1 /***************************************************************************/
2 /* */
3 /* psblues.h */
4 /* */
5 /* Adobe's code for handling Blue Zones (specification). */
6 /* */
7 /* Copyright 2009-2013 Adobe Systems Incorporated. */
8 /* */
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10 /* object code form as indicated by the copyright notice(s) included */
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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 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 */