// Copyright 2008 Google Inc. All Rights Reserved.

// Author: shobhitsaxena@google.com (Shobhit Saxena)

// 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_TEXTORD_DEVNAGARI_PROCESSING_H_

#define TESSERACT_TEXTORD_DEVNAGARI_PROCESSING_H_

#include "image.h"    // for Image

#include "ocrblock.h"

#include "params.h"

namespace tesseract {

extern INT_VAR_H(devanagari_split_debuglevel);

extern BOOL_VAR_H(devanagari_split_debugimage);

class TBOX;

class DebugPixa;

class PixelHistogram {

public:

  PixelHistogram() {

    hist_ = nullptr;

    length_ = 0;

  }

  ~PixelHistogram() {

    Clear();

  }

  void Clear() {

    delete[] hist_;

    length_ = 0;

  }

  int *hist() const {

    return hist_;

  }

  int length() const {

    return length_;

  }

  // Methods to construct histograms from images. These clear any existing data.

  void ConstructVerticalCountHist(Image pix);

  void ConstructHorizontalCountHist(Image pix);

  // This method returns the global-maxima for the histogram. The frequency of

  // the global maxima is returned in count, if specified.

  int GetHistogramMaximum(int *count) const;

private:

  int *hist_;

  int length_;

};

class ShiroRekhaSplitter {

public:

  enum SplitStrategy {

    NO_SPLIT = 0,  // No splitting is performed for the phase.

    MINIMAL_SPLIT, // Blobs are split minimally.

    MAXIMAL_SPLIT  // Blobs are split maximally.

  };

  ShiroRekhaSplitter();

  virtual ~ShiroRekhaSplitter();

  // Top-level method to perform splitting based on current settings.

  // Returns true if a split was actually performed.

  // If split_for_pageseg is true, the pageseg_split_strategy_ is used for

  // splitting. If false, the ocr_split_strategy_ is used.

  bool Split(bool split_for_pageseg, DebugPixa *pixa_debug);

  // Clears the memory held by this object.

  void Clear();

  // Refreshes the words in the segmentation block list by using blobs in the

  // input blob list.

  // The segmentation block list must be set.

  void RefreshSegmentationWithNewBlobs(C_BLOB_LIST *new_blobs);

  // Returns true if the split strategies for pageseg and ocr are different.

  bool HasDifferentSplitStrategies() const {

    return pageseg_split_strategy_ != ocr_split_strategy_;

  }

  // This only keeps a copy of the block list pointer. At split call, the list

  // object should still be alive. This block list is used as a golden

  // segmentation when performing splitting.

  void set_segmentation_block_list(BLOCK_LIST *block_list) {

    segmentation_block_list_ = block_list;

  }

  static const int kUnspecifiedXheight = -1;

  void set_global_xheight(int xheight) {

    global_xheight_ = xheight;

  }

  void set_perform_close(bool perform) {

    perform_close_ = perform;

  }

  // Returns the image obtained from shiro-rekha splitting. The returned object

  // is owned by this class. Callers may want to clone the returned pix to keep

  // it alive beyond the life of ShiroRekhaSplitter object.

  Image splitted_image() {

    return splitted_image_;

  }

  // On setting the input image, a clone of it is owned by this class.

  void set_orig_pix(Image pix);

  // Returns the input image provided to the object. This object is owned by

  // this class. Callers may want to clone the returned pix to work with it.

  Image orig_pix() {

    return orig_pix_;

  }

  SplitStrategy ocr_split_strategy() const {

    return ocr_split_strategy_;

  }

  void set_ocr_split_strategy(SplitStrategy strategy) {

    ocr_split_strategy_ = strategy;

  }

  SplitStrategy pageseg_split_strategy() const {

    return pageseg_split_strategy_;

  }

  void set_pageseg_split_strategy(SplitStrategy strategy) {

    pageseg_split_strategy_ = strategy;

  }

  BLOCK_LIST *segmentation_block_list() {

    return segmentation_block_list_;

  }

  // This method returns the computed mode-height of blobs in the pix.

  // It also prunes very small blobs from calculation. Could be used to provide

  // a global xheight estimate for images which have the same point-size text.

  static int GetModeHeight(Image pix);

private:

  // Method to perform a close operation on the input image. The xheight

  // estimate decides the size of sel used.

  static void PerformClose(Image pix, int xheight_estimate);

  // This method resolves the cc bbox to a particular row and returns the row's

  // xheight. This uses block_list_ if available, else just returns the

  // global_xheight_ estimate currently set in the object.

  int GetXheightForCC(Box *cc_bbox);

  // Returns a list of regions (boxes) which should be cleared in the original

  // image so as to perform shiro-rekha splitting. Pix is assumed to carry one

  // (or less) word only. Xheight measure could be the global estimate, the row

  // estimate, or unspecified. If unspecified, over splitting may occur, since a

  // conservative estimate of stroke width along with an associated multiplier

  // is used in its place. It is advisable to have a specified xheight when

  // splitting for classification/training.

  void SplitWordShiroRekha(SplitStrategy split_strategy, Image pix, int xheight, int word_left,

                           int word_top, Boxa *regions_to_clear);

  // Returns a new box object for the corresponding TBOX, based on the original

  // image's coordinate system.

  Box *GetBoxForTBOX(const TBOX &tbox) const;

  // This method returns y-extents of the shiro-rekha computed from the input

  // word image.

  static void GetShiroRekhaYExtents(Image word_pix, int *shirorekha_top, int *shirorekha_bottom,

                                    int *shirorekha_ylevel);

  Image orig_pix_;       // Just a clone of the input image passed.

  Image splitted_image_; // Image produced after the last splitting round. The

                        // object is owned by this class.

  SplitStrategy pageseg_split_strategy_;

  SplitStrategy ocr_split_strategy_;

  Image debug_image_;

  // This block list is used as a golden segmentation when performing splitting.

  BLOCK_LIST *segmentation_block_list_;

  int global_xheight_;

  bool perform_close_; // Whether a morphological close operation should be

                       // performed before CCs are run through splitting.

};

} // namespace tesseract.

#endif // TESSERACT_TEXTORD_DEVNAGARI_PROCESSING_H_