t1gload.c

Qt/Embedded是一个多平台的C++图形用户界面应用程序框架

/*******************************************************************
 *
 *  t1gload.c                                                   1.0
 *
 *    Type1 Glyph Loader.
 *
 *  Copyright 1996-1999 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.
 *
 ******************************************************************/

#include <t1gload.h>
#include <ftdebug.h>
#include <ftstream.h>

#ifndef T1_CONFIG_OPTION_DISABLE_HINTER
#include <t1hinter.h>
#endif

  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********           GENERIC CHARSTRINGS PARSING             *********/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/

/*********************************************************************
 *
 * <Function>
 *    T1_Init_Builder
 *
 * <Description>
 *    Initialise a given glyph builder.
 *
 * <Input>
 *    builder :: glyph builder to initialise
 *    face    :: current face object
 *    size    :: current size object
 *    glyph   :: current glyph object
 *    funcs   :: glyph builder functions (or "methods").
 *
 *********************************************************************/

  EXPORT_FUNC
  void  T1_Init_Builder( T1_Builder*             builder,
                         T1_Face                 face,
                         T1_Size                 size,
                         T1_GlyphSlot            glyph,
                         const T1_Builder_Funcs* funcs )
  {
    builder->funcs       = *funcs;
    builder->path_begun  = 0;
    builder->load_points = 1;

    builder->face   = face;
    builder->size   = size;
    builder->glyph  = glyph;
    builder->memory = face->root.memory;

    if (glyph)
    {
      builder->base         = glyph->root.outline;
      builder->max_points   = glyph->max_points;
      builder->max_contours = glyph->max_contours;
    }

    if (size)
    {
      builder->scale_x = size->root.metrics.x_scale;
      builder->scale_y = size->root.metrics.y_scale;
    }

    builder->pos_x = 0;
    builder->pos_y = 0;

    builder->left_bearing.x = 0;
    builder->left_bearing.y = 0;
    builder->advance.x      = 0;
    builder->advance.y      = 0;

    builder->base.n_points   = 0;
    builder->base.n_contours = 0;
    builder->current         = builder->base;

    builder->pass       = 0;
    builder->hint_point = 0;
  }


/*********************************************************************
 *
 * <Function>
 *    T1_Done_Builder
 *
 * <Description>
 *    Finalise a given glyph builder. Its content can still be
 *    used after the call, but the function saves important information
 *    within the corresponding glyph slot.
 *
 * <Input>
 *    builder :: glyph builder to initialise
 *
 *********************************************************************/

  EXPORT_FUNC
  void T1_Done_Builder( T1_Builder*  builder )
  {
    T1_GlyphSlot  glyph = builder->glyph;

    if (glyph)
    {
      glyph->root.outline = builder->base;
      glyph->max_points   = builder->max_points;
      glyph->max_contours = builder->max_contours;
    }
  }



/*********************************************************************
 *
 * <Function>
 *    T1_Init_Decoder
 *
 * <Description>
 *    Initialise a given Type 1 decoder for parsing
 *
 * <Input>
 *    decoder :: Type 1 decoder to initialise
 *    funcs   :: hinter functions interface
 *
 *********************************************************************/

  EXPORT_FUNC
  void  T1_Init_Decoder( T1_Decoder*             decoder,
                         const T1_Hinter_Funcs*  funcs )
  {
    decoder->hinter = *funcs;    /* copy hinter interface */
    decoder->top    = 0;
    decoder->zone   = 0;

    decoder->flex_state       = 0;
    decoder->num_flex_vectors = 0;

    /* Clear loader */
    MEM_Set( &decoder->builder, 0, sizeof(decoder->builder) );
  }


/*********************************************************************
 *
 * <Function>
 *    lookup_glyph_by_stdcharcode
 *
 * <Description>
 *    Lookup a given glyph by its StandardEncoding charcode. Used
 *    to implement the SEAC Type 1 operator.
 *
 * <Input>
 *    face     :: current face object         
 *    charcode :: charcode to look for
 *
 * <Return>
 *    glyph index in font face. Returns -1 if the corresponding
 *    glyph wasn't found.
 *
 *********************************************************************/

  static
  T1_Int    lookup_glyph_by_stdcharcode( T1_Face  face,
                                         T1_Int   charcode )
  {
    T1_Int              n;
    const T1_String*    glyph_name;
    PSNames_Interface*  psnames = (PSNames_Interface*)face->psnames;
    
    /* check range of standard char code */
    if (charcode < 0 || charcode > 255)
      return -1;
      
    glyph_name = psnames->adobe_std_strings(
                    psnames->adobe_std_encoding[charcode]);
    
    for ( n = 0; n < face->type1.num_glyphs; n++ )
    {
      T1_String*  name = (T1_String*)face->type1.glyph_names[n];
      
      if ( name && strcmp(name,glyph_name) == 0 )
        return n;
    }

    return -1;
  }


/*********************************************************************
 *
 * <Function>
 *    t1operator_seac
 *
 * <Description>
 *    Implements the "seac" Type 1 operator for a Type 1 decoder
 *
 * <Input>
 *    decoder  :: current Type 1 decoder
 *    asb      :: accent's side bearing
 *    adx      :: horizontal position of accent
 *    ady      :: vertical position of accent
 *    bchar    :: base character's StandardEncoding charcode
 *    achar    :: accent character's StandardEncoding charcode
 *
 * <Return>
 *    Error code. 0 means success.                               
 *
 *********************************************************************/

  static
  T1_Error  t1operator_seac( T1_Decoder*  decoder,
                             T1_Pos       asb,
                             T1_Pos       adx,
                             T1_Pos       ady,
                             T1_Int       bchar,
                             T1_Int       achar )
  {
    T1_Error     error;
    T1_Face      face = decoder->builder.face;
    T1_Int       bchar_index, achar_index, n_base_points;
    FT_Outline*  cur  = &decoder->builder.current;
    FT_Outline*  base = &decoder->builder.base;
    T1_Vector    left_bearing, advance;
    T1_Font*     type1 = &face->type1;
    
    bchar_index = lookup_glyph_by_stdcharcode( face, bchar );
    achar_index = lookup_glyph_by_stdcharcode( face, achar );
    
    if (bchar_index < 0 || achar_index < 0)
    {
      FT_ERROR(( "T1.Parse_Seac : invalid seac character code arguments\n" ));
      return T1_Err_Syntax_Error;
    }

    /* First load "bchar" in builder */
    /* now load the unscaled outline */
    cur->n_points   = 0;
    cur->n_contours = 0;
    cur->points     = base->points   + base->n_points;
    cur->tags      = base->tags    + base->n_points;
    cur->contours   = base->contours + base->n_contours;

    error = T1_Parse_CharStrings( decoder,
                                  type1->charstrings    [bchar_index],
                                  type1->charstrings_len[bchar_index],
                                  type1->num_subrs,
                                  type1->subrs,
                                  type1->subrs_len );
    if (error) return error;

    n_base_points   = cur->n_points;

    /* save the left bearing and width of the base character */
    /* as they will be erased by the next load..             */
    left_bearing = decoder->builder.left_bearing;
    advance      = decoder->builder.advance;

    decoder->builder.left_bearing.x = 0;
    decoder->builder.left_bearing.y = 0;    

    /* Now load "achar" on top of */
    /* the base outline           */
    /*                            */ 
    cur->n_points   = 0;
    cur->n_contours = 0;
    cur->points     = base->points   + base->n_points;
    cur->tags      = base->tags    + base->n_points;
    cur->contours   = base->contours + base->n_contours;

    error = T1_Parse_CharStrings( decoder,
                                  type1->charstrings    [achar_index],
                                  type1->charstrings_len[achar_index],
                                  type1->num_subrs,
                                  type1->subrs,
                                  type1->subrs_len );
    if (error) return error;

    /* adjust contours in accented character outline */
    {
      T1_Int  n;

      for ( n = 0; n < cur->n_contours; n++ )
        cur->contours[n] += n_base_points;
    }

    /* restore the left side bearing and   */
    /* advance width of the base character */
    decoder->builder.left_bearing = left_bearing;
    decoder->builder.advance      = advance;

    /* Finally, move the accent */
    FT_Outline_Translate( cur, adx - asb, ady );
    
    (void)asb;           /* ignore this parameter */
    return T1_Err_Ok;
  }

/*********************************************************************
 *
 * <Function>
 *    t1operator_flex
 *
 * <Description>
 *    Implements the "flex" Type 1 operator for a Type 1 decoder
 *
 * <Input>
 *    decoder   :: current Type 1 decoder
 *    threshold :: threshold
 *    end_x     :: position of final flex point
 *    end_y     :: position of final flex point
 *
 * <Return>
 *    Error code. 0 means success.                               
 *
 *********************************************************************/

  static
  T1_Error  t1operator_flex( T1_Decoder*  decoder,
                             T1_Pos       threshold,
                             T1_Pos       end_x,
                             T1_Pos       end_y )
  {
    T1_Vector    vec;
    T1_Vector*   flex  = decoder->flex_vectors;
    T1_Int       n;

    /* we don't even try to test the threshold in the non-hinting  */
    /* builder, even if the flex operator is said to be a path      */
    /* construction statement in the specification. This is better */
    /* left to the hinter..                                        */

    flex = decoder->flex_vectors;
    vec  = *flex++;

    for ( n = 0; n < 6; n++ )
    {
      flex->x += vec.x;
      flex->y += vec.y;

      vec = *flex++;
    }


    (void)threshold;
    (void)end_x;
    (void)end_y;

    flex  = decoder->flex_vectors;

    return  decoder->builder.funcs.rcurve_to( &decoder->builder,
                                              flex[0].x, flex[0].y,
                                              flex[1].x, flex[1].y,
                                              flex[2].x, flex[2].y ) ||

            decoder->builder.funcs.rcurve_to( &decoder->builder,
                                              flex[3].x, flex[3].y,
                                              flex[4].x, flex[4].y,
                                              flex[5].x, flex[5].y );
  }


/*********************************************************************
 *
 * <Function>
 *    T1_Parse_CharStrings
 *
 * <Description>
 *    Parses a given Type 1 charstrings program
 *
 * <Input>
 *    decoder          :: current Type 1 decoder
 *    charstring_base  :: base of the charstring stream
 *    charstring_len   :: length in bytes of the charstring stream
 *    num_subrs        :: number of sub-routines
 *    subrs_base       :: array of sub-routines addresses
 *    subrs_len        :: array of sub-routines lengths
 *
 * <Return>
 *    Error code. 0 means success.                               
 *