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1 /****************************************************************************
2  *
3  * psblues.h
4  *
5  *   Adobe's code for handling Blue Zones (specification).
6  *
7  * Copyright 2009-2013 Adobe Systems Incorporated.
8  *
9  * This software, and all works of authorship, whether in source or
10  * object code form as indicated by the copyright notice(s) included
11  * herein (collectively, the "Work") is made available, and may only be
12  * used, modified, and distributed under the FreeType Project License,
13  * LICENSE.TXT.  Additionally, subject to the terms and conditions of the
14  * FreeType Project License, each contributor to the Work hereby grants
15  * to any individual or legal entity exercising permissions granted by
16  * the FreeType Project License and this section (hereafter, "You" or
17  * "Your") a perpetual, worldwide, non-exclusive, no-charge,
18  * royalty-free, irrevocable (except as stated in this section) patent
19  * license to make, have made, use, offer to sell, sell, import, and
20  * otherwise transfer the Work, where such license applies only to those
21  * patent claims licensable by such contributor that are necessarily
22  * infringed by their contribution(s) alone or by combination of their
23  * contribution(s) with the Work to which such contribution(s) was
24  * submitted.  If You institute patent litigation against any entity
25  * (including a cross-claim or counterclaim in a lawsuit) alleging that
26  * the Work or a contribution incorporated within the Work constitutes
27  * direct or contributory patent infringement, then any patent licenses
28  * granted to You under this License for that Work shall terminate as of
29  * the date such litigation is filed.
30  *
31  * By using, modifying, or distributing the Work you indicate that you
32  * have read and understood the terms and conditions of the
33  * FreeType Project License as well as those provided in this section,
34  * and you accept them fully.
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 PSBLUES_H_
69 #define PSBLUES_H_
70 
71 
72 #include "psglue.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 /* PSBLUES_H_ */
183 
184 
185 /* END */
186