shithub: freetype+ttf2subf

ref: db5285a0423b6cc5ec9d7ac010aecb877ac229da
dir: /include/freetype/ftglyph.h/

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/***************************************************************************/
/*                                                                         */
/*  ftglyph.h                                                              */
/*                                                                         */
/*    FreeType convenience functions to handle glyphs..                    */
/*                                                                         */
/*  Copyright 1996-2000 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used        */
/*  modified and distributed under the terms of the FreeType project       */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/*  This file contains the definition of several convenience functions     */
/*  that can be used by client applications to easily retrieve glyph       */
/*  bitmaps and outlines from a given face.                                */
/*                                                                         */
/*  These functions should be optional if you're writing a font server     */
/*  or text layout engine on top of FreeType. However, they are pretty     */
/*  handy for many other simple uses of the library..                      */
/*                                                                         */
/***************************************************************************/

#ifndef FTGLYPH_H
#define FTGLYPH_H

#include <freetype/freetype.h>

#ifdef __cplusplus
  extern "C" {
#endif

  /* forward declaration to a private type */
  typedef struct FT_Glyph_Class_  FT_Glyph_Class;

 /***********************************************************************
  *
  * <Struct>
  *    FT_GlyphRec
  *
  * <Description>
  *    The root glyph structure contains a given glyph image plus its
  *    advance width in 16.16 fixed float format..
  *
  * <Field>
  *    library  :: a handle to the FreeType library object.
  *    clazz    :: a pointer to the glyph's class. Private.
  *    format   :: the format of the glyph's image
  *    advance  :: a 16.16 vector that gives the glyph's advance width
  *
  ***********************************************************************/

  typedef struct FT_GlyphRec_
  {
    FT_Library             library;
    const FT_Glyph_Class*  clazz;
    FT_Glyph_Format        format;
    FT_Vector              advance;

  } FT_GlyphRec, *FT_Glyph;


 /***********************************************************************
  *
  * <Struct>
  *    FT_BitmapGlyphRec
  *
  * <Description>
  *    A structure used for bitmap glyph images.. This really is
  *    a "sub-class" of "FT_GlyphRec".
  *
  * <Field>
  *    root     :: the root FT_Glyph fields
  *    left     :: left-side bearing, i.e. the horizontal distance from
  *                the current pen position to the left border of the glyph
  *                bitmap.
  *    top      :: top-side bearing, i.e. the vertical distance from the
  *                current pen position to the top border of the glyph bitmap
  *                this distance is positive for upwards-y !!
  *    bitmap   :: a descriptor for the bitmap.
  *
  * <Note>
  *    You can typecast a FT_Glyph to FT_BitmapGlyph when you have
  *    glyph->format == ft_glyph_format_bitmap. This lets you access
  *    the bitmap's content easily..
  *
  *    the corresponding pixel buffer is always owned by the BitmapGlyph
  *    and is thus created and destroyed with it..
  *
  ***********************************************************************/

  typedef struct FT_BitmapGlyphRec_
  {
    FT_GlyphRec  root;
    FT_Int       left;
    FT_Int       top;
    FT_Bitmap    bitmap;

  } FT_BitmapGlyphRec, *FT_BitmapGlyph;


 /***********************************************************************
  *
  * <Struct>
  *    FT_OutlineGlyphRec
  *
  * <Description>
  *    A structure used for outline (vectorial) glyph images..     
  *    This really is a "sub-class" of FT_GlyphRec.
  *
  * <Field>
  *    root     :: the root FT_Glyph fields.
  *    outline  :: a descriptor for the outline
  *
  * <Note>
  *    You can typecast a FT_Glyph to FT_OutlineGlyph when you have
  *    glyph->format == ft_glyph_format_outline. This lets you access
  *    the outline's content easily..
  *
  *    As the outline is extracted from a glyph slot, its coordinates
  *    are expressed normally in 26.6 pixels, unless the flag
  *    FT_LOAD_NO_SCALE was used in FT_Load_Glyph / FT_Load_Char..
  *
  *    the outline's tables are always owned by the object and are
  *    destroyed with it..
  *
  ***********************************************************************/

  typedef struct FT_OutlineGlyphRec_
  {
    FT_GlyphRec  root;
    FT_Outline   outline;

  } FT_OutlineGlyphRec, *FT_OutlineGlyph;



 /***********************************************************************
  *
  * <Function>
  *    FT_Get_Glyph
  *
  * <Description>
  *    A function used to extract one glyph image from a slot..
  *
  * <Input>
  *    slot    :: handle to source glyph slot.
  *
  * <Output>
  *    aglyph  :: handle to the glyph object.
  *
  * <Return>
  *    Error code. 0 means success.
  *
  * <Note>
  *
  *
  ***********************************************************************/

  FT_EXPORT_DEF(FT_Error)  FT_Get_Glyph( FT_GlyphSlot   slot,
                                         FT_Glyph      *aglyph );

 /***********************************************************************
  *
  * <Function>
  *    FT_Glyph_Copy
  *
  * <Description>
  *    A function used to copy one glyph image.
  *
  * <Input>
  *    source  :: handle to source glyph object
  *
  * <Output>
  *    target  :: handle to target glyph object. 0 in case of error
  *
  * <Return>
  *    Error code. 0 means success.
  *
  ***********************************************************************/

  FT_EXPORT_DEF(FT_Error)  FT_Glyph_Copy( FT_Glyph   source,
                                          FT_Glyph  *target );


 /***********************************************************************
  *
  * <Function>
  *    FT_Glyph_Transform
  *
  * <Description>
  *    Transforms a glyph image, when it's format is scalable
  *
  * <Input>
  *    glyph  :: handle to target glyph object
  *
  *    matrix :: pointer to 2x2 matrix to apply
  *
  *    delta  :: pointer to a 2d vector to apply. coordinates are
  *              expressed in 1/64th of a pixel..
  *
  * <Return>
  *    error code (is not 0, the glyph format is not scalable).
  *
  * <Note>
  *    the 2x2 transform matrix is also applied to the glyph's
  *    advance vector
  *
  ***********************************************************************/

  FT_EXPORT_DEF(FT_Error)  FT_Glyph_Transform( FT_Glyph    glyph,
                                               FT_Matrix*  matrix,
                                               FT_Vector*  delta );
   
 /***********************************************************************
  *
  * <Function>
  *    FT_Glyph_Get_CBox
  *
  * <Description>
  *    Returns the glyph image's bounding box.
  *
  * <Input>
  *    glyph :: handle to source glyph object
  *    mode  :: a set of bit flags that indicate how to interpret
  *             the meaning of the box's coordinates
  *
  * <Output>
  *    box   :: the glyph bounding box. Coordinates are expressed in
  *             1/64th of pixels, it is grid-fitted..
  *
  * <Note>
  *    Coordinates are relative to the glyph origin, using the Y-upwards
  *    convention..
  *
  *    if 'ft_glyph_bbox_subpixels' is set in "mode", the bbox coordinates
  *    are returned in 26.6 pixels (i.e. 1/64th of pixels).
  *
  *    otherwise, coordinates are in integer pixels.
  *
  *    note that the maximum coordinates are exclusive, which means that
  *    once can compute the width and height of the glyph image (be it
  *    in integer or 26.6 pixels) as:
  *
  *        width  = bbox.xMax - bbox.xMin;
  *        height = bbox.yMax - bbox.yMin;
  *
  *    Note also that for 26.6 coordinates, if the 'ft_glyph_bbox_gridfit'
  *    flag is set in "mode", the coordinates will also be grid-fitted,
  *    which corresponds to:
  *
  *        bbox.xMin = FLOOR(bbox.xMin);
  *        bbox.yMin = FLOOR(bbox.yMin);
  *        bbox.xMax = CEILING(bbox.xMax);
  *        bbox.yMax = CEILING(bbox.yMax);
  *
  ***********************************************************************/

  enum
  {
    ft_glyph_bbox_pixels    = 0,
    ft_glyph_bbox_subpixels = 1,
    ft_glyph_bbox_gridfit   = 2
  };

  FT_EXPORT_DEF(void)  FT_Glyph_Get_CBox( FT_Glyph  glyph,
                                          FT_UInt   bbox_mode,
                                          FT_BBox  *cbox );


 /***********************************************************************
  *
  * <Function>
  *    FT_Glyph_To_Bitmap
  *
  * <Description>
  *    converts a given glyph object to a bitmap glyph object
  *
  * <InOut>
  *    glyph  :: pointer to a handle to the target glyph
  *
  * <Input>
  *    render_mode :: a set of bit flags that describe how
  *
  *    origin      :: pointer to a vector used to translate the glyph image
  *                   before rendering. Can be 0 (for no translation). The
  *                   origin is expressed in 26.6 pixels..
  *
  *    destroy     :: a boolean that indicates that the original glyph image
  *                   should be destroyed by this function. The glyph is
  *                   never destroyed in case of error..
  *
  * <Return>
  *    Error code. 0 means success
  *
  * <Note>
  *    the glyph image is translated with the "origin" vector before
  *    rendering.. In case of error, it it translated back to its original
  *    position and the glyph is untouched..
  *
  *    The first parameter is a pointer to a FT_Glyph handle, that
  *    will be replaced by this function. Typically, you would use:
  *
  *    {
  *        FT_Glyph        glyph;
  *        FT_BitmapGlyph  glyph_bitmap;
  *
  *        // load glyph
  *        error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAUT );
  *
  *        // extract glyph image
  *        error = FT_Get_Glyph( face->glyph, &glyph );
  *
  *        // convert to a bitmap (default render mode + destroy old)
  *        if (glyph->format != ft_glyph_format_bitmap)
  *        {
  *          error = FT_Glyph_To_Bitmap( &glyph, ft_render_mode_default, 0, 1 );
  *          if (error) // glyph unchanged..
  *        }
  *
  *        // access bitmap content by typecasting
  *        glyph_bitmap = (FT_BitmapGlyph)glyph;
  *
  *        // do funny stuff with it, like blitting/drawing
  *        ....
  *
  *        // discard glyph image (bitmap or not)
  *        FT_Done_Glyph( glyph );
  *
  *
  *    This function will always fail if the glyph's format isn't scalable
  *
  ***********************************************************************/

  FT_EXPORT_DEF(FT_Error)  FT_Glyph_To_Bitmap( FT_Glyph   *the_glyph,
                                               FT_ULong    render_mode,
                                               FT_Vector*  origin,
                                               FT_Bool     destroy );
                                               
 /***********************************************************************
  *
  * <Function>
  *    FT_Done_Glyph
  *
  * <Description>
  *    Destroys a given glyph..
  *
  * <Input>
  *    glyph  :: handle to target glyph object
  *
  ***********************************************************************/

  FT_EXPORT_DEF(void)  FT_Done_Glyph( FT_Glyph  glyph );


  /* other helpful functions */

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Matrix_Multiply                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Performs the matrix operation `b = a*b'.                           */
  /*                                                                       */
  /* <Input>                                                               */
  /*    a :: A pointer to matrix `a'.                                      */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    b :: A pointer to matrix `b'.                                      */
  /*                                                                       */
  /* <MT-Note>                                                             */
  /*    Yes.                                                               */
  /*                                                                       */
  FT_EXPORT_DEF(void)  FT_Matrix_Multiply( FT_Matrix*  a,
                                           FT_Matrix*  b );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Matrix_Invert                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Inverts a 2x2 matrix.  Returns an error if it can't be inverted.   */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    matrix :: A pointer to the target matrix.  Remains untouched in    */
  /*              case of error.                                           */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  /* <MT-Note>                                                             */
  /*    Yes.                                                               */
  /*                                                                       */
  FT_EXPORT_DEF(FT_Error)   FT_Matrix_Invert( FT_Matrix*  matrix );


#ifdef __cplusplus
  }
#endif

#endif /* FTGLYPH_H */