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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  cf2hints.h                                                             */
      4 /*                                                                         */
      5 /*    Adobe's code for handling CFF hints (body).                          */
      6 /*                                                                         */
      7 /*  Copyright 2007-2013 Adobe Systems Incorporated.                        */
      8 /*                                                                         */
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     35 /*                                                                         */
     36 /***************************************************************************/
     37 
     38 
     39 #ifndef __CF2HINTS_H__
     40 #define __CF2HINTS_H__
     41 
     42 
     43 FT_BEGIN_HEADER
     44 
     45 
     46   enum
     47   {
     48     CF2_MAX_HINTS = 96    /* maximum # of hints */
     49   };
     50 
     51 
     52   /*
     53    * A HintMask object stores a bit mask that specifies which hints in the
     54    * charstring are active at a given time.  Hints in CFF must be declared
     55    * at the start, before any drawing operators, with horizontal hints
     56    * preceding vertical hints.  The HintMask is ordered the same way, with
     57    * horizontal hints immediately followed by vertical hints.  Clients are
     58    * responsible for knowing how many of each type are present.
     59    *
     60    * The maximum total number of hints is 96, as specified by the CFF
     61    * specification.
     62    *
     63    * A HintMask is built 0 or more times while interpreting a charstring, by
     64    * the HintMask operator.  There is only one HintMask, but it is built or
     65    * rebuilt each time there is a hint substitution (HintMask operator) in
     66    * the charstring.  A default HintMask with all bits set is built if there
     67    * has been no HintMask operator prior to the first drawing operator.
     68    *
     69    */
     70 
     71   typedef struct  CF2_HintMaskRec_
     72   {
     73     FT_Error*  error;
     74 
     75     FT_Bool  isValid;
     76     FT_Bool  isNew;
     77 
     78     size_t  bitCount;
     79     size_t  byteCount;
     80 
     81     FT_Byte  mask[( CF2_MAX_HINTS + 7 ) / 8];
     82 
     83   } CF2_HintMaskRec, *CF2_HintMask;
     84 
     85 
     86   typedef struct  CF2_StemHintRec_
     87   {
     88     FT_Bool  used;     /* DS positions are valid         */
     89 
     90     CF2_Fixed  min;    /* original character space value */
     91     CF2_Fixed  max;
     92 
     93     CF2_Fixed  minDS;  /* DS position after first use    */
     94     CF2_Fixed  maxDS;
     95 
     96   } CF2_StemHintRec, *CF2_StemHint;
     97 
     98 
     99   /*
    100    * A HintMap object stores a piecewise linear function for mapping
    101    * y-coordinates from character space to device space, providing
    102    * appropriate pixel alignment to stem edges.
    103    *
    104    * The map is implemented as an array of `CF2_Hint' elements, each
    105    * representing an edge.  When edges are paired, as from stem hints, the
    106    * bottom edge must immediately precede the top edge in the array.
    107    * Element character space AND device space positions must both increase
    108    * monotonically in the array.  `CF2_Hint' elements are also used as
    109    * parameters to `cf2_blues_capture'.
    110    *
    111    * The `cf2_hintmap_build' method must be called before any drawing
    112    * operation (beginning with a Move operator) and at each hint
    113    * substitution (HintMask operator).
    114    *
    115    * The `cf2_hintmap_map' method is called to transform y-coordinates at
    116    * each drawing operation (move, line, curve).
    117    *
    118    */
    119 
    120   /* TODO: make this a CF2_ArrStack and add a deep copy method */
    121   enum
    122   {
    123     CF2_MAX_HINT_EDGES = CF2_MAX_HINTS * 2
    124   };
    125 
    126 
    127   typedef struct  CF2_HintMapRec_
    128   {
    129     CF2_Font  font;
    130 
    131     /* initial map based on blue zones */
    132     struct CF2_HintMapRec_*  initialHintMap;
    133 
    134     /* working storage for 2nd pass adjustHints */
    135     CF2_ArrStack  hintMoves;
    136 
    137     FT_Bool  isValid;
    138     FT_Bool  hinted;
    139 
    140     CF2_Fixed  scale;
    141     CF2_UInt   count;
    142 
    143     /* start search from this index */
    144     CF2_UInt  lastIndex;
    145 
    146     CF2_HintRec  edge[CF2_MAX_HINT_EDGES]; /* 192 */
    147 
    148   } CF2_HintMapRec, *CF2_HintMap;
    149 
    150 
    151   FT_LOCAL( FT_Bool )
    152   cf2_hint_isValid( const CF2_Hint  hint );
    153   FT_LOCAL( FT_Bool )
    154   cf2_hint_isTop( const CF2_Hint  hint );
    155   FT_LOCAL( FT_Bool )
    156   cf2_hint_isBottom( const CF2_Hint  hint );
    157   FT_LOCAL( void )
    158   cf2_hint_lock( CF2_Hint  hint );
    159 
    160 
    161   FT_LOCAL( void )
    162   cf2_hintmap_init( CF2_HintMap   hintmap,
    163                     CF2_Font      font,
    164                     CF2_HintMap   initialMap,
    165                     CF2_ArrStack  hintMoves,
    166                     CF2_Fixed     scale );
    167   FT_LOCAL( void )
    168   cf2_hintmap_build( CF2_HintMap   hintmap,
    169                      CF2_ArrStack  hStemHintArray,
    170                      CF2_ArrStack  vStemHintArray,
    171                      CF2_HintMask  hintMask,
    172                      CF2_Fixed     hintOrigin,
    173                      FT_Bool       initialMap );
    174 
    175 
    176   /*
    177    * GlyphPath is a wrapper for drawing operations that scales the
    178    * coordinates according to the render matrix and HintMap.  It also tracks
    179    * open paths to control ClosePath and to insert MoveTo for broken fonts.
    180    *
    181    */
    182   typedef struct  CF2_GlyphPathRec_
    183   {
    184     /* TODO: gather some of these into a hinting context */
    185 
    186     CF2_Font              font;           /* font instance    */
    187     CF2_OutlineCallbacks  callbacks;      /* outline consumer */
    188 
    189 
    190     CF2_HintMapRec  hintMap;        /* current hint map            */
    191     CF2_HintMapRec  firstHintMap;   /* saved copy                  */
    192     CF2_HintMapRec  initialHintMap; /* based on all captured hints */
    193 
    194     CF2_ArrStackRec  hintMoves;  /* list of hint moves for 2nd pass */
    195 
    196     CF2_Fixed  scaleX;         /* matrix a */
    197     CF2_Fixed  scaleC;         /* matrix c */
    198     CF2_Fixed  scaleY;         /* matrix d */
    199 
    200     FT_Vector  fractionalTranslation;  /* including deviceXScale */
    201 #if 0
    202     CF2_Fixed  hShift;    /* character space horizontal shift */
    203                           /* (for fauxing)                    */
    204 #endif
    205 
    206     FT_Bool  pathIsOpen;     /* true after MoveTo                     */
    207     FT_Bool  darken;         /* true if stem darkening                */
    208     FT_Bool  moveIsPending;  /* true between MoveTo and offset MoveTo */
    209 
    210     /* references used to call `cf2_hintmap_build', if necessary */
    211     CF2_ArrStack         hStemHintArray;
    212     CF2_ArrStack         vStemHintArray;
    213     CF2_HintMask         hintMask;     /* ptr to the current mask */
    214     CF2_Fixed            hintOriginY;  /* copy of current origin  */
    215     const CF2_BluesRec*  blues;
    216 
    217     CF2_Fixed  xOffset;        /* character space offsets */
    218     CF2_Fixed  yOffset;
    219 
    220     /* character space miter limit threshold */
    221     CF2_Fixed  miterLimit;
    222     /* vertical/horzizontal snap distance in character space */
    223     CF2_Fixed  snapThreshold;
    224 
    225     FT_Vector  offsetStart0;  /* first and second points of first */
    226     FT_Vector  offsetStart1;  /* element with offset applied      */
    227 
    228     /* current point, character space, before offset */
    229     FT_Vector  currentCS;
    230     /* current point, device space */
    231     FT_Vector  currentDS;
    232     FT_Vector  start;         /* start point of subpath */
    233 
    234     /* the following members constitute the `queue' of one element */
    235     FT_Bool  elemIsQueued;
    236     CF2_Int  prevElemOp;
    237 
    238     FT_Vector  prevElemP0;
    239     FT_Vector  prevElemP1;
    240     FT_Vector  prevElemP2;
    241     FT_Vector  prevElemP3;
    242 
    243   } CF2_GlyphPathRec, *CF2_GlyphPath;
    244 
    245 
    246   FT_LOCAL( void )
    247   cf2_glyphpath_init( CF2_GlyphPath         glyphpath,
    248                       CF2_Font              font,
    249                       CF2_OutlineCallbacks  callbacks,
    250                       CF2_Fixed             scaleY,
    251                       /* CF2_Fixed hShift, */
    252                       CF2_ArrStack          hStemHintArray,
    253                       CF2_ArrStack          vStemHintArray,
    254                       CF2_HintMask          hintMask,
    255                       CF2_Fixed             hintOrigin,
    256                       const CF2_Blues       blues,
    257                       const FT_Vector*      fractionalTranslation );
    258   FT_LOCAL( void )
    259   cf2_glyphpath_finalize( CF2_GlyphPath  glyphpath );
    260 
    261   FT_LOCAL( void )
    262   cf2_glyphpath_moveTo( CF2_GlyphPath  glyphpath,
    263                         CF2_Fixed      x,
    264                         CF2_Fixed      y );
    265   FT_LOCAL( void )
    266   cf2_glyphpath_lineTo( CF2_GlyphPath  glyphpath,
    267                         CF2_Fixed      x,
    268                         CF2_Fixed      y );
    269   FT_LOCAL( void )
    270   cf2_glyphpath_curveTo( CF2_GlyphPath  glyphpath,
    271                          CF2_Fixed      x1,
    272                          CF2_Fixed      y1,
    273                          CF2_Fixed      x2,
    274                          CF2_Fixed      y2,
    275                          CF2_Fixed      x3,
    276                          CF2_Fixed      y3 );
    277   FT_LOCAL( void )
    278   cf2_glyphpath_closeOpenPath( CF2_GlyphPath  glyphpath );
    279 
    280 
    281 FT_END_HEADER
    282 
    283 
    284 #endif /* __CF2HINTS_H__ */
    285 
    286 
    287 /* END */
    288