tesseract  5.0.0
fontinfo.h
Go to the documentation of this file.
1 // File: fontinfo.h
3 // Description: Font information classes abstracted from intproto.h/cpp.
4 // Author: rays@google.com (Ray Smith)
5 //
6 // (C) Copyright 2011, Google Inc.
7 // Licensed under the Apache License, Version 2.0 (the "License");
8 // you may not use this file except in compliance with the License.
9 // You may obtain a copy of the License at
10 // http://www.apache.org/licenses/LICENSE-2.0
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 //
18 
19 #ifndef TESSERACT_CCSTRUCT_FONTINFO_H_
20 #define TESSERACT_CCSTRUCT_FONTINFO_H_
21 
22 #include "errcode.h"
23 
24 #include <tesseract/unichar.h>
25 #include "genericvector.h"
26 
27 #include <cstdint> // for uint16_t, uint32_t
28 #include <cstdio> // for FILE
29 #include <vector>
30 
31 namespace tesseract {
32 
33 template <typename T>
34 class UnicityTable;
35 
36 // Simple struct to hold a font and a score. The scores come from the low-level
37 // integer matcher, so they are in the uint16_t range. Fonts are an index to
38 // fontinfo_table.
39 // These get copied around a lot, so best to keep them small.
40 struct ScoredFont {
41  ScoredFont() : fontinfo_id(-1), score(0) {}
42  ScoredFont(int font_id, uint16_t classifier_score)
43  : fontinfo_id(font_id), score(classifier_score) {}
44 
45  // Index into fontinfo table, but inside the classifier, may be a shapetable
46  // index.
47  int32_t fontinfo_id;
48  // Raw score from the low-level classifier.
49  uint16_t score;
50 };
51 
52 // Struct for information about spacing between characters in a particular font.
54  int16_t x_gap_before;
55  int16_t x_gap_after;
56  std::vector<UNICHAR_ID> kerned_unichar_ids;
57  std::vector<int16_t> kerned_x_gaps;
58 };
59 
60 /*
61  * font_properties contains properties about boldness, italicness, fixed pitch,
62  * serif, fraktur
63  */
64 struct FontInfo {
65  FontInfo() : name(nullptr), properties(0), universal_id(0), spacing_vec(nullptr) {}
66  ~FontInfo() = default;
67 
68  bool operator==(const FontInfo &rhs) const {
69  return strcmp(name, rhs.name) == 0;
70  }
71 
72  // Writes to the given file. Returns false in case of error.
73  bool Serialize(FILE *fp) const;
74  // Reads from the given file. Returns false in case of error.
75  // If swap is true, assumes a big/little-endian swap is needed.
76  bool DeSerialize(TFile *fp);
77 
78  // Reserves unicharset_size spots in spacing_vec.
79  void init_spacing(int unicharset_size) {
80  spacing_vec = new std::vector<FontSpacingInfo *>(unicharset_size);
81  }
82  // Adds the given pointer to FontSpacingInfo to spacing_vec member
83  // (FontInfo class takes ownership of the pointer).
84  // Note: init_spacing should be called before calling this function.
85  void add_spacing(UNICHAR_ID uch_id, FontSpacingInfo *spacing_info) {
86  ASSERT_HOST(static_cast<size_t>(uch_id) < spacing_vec->size());
87  (*spacing_vec)[uch_id] = spacing_info;
88  }
89 
90  // Returns the pointer to FontSpacingInfo for the given UNICHAR_ID.
91  const FontSpacingInfo *get_spacing(UNICHAR_ID uch_id) const {
92  return (spacing_vec == nullptr || spacing_vec->size() <= static_cast<size_t>(uch_id)) ? nullptr
93  : (*spacing_vec)[uch_id];
94  }
95 
96  // Fills spacing with the value of the x gap expected between the two given
97  // UNICHAR_IDs. Returns true on success.
98  bool get_spacing(UNICHAR_ID prev_uch_id, UNICHAR_ID uch_id, int *spacing) const {
99  const FontSpacingInfo *prev_fsi = this->get_spacing(prev_uch_id);
100  const FontSpacingInfo *fsi = this->get_spacing(uch_id);
101  if (prev_fsi == nullptr || fsi == nullptr) {
102  return false;
103  }
104  size_t i = 0;
105  for (; i < prev_fsi->kerned_unichar_ids.size(); ++i) {
106  if (prev_fsi->kerned_unichar_ids[i] == uch_id) {
107  break;
108  }
109  }
110  if (i < prev_fsi->kerned_unichar_ids.size()) {
111  *spacing = prev_fsi->kerned_x_gaps[i];
112  } else {
113  *spacing = prev_fsi->x_gap_after + fsi->x_gap_before;
114  }
115  return true;
116  }
117 
118  bool is_italic() const {
119  return properties & 1;
120  }
121  bool is_bold() const {
122  return (properties & 2) != 0;
123  }
124  bool is_fixed_pitch() const {
125  return (properties & 4) != 0;
126  }
127  bool is_serif() const {
128  return (properties & 8) != 0;
129  }
130  bool is_fraktur() const {
131  return (properties & 16) != 0;
132  }
133 
134  char *name;
135  uint32_t properties;
136  // The universal_id is a field reserved for the initialization process
137  // to assign a unique id number to all fonts loaded for the current
138  // combination of languages. This id will then be returned by
139  // ResultIterator::WordFontAttributes.
140  int32_t universal_id;
141  // Horizontal spacing between characters (indexed by UNICHAR_ID).
142  std::vector<FontSpacingInfo *> *spacing_vec;
143 };
144 
145 // Every class (character) owns a FontSet that represents all the fonts that can
146 // render this character.
147 // Since almost all the characters from the same script share the same set of
148 // fonts, the sets are shared over multiple classes (see
149 // Classify::fontset_table_). Thus, a class only store an id to a set.
150 // Because some fonts cannot render just one character of a set, there are a
151 // lot of FontSet that differ only by one font. Rather than storing directly
152 // the FontInfo in the FontSet structure, it's better to share FontInfos among
153 // FontSets (Classify::fontinfo_table_).
154 using FontSet = std::vector<int>;
155 
156 // Class that adds a bit of functionality on top of GenericVector to
157 // implement a table of FontInfo that replaces UniCityTable<FontInfo>.
158 // TODO(rays) change all references once all existing traineddata files
159 // are replaced.
160 class FontInfoTable : public GenericVector<FontInfo> {
161 public:
162  TESS_API // when you remove inheritance from GenericVector, move this on
163  // class level
164  FontInfoTable();
165  TESS_API
167 
168  // Writes to the given file. Returns false in case of error.
169  TESS_API
170  bool Serialize(FILE *fp) const;
171  // Reads from the given file. Returns false in case of error.
172  // If swap is true, assumes a big/little-endian swap is needed.
173  TESS_API
174  bool DeSerialize(TFile *fp);
175 
176  // Returns true if the given set of fonts includes one with the same
177  // properties as font_id.
178  TESS_API
179  bool SetContainsFontProperties(int font_id, const std::vector<ScoredFont> &font_set) const;
180  // Returns true if the given set of fonts includes multiple properties.
181  TESS_API
182  bool SetContainsMultipleFontProperties(const std::vector<ScoredFont> &font_set) const;
183 
184  // Moves any non-empty FontSpacingInfo entries from other to this.
185  TESS_API
186  void MoveSpacingInfoFrom(FontInfoTable *other);
187  // Moves this to the target unicity table.
188  TESS_API
189  void MoveTo(UnicityTable<FontInfo> *target);
190 };
191 
192 // Deletion callbacks for GenericVector.
194 
195 // Callbacks used by UnicityTable to read/write FontInfo/FontSet structures.
196 bool read_info(TFile *f, FontInfo *fi);
197 bool write_info(FILE *f, const FontInfo &fi);
198 bool read_spacing_info(TFile *f, FontInfo *fi);
199 bool write_spacing_info(FILE *f, const FontInfo &fi);
200 bool write_set(FILE *f, const FontSet &fs);
201 
202 } // namespace tesseract.
203 
204 #endif /* THIRD_PARTY_TESSERACT_CCSTRUCT_FONTINFO_H_ */
#define ASSERT_HOST(x)
Definition: errcode.h:59
void FontInfoDeleteCallback(FontInfo f)
Definition: fontinfo.cpp:129
bool write_set(FILE *f, const FontSet &fs)
Definition: fontinfo.cpp:222
bool write_info(FILE *f, const FontInfo &fi)
Definition: fontinfo.cpp:157
bool write_spacing_info(FILE *f, const FontInfo &fi)
Definition: fontinfo.cpp:194
std::vector< int > FontSet
Definition: fontinfo.h:154
int UNICHAR_ID
Definition: unichar.h:36
bool read_info(TFile *f, FontInfo *fi)
Definition: fontinfo.cpp:143
bool read_spacing_info(TFile *f, FontInfo *fi)
Definition: fontinfo.cpp:163
ScoredFont(int font_id, uint16_t classifier_score)
Definition: fontinfo.h:42
std::vector< int16_t > kerned_x_gaps
Definition: fontinfo.h:57
std::vector< UNICHAR_ID > kerned_unichar_ids
Definition: fontinfo.h:56
int32_t universal_id
Definition: fontinfo.h:140
bool get_spacing(UNICHAR_ID prev_uch_id, UNICHAR_ID uch_id, int *spacing) const
Definition: fontinfo.h:98
bool is_italic() const
Definition: fontinfo.h:118
bool operator==(const FontInfo &rhs) const
Definition: fontinfo.h:68
bool DeSerialize(TFile *fp)
Definition: fontinfo.cpp:37
std::vector< FontSpacingInfo * > * spacing_vec
Definition: fontinfo.h:142
bool is_fixed_pitch() const
Definition: fontinfo.h:124
bool Serialize(FILE *fp) const
Definition: fontinfo.cpp:26
const FontSpacingInfo * get_spacing(UNICHAR_ID uch_id) const
Definition: fontinfo.h:91
bool is_bold() const
Definition: fontinfo.h:121
uint32_t properties
Definition: fontinfo.h:135
void init_spacing(int unicharset_size)
Definition: fontinfo.h:79
bool is_fraktur() const
Definition: fontinfo.h:130
void add_spacing(UNICHAR_ID uch_id, FontSpacingInfo *spacing_info)
Definition: fontinfo.h:85
bool is_serif() const
Definition: fontinfo.h:127
TESS_API bool DeSerialize(TFile *fp)
Definition: fontinfo.cpp:60
TESS_API FontInfoTable()
Definition: fontinfo.cpp:47
TESS_API void MoveSpacingInfoFrom(FontInfoTable *other)
Definition: fontinfo.cpp:95
TESS_API bool SetContainsFontProperties(int font_id, const std::vector< ScoredFont > &font_set) const
Definition: fontinfo.cpp:67
TESS_API bool Serialize(FILE *fp) const
Definition: fontinfo.cpp:55
TESS_API void MoveTo(UnicityTable< FontInfo > *target)
Definition: fontinfo.cpp:116
TESS_API bool SetContainsMultipleFontProperties(const std::vector< ScoredFont > &font_set) const
Definition: fontinfo.cpp:79
#define TESS_API
Definition: export.h:34