ttgload.c

奇趣公司比较新的qt/emd版本

/***************************************************************************/
/*                                                                         */
/*  ttgload.c                                                              */
/*                                                                         */
/*    TrueType Glyph Loader (body).                                        */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007 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 <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_CALC_H
#include FT_INTERNAL_STREAM_H
#include FT_INTERNAL_SFNT_H
#include FT_TRUETYPE_TAGS_H
#include FT_OUTLINE_H

#include "ttgload.h"
#include "ttpload.h"

#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include "ttgxvar.h"
#endif

#include "tterrors.h"


  /*************************************************************************/
  /*                                                                       */
  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  /* messages during execution.                                            */
  /*                                                                       */
#undef  FT_COMPONENT
#define FT_COMPONENT  trace_ttgload


  /*************************************************************************/
  /*                                                                       */
  /* Composite font flags.                                                 */
  /*                                                                       */
#define ARGS_ARE_WORDS             0x0001
#define ARGS_ARE_XY_VALUES         0x0002
#define ROUND_XY_TO_GRID           0x0004
#define WE_HAVE_A_SCALE            0x0008
/* reserved                        0x0010 */
#define MORE_COMPONENTS            0x0020
#define WE_HAVE_AN_XY_SCALE        0x0040
#define WE_HAVE_A_2X2              0x0080
#define WE_HAVE_INSTR              0x0100
#define USE_MY_METRICS             0x0200
#define OVERLAP_COMPOUND           0x0400
#define SCALED_COMPONENT_OFFSET    0x0800
#define UNSCALED_COMPONENT_OFFSET  0x1000


  /*************************************************************************/
  /*                                                                       */
  /* Returns the horizontal metrics in font units for a given glyph.  If   */
  /* `check' is true, take care of monospaced fonts by returning the       */
  /* advance width maximum.                                                */
  /*                                                                       */
  static void
  Get_HMetrics( TT_Face     face,
                FT_UInt     idx,
                FT_Bool     check,
                FT_Short*   lsb,
                FT_UShort*  aw )
  {
    ( (SFNT_Service)face->sfnt )->get_metrics( face, 0, idx, lsb, aw );

    if ( check && face->postscript.isFixedPitch )
      *aw = face->horizontal.advance_Width_Max;
  }


  /*************************************************************************/
  /*                                                                       */
  /* Returns the vertical metrics in font units for a given glyph.         */
  /* Greg Hitchcock from Microsoft told us that if there were no `vmtx'    */
  /* table, typoAscender/Descender from the `OS/2' table would be used     */
  /* instead, and if there were no `OS/2' table, use ascender/descender    */
  /* from the `hhea' table.  But that is not what Microsoft's rasterizer   */
  /* apparently does: It uses the ppem value as the advance height, and    */
  /* sets the top side bearing to be zero.                                 */
  /*                                                                       */
  /* The monospace `check' is probably not meaningful here, but we leave   */
  /* it in for a consistent interface.                                     */
  /*                                                                       */
  static void
  Get_VMetrics( TT_Face     face,
                FT_UInt     idx,
                FT_Bool     check,
                FT_Short*   tsb,
                FT_UShort*  ah )
  {
    FT_UNUSED( check );

    if ( face->vertical_info )
      ( (SFNT_Service)face->sfnt )->get_metrics( face, 1, idx, tsb, ah );

#if 1             /* Empirically determined, at variance with what MS said */

    else
    {
      *tsb = 0;
      *ah  = face->root.units_per_EM;
    }

#else      /* This is what MS said to do.  It isn't what they do, however. */

    else if ( face->os2.version != 0xFFFFU )
    {
      *tsb = face->os2.sTypoAscender;
      *ah  = face->os2.sTypoAscender - face->os2.sTypoDescender;
    }
    else
    {
      *tsb = face->horizontal.Ascender;
      *ah  = face->horizontal.Ascender - face->horizontal.Descender;
    }

#endif

  }


  /*************************************************************************/
  /*                                                                       */
  /* Translates an array of coordinates.                                   */
  /*                                                                       */
  static void
  translate_array( FT_UInt     n,
                   FT_Vector*  coords,
                   FT_Pos      delta_x,
                   FT_Pos      delta_y )
  {
    FT_UInt  k;


    if ( delta_x )
      for ( k = 0; k < n; k++ )
        coords[k].x += delta_x;

    if ( delta_y )
      for ( k = 0; k < n; k++ )
        coords[k].y += delta_y;
  }


#undef  IS_HINTED
#define IS_HINTED( flags )  ( ( flags & FT_LOAD_NO_HINTING ) == 0 )


  /*************************************************************************/
  /*                                                                       */
  /* The following functions are used by default with TrueType fonts.      */
  /* However, they can be replaced by alternatives if we need to support   */
  /* TrueType-compressed formats (like MicroType) in the future.           */
  /*                                                                       */
  /*************************************************************************/

  FT_CALLBACK_DEF( FT_Error )
  TT_Access_Glyph_Frame( TT_Loader  loader,
                         FT_UInt    glyph_index,
                         FT_ULong   offset,
                         FT_UInt    byte_count )
  {
    FT_Error   error;
    FT_Stream  stream = loader->stream;

    /* for non-debug mode */
    FT_UNUSED( glyph_index );


    FT_TRACE5(( "Glyph %ld\n", glyph_index ));

    /* the following line sets the `error' variable through macros! */
    if ( FT_STREAM_SEEK( offset ) || FT_FRAME_ENTER( byte_count ) )
      return error;

    loader->cursor = stream->cursor;
    loader->limit  = stream->limit;

    return TT_Err_Ok;
  }


  FT_CALLBACK_DEF( void )
  TT_Forget_Glyph_Frame( TT_Loader  loader )
  {
    FT_Stream  stream = loader->stream;


    FT_FRAME_EXIT();
  }


  FT_CALLBACK_DEF( FT_Error )
  TT_Load_Glyph_Header( TT_Loader  loader )
  {
    FT_Byte*  p     = loader->cursor;
    FT_Byte*  limit = loader->limit;


    if ( p + 10 > limit )
      return TT_Err_Invalid_Outline;

    loader->n_contours = FT_NEXT_SHORT( p );

    loader->bbox.xMin = FT_NEXT_SHORT( p );
    loader->bbox.yMin = FT_NEXT_SHORT( p );
    loader->bbox.xMax = FT_NEXT_SHORT( p );
    loader->bbox.yMax = FT_NEXT_SHORT( p );

    FT_TRACE5(( "  # of contours: %d\n", loader->n_contours ));
    FT_TRACE5(( "  xMin: %4d  xMax: %4d\n", loader->bbox.xMin,
                                            loader->bbox.xMax ));
    FT_TRACE5(( "  yMin: %4d  yMax: %4d\n", loader->bbox.yMin,
                                            loader->bbox.yMax ));
    loader->cursor = p;

    return TT_Err_Ok;
  }


  FT_CALLBACK_DEF( FT_Error )
  TT_Load_Simple_Glyph( TT_Loader  load )
  {
    FT_Error        error;
    FT_Byte*        p          = load->cursor;
    FT_Byte*        limit      = load->limit;
    FT_GlyphLoader  gloader    = load->gloader;
    FT_Int          n_contours = load->n_contours;
    FT_Outline*     outline;
    TT_Face         face       = (TT_Face)load->face;
    FT_UShort       n_ins;
    FT_Int          n, n_points;

    FT_Byte         *flag, *flag_limit;
    FT_Byte         c, count;
    FT_Vector       *vec, *vec_limit;
    FT_Pos          x;
    FT_Short        *cont, *cont_limit;


    /* check that we can add the contours to the glyph */
    error = FT_GLYPHLOADER_CHECK_POINTS( gloader, 0, n_contours );
    if ( error )
      goto Fail;

    /* reading the contours' endpoints & number of points */
    cont       = gloader->current.outline.contours;
    cont_limit = cont + n_contours;

    /* check space for contours array + instructions count */
    if ( n_contours >= 0xFFF || p + (n_contours + 1) * 2 > limit )
      goto Invalid_Outline;

    for ( ; cont < cont_limit; cont++ )
      cont[0] = FT_NEXT_USHORT( p );

    n_points = 0;
    if ( n_contours > 0 )
    {
      n_points = cont[-1] + 1;
      if ( n_points < 0 )
        goto Invalid_Outline;
    }

    /* note that we will add four phantom points later */
    error = FT_GLYPHLOADER_CHECK_POINTS( gloader, n_points + 4, 0 );
    if ( error )
      goto Fail;

    /* we'd better check the contours table right now */
    outline = &gloader->current.outline;

    for ( cont = outline->contours + 1; cont < cont_limit; cont++ )
      if ( cont[-1] >= cont[0] )
        goto Invalid_Outline;

    /* reading the bytecode instructions */
    load->glyph->control_len  = 0;
    load->glyph->control_data = 0;

    if ( p + 2 > limit )
      goto Invalid_Outline;

    n_ins = FT_NEXT_USHORT( p );

    FT_TRACE5(( "  Instructions size: %u\n", n_ins ));

    if ( n_ins > face->max_profile.maxSizeOfInstructions )
    {
      FT_TRACE0(( "TT_Load_Simple_Glyph: Too many instructions!\n" ));
      error = TT_Err_Too_Many_Hints;
      goto Fail;
    }

    if ( ( limit - p ) < n_ins )
    {
      FT_TRACE0(( "TT_Load_Simple_Glyph: Instruction count mismatch!\n" ));
      error = TT_Err_Too_Many_Hints;
      goto Fail;
    }

#ifdef TT_USE_BYTECODE_INTERPRETER

    if ( IS_HINTED( load->load_flags ) )
    {
      load->glyph->control_len  = n_ins;
      load->glyph->control_data = load->exec->glyphIns;

      FT_MEM_COPY( load->exec->glyphIns, p, (FT_Long)n_ins );
    }

#endif /* TT_USE_BYTECODE_INTERPRETER */

    p += n_ins;

    /* reading the point tags */
    flag       = (FT_Byte*)outline->tags;
    flag_limit = flag + n_points;

    FT_ASSERT( flag != NULL );

    while ( flag < flag_limit )
    {
      if ( p + 1 > limit )
        goto Invalid_Outline;

      *flag++ = c = FT_NEXT_BYTE( p );
      if ( c & 8 )
      {
        if ( p + 1 > limit )
          goto Invalid_Outline;

        count = FT_NEXT_BYTE( p );
        if ( flag + (FT_Int)count > flag_limit )
          goto Invalid_Outline;

        for ( ; count > 0; count-- )
          *flag++ = c;
      }
    }

    /* reading the X coordinates */

    vec       = outline->points;
    vec_limit = vec + n_points;
    flag      = (FT_Byte*)outline->tags;
    x         = 0;

    for ( ; vec < vec_limit; vec++, flag++ )
    {
      FT_Pos  y = 0;


      if ( *flag & 2 )
      {
        if ( p + 1 > limit )
          goto Invalid_Outline;

        y = (FT_Pos)FT_NEXT_BYTE( p );
        if ( ( *flag & 16 ) == 0 )
          y = -y;
      }
      else if ( ( *flag & 16 ) == 0 )
      {
        if ( p + 2 > limit )
          goto Invalid_Outline;

        y = (FT_Pos)FT_NEXT_SHORT( p );
      }

      x     += y;
      vec->x = x;