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ltrresultiterator.h
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1
2 // File: ltrresultiterator.h
3 // Description: Iterator for tesseract results in strict left-to-right
4 // order that avoids using tesseract internal data structures.
5 // Author: Ray Smith
6 // Created: Fri Feb 26 11:01:06 PST 2010
7 //
8 // (C) Copyright 2010, Google Inc.
9 // Licensed under the Apache License, Version 2.0 (the "License");
10 // you may not use this file except in compliance with the License.
11 // You may obtain a copy of the License at
12 // http://www.apache.org/licenses/LICENSE-2.0
13 // Unless required by applicable law or agreed to in writing, software
14 // distributed under the License is distributed on an "AS IS" BASIS,
15 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 // See the License for the specific language governing permissions and
17 // limitations under the License.
18 //
20
21 #ifndef TESSERACT_CCMAIN_LTR_RESULT_ITERATOR_H__
22 #define TESSERACT_CCMAIN_LTR_RESULT_ITERATOR_H__
23
24 #include "platform.h"
25 #include "pageiterator.h"
26 #include "unicharset.h"
27
28 class BLOB_CHOICE_IT;
29 class WERD_RES;
30
31 namespace tesseract {
32
33 class Tesseract;
34
35 // Class to iterate over tesseract results, providing access to all levels
36 // of the page hierarchy, without including any tesseract headers or having
37 // to handle any tesseract structures.
38 // WARNING! This class points to data held within the TessBaseAPI class, and
39 // therefore can only be used while the TessBaseAPI class still exists and
40 // has not been subjected to a call of Init, SetImage, Recognize, Clear, End
41 // DetectOS, or anything else that changes the internal PAGE_RES.
42 // See apitypes.h for the definition of PageIteratorLevel.
43 // See also base class PageIterator, which contains the bulk of the interface.
44 // LTRResultIterator adds text-specific methods for access to OCR output.
45
46 class TESS_API LTRResultIterator : public PageIterator {
47 friend class ChoiceIterator;
48 public:
49 // page_res and tesseract come directly from the BaseAPI.
50 // The rectangle parameters are copied indirectly from the Thresholder,
51 // via the BaseAPI. They represent the coordinates of some rectangle in an
52 // original image (in top-left-origin coordinates) and therefore the top-left
53 // needs to be added to any output boxes in order to specify coordinates
54 // in the original image. See TessBaseAPI::SetRectangle.
55 // The scale and scaled_yres are in case the Thresholder scaled the image
56 // rectangle prior to thresholding. Any coordinates in tesseract's image
57 // must be divided by scale before adding (rect_left, rect_top).
58 // The scaled_yres indicates the effective resolution of the binary image
59 // that tesseract has been given by the Thresholder.
60 // After the constructor, Begin has already been called.
61 LTRResultIterator(PAGE_RES* page_res, Tesseract* tesseract,
62 int scale, int scaled_yres,
63 int rect_left, int rect_top,
64 int rect_width, int rect_height);
65 virtual ~LTRResultIterator();
66
67 // LTRResultIterators may be copied! This makes it possible to iterate over
68 // all the objects at a lower level, while maintaining an iterator to
69 // objects at a higher level. These constructors DO NOT CALL Begin, so
70 // iterations will continue from the location of src.
71 // TODO: For now the copy constructor and operator= only need the base class
72 // versions, but if new data members are added, don't forget to add them!
73
74 // ============= Moving around within the page ============.
75
76 // See PageIterator.
77
78 // ============= Accessing data ==============.
79
80 // Returns the null terminated UTF-8 encoded text string for the current
81 // object at the given level. Use delete [] to free after use.
82 char* GetUTF8Text(PageIteratorLevel level) const;
83
84 // Set the string inserted at the end of each text line. "\n" by default.
85 void SetLineSeparator(const char *new_line);
86
87 // Set the string inserted at the end of each paragraph. "\n" by default.
88 void SetParagraphSeparator(const char *new_para);
89
90 // Returns the mean confidence of the current object at the given level.
91 // The number should be interpreted as a percent probability. (0.0f-100.0f)
92 float Confidence(PageIteratorLevel level) const;
93
94 // ============= Functions that refer to words only ============.
95
96 // Returns the font attributes of the current word. If iterating at a higher
97 // level object than words, eg textlines, then this will return the
98 // attributes of the first word in that textline.
99 // The actual return value is a string representing a font name. It points
100 // to an internal table and SHOULD NOT BE DELETED. Lifespan is the same as
101 // the iterator itself, ie rendered invalid by various members of
102 // TessBaseAPI, including Init, SetImage, End or deleting the TessBaseAPI.
103 // Pointsize is returned in printers points (1/72 inch.)
104 const char* WordFontAttributes(bool* is_bold,
105 bool* is_italic,
106 bool* is_underlined,
107 bool* is_monospace,
108 bool* is_serif,
109 bool* is_smallcaps,
110 int* pointsize,
111 int* font_id) const;
112
113 // Return the name of the language used to recognize this word.
114 // On error, NULL. Do not delete this pointer.
115 const char* WordRecognitionLanguage() const;
116
117 // Return the overall directionality of this word.
118 StrongScriptDirection WordDirection() const;
119
120 // Returns true if the current word was found in a dictionary.
121 bool WordIsFromDictionary() const;
122
123 // Returns true if the current word is numeric.
124 bool WordIsNumeric() const;
125
126 // Returns true if the word contains blamer information.
127 bool HasBlamerInfo() const;
128
129 // Returns the pointer to ParamsTrainingBundle stored in the BlamerBundle
130 // of the current word.
131 void *GetParamsTrainingBundle() const;
132
133 // Returns a pointer to the string with blamer information for this word.
134 // Assumes that the word's blamer_bundle is not NULL.
135 const char *GetBlamerDebug() const;
136
137 // Returns a pointer to the string with misadaption information for this word.
138 // Assumes that the word's blamer_bundle is not NULL.
139 const char *GetBlamerMisadaptionDebug() const;
140
141 // Returns a null terminated UTF-8 encoded truth string for the current word.
142 // Use delete [] to free after use.
143 char* WordTruthUTF8Text() const;
144
145 // Returns a pointer to serialized choice lattice.
146 // Fills lattice_size with the number of bytes in lattice data.
147 const char *WordLattice(int *lattice_size) const;
148
149 // ============= Functions that refer to symbols only ============.
150
151 // Returns true if the current symbol is a superscript.
152 // If iterating at a higher level object than symbols, eg words, then
153 // this will return the attributes of the first symbol in that word.
154 bool SymbolIsSuperscript() const;
155 // Returns true if the current symbol is a subscript.
156 // If iterating at a higher level object than symbols, eg words, then
157 // this will return the attributes of the first symbol in that word.
158 bool SymbolIsSubscript() const;
159 // Returns true if the current symbol is a dropcap.
160 // If iterating at a higher level object than symbols, eg words, then
161 // this will return the attributes of the first symbol in that word.
162 bool SymbolIsDropcap() const;
163
164 protected:
165 const char *line_separator_;
166 const char *paragraph_separator_;
167 };
168
169 // Class to iterate over the classifier choices for a single RIL_SYMBOL.
170 class ChoiceIterator {
171 public:
172 // Construction is from a LTRResultIterator that points to the symbol of
173 // interest. The ChoiceIterator allows a one-shot iteration over the
174 // choices for this symbol and after that is is useless.
175 explicit ChoiceIterator(const LTRResultIterator& result_it);
176 ~ChoiceIterator();
177
178 // Moves to the next choice for the symbol and returns false if there
179 // are none left.
180 bool Next();
181
182 // ============= Accessing data ==============.
183
184 // Returns the null terminated UTF-8 encoded text string for the current
185 // choice.
186 // NOTE: Unlike LTRResultIterator::GetUTF8Text, the return points to an
187 // internal structure and should NOT be delete[]ed to free after use.
188 const char* GetUTF8Text() const;
189
190 // Returns the confidence of the current choice.
191 // The number should be interpreted as a percent probability. (0.0f-100.0f)
192 float Confidence() const;
193
194 private:
195 // Pointer to the WERD_RES object owned by the API.
196 WERD_RES* word_res_;
197 // Iterator over the blob choices.
198 BLOB_CHOICE_IT* choice_it_;
199 };
200
201 } // namespace tesseract.
202
203 #endif // TESSERACT_CCMAIN_LTR_RESULT_ITERATOR_H__