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 /****************************************************************************
  *
  * ftglyph.h
  *
  *   FreeType convenience functions to handle glyphs (specification).
  *
  * Copyright (C) 1996-2023 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 are 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 FREETYPE_H
 #error "freetype.h of FreeType 1 has been loaded!"
 #error "Please fix the directory search order for header files"
 #error "so that freetype.h of FreeType 2 is found first."
 #endif
 
 
 FT_BEGIN_HEADER
 
 
   /**************************************************************************
    *
    * @section:
    *   glyph_management
    *
    * @title:
    *   Glyph Management
    *
    * @abstract:
    *   Generic interface to manage individual glyph data.
    *
    * @description:
    *   This section contains definitions used to manage glyph data through
    *   generic @FT_Glyph objects.  Each of them can contain a bitmap,
    *   a vector outline, or even images in other formats.  These objects are
    *   detached from @FT_Face, contrary to @FT_GlyphSlot.
    *
    */
 
 
   /* forward declaration to a private type */
   typedef struct FT_Glyph_Class_  FT_Glyph_Class;
 
 
   /**************************************************************************
    *
    * @type:
    *   FT_Glyph
    *
    * @description:
    *   Handle to an object used to model generic glyph images.  It is a
    *   pointer to the @FT_GlyphRec structure and can contain a glyph bitmap
    *   or pointer.
    *
    * @note:
    *   Glyph objects are not owned by the library.  You must thus release
    *   them manually (through @FT_Done_Glyph) _before_ calling
    *   @FT_Done_FreeType.
    */
   typedef struct FT_GlyphRec_*  FT_Glyph;
 
 
   /**************************************************************************
    *
    * @struct:
    *   FT_GlyphRec
    *
    * @description:
    *   The root glyph structure contains a given glyph image plus its advance
    *   width in 16.16 fixed-point format.
    *
    * @fields:
    *   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;
 
 
   /**************************************************************************
    *
    * @type:
    *   FT_BitmapGlyph
    *
    * @description:
    *   A handle to an object used to model a bitmap glyph image.  This is a
    *   'sub-class' of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec.
    */
   typedef struct FT_BitmapGlyphRec_*  FT_BitmapGlyph;
 
 
   /**************************************************************************
    *
    * @struct:
    *   FT_BitmapGlyphRec
    *
    * @description:
    *   A structure used for bitmap glyph images.  This really is a
    *   'sub-class' of @FT_GlyphRec.
    *
    * @fields:
    *   root ::
    *     The root fields of @FT_Glyph.
    *
    *   left ::
    *     The left-side bearing, i.e., the horizontal distance from the
    *     current pen position to the left border of the glyph bitmap.
    *
    *   top ::
    *     The 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 an @FT_Glyph to @FT_BitmapGlyph if you have
    *   `glyph->format == FT_GLYPH_FORMAT_BITMAP`.  This lets you access the
    *   bitmap's contents easily.
    *
    *   The corresponding pixel buffer is always owned by @FT_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;
 
 
   /**************************************************************************
    *
    * @type:
    *   FT_OutlineGlyph
    *
    * @description:
    *   A handle to an object used to model an outline glyph image.  This is a
    *   'sub-class' of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec.
    */
   typedef struct FT_OutlineGlyphRec_*  FT_OutlineGlyph;
 
 
   /**************************************************************************
    *
    * @struct:
    *   FT_OutlineGlyphRec
    *
    * @description:
    *   A structure used for outline (vectorial) glyph images.  This really is
    *   a 'sub-class' of @FT_GlyphRec.
    *
    * @fields:
    *   root ::
    *     The root @FT_Glyph fields.
    *
    *   outline ::
    *     A descriptor for the outline.
    *
    * @note:
    *   You can typecast an @FT_Glyph to @FT_OutlineGlyph if 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 or @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;
 
 
   /**************************************************************************
    *
    * @type:
    *   FT_SvgGlyph
    *
    * @description:
    *   A handle to an object used to model an SVG glyph.  This is a
    *   'sub-class' of @FT_Glyph, and a pointer to @FT_SvgGlyphRec.
    *
    * @since:
    *   2.12
    */
   typedef struct FT_SvgGlyphRec_*  FT_SvgGlyph;
 
 
   /**************************************************************************
    *
    * @struct:
    *   FT_SvgGlyphRec
    *
    * @description:
    *   A structure used for OT-SVG glyphs.  This is a 'sub-class' of
    *   @FT_GlyphRec.
    *
    * @fields:
    *   root ::
    *     The root @FT_GlyphRec fields.
    *
    *   svg_document ::
    *     A pointer to the SVG document.
    *
    *   svg_document_length ::
    *     The length of `svg_document`.
    *
    *   glyph_index ::
    *     The index of the glyph to be rendered.
    *
    *   metrics ::
    *     A metrics object storing the size information.
    *
    *   units_per_EM ::
    *     The size of the EM square.
    *
    *   start_glyph_id ::
    *     The first glyph ID in the glyph range covered by this document.
    *
    *   end_glyph_id ::
    *     The last glyph ID in the glyph range covered by this document.
    *
    *   transform ::
    *     A 2x2 transformation matrix to apply to the glyph while rendering
    *     it.
    *
    *   delta ::
    *     Translation to apply to the glyph while rendering.
    *
    * @note:
    *   The Glyph Management API requires @FT_Glyph or its 'sub-class' to have
    *   all the information needed to completely define the glyph's rendering.
    *   Outline-based glyphs can directly apply transformations to the outline
    *   but this is not possible for an SVG document that hasn't been parsed.
    *   Therefore, the transformation is stored along with the document.  In
    *   the absence of a 'ViewBox' or 'Width'/'Height' attribute, the size of
    *   the ViewPort should be assumed to be 'units_per_EM'.
    */
   typedef struct  FT_SvgGlyphRec_
   {
     FT_GlyphRec  root;
 
     FT_Byte*  svg_document;
     FT_ULong  svg_document_length;
 
     FT_UInt  glyph_index;
 
     FT_Size_Metrics  metrics;
     FT_UShort        units_per_EM;
 
     FT_UShort  start_glyph_id;
     FT_UShort  end_glyph_id;
 
     FT_Matrix  transform;
     FT_Vector  delta;
 
   } FT_SvgGlyphRec;
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_New_Glyph
    *
    * @description:
    *   A function used to create a new empty glyph image.  Note that the
    *   created @FT_Glyph object must be released with @FT_Done_Glyph.
    *
    * @input:
    *   library ::
    *     A handle to the FreeType library object.
    *
    *   format ::
    *     The format of the glyph's image.
    *
    * @output:
    *   aglyph ::
    *     A handle to the glyph object.
    *
    * @return:
    *   FreeType error code.  0~means success.
    *
    * @since:
    *   2.10
    */
   FT_EXPORT( FT_Error )
   FT_New_Glyph( FT_Library       library,
                 FT_Glyph_Format  format,
                 FT_Glyph         *aglyph );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Get_Glyph
    *
    * @description:
    *   A function used to extract a glyph image from a slot.  Note that the
    *   created @FT_Glyph object must be released with @FT_Done_Glyph.
    *
    * @input:
    *   slot ::
    *     A handle to the source glyph slot.
    *
    * @output:
    *   aglyph ::
    *     A handle to the glyph object.  `NULL` in case of error.
    *
    * @return:
    *   FreeType error code.  0~means success.
    *
    * @note:
    *   Because `*aglyph->advance.x` and `*aglyph->advance.y` are 16.16
    *   fixed-point numbers, `slot->advance.x` and `slot->advance.y` (which
    *   are in 26.6 fixed-point format) must be in the range ]-32768;32768[.
    */
   FT_EXPORT( FT_Error )
   FT_Get_Glyph( FT_GlyphSlot  slot,
                 FT_Glyph     *aglyph );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Glyph_Copy
    *
    * @description:
    *   A function used to copy a glyph image.  Note that the created
    *   @FT_Glyph object must be released with @FT_Done_Glyph.
    *
    * @input:
    *   source ::
    *     A handle to the source glyph object.
    *
    * @output:
    *   target ::
    *     A handle to the target glyph object.  `NULL` in case of error.
    *
    * @return:
    *   FreeType error code.  0~means success.
    */
   FT_EXPORT( FT_Error )
   FT_Glyph_Copy( FT_Glyph   source,
                  FT_Glyph  *target );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Glyph_Transform
    *
    * @description:
    *   Transform a glyph image if its format is scalable.
    *
    * @inout:
    *   glyph ::
    *     A handle to the target glyph object.
    *
    * @input:
    *   matrix ::
    *     A pointer to a 2x2 matrix to apply.
    *
    *   delta ::
    *     A pointer to a 2d vector to apply.  Coordinates are expressed in
    *     1/64 of a pixel.
    *
    * @return:
    *   FreeType error code (if not 0, the glyph format is not scalable).
    *
    * @note:
    *   The 2x2 transformation matrix is also applied to the glyph's advance
    *   vector.
    */
   FT_EXPORT( FT_Error )
   FT_Glyph_Transform( FT_Glyph          glyph,
                       const FT_Matrix*  matrix,
                       const FT_Vector*  delta );
 
 
   /**************************************************************************
    *
    * @enum:
    *   FT_Glyph_BBox_Mode
    *
    * @description:
    *   The mode how the values of @FT_Glyph_Get_CBox are returned.
    *
    * @values:
    *   FT_GLYPH_BBOX_UNSCALED ::
    *     Return unscaled font units.
    *
    *   FT_GLYPH_BBOX_SUBPIXELS ::
    *     Return unfitted 26.6 coordinates.
    *
    *   FT_GLYPH_BBOX_GRIDFIT ::
    *     Return grid-fitted 26.6 coordinates.
    *
    *   FT_GLYPH_BBOX_TRUNCATE ::
    *     Return coordinates in integer pixels.
    *
    *   FT_GLYPH_BBOX_PIXELS ::
    *     Return grid-fitted pixel coordinates.
    */
   typedef enum  FT_Glyph_BBox_Mode_
   {
     FT_GLYPH_BBOX_UNSCALED  = 0,
     FT_GLYPH_BBOX_SUBPIXELS = 0,
     FT_GLYPH_BBOX_GRIDFIT   = 1,
     FT_GLYPH_BBOX_TRUNCATE  = 2,
     FT_GLYPH_BBOX_PIXELS    = 3
 
   } FT_Glyph_BBox_Mode;
 
 
   /* these constants are deprecated; use the corresponding */
   /* `FT_Glyph_BBox_Mode` values instead                   */
 #define ft_glyph_bbox_unscaled   FT_GLYPH_BBOX_UNSCALED
 #define ft_glyph_bbox_subpixels  FT_GLYPH_BBOX_SUBPIXELS
 #define ft_glyph_bbox_gridfit    FT_GLYPH_BBOX_GRIDFIT
 #define ft_glyph_bbox_truncate   FT_GLYPH_BBOX_TRUNCATE
 #define ft_glyph_bbox_pixels     FT_GLYPH_BBOX_PIXELS
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Glyph_Get_CBox
    *
    * @description:
    *   Return a glyph's 'control box'.  The control box encloses all the
    *   outline's points, including Bezier control points.  Though it
    *   coincides with the exact bounding box for most glyphs, it can be
    *   slightly larger in some situations (like when rotating an outline that
    *   contains Bezier outside arcs).
    *
    *   Computing the control box is very fast, while getting the bounding box
    *   can take much more time as it needs to walk over all segments and arcs
    *   in the outline.  To get the latter, you can use the 'ftbbox'
    *   component, which is dedicated to this single task.
    *
    * @input:
    *   glyph ::
    *     A handle to the source glyph object.
    *
    *   mode ::
    *     The mode that indicates how to interpret the returned bounding box
    *     values.
    *
    * @output:
    *   acbox ::
    *     The glyph coordinate bounding box.  Coordinates are expressed in
    *     1/64 of pixels if it is grid-fitted.
    *
    * @note:
    *   Coordinates are relative to the glyph origin, using the y~upwards
    *   convention.
    *
    *   If the glyph has been loaded with @FT_LOAD_NO_SCALE, `bbox_mode` must
    *   be set to @FT_GLYPH_BBOX_UNSCALED to get unscaled font units in 26.6
    *   pixel format.  The value @FT_GLYPH_BBOX_SUBPIXELS is another name for
    *   this constant.
    *
    *   If the font is tricky and the glyph has been loaded with
    *   @FT_LOAD_NO_SCALE, the resulting CBox is meaningless.  To get
    *   reasonable values for the CBox it is necessary to load the glyph at a
    *   large ppem value (so that the hinting instructions can properly shift
    *   and scale the subglyphs), then extracting the CBox, which can be
    *   eventually converted back to font units.
    *
    *   Note that the maximum coordinates are exclusive, which means that one
    *   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 `bbox_mode` is set to
    *   @FT_GLYPH_BBOX_GRIDFIT, 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);
    *   ```
    *
    *   To get the bbox in pixel coordinates, set `bbox_mode` to
    *   @FT_GLYPH_BBOX_TRUNCATE.
    *
    *   To get the bbox in grid-fitted pixel coordinates, set `bbox_mode` to
    *   @FT_GLYPH_BBOX_PIXELS.
    */
   FT_EXPORT( void )
   FT_Glyph_Get_CBox( FT_Glyph  glyph,
                      FT_UInt   bbox_mode,
                      FT_BBox  *acbox );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Glyph_To_Bitmap
    *
    * @description:
    *   Convert a given glyph object to a bitmap glyph object.
    *
    * @inout:
    *   the_glyph ::
    *     A pointer to a handle to the target glyph.
    *
    * @input:
    *   render_mode ::
    *     An enumeration that describes how the data is rendered.
    *
    *   origin ::
    *     A pointer to a vector used to translate the glyph image before
    *     rendering.  Can be~0 (if 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.  It is never destroyed in case of error.
    *
    * @return:
    *   FreeType error code.  0~means success.
    *
    * @note:
    *   This function does nothing if the glyph format isn't scalable.
    *
    *   The glyph image is translated with the `origin` vector before
    *   rendering.
    *
    *   The first parameter is a pointer to an @FT_Glyph handle that will be
    *   _replaced_ by this function (with newly allocated data).  Typically,
    *   you would do something like the following (omitting error handling).
    *
    *   ```
    *     FT_Glyph        glyph;
    *     FT_BitmapGlyph  glyph_bitmap;
    *
    *
    *     // load glyph
    *     error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAULT );
    *
    *     // extract glyph image
    *     error = FT_Get_Glyph( face->glyph, &glyph );
    *
    *     // convert to a bitmap (default render mode + destroying old)
    *     if ( glyph->format != FT_GLYPH_FORMAT_BITMAP )
    *     {
    *       error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL,
    *                                   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 );
    *   ```
    *
    *   Here is another example, again without error handling.
    *
    *   ```
    *     FT_Glyph  glyphs[MAX_GLYPHS]
    *
    *
    *     ...
    *
    *     for ( idx = 0; i < MAX_GLYPHS; i++ )
    *       error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) ||
    *               FT_Get_Glyph ( face->glyph, &glyphs[idx] );
    *
    *     ...
    *
    *     for ( idx = 0; i < MAX_GLYPHS; i++ )
    *     {
    *       FT_Glyph  bitmap = glyphs[idx];
    *
    *
    *       ...
    *
    *       // after this call, `bitmap' no longer points into
    *       // the `glyphs' array (and the old value isn't destroyed)
    *       FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 );
    *
    *       ...
    *
    *       FT_Done_Glyph( bitmap );
    *     }
    *
    *     ...
    *
    *     for ( idx = 0; i < MAX_GLYPHS; i++ )
    *       FT_Done_Glyph( glyphs[idx] );
    *   ```
    */
   FT_EXPORT( FT_Error )
   FT_Glyph_To_Bitmap( FT_Glyph*         the_glyph,
                       FT_Render_Mode    render_mode,
                       const FT_Vector*  origin,
                       FT_Bool           destroy );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Done_Glyph
    *
    * @description:
    *   Destroy a given glyph.
    *
    * @input:
    *   glyph ::
    *     A handle to the target glyph object.  Can be `NULL`.
    */
   FT_EXPORT( void )
   FT_Done_Glyph( FT_Glyph  glyph );
 
   /* */
 
 
   /* other helpful functions */
 
   /**************************************************************************
    *
    * @section:
    *   computations
    *
    */
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Matrix_Multiply
    *
    * @description:
    *   Perform the matrix operation `b = a*b`.
    *
    * @input:
    *   a ::
    *     A pointer to matrix `a`.
    *
    * @inout:
    *   b ::
    *     A pointer to matrix `b`.
    *
    * @note:
    *   The result is undefined if either `a` or `b` is zero.
    *
    *   Since the function uses wrap-around arithmetic, results become
    *   meaningless if the arguments are very large.
    */
   FT_EXPORT( void )
   FT_Matrix_Multiply( const FT_Matrix*  a,
                       FT_Matrix*        b );
 
 
   /**************************************************************************
    *
    * @function:
    *   FT_Matrix_Invert
    *
    * @description:
    *   Invert a 2x2 matrix.  Return 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.
    */
   FT_EXPORT( FT_Error )
   FT_Matrix_Invert( FT_Matrix*  matrix );
 
   /* */
 
 
 FT_END_HEADER
 
 #endif /* FTGLYPH_H_ */
 
 
 /* END */
 
 
 /* Local Variables: */
 /* coding: utf-8    */
 /* End:             */

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