tesseract  5.0.0
alignedblob.h
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1 // File: alignedblob.h
3 // Description: A class to find vertically aligned blobs in a BBGrid,
4 // and a struct to hold control parameters.
5 // Author: Ray Smith
6 //
7 // (C) Copyright 2008, Google Inc.
8 // Licensed under the Apache License, Version 2.0 (the "License");
9 // you may not use this file except in compliance with the License.
10 // You may obtain a copy of the License at
11 // http://www.apache.org/licenses/LICENSE-2.0
12 // Unless required by applicable law or agreed to in writing, software
13 // distributed under the License is distributed on an "AS IS" BASIS,
14 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 // See the License for the specific language governing permissions and
16 // limitations under the License.
17 //
19 
20 #ifndef TESSERACT_TEXTORD_ALIGNEDBLOB_H_
21 #define TESSERACT_TEXTORD_ALIGNEDBLOB_H_
22 
23 #include "bbgrid.h"
24 #include "blobbox.h"
25 #include "tabvector.h"
26 
27 namespace tesseract {
28 
32 
33 // Simple structure to hold the search parameters for AlignedBlob.
34 // The members are mostly derived from constants, which are
35 // conditioned on the alignment parameter.
36 // For finding vertical lines, a different set of constants are
37 // used, conditioned on the different constructor.
39  // Constructor to set the parameters for finding aligned and ragged tabs.
40  // Vertical_x and vertical_y are the current estimates of the true vertical
41  // direction (up) in the image. Height is the height of the starter blob.
42  // v_gap_multiple is the multiple of height that will be used as a limit
43  // on vertical gap before giving up and calling the line ended.
44  // resolution is the original image resolution, and align0 indicates the
45  // type of tab stop to be found.
46  AlignedBlobParams(int vertical_x, int vertical_y, int height, int v_gap_multiple,
47  int min_gutter_width, int resolution, TabAlignment alignment0);
48  // Constructor to set the parameters for finding vertical lines.
49  // Vertical_x and vertical_y are the current estimates of the true vertical
50  // direction (up) in the image. Width is the width of the starter blob.
51  AlignedBlobParams(int vertical_x, int vertical_y, int width);
52 
53  // Fit the vertical vector into an ICOORD, which is 16 bit.
54  void set_vertical(int vertical_x, int vertical_y);
55 
56  double gutter_fraction; // Multiple of height used for min_gutter.
57  bool right_tab; // We are looking at right edges.
58  bool ragged; // We are looking for a ragged (vs aligned) edge.
59  TabAlignment alignment; // The type we are trying to produce.
60  TabType confirmed_type; // Type to flag blobs if accepted.
61  int max_v_gap; // Max vertical gap to be tolerated.
62  int min_gutter; // Minimum gutter between columns.
63  // Tolerances allowed on horizontal alignment of aligned edges.
64  int l_align_tolerance; // Left edges.
65  int r_align_tolerance; // Right edges.
66  // Conditions for accepting a line.
67  int min_points; // Minimum number of points to be OK.
68  int min_length; // Min length of completed line.
69 
70  ICOORD vertical; // Current estimate of logical vertical.
71 };
72 
73 // The AlignedBlob class contains code to find vertically aligned blobs.
74 // This is factored out into a separate class, so it can be used by both
75 // vertical line finding (LineFind) and tabstop finding (TabFind).
76 class TESS_API AlignedBlob : public BlobGrid {
77 public:
78  AlignedBlob(int gridsize, const ICOORD &bleft, const ICOORD &tright);
79  ~AlignedBlob() override;
80 
81  // Return true if the given coordinates are within the test rectangle
82  // and the debug level is at least the given detail level.
83  static bool WithinTestRegion(int detail_level, int x, int y);
84 
85  // Display the tab codes of the BLOBNBOXes in this grid.
86  ScrollView *DisplayTabs(const char *window_name, ScrollView *tab_win);
87 
88  // Finds a vector corresponding to a set of vertically aligned blob edges
89  // running through the given box. The type of vector returned and the
90  // search parameters are determined by the AlignedBlobParams.
91  // vertical_x and y are updated with an estimate of the real
92  // vertical direction. (skew finding.)
93  // Returns nullptr if no decent vector can be found.
94  TabVector *FindVerticalAlignment(AlignedBlobParams align_params, BLOBNBOX *bbox, int *vertical_x,
95  int *vertical_y);
96 
97 private:
98  // Find a set of blobs that are aligned in the given vertical
99  // direction with the given blob. Returns a list of aligned
100  // blobs and the number in the list.
101  // For other parameters see FindAlignedBlob below.
102  int AlignTabs(const AlignedBlobParams &params, bool top_to_bottom, BLOBNBOX *bbox,
103  BLOBNBOX_CLIST *good_points, int *end_y);
104 
105  // Search vertically for a blob that is aligned with the input bbox.
106  // The search parameters are determined by AlignedBlobParams.
107  // top_to_bottom tells whether to search down or up.
108  // The return value is nullptr if nothing was found in the search box
109  // or if a blob was found in the gutter. On a nullptr return, end_y
110  // is set to the edge of the search box or the leading edge of the
111  // gutter blob if one was found.
112  BLOBNBOX *FindAlignedBlob(const AlignedBlobParams &p, bool top_to_bottom, BLOBNBOX *bbox,
113  int x_start, int *end_y);
114 };
115 
116 } // namespace tesseract.
117 
118 #endif // TESSERACT_TEXTORD_ALIGNEDBLOB_H_
bool textord_debug_printable
Definition: alignedblob.cpp:43
BOOL_VAR_H(wordrec_display_splits)
int textord_debug_tabfind
Definition: alignedblob.cpp:29
INT_VAR_H(editor_image_xpos)
int textord_debug_bugs
Definition: alignedblob.cpp:30
integer coordinate
Definition: points.h:36
void set_vertical(int vertical_x, int vertical_y)
AlignedBlobParams(int vertical_x, int vertical_y, int height, int v_gap_multiple, int min_gutter_width, int resolution, TabAlignment alignment0)
Definition: alignedblob.cpp:81
#define TESS_API
Definition: export.h:34