tesseract  3.03
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00001 
00002 // File:        fontinfo.h
00003 // Description: Font information classes abstracted from intproto.h/cpp.
00004 // Author:      rays@google.com (Ray Smith)
00005 // Created:     Tue May 17 17:08:01 PDT 2011
00006 //
00007 // (C) Copyright 2011, Google Inc.
00008 // Licensed under the Apache License, Version 2.0 (the "License");
00009 // you may not use this file except in compliance with the License.
00010 // You may obtain a copy of the License at
00011 // http://www.apache.org/licenses/LICENSE-2.0
00012 // Unless required by applicable law or agreed to in writing, software
00013 // distributed under the License is distributed on an "AS IS" BASIS,
00014 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00015 // See the License for the specific language governing permissions and
00016 // limitations under the License.
00017 //
00019 
00020 
00021 #ifndef TESSERACT_CCSTRUCT_FONTINFO_H_
00022 #define TESSERACT_CCSTRUCT_FONTINFO_H_
00023 
00024 #include "genericvector.h"
00025 #include "host.h"
00026 #include "unichar.h"
00027 
00028 template <typename T> class UnicityTable;
00029 
00030 namespace tesseract {
00031 
00032 class BitVector;
00033 
00034 // Struct for information about spacing between characters in a particular font.
00035 struct FontSpacingInfo {
00036   inT16 x_gap_before;
00037   inT16 x_gap_after;
00038   GenericVector<UNICHAR_ID> kerned_unichar_ids;
00039   GenericVector<inT16> kerned_x_gaps;
00040 };
00041 
00042 /*
00043  * font_properties contains properties about boldness, italicness, fixed pitch,
00044  * serif, fraktur
00045  */
00046 struct FontInfo {
00047   FontInfo() : name(NULL), properties(0), universal_id(0), spacing_vec(NULL) {}
00048   ~FontInfo() {}
00049 
00050   // Writes to the given file. Returns false in case of error.
00051   bool Serialize(FILE* fp) const;
00052   // Reads from the given file. Returns false in case of error.
00053   // If swap is true, assumes a big/little-endian swap is needed.
00054   bool DeSerialize(bool swap, FILE* fp);
00055 
00056   // Reserves unicharset_size spots in spacing_vec.
00057   void init_spacing(int unicharset_size) {
00058     spacing_vec = new GenericVector<FontSpacingInfo *>();
00059     spacing_vec->init_to_size(unicharset_size, NULL);
00060   }
00061   // Adds the given pointer to FontSpacingInfo to spacing_vec member
00062   // (FontInfo class takes ownership of the pointer).
00063   // Note: init_spacing should be called before calling this function.
00064   void add_spacing(UNICHAR_ID uch_id, FontSpacingInfo *spacing_info) {
00065     ASSERT_HOST(spacing_vec != NULL && spacing_vec->size() > uch_id);
00066     (*spacing_vec)[uch_id] = spacing_info;
00067   }
00068 
00069   // Returns the pointer to FontSpacingInfo for the given UNICHAR_ID.
00070   const FontSpacingInfo *get_spacing(UNICHAR_ID uch_id) const {
00071     return (spacing_vec == NULL || spacing_vec->size() <= uch_id) ?
00072         NULL : (*spacing_vec)[uch_id];
00073   }
00074 
00075   // Fills spacing with the value of the x gap expected between the two given
00076   // UNICHAR_IDs. Returns true on success.
00077   bool get_spacing(UNICHAR_ID prev_uch_id,
00078                    UNICHAR_ID uch_id,
00079                    int *spacing) const {
00080     const FontSpacingInfo *prev_fsi = this->get_spacing(prev_uch_id);
00081     const FontSpacingInfo *fsi = this->get_spacing(uch_id);
00082     if (prev_fsi == NULL || fsi == NULL) return false;
00083     int i = 0;
00084     for (; i < prev_fsi->kerned_unichar_ids.size(); ++i) {
00085       if (prev_fsi->kerned_unichar_ids[i] == uch_id) break;
00086     }
00087     if (i < prev_fsi->kerned_unichar_ids.size()) {
00088       *spacing = prev_fsi->kerned_x_gaps[i];
00089     } else {
00090       *spacing = prev_fsi->x_gap_after + fsi->x_gap_before;
00091     }
00092     return true;
00093   }
00094 
00095   bool is_italic() const { return properties & 1; }
00096   bool is_bold() const { return (properties & 2) != 0; }
00097   bool is_fixed_pitch() const { return (properties & 4) != 0; }
00098   bool is_serif() const { return (properties & 8) != 0; }
00099   bool is_fraktur() const { return (properties & 16) != 0; }
00100 
00101   char* name;
00102   uinT32 properties;
00103   // The universal_id is a field reserved for the initialization process
00104   // to assign a unique id number to all fonts loaded for the current
00105   // combination of languages. This id will then be returned by
00106   // ResultIterator::WordFontAttributes.
00107   inT32 universal_id;
00108   // Horizontal spacing between characters (indexed by UNICHAR_ID).
00109   GenericVector<FontSpacingInfo *> *spacing_vec;
00110 };
00111 
00112 // Every class (character) owns a FontSet that represents all the fonts that can
00113 // render this character.
00114 // Since almost all the characters from the same script share the same set of
00115 // fonts, the sets are shared over multiple classes (see
00116 // Classify::fontset_table_). Thus, a class only store an id to a set.
00117 // Because some fonts cannot render just one character of a set, there are a
00118 // lot of FontSet that differ only by one font. Rather than storing directly
00119 // the FontInfo in the FontSet structure, it's better to share FontInfos among
00120 // FontSets (Classify::fontinfo_table_).
00121 struct FontSet {
00122   int           size;
00123   int*          configs;  // FontInfo ids
00124 };
00125 
00126 // Class that adds a bit of functionality on top of GenericVector to
00127 // implement a table of FontInfo that replaces UniCityTable<FontInfo>.
00128 // TODO(rays) change all references once all existing traineddata files
00129 // are replaced.
00130 class FontInfoTable : public GenericVector<FontInfo> {
00131  public:
00132   FontInfoTable();
00133   ~FontInfoTable();
00134 
00135   // Writes to the given file. Returns false in case of error.
00136   bool Serialize(FILE* fp) const;
00137   // Reads from the given file. Returns false in case of error.
00138   // If swap is true, assumes a big/little-endian swap is needed.
00139   bool DeSerialize(bool swap, FILE* fp);
00140 
00141   // Returns true if the given set of fonts includes one with the same
00142   // properties as font_id.
00143   bool SetContainsFontProperties(int font_id,
00144                                  const GenericVector<int>& font_set) const;
00145   // Returns true if the given set of fonts includes multiple properties.
00146   bool SetContainsMultipleFontProperties(
00147       const GenericVector<int>& font_set) const;
00148 
00149   // Moves any non-empty FontSpacingInfo entries from other to this.
00150   void MoveSpacingInfoFrom(FontInfoTable* other);
00151   // Moves this to the target unicity table.
00152   void MoveTo(UnicityTable<FontInfo>* target);
00153 };
00154 
00155 // Compare FontInfo structures.
00156 bool CompareFontInfo(const FontInfo& fi1, const FontInfo& fi2);
00157 // Compare FontSet structures.
00158 bool CompareFontSet(const FontSet& fs1, const FontSet& fs2);
00159 // Deletion callbacks for GenericVector.
00160 void FontInfoDeleteCallback(FontInfo f);
00161 void FontSetDeleteCallback(FontSet fs);
00162 
00163 // Callbacks used by UnicityTable to read/write FontInfo/FontSet structures.
00164 bool read_info(FILE* f, FontInfo* fi, bool swap);
00165 bool write_info(FILE* f, const FontInfo& fi);
00166 bool read_spacing_info(FILE *f, FontInfo* fi, bool swap);
00167 bool write_spacing_info(FILE* f, const FontInfo& fi);
00168 bool read_set(FILE* f, FontSet* fs, bool swap);
00169 bool write_set(FILE* f, const FontSet& fs);
00170 
00171 }  // namespace tesseract.
00172 
00173 #endif /* THIRD_PARTY_TESSERACT_CCSTRUCT_FONTINFO_H_ */
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