ttgload.c

神龙卡开发原代码

/*******************************************************************
 *
 *  ttgload.c                                                   1.0
 *
 *    TrueType 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 "tttypes.h"
#include "ttdebug.h"
#include "ttcalc.h"
#include "ttfile.h"

#include "tttables.h"
#include "ttobjs.h"
#include "ttgload.h"

#include "ttmemory.h"
#include "tttags.h"
#include "ttload.h"

/* required by the tracing mode */
#undef  TT_COMPONENT
#define TT_COMPONENT  trace_gload


/* composite font flags */

#define ARGS_ARE_WORDS       0x001
#define ARGS_ARE_XY_VALUES   0x002
#define ROUND_XY_TO_GRID     0x004
#define WE_HAVE_A_SCALE      0x008
/* reserved                  0x010 */
#define MORE_COMPONENTS      0x020
#define WE_HAVE_AN_XY_SCALE  0x040
#define WE_HAVE_A_2X2        0x080
#define WE_HAVE_INSTR        0x100
#define USE_MY_METRICS       0x200


/********************************************************/
/* Return 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).                              */
/*                                                      */
/* This function will much probably move to another     */
/* component in the short future, but I haven't decided */
/* which yet...                                         */

  LOCAL_FUNC
  void  TT_Get_Metrics( TT_Horizontal_Header*  header,
                        UShort                 index,
                        Short*                 bearing,
                        UShort*                advance )
  {
    PLongMetrics  longs_m;

    UShort  k = header->number_Of_HMetrics;


    if ( index < k )
    {
      longs_m = (PLongMetrics)header->long_metrics + index;
      *bearing = longs_m->bearing;
      *advance = longs_m->advance;
    }
    else
    {
      *bearing = ((PShortMetrics)header->short_metrics)[index - k];
      *advance = ((PLongMetrics)header->long_metrics)[k - 1].advance;
    }
  }


/********************************************************/
/* Return horizontal metrics in font units for a given  */
/* glyph.  If `check' is true, take care of mono-spaced */
/* fonts by returning the advance width max.            */

  static void Get_HMetrics( PFace    face,
                            UShort   index,
                            Bool     check,
                            Short*   lsb,
                            UShort*  aw )
  {
    TT_Get_Metrics( &face->horizontalHeader, index, lsb, aw );

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


/********************************************************/
/* Return advance width table for a given pixel size    */
/* if it is found in the font's `hdmx' table (if any).  */

  static PByte  Get_Advance_Widths( PFace   face,
                                    UShort  ppem )
  {
    UShort  n;


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

    return NULL;
  }


/********************************************************/
/* Copy current glyph into original one.                */

#define cur_to_org( n, zone ) \
          MEM_Copy( (zone)->org, (zone)->cur, (n) * sizeof ( TT_Vector ) )

/********************************************************/
/* copy original glyph into current one                 */

#define org_to_cur( n, zone ) \
          MEM_Copy( (zone)->cur, (zone)->org, (n) * sizeof ( TT_Vector ) )

/********************************************************/
/* translate an array of coordinates                    */

  static void  translate_array( UShort     n,
                                TT_Vector* coords,
                                TT_Pos     delta_x,
                                TT_Pos     delta_y )
  {
    UShort  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;
  }


/********************************************************/
/* mount one zone on top of another                     */

  static void  mount_zone( PGlyph_Zone  source,
                           PGlyph_Zone  target )
  {
    UShort  np;
    Short   nc;

    np = source->n_points;
    nc = source->n_contours;

    target->org   = source->org + np;
    target->cur   = source->cur + np;
    target->touch = source->touch + np;

    target->contours = source->contours + nc;

    target->n_points   = 0;
    target->n_contours = 0;
  }


/*******************************************************************
 *
 *  Function:  Load_Simple_Glyph
 *
 ******************************************************************/

  static TT_Error  Load_Simple_Glyph( PExecution_Context  exec,
                                      TT_Stream           input,
                                      Short               n_contours,
                                      Short               left_contours,
                                      UShort              left_points,
                                      UShort              load_flags,
                                      PSubglyph_Record    subg )
  {
    DEFINE_LOAD_LOCALS( input );

    PGlyph_Zone  pts;
    Short        k;
    UShort       j;
    UShort       n_points, n_ins;
    PFace        face;
    Byte*        flag;
    TT_Vector*   vec;
    TT_F26Dot6   x, y;


    face = exec->face;

    /* simple check */
    if ( n_contours > left_contours )
    {
      PTRACE0(( "ERROR: Glyph index %ld has %d contours > left %d\n",
                   subg->index, n_contours, left_contours ));
      return TT_Err_Too_Many_Contours;
    }


    /* preparing the execution context */
    mount_zone( &subg->zone, &exec->pts );

    /* reading the contours endpoints */
    if ( ACCESS_Frame( (n_contours + 1) * 2L ) )
      return error;

    PTRACE4(( " Contour endpoints:" ));

    for ( k = 0; k < n_contours; k++ )
    {
      exec->pts.contours[k] = GET_UShort();
      PTRACE4(( " %d", exec->pts.contours[k] ));
    }
    PTRACE4(( "\n" ));

    if ( n_contours > 0 )
      n_points = exec->pts.contours[n_contours - 1] + 1;
    else
      n_points = 0;

    n_ins = GET_UShort();

    FORGET_Frame();

    if ( n_points > left_points )
    {
      PTRACE0(( "ERROR: Too many points in glyph %ld\n", subg->index ));
      return TT_Err_Too_Many_Points;
    }

    /* loading instructions */

    PTRACE4(( " Instructions size: %d\n", n_ins ));

    if ( n_ins > face->maxProfile.maxSizeOfInstructions )
    {
      PTRACE0(( "ERROR: Too many instructions!\n" ));
      return TT_Err_Too_Many_Ins;
    }

    if ( FILE_Read( exec->glyphIns, n_ins ) )
      return error;

    if ( (error = Set_CodeRange( exec,
                                 TT_CodeRange_Glyph,
                                 exec->glyphIns,
                                 n_ins )) != TT_Err_Ok )
      return error;


    /* read the flags */

    if ( CHECK_ACCESS_Frame( n_points * 5L ) )
      return error;

    j    = 0;
    flag = exec->pts.touch;

    while ( j < n_points )
    {
      Byte  c, cnt;

      flag[j] = c = GET_Byte();
      j++;

      if ( c & 8 )
      {
        cnt = GET_Byte();
        while( cnt > 0 )
        {
          flag[j++] = c;
          cnt--;
        }
      }
    }

    /* read the X */

    x    = 0;
    vec  = exec->pts.org;

    for ( j = 0; j < n_points; j++ )
    {
      if ( flag[j] & 2 )
      {
        if ( flag[j] & 16 )
          x += GET_Byte();
        else
          x -= GET_Byte();
      }
      else
      {
        if ( (flag[j] & 16) == 0 )
          x += GET_Short();
      }

      vec[j].x = x;
    }


   /* read the Y */

    y    = 0;

    for ( j = 0; j < n_points; j++ )
    {
      if ( flag[j] & 4 )
      {
        if ( flag[j] & 32 )
          y += GET_Byte();
        else
          y -= GET_Byte();
      }
      else
      {
        if ( (flag[j] & 32) == 0 )
          y += GET_Short();
      }

      vec[j].y = y;
    }

    FORGET_Frame();

    /* Now add the two shadow points at n and n + 1.    */
    /* We need the left side bearing and advance width. */

    /* pp1 = xMin - lsb */
    vec[n_points].x = subg->metrics.bbox.xMin - subg->metrics.horiBearingX;
    vec[n_points].y = 0;

    /* pp2 = pp1 + aw */
    vec[n_points+1].x = vec[n_points].x + subg->metrics.horiAdvance;
    vec[n_points+1].y = 0;

    /* clear the touch flags */

    for ( j = 0; j < n_points; j++ )
      exec->pts.touch[j] &= TT_Flag_On_Curve;

    exec->pts.touch[n_points    ] = 0;
    exec->pts.touch[n_points + 1] = 0;

    /* Note that we return two more points that are not */
    /* part of the glyph outline.                       */

    n_points += 2;

    /* now eventually scale and hint the glyph */

    pts = &exec->pts;
    pts->n_points   = n_points;
    pts->n_contours = n_contours;

    if ( (load_flags & TTLOAD_SCALE_GLYPH) == 0 )
    {
      /* no scaling, just copy the orig arrays into the cur ones */
      org_to_cur( n_points, pts );
    }
    else
    {
     /* first scale the glyph points */

      for ( j = 0; j < n_points; j++ )
      {
        pts->org[j].x = Scale_X( &exec->metrics, pts->org[j].x );
        pts->org[j].y = Scale_Y( &exec->metrics, pts->org[j].y );
      }

      /* if hinting, round pp1, and shift the glyph accordingly */
      if ( subg->is_hinted )
      {
        x = pts->org[n_points - 2].x;
        x = ((x+32) & -64) - x;
        translate_array( n_points, pts->org, x, 0 );

        org_to_cur( n_points, pts );

        pts->cur[n_points - 1].x = (pts->cur[n_points - 1].x + 32) & -64;

        /* now consider hinting */
        if ( n_ins > 0 )
        {
          exec->is_composite     = FALSE;
          exec->pedantic_hinting = load_flags & TTLOAD_PEDANTIC;

          error = Context_Run( exec, FALSE );
          if (error && exec->pedantic_hinting)
            return error;
        }
      }
      else
        org_to_cur( n_points, pts );
    }

    /* save glyph phantom points */
    if (!subg->preserve_pps)
    {
      subg->pp1 = pts->cur[n_points - 2];
      subg->pp2 = pts->cur[n_points - 1];
    }

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Load_Composite_End
 *
 ******************************************************************/

  static
  TT_Error  Load_Composite_End( UShort              n_points,
                                Short               n_contours,
                                PExecution_Context  exec,
                                PSubglyph_Record    subg,
                                UShort              load_flags,
                                TT_Stream           input )
  {
    DEFINE_LOAD_LOCALS( input );

    UShort       k, n_ins;
    PGlyph_Zone  pts;


    if ( subg->is_hinted                    &&
         subg->element_flag & WE_HAVE_INSTR )
    {
      if ( ACCESS_Frame( 2L ) )
        return error;

      n_ins = GET_UShort();     /* read size of instructions */
      FORGET_Frame();

      PTRACE4(( " Instructions size: %d\n", n_ins ));