1/***************************************************************************/
2/*                                                                         */
3/*  cf2blues.h                                                             */
4/*                                                                         */
5/*    Adobe's code for handling Blue Zones (specification).                */
6/*                                                                         */
7/*  Copyright 2009-2013 Adobe Systems Incorporated.                        */
8/*                                                                         */
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35/*                                                                         */
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
75FT_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_floatToFixed( 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
179FT_END_HEADER
180
181
182#endif /* __CF2BLUES_H__ */
183
184
185/* END */
186