( FT_Face face, FT_UInt glyph_index );
  };


  class TranslucentTexture : public Texture {
  public:
    TranslucentTexture ( const char* filename, float point_size = 12,
                         FT_UInt resolution = 100 );
    TranslucentTexture ( FT_Face face, float point_size = 12,
                         FT_UInt resolution = 100 );
    ~TranslucentTexture ( void );
  private:
    GLubyte* invertPixmap ( const FT_Bitmap& bitmap, int* width, int* height );
    void bindTexture ( FT_Face face, FT_UInt glyph_index );
  };
} // Close OGLFT namespace
#endif /* OGLFT_H */

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