ttgload.c

qt-x11-opensource-src-4.1.4.tar.gz源码

/***************************************************************************/
/*                                                                         */
/*  ttgload.c                                                              */
/*                                                                         */
/*    TrueType Glyph Loader (body).                                        */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005 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


/* Maximum recursion depth we allow for composite glyphs.
 * The TrueType spec doesn't say anything about recursion,
 * so it isn't clear that recursion is allowed at all. But
 * we'll be generous.
 */
#define TT_MAX_COMPOSITE_RECURSE 5



  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_get_metrics                                                */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Returns the horizontal or vertical metrics in font units for a     */
  /*    given glyph.  The metrics are the left side bearing (resp. top     */
  /*    side bearing) and advance width (resp. advance height).            */
  /*                                                                       */
  /* <Input>                                                               */
  /*    header  :: A pointer to either the horizontal or vertical metrics  */
  /*               structure.                                              */
  /*                                                                       */
  /*    idx     :: The glyph index.                                        */
  /*                                                                       */
  /* <Output>                                                              */
  /*    bearing :: The bearing, either left side or top side.              */
  /*                                                                       */
  /*    advance :: The advance width resp. advance height.                 */
  /*                                                                       */
  /* <Note>                                                                */
  /*    This function will much probably move to another component in the  */
  /*    near future, but I haven't decided which yet.                      */
  /*                                                                       */
#ifdef FT_OPTIMIZE_MEMORY

  static void
  tt_face_get_metrics( TT_Face     face,
                       FT_Bool     vertical,
                       FT_UInt     idx,
                       FT_Short   *abearing,
                       FT_UShort  *aadvance )
  {
    TT_HoriHeader*  header;
    FT_Byte*        p;
    FT_Byte*        limit;
    FT_UShort       k;


    if ( vertical )
    {
      header = (TT_HoriHeader*)&face->vertical;
      p      = face->vert_metrics;
      limit  = p + face->vert_metrics_size;
    }
    else
    {
      header = &face->horizontal;
      p      = face->horz_metrics;
      limit  = p + face->horz_metrics_size;
    }
    
    k = header->number_Of_HMetrics;
    
    if ( k > 0 )
    {
      if ( idx < (FT_UInt)k )
      {
        p += 4 * idx;
        if ( p + 4 > limit )
          goto NoData;
          
        *aadvance = FT_NEXT_USHORT( p );
        *abearing = FT_NEXT_SHORT( p );
      }
      else
      {
        p += 4 * ( k - 1 );
        if ( p + 4 > limit )
          goto NoData;
          
        *aadvance = FT_NEXT_USHORT( p );
        p += 2 + 2 * ( idx - k );
        if ( p + 2 > limit )
          *abearing = 0;
        else
          *abearing = FT_PEEK_SHORT( p );
      }
    }
    else
    {
    NoData:
      *abearing = 0;
      *aadvance = 0;
    }
  }

#else /* !FT_OPTIMIZE_MEMORY */

  static void
  tt_face_get_metrics( TT_Face     face,
                       FT_Bool     vertical,
                       FT_UInt     idx,
                       FT_Short   *abearing,
                       FT_UShort  *aadvance )
  {
    TT_HoriHeader*  header = vertical ? (TT_HoriHeader*)&face->vertical
                                      :                 &face->horizontal;
    TT_LongMetrics  longs_m;
    FT_UShort       k      = header->number_Of_HMetrics;


    if ( k == 0 )
    {
      *abearing = *aadvance = 0;
      return;
    }

    if ( idx < (FT_UInt)k )
    {
      longs_m   = (TT_LongMetrics)header->long_metrics + idx;
      *abearing = longs_m->bearing;
      *aadvance = longs_m->advance;
    }
    else
    {
      *abearing = ((TT_ShortMetrics*)header->short_metrics)[idx - k];
      *aadvance = ((TT_LongMetrics)header->long_metrics)[k - 1].advance;
    }
  }

#endif /* !FT_OPTIMIZE_MEMORY */


  /*************************************************************************/
  /*                                                                       */
  /* 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 )
  {
    tt_face_get_metrics( face, 0, idx, lsb, aw );

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


  /*************************************************************************/
  /*                                                                       */
  /* Returns the advance width table for a given pixel size if it is found */
  /* in the font's `hdmx' table (if any).                                  */
  /*                                                                       */
  static FT_Byte*
  Get_Advance_WidthPtr( TT_Face  face,
                        FT_Int   ppem,
                        FT_UInt  gindex )
  {
#ifdef FT_OPTIMIZE_MEMORY

    FT_UInt   nn;
    FT_Byte*  result      = NULL;
    FT_ULong  record_size = face->hdmx_record_size;
    FT_Byte*  record      = face->hdmx_table + 8;
    

    for ( nn = 0; nn < face->hdmx_record_count; nn++ )
      if ( face->hdmx_record_sizes[nn] == ppem )
      {
        gindex += 2;
        if ( gindex < record_size )
          result = record + gindex;
        break;
      }

    return result;

#else

    FT_UShort  n;


    for ( n = 0; n < face->hdmx.num_records; n++ )
      if ( face->hdmx.records[n].ppem == ppem )
        return &face->hdmx.records[n].widths[gindex];

    return NULL;

#endif
  }


  /*************************************************************************/
  /*                                                                       */
  /* 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 )
      tt_face_get_metrics( face, 1, idx, tsb, ah );

#if 1             /* Emperically 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

  }


#define cur_to_org( n, zone ) \
          FT_ARRAY_COPY( (zone)->org, (zone)->cur, (n) )

#define org_to_cur( n, zone ) \
          FT_ARRAY_COPY( (zone)->cur, (zone)->org, (n) )


  /*************************************************************************/
  /*                                                                       */
  /* 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;
  }


  static void
  tt_prepare_zone( TT_GlyphZone  zone,
                   FT_GlyphLoad  load,
                   FT_UInt       start_point,
                   FT_UInt       start_contour )
  {
    zone->n_points   = (FT_UShort)( load->outline.n_points - start_point );
    zone->n_contours = (FT_Short) ( load->outline.n_contours - start_contour );
    zone->org        = load->extra_points + start_point;
    zone->cur        = load->outline.points + start_point;
    zone->tags       = (FT_Byte*)load->outline.tags + start_point;
    zone->contours   = (FT_UShort*)load->outline.contours + start_contour;
  }


#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;

    return TT_Err_Ok;
  }


  FT_CALLBACK_DEF( void )
  TT_Forget_Glyph_Frame( TT_Loader  loader )
  {