sdk/lib/3rdparty/freetype/src/cff/cf2blues.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  cf2blues.h                                                             */
   4 /*                                                                         */
   5 /*    Adobe's code for handling Blue Zones (specification).                */
   6 /*                                                                         */
   7 /*  Copyright 2009-2013 Adobe Systems Incorporated.                        */
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  36 /***************************************************************************/
  37
  38
  39   /*
  40    * A `CF2_Blues' object stores the blue zones (horizontal alignment
  41    * zones) of a font.  These are specified in the CFF private dictionary
  42    * by `BlueValues', `OtherBlues', `FamilyBlues', and `FamilyOtherBlues'.
  43    * Each zone is defined by a top and bottom edge in character space.
  44    * Further, each zone is either a top zone or a bottom zone, as recorded
  45    * by `bottomZone'.
  46    *
  47    * The maximum number of `BlueValues' and `FamilyBlues' is 7 each.
  48    * However, these are combined to produce a total of 7 zones.
  49    * Similarly, the maximum number of `OtherBlues' and `FamilyOtherBlues'
  50    * is 5 and these are combined to produce an additional 5 zones.
  51    *
  52    * Blue zones are used to `capture' hints and force them to a common
  53    * alignment point.  This alignment is recorded in device space in
  54    * `dsFlatEdge'.  Except for this value, a `CF2_Blues' object could be
  55    * constructed independently of scaling.  Construction may occur once
  56    * the matrix is known.  Other features implemented in the Capture
  57    * method are overshoot suppression, overshoot enforcement, and Blue
  58    * Boost.
  59    *
  60    * Capture is determined by `BlueValues' and `OtherBlues', but the
  61    * alignment point may be adjusted to the scaled flat edge of
  62    * `FamilyBlues' or `FamilyOtherBlues'.  No alignment is done to the
  63    * curved edge of a zone.
  64    *
  65    */
  66
  67
  68 #ifndef CF2BLUES_H_
  69 #define CF2BLUES_H_
  70
  71
  72 #include "cf2glue.h"
  73
  74
  75 FT_BEGIN_HEADER
  76
  77
  78   /*
  79    * `CF2_Hint' is shared by `cf2hints.h' and
  80    * `cf2blues.h', but `cf2blues.h' depends on
  81    * `cf2hints.h', so define it here.  Note: The typedef is in
  82    * `cf2glue.h'.
  83    *
  84    */
  85   enum
  86   {
  87     CF2_GhostBottom = 0x1,  /* a single bottom edge           */
  88     CF2_GhostTop    = 0x2,  /* a single top edge              */
  89     CF2_PairBottom  = 0x4,  /* the bottom edge of a stem hint */
  90     CF2_PairTop     = 0x8,  /* the top edge of a stem hint    */
  91     CF2_Locked      = 0x10, /* this edge has been aligned     */
  92                             /* by a blue zone                 */
  93     CF2_Synthetic   = 0x20  /* this edge was synthesized      */
  94   };
  95
  96
  97   /*
  98    * Default value for OS/2 typoAscender/Descender when their difference
  99    * is not equal to `unitsPerEm'.  The default is based on -250 and 1100
 100    * in `CF2_Blues', assuming 1000 units per em here.
 101    *
 102    */
 103   enum
 104   {
 105     CF2_ICF_Top    = cf2_intToFixed(  880 ),
 106     CF2_ICF_Bottom = cf2_intToFixed( -120 )
 107   };
 108
 109
 110   /*
 111    * Constant used for hint adjustment and for synthetic em box hint
 112    * placement.
 113    */
 114 #define CF2_MIN_COUNTER  cf2_doubleToFixed( 0.5 )
 115
 116
 117   /* shared typedef is in cf2glue.h */
 118   struct  CF2_HintRec_
 119   {
 120     CF2_UInt  flags;  /* attributes of the edge            */
 121     size_t    index;  /* index in original stem hint array */
 122                       /* (if not synthetic)                */
 123     CF2_Fixed  csCoord;
 124     CF2_Fixed  dsCoord;
 125     CF2_Fixed  scale;
 126   };
 127
 128
 129   typedef struct  CF2_BlueRec_
 130   {
 131     CF2_Fixed  csBottomEdge;
 132     CF2_Fixed  csTopEdge;
 133     CF2_Fixed  csFlatEdge; /* may be from either local or Family zones */
 134     CF2_Fixed  dsFlatEdge; /* top edge of bottom zone or bottom edge   */
 135                            /* of top zone (rounded)                    */
 136     FT_Bool  bottomZone;
 137
 138   } CF2_BlueRec;
 139
 140
 141   /* max total blue zones is 12 */
 142   enum
 143   {
 144     CF2_MAX_BLUES      = 7,
 145     CF2_MAX_OTHERBLUES = 5
 146   };
 147
 148
 149   typedef struct  CF2_BluesRec_
 150   {
 151     CF2_Fixed  scale;
 152     CF2_UInt   count;
 153     FT_Bool    suppressOvershoot;
 154     FT_Bool    doEmBoxHints;
 155
 156     CF2_Fixed  blueScale;
 157     CF2_Fixed  blueShift;
 158     CF2_Fixed  blueFuzz;
 159
 160     CF2_Fixed  boost;
 161
 162     CF2_HintRec  emBoxTopEdge;
 163     CF2_HintRec  emBoxBottomEdge;
 164
 165     CF2_BlueRec  zone[CF2_MAX_BLUES + CF2_MAX_OTHERBLUES];
 166
 167   } CF2_BluesRec, *CF2_Blues;
 168
 169
 170   FT_LOCAL( void )
 171   cf2_blues_init( CF2_Blues  blues,
 172                   CF2_Font   font );
 173   FT_LOCAL( FT_Bool )
 174   cf2_blues_capture( const CF2_Blues  blues,
 175                      CF2_Hint         bottomHintEdge,
 176                      CF2_Hint         topHintEdge );
 177
 178
 179 FT_END_HEADER
 180
 181
 182 #endif /* CF2BLUES_H_ */
 183
 184
 185 /* END */