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kc3-lang/ftgl/include/FTFont.h

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  • Author : henry
    Date : 2004-10-03 21:10:47
    Hash : f4e9d7a3
    Message : Update comments

  • include/FTFont.h
  • #ifndef    __FTFont__
    #define    __FTFont__
    
    #include <ft2build.h>
    #include FT_FREETYPE_H
    
    #include "FTFace.h"
    #include "FTGL.h"
    
    class FTGlyphContainer;
    class FTGlyph;
    
    
    /**
     * FTFont is the public interface for the FTGL library.
     *
     * Specific font classes are derived from this class. It uses the helper
     * classes FTFace and FTSize to access the Freetype library. This class
     * is abstract and deriving classes must implement the protected
     * <code>MakeGlyph</code> function to create glyphs of the
     * appropriate type.
     *
     * It is good practice after using these functions to test the error
     * code returned. <code>FT_Error Error()</code>. Check the freetype file fterrdef.h
     * for error definitions.
     *
     * @see     FTFace
     * @see     FTSize
     * @see     FTGlyphContainer
     * @see     FTGlyph
     */
    class FTGL_EXPORT FTFont
    {
        public:
            /**
             * Open and read a font file. Sets Error flag.
             *
             * @param fontname  font file name.
             */
            FTFont( const char* fontname);
            
            /**
             * Open and read a font from a buffer in memory. Sets Error flag.
             * The buffer is owned by the client and is NOT copied by FTGL. The
             * pointer must be valid while using FTGL.
             *
             * @param pBufferBytes  the in-memory buffer
             * @param bufferSizeInBytes  the length of the buffer in bytes
             */
            FTFont( const unsigned char *pBufferBytes, size_t bufferSizeInBytes);
            
            /**
             * Destructor
             */
            virtual ~FTFont();
            
            /**
             * Attach auxilliary file to font e.g font metrics.
             *
             * Note: not all font formats implement this function.
             *
             * @param filename  auxilliary font file name.
             * @return          <code>true</code> if file has been attached
             *                  successfully.
             */
            bool Attach( const char* filename);
    
            /**
             * Attach auxilliary data to font e.g font metrics, from memory
             *
             * Note: not all font formats implement this function.
             *
             * @param pBufferBytes  the in-memory buffer
             * @param bufferSizeInBytes  the length of the buffer in bytes
             * @return          <code>true</code> if file has been attached
             *                  successfully.
             */
            bool Attach( const unsigned char *pBufferBytes, size_t bufferSizeInBytes);
    
            /**
             * Set the character map for the face.
             *
             * @param encoding      Freetype enumerate for char map code.
             * @return              <code>true</code> if charmap was valid and
             *                      set correctly
             */
            bool CharMap( FT_Encoding encoding );
    
            /**
             * Get the number of character maps in this face.
             *
             * @return character map count.
             */
            unsigned int CharMapCount();
    
            /**
             * Get a list of character maps in this face.
             *
             * @return pointer to the first encoding.
             */
            FT_Encoding* CharMapList();
            
            /**
             * Set the char size for the current face.
             *
             * @param size      the face size in points (1/72 inch)
             * @param res       the resolution of the target device.
             * @return          <code>true</code> if size was set correctly
             */
            virtual bool FaceSize( const unsigned int size, const unsigned int res = 72);
            
            /**
             * Get the current face size in points.
             *
             * @return face size
             */
            unsigned int FaceSize() const;
            
            /**
             * Set the extrusion distance for the font. Only implemented by
             * FTGLExtrdFont
             *
             * @param depth  The extrusion distance.
             */
            virtual void Depth( float depth){}
    
            /**
             * Enable or disable the use of Display Lists inside FTGL
             *
             * @param  useList <code>true</code> turns ON display lists.
             *                 <code>false</code> turns OFF display lists.
             */
            void UseDisplayList( bool useList);
            
            /**
             * Get the global ascender height for the face.
             *
             * @return  Ascender height
             */
            float Ascender() const;
            
            /**
             * Gets the global descender height for the face.
             *
             * @return  Descender height
             */
            float Descender() const;
            
            /**
             * Gets the line spacing for the font.
             *
             * @return  Line height
             */
            float LineHeight() const;
            
            /**
             * Get the bounding box for a string.
             *
             * @param string    a char string
             * @param llx       lower left near x coord
             * @param lly       lower left near y coord
             * @param llz       lower left near z coord
             * @param urx       upper right far x coord
             * @param ury       upper right far y coord
             * @param urz       upper right far z coord
             */
            void BBox( const char* string, float& llx, float& lly, float& llz, float& urx, float& ury, float& urz);
    
            /**
             * Get the bounding box for a string.
             *
             * @param string    a wchar_t string
             * @param llx       lower left near x coord
             * @param lly       lower left near y coord
             * @param llz       lower left near z coord
             * @param urx       upper right far x coord
             * @param ury       upper right far y coord
             * @param urz       upper right far z coord
             */
            void BBox( const wchar_t* string, float& llx, float& lly, float& llz, float& urx, float& ury, float& urz);
    
            /**
             * Get the advance width for a string.
             *
             * @param string    a wchar_t string
             * @return      advance width
             */
            float Advance( const wchar_t* string);
    
            /**
             * Get the advance width for a string.
             *
             * @param string    a char string
             * @return      advance width
             */
            float Advance( const char* string);
    
            /**
             * Render a string of characters
             * 
             * @param string    'C' style string to be output.   
             */
            virtual void Render( const char* string );
    
            /**
             * Render a string of characters
             * 
             * @param string    wchar_t string to be output.     
             */
            virtual void Render( const wchar_t* string );
    
            /**
             * Queries the Font for errors.
             *
             * @return  The current error code.
             */
            FT_Error Error() const { return err;}
    
        protected:
            /**
             * Construct a glyph of the correct type.
             *
             * Clients must overide the function and return their specialised
             * FTGlyph.
             *
             * @param g The glyph index NOT the char code.
             * @return  An FT****Glyph or <code>null</code> on failure.
             */
            virtual FTGlyph* MakeGlyph( unsigned int g) = 0;
            
            /**
             * Current face object
             */
            FTFace face;
            
            /**
             * Current size object
             */
            FTSize charSize;
    
            /**
             * Flag to enable or disable the use of Display Lists inside FTGL
             * <code>true</code> turns ON display lists.
             * <code>false</code> turns OFF display lists.
             */
            bool useDisplayLists;
    
            /**
             * Current error code. Zero means no error.
             */
            FT_Error err;
            
        private:        
            /**
             * Render a character
             * This function does an implicit conversion on it's arguments.
             * 
             * @param chr       current character
             * @param nextChr   next character
             */
            inline void DoRender( const unsigned int chr, const unsigned int nextChr);
            
            /**
             * Check that the glyph at <code>chr</code> exist. If not load it.
             *
             * @param chr  character index
             * @return <code>true</code> if the glyph can be created.
             */
            inline bool CheckGlyph( const unsigned int chr);
    
            /**
             * An object that holds a list of glyphs
             */
            FTGlyphContainer* glyphList;
            
            /**
             * Current pen or cursor position;
             */
            FTPoint pen;
    };
    
    
    #endif  //  __FTFont__