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fontinfo.h
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1 
2 // File: fontinfo.h
3 // Description: Font information classes abstracted from intproto.h/cpp.
4 // Author: rays@google.com (Ray Smith)
5 // Created: Tue May 17 17:08:01 PDT 2011
6 //
7 // (C) Copyright 2011, Google Inc.
8 // Licensed under the Apache License, Version 2.0 (the "License");
9 // you may not use this file except in compliance with the License.
10 // You may obtain a copy of the License at
11 // http://www.apache.org/licenses/LICENSE-2.0
12 // Unless required by applicable law or agreed to in writing, software
13 // distributed under the License is distributed on an "AS IS" BASIS,
14 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 // See the License for the specific language governing permissions and
16 // limitations under the License.
17 //
19 
20 
21 #ifndef TESSERACT_CCSTRUCT_FONTINFO_H_
22 #define TESSERACT_CCSTRUCT_FONTINFO_H_
23 
24 #include "genericvector.h"
25 #include "host.h"
26 #include "unichar.h"
27 
28 namespace tesseract {
29 
30 // Struct for information about spacing between characters in a particular font.
36 };
37 
38 /*
39  * font_properties contains properties about boldness, italicness, fixed pitch,
40  * serif, fraktur
41  */
42 struct FontInfo {
44  ~FontInfo() {}
45  // Reserves unicharset_size spots in spacing_vec.
46  void init_spacing(int unicharset_size) {
48  spacing_vec->init_to_size(unicharset_size, NULL);
49  }
50  // Adds the given pointer to FontSpacingInfo to spacing_vec member
51  // (FontInfo class takes ownership of the pointer).
52  // Note: init_spacing should be called before calling this function.
53  void add_spacing(UNICHAR_ID uch_id, FontSpacingInfo *spacing_info) {
54  ASSERT_HOST(spacing_vec != NULL && spacing_vec->size() > uch_id);
55  (*spacing_vec)[uch_id] = spacing_info;
56  }
57 
58  // Returns the pointer to FontSpacingInfo for the given UNICHAR_ID.
59  const FontSpacingInfo *get_spacing(UNICHAR_ID uch_id) const {
60  return (spacing_vec == NULL || spacing_vec->size() <= uch_id) ?
61  NULL : (*spacing_vec)[uch_id];
62  }
63 
64  // Fills spacing with the value of the x gap expected between the two given
65  // UNICHAR_IDs. Returns true on success.
66  bool get_spacing(UNICHAR_ID prev_uch_id,
67  UNICHAR_ID uch_id,
68  int *spacing) const {
69  const FontSpacingInfo *prev_fsi = this->get_spacing(prev_uch_id);
70  const FontSpacingInfo *fsi = this->get_spacing(uch_id);
71  if (prev_fsi == NULL || fsi == NULL) return false;
72  int i = 0;
73  for (; i < prev_fsi->kerned_unichar_ids.size(); ++i) {
74  if (prev_fsi->kerned_unichar_ids[i] == uch_id) break;
75  }
76  if (i < prev_fsi->kerned_unichar_ids.size()) {
77  *spacing = prev_fsi->kerned_x_gaps[i];
78  } else {
79  *spacing = prev_fsi->x_gap_after + fsi->x_gap_before;
80  }
81  return true;
82  }
83 
84  bool is_italic() const { return properties & 1; }
85  bool is_bold() const { return (properties & 2) != 0; }
86  bool is_fixed_pitch() const { return (properties & 4) != 0; }
87  bool is_serif() const { return (properties & 8) != 0; }
88  bool is_fraktur() const { return (properties & 16) != 0; }
89 
90  char* name;
92  // The universal_id is a field reserved for the initialization process
93  // to assign a unique id number to all fonts loaded for the current
94  // combination of languages. This id will then be returned by
95  // ResultIterator::WordFontAttributes.
97  // Horizontal spacing between characters (indexed by UNICHAR_ID).
99 };
100 
101 // Every class (character) owns a FontSet that represents all the fonts that can
102 // render this character.
103 // Since almost all the characters from the same script share the same set of
104 // fonts, the sets are shared over multiple classes (see
105 // Classify::fontset_table_). Thus, a class only store an id to a set.
106 // Because some fonts cannot render just one character of a set, there are a
107 // lot of FontSet that differ only by one font. Rather than storing directly
108 // the FontInfo in the FontSet structure, it's better to share FontInfos among
109 // FontSets (Classify::fontinfo_table_).
110 struct FontSet {
111  int size;
112  int* configs; // FontInfo ids
113 };
114 
115 // Compare FontInfo structures.
116 bool CompareFontInfo(const FontInfo& fi1, const FontInfo& fi2);
117 // Compare FontSet structures.
118 bool CompareFontSet(const FontSet& fs1, const FontSet& fs2);
119 // Deletion callbacks for GenericVector.
122 
123 // Callbacks used by UnicityTable to read/write FontInfo/FontSet structures.
124 bool read_info(FILE* f, FontInfo* fi, bool swap);
125 bool write_info(FILE* f, const FontInfo& fi);
126 bool read_spacing_info(FILE *f, FontInfo* fi, bool swap);
127 bool write_spacing_info(FILE* f, const FontInfo& fi);
128 bool read_set(FILE* f, FontSet* fs, bool swap);
129 bool write_set(FILE* f, const FontSet& fs);
130 
131 } // namespace tesseract.
132 
133 #endif /* THIRD_PARTY_TESSERACT_CCSTRUCT_FONTINFO_H_ */