mirror of
https://github.com/tesseract-ocr/tesseract.git
synced 2024-11-24 11:09:06 +08:00
245 lines
8.9 KiB
C++
245 lines
8.9 KiB
C++
///////////////////////////////////////////////////////////////////////
|
|
// File: resultiterator.h
|
|
// Description: Iterator for tesseract results that is capable of
|
|
// iterating in proper reading order over Bi Directional
|
|
// (e.g. mixed Hebrew and English) text.
|
|
// Author: David Eger
|
|
// Created: Fri May 27 13:58:06 PST 2011
|
|
//
|
|
// (C) Copyright 2011, Google Inc.
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
//
|
|
///////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef TESSERACT_CCMAIN_RESULT_ITERATOR_H__
|
|
#define TESSERACT_CCMAIN_RESULT_ITERATOR_H__
|
|
|
|
#include "platform.h"
|
|
#include "ltrresultiterator.h"
|
|
|
|
template <typename T> class GenericVector;
|
|
template <typename T> class GenericVectorEqEq;
|
|
class BLOB_CHOICE_IT;
|
|
class WERD_RES;
|
|
class STRING;
|
|
|
|
namespace tesseract {
|
|
|
|
class Tesseract;
|
|
|
|
class TESS_API ResultIterator : public LTRResultIterator {
|
|
public:
|
|
static ResultIterator *StartOfParagraph(const LTRResultIterator &resit);
|
|
|
|
/**
|
|
* ResultIterator is copy constructible!
|
|
* The default copy constructor works just fine for us.
|
|
*/
|
|
virtual ~ResultIterator() {}
|
|
|
|
// ============= Moving around within the page ============.
|
|
/**
|
|
* Moves the iterator to point to the start of the page to begin
|
|
* an iteration.
|
|
*/
|
|
virtual void Begin();
|
|
|
|
/**
|
|
* Moves to the start of the next object at the given level in the
|
|
* page hierarchy in the appropriate reading order and returns false if
|
|
* the end of the page was reached.
|
|
* NOTE that RIL_SYMBOL will skip non-text blocks, but all other
|
|
* PageIteratorLevel level values will visit each non-text block once.
|
|
* Think of non text blocks as containing a single para, with a single line,
|
|
* with a single imaginary word.
|
|
* Calls to Next with different levels may be freely intermixed.
|
|
* This function iterates words in right-to-left scripts correctly, if
|
|
* the appropriate language has been loaded into Tesseract.
|
|
*/
|
|
virtual bool Next(PageIteratorLevel level);
|
|
|
|
/**
|
|
* IsAtBeginningOf() returns whether we're at the logical beginning of the
|
|
* given level. (as opposed to ResultIterator's left-to-right top-to-bottom
|
|
* order). Otherwise, this acts the same as PageIterator::IsAtBeginningOf().
|
|
* For a full description, see pageiterator.h
|
|
*/
|
|
virtual bool IsAtBeginningOf(PageIteratorLevel level) const;
|
|
|
|
/**
|
|
* Implement PageIterator's IsAtFinalElement correctly in a BiDi context.
|
|
* For instance, IsAtFinalElement(RIL_PARA, RIL_WORD) returns whether we
|
|
* point at the last word in a paragraph. See PageIterator for full comment.
|
|
*/
|
|
virtual bool IsAtFinalElement(PageIteratorLevel level,
|
|
PageIteratorLevel element) const;
|
|
|
|
// ============= Accessing data ==============.
|
|
|
|
/**
|
|
* Returns the null terminated UTF-8 encoded text string for the current
|
|
* object at the given level. Use delete [] to free after use.
|
|
*/
|
|
virtual char* GetUTF8Text(PageIteratorLevel level) const;
|
|
|
|
/**
|
|
* Return whether the current paragraph's dominant reading direction
|
|
* is left-to-right (as opposed to right-to-left).
|
|
*/
|
|
bool ParagraphIsLtr() const;
|
|
|
|
// ============= Exposed only for testing =============.
|
|
|
|
/**
|
|
* Yields the reading order as a sequence of indices and (optional)
|
|
* meta-marks for a set of words (given left-to-right).
|
|
* The meta marks are passed as negative values:
|
|
* kMinorRunStart Start of minor direction text.
|
|
* kMinorRunEnd End of minor direction text.
|
|
* kComplexWord The next indexed word contains both left-to-right and
|
|
* right-to-left characters and was treated as neutral.
|
|
*
|
|
* For example, suppose we have five words in a text line,
|
|
* indexed [0,1,2,3,4] from the leftmost side of the text line.
|
|
* The following are all believable reading_orders:
|
|
*
|
|
* Left-to-Right (in ltr paragraph):
|
|
* { 0, 1, 2, 3, 4 }
|
|
* Left-to-Right (in rtl paragraph):
|
|
* { kMinorRunStart, 0, 1, 2, 3, 4, kMinorRunEnd }
|
|
* Right-to-Left (in rtl paragraph):
|
|
* { 4, 3, 2, 1, 0 }
|
|
* Left-to-Right except for an RTL phrase in words 2, 3 in an ltr paragraph:
|
|
* { 0, 1, kMinorRunStart, 3, 2, kMinorRunEnd, 4 }
|
|
*/
|
|
static void CalculateTextlineOrder(
|
|
bool paragraph_is_ltr,
|
|
const GenericVector<StrongScriptDirection> &word_dirs,
|
|
GenericVectorEqEq<int> *reading_order);
|
|
|
|
static const int kMinorRunStart;
|
|
static const int kMinorRunEnd;
|
|
static const int kComplexWord;
|
|
|
|
protected:
|
|
/**
|
|
* We presume the data associated with the given iterator will outlive us.
|
|
* NB: This is private because it does something that is non-obvious:
|
|
* it resets to the beginning of the paragraph instead of staying wherever
|
|
* resit might have pointed.
|
|
*/
|
|
TESS_LOCAL explicit ResultIterator(const LTRResultIterator &resit);
|
|
|
|
private:
|
|
/**
|
|
* Calculates the current paragraph's dominant writing direction.
|
|
* Typically, members should use current_paragraph_ltr_ instead.
|
|
*/
|
|
bool CurrentParagraphIsLtr() const;
|
|
|
|
/**
|
|
* Returns word indices as measured from resit->RestartRow() = index 0
|
|
* for the reading order of words within a textline given an iterator
|
|
* into the middle of the text line.
|
|
* In addition to non-negative word indices, the following negative values
|
|
* may be inserted:
|
|
* kMinorRunStart Start of minor direction text.
|
|
* kMinorRunEnd End of minor direction text.
|
|
* kComplexWord The previous word contains both left-to-right and
|
|
* right-to-left characters and was treated as neutral.
|
|
*/
|
|
void CalculateTextlineOrder(bool paragraph_is_ltr,
|
|
const LTRResultIterator &resit,
|
|
GenericVectorEqEq<int> *indices) const;
|
|
/** Same as above, but the caller's ssd gets filled in if ssd != NULL. */
|
|
void CalculateTextlineOrder(bool paragraph_is_ltr,
|
|
const LTRResultIterator &resit,
|
|
GenericVector<StrongScriptDirection> *ssd,
|
|
GenericVectorEqEq<int> *indices) const;
|
|
|
|
/**
|
|
* What is the index of the current word in a strict left-to-right reading
|
|
* of the row?
|
|
*/
|
|
int LTRWordIndex() const;
|
|
|
|
/**
|
|
* Given an iterator pointing at a word, returns the logical reading order
|
|
* of blob indices for the word.
|
|
*/
|
|
void CalculateBlobOrder(GenericVector<int> *blob_indices) const;
|
|
|
|
/** Precondition: current_paragraph_is_ltr_ is set. */
|
|
void MoveToLogicalStartOfTextline();
|
|
|
|
/**
|
|
* Precondition: current_paragraph_is_ltr_ and in_minor_direction_
|
|
* are set.
|
|
*/
|
|
void MoveToLogicalStartOfWord();
|
|
|
|
/** Are we pointing at the final (reading order) symbol of the word? */
|
|
bool IsAtFinalSymbolOfWord() const;
|
|
|
|
/** Are we pointing at the first (reading order) symbol of the word? */
|
|
bool IsAtFirstSymbolOfWord() const;
|
|
|
|
/**
|
|
* Append any extra marks that should be appended to this word when printed.
|
|
* Mostly, these are Unicode BiDi control characters.
|
|
*/
|
|
void AppendSuffixMarks(STRING *text) const;
|
|
|
|
/** Appends the current word in reading order to the given buffer.*/
|
|
void AppendUTF8WordText(STRING *text) const;
|
|
|
|
/**
|
|
* Appends the text of the current text line, *assuming this iterator is
|
|
* positioned at the beginning of the text line* This function
|
|
* updates the iterator to point to the first position past the text line.
|
|
* Each textline is terminated in a single newline character.
|
|
* If the textline ends a paragraph, it gets a second terminal newline.
|
|
*/
|
|
void IterateAndAppendUTF8TextlineText(STRING *text);
|
|
|
|
/**
|
|
* Appends the text of the current paragraph in reading order
|
|
* to the given buffer.
|
|
* Each textline is terminated in a single newline character, and the
|
|
* paragraph gets an extra newline at the end.
|
|
*/
|
|
void AppendUTF8ParagraphText(STRING *text) const;
|
|
|
|
/** Returns whether the bidi_debug flag is set to at least min_level. */
|
|
bool BidiDebug(int min_level) const;
|
|
|
|
bool current_paragraph_is_ltr_;
|
|
|
|
/**
|
|
* Is the currently pointed-at character at the beginning of
|
|
* a minor-direction run?
|
|
*/
|
|
bool at_beginning_of_minor_run_;
|
|
|
|
/** Is the currently pointed-at character in a minor-direction sequence? */
|
|
bool in_minor_direction_;
|
|
|
|
/**
|
|
* Should detected inter-word spaces be preserved, or "compressed" to a single
|
|
* space character (default behavior).
|
|
*/
|
|
bool preserve_interword_spaces_;
|
|
};
|
|
|
|
} // namespace tesseract.
|
|
|
|
#endif // TESSERACT_CCMAIN_RESULT_ITERATOR_H__
|