src/sfnt/ttmtx.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ttmtx.c                                                                */
   4 /*                                                                         */
   5 /*    Load the metrics tables common to TTF and OTF fonts (body).          */
   6 /*                                                                         */
   7 /*  Copyright 2006-2009, 2011-2014 by                                      */
   8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
   9 /*                                                                         */
  10 /*  This file is part of the FreeType project, and may only be used,       */
  11 /*  modified, and distributed under the terms of the FreeType project      */
  12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
  13 /*  this file you indicate that you have read the license and              */
  14 /*  understand and accept it fully.                                        */
  15 /*                                                                         */
  16 /***************************************************************************/
  17
  18
  19 #include <ft2build.h>
  20 #include FT_INTERNAL_DEBUG_H
  21 #include FT_INTERNAL_STREAM_H
  22 #include FT_TRUETYPE_TAGS_H
  23 #include "ttmtx.h"
  24
  25 #include "sferrors.h"
  26
  27
  28   /*************************************************************************/
  29   /*                                                                       */
  30   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  31   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  32   /* messages during execution.                                            */
  33   /*                                                                       */
  34 #undef  FT_COMPONENT
  35 #define FT_COMPONENT  trace_ttmtx
  36
  37
  38   /*************************************************************************/
  39   /*                                                                       */
  40   /* <Function>                                                            */
  41   /*    tt_face_load_hmtx                                                  */
  42   /*                                                                       */
  43   /* <Description>                                                         */
  44   /*    Load the `hmtx' or `vmtx' table into a face object.                */
  45   /*                                                                       */
  46   /* <Input>                                                               */
  47   /*    face     :: A handle to the target face object.                    */
  48   /*                                                                       */
  49   /*    stream   :: The input stream.                                      */
  50   /*                                                                       */
  51   /*    vertical :: A boolean flag.  If set, load `vmtx'.                  */
  52   /*                                                                       */
  53   /* <Return>                                                              */
  54   /*    FreeType error code.  0 means success.                             */
  55   /*                                                                       */
  56   FT_LOCAL_DEF( FT_Error )
  57   tt_face_load_hmtx( TT_Face    face,
  58                      FT_Stream  stream,
  59                      FT_Bool    vertical )
  60   {
  61     FT_Error   error;
  62     FT_ULong   tag, table_size;
  63     FT_ULong*  ptable_offset;
  64     FT_ULong*  ptable_size;
  65
  66
  67     if ( vertical )
  68     {
  69       tag           = TTAG_vmtx;
  70       ptable_offset = &face->vert_metrics_offset;
  71       ptable_size   = &face->vert_metrics_size;
  72     }
  73     else
  74     {
  75       tag           = TTAG_hmtx;
  76       ptable_offset = &face->horz_metrics_offset;
  77       ptable_size   = &face->horz_metrics_size;
  78     }
  79
  80     error = face->goto_table( face, tag, stream, &table_size );
  81     if ( error )
  82       goto Fail;
  83
  84     *ptable_size   = table_size;
  85     *ptable_offset = FT_STREAM_POS();
  86
  87   Fail:
  88     return error;
  89   }
  90
  91
  92   /*************************************************************************/
  93   /*                                                                       */
  94   /* <Function>                                                            */
  95   /*    tt_face_load_hhea                                                  */
  96   /*                                                                       */
  97   /* <Description>                                                         */
  98   /*    Load the `hhea' or 'vhea' table into a face object.                */
  99   /*                                                                       */
 100   /* <Input>                                                               */
 101   /*    face     :: A handle to the target face object.                    */
 102   /*                                                                       */
 103   /*    stream   :: The input stream.                                      */
 104   /*                                                                       */
 105   /*    vertical :: A boolean flag.  If set, load `vhea'.                  */
 106   /*                                                                       */
 107   /* <Return>                                                              */
 108   /*    FreeType error code.  0 means success.                             */
 109   /*                                                                       */
 110   FT_LOCAL_DEF( FT_Error )
 111   tt_face_load_hhea( TT_Face    face,
 112                      FT_Stream  stream,
 113                      FT_Bool    vertical )
 114   {
 115     FT_Error        error;
 116     TT_HoriHeader*  header;
 117
 118     static const FT_Frame_Field  metrics_header_fields[] =
 119     {
 120 #undef  FT_STRUCTURE
 121 #define FT_STRUCTURE  TT_HoriHeader
 122
 123       FT_FRAME_START( 36 ),
 124         FT_FRAME_ULONG ( Version ),
 125         FT_FRAME_SHORT ( Ascender ),
 126         FT_FRAME_SHORT ( Descender ),
 127         FT_FRAME_SHORT ( Line_Gap ),
 128         FT_FRAME_USHORT( advance_Width_Max ),
 129         FT_FRAME_SHORT ( min_Left_Side_Bearing ),
 130         FT_FRAME_SHORT ( min_Right_Side_Bearing ),
 131         FT_FRAME_SHORT ( xMax_Extent ),
 132         FT_FRAME_SHORT ( caret_Slope_Rise ),
 133         FT_FRAME_SHORT ( caret_Slope_Run ),
 134         FT_FRAME_SHORT ( caret_Offset ),
 135         FT_FRAME_SHORT ( Reserved[0] ),
 136         FT_FRAME_SHORT ( Reserved[1] ),
 137         FT_FRAME_SHORT ( Reserved[2] ),
 138         FT_FRAME_SHORT ( Reserved[3] ),
 139         FT_FRAME_SHORT ( metric_Data_Format ),
 140         FT_FRAME_USHORT( number_Of_HMetrics ),
 141       FT_FRAME_END
 142     };
 143
 144
 145     if ( vertical )
 146     {
 147       void  *v = &face->vertical;
 148
 149
 150       error = face->goto_table( face, TTAG_vhea, stream, 0 );
 151       if ( error )
 152         goto Fail;
 153
 154       header = (TT_HoriHeader*)v;
 155     }
 156     else
 157     {
 158       error = face->goto_table( face, TTAG_hhea, stream, 0 );
 159       if ( error )
 160         goto Fail;
 161
 162       header = &face->horizontal;
 163     }
 164
 165     if ( FT_STREAM_READ_FIELDS( metrics_header_fields, header ) )
 166       goto Fail;
 167
 168     FT_TRACE3(( "Ascender:          %5d\n", header->Ascender ));
 169     FT_TRACE3(( "Descender:         %5d\n", header->Descender ));
 170     FT_TRACE3(( "number_Of_Metrics: %5u\n", header->number_Of_HMetrics ));
 171
 172     header->long_metrics  = NULL;
 173     header->short_metrics = NULL;
 174
 175   Fail:
 176     return error;
 177   }
 178
 179
 180   /*************************************************************************/
 181   /*                                                                       */
 182   /* <Function>                                                            */
 183   /*    tt_face_get_metrics                                                */
 184   /*                                                                       */
 185   /* <Description>                                                         */
 186   /*    Return the horizontal or vertical metrics in font units for a      */
 187   /*    given glyph.  The values are the left side bearing (top side       */
 188   /*    bearing for vertical metrics) and advance width (advance height    */
 189   /*    for vertical metrics).                                             */
 190   /*                                                                       */
 191   /* <Input>                                                               */
 192   /*    face     :: A pointer to the TrueType face structure.              */
 193   /*                                                                       */
 194   /*    vertical :: If set to TRUE, get vertical metrics.                  */
 195   /*                                                                       */
 196   /*    gindex   :: The glyph index.                                       */
 197   /*                                                                       */
 198   /* <Output>                                                              */
 199   /*    abearing :: The bearing, either left side or top side.             */
 200   /*                                                                       */
 201   /*    aadvance :: The advance width or advance height, depending on      */
 202   /*                the `vertical' flag.                                   */
 203   /*                                                                       */
 204   FT_LOCAL_DEF( void )
 205   tt_face_get_metrics( TT_Face     face,
 206                        FT_Bool     vertical,
 207                        FT_UInt     gindex,
 208                        FT_Short   *abearing,
 209                        FT_UShort  *aadvance )
 210   {
 211     FT_Error        error;
 212     FT_Stream       stream = face->root.stream;
 213     TT_HoriHeader*  header;
 214     FT_ULong        table_pos, table_size, table_end;
 215     FT_UShort       k;
 216
 217
 218     if ( vertical )
 219     {
 220       void*  v = &face->vertical;
 221
 222
 223       header     = (TT_HoriHeader*)v;
 224       table_pos  = face->vert_metrics_offset;
 225       table_size = face->vert_metrics_size;
 226     }
 227     else
 228     {
 229       header     = &face->horizontal;
 230       table_pos  = face->horz_metrics_offset;
 231       table_size = face->horz_metrics_size;
 232     }
 233
 234     table_end = table_pos + table_size;
 235
 236     k = header->number_Of_HMetrics;
 237
 238     if ( k > 0 )
 239     {
 240       if ( gindex < (FT_UInt)k )
 241       {
 242         table_pos += 4 * gindex;
 243         if ( table_pos + 4 > table_end )
 244           goto NoData;
 245
 246         if ( FT_STREAM_SEEK( table_pos ) ||
 247              FT_READ_USHORT( *aadvance ) ||
 248              FT_READ_SHORT( *abearing )  )
 249           goto NoData;
 250       }
 251       else
 252       {
 253         table_pos += 4 * ( k - 1 );
 254         if ( table_pos + 4 > table_end )
 255           goto NoData;
 256
 257         if ( FT_STREAM_SEEK( table_pos ) ||
 258              FT_READ_USHORT( *aadvance ) )
 259           goto NoData;
 260
 261         table_pos += 4 + 2 * ( gindex - k );
 262         if ( table_pos + 2 > table_end )
 263           *abearing = 0;
 264         else
 265         {
 266           if ( !FT_STREAM_SEEK( table_pos ) )
 267             (void)FT_READ_SHORT( *abearing );
 268         }
 269       }
 270     }
 271     else
 272     {
 273     NoData:
 274       *abearing = 0;
 275       *aadvance = 0;
 276     }
 277   }
 278
 279
 280 /* END */