/*====================================================================*

 -  Copyright (C) 2001 Leptonica.  All rights reserved.

 -

 -  Redistribution and use in source and binary forms, with or without

 -  modification, are permitted provided that the following conditions

 -  are met:

 -  1. Redistributions of source code must retain the above copyright

 -     notice, this list of conditions and the following disclaimer.

 -  2. Redistributions in binary form must reproduce the above

 -     copyright notice, this list of conditions and the following

 -     disclaimer in the documentation and/or other materials

 -     provided with the distribution.

 -

 -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY

 -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *====================================================================*/

/*!

 * \file classapp.c

 * <pre>

 *

 *      Top-level jb2 correlation and rank-hausdorff

 *         l_int32         jbCorrelation()

 *         l_int32         jbRankHaus()

 *

 *      Extract and classify words in textline order

 *         JBCLASSER      *jbWordsInTextlines()

 *         l_int32         pixGetWordsInTextlines()

 *         l_int32         pixGetWordBoxesInTextlines()

 *

 *      Extract word and character bounding boxes

 *         l_int32         pixFindWordAndCharacterBoxes()

 *

 *      Use word bounding boxes to compare page images

 *         NUMAA          *boxaExtractSortedPattern()

 *         l_int32         numaaCompareImagesByBoxes()

 *         static l_int32  testLineAlignmentX()

 *         static l_int32  countAlignedMatches()

 *         static void     printRowIndices()

 * </pre>

 */

#ifdef HAVE_CONFIG_H

#include <config_auto.h>

#endif  /* HAVE_CONFIG_H */

#include <string.h>

#include "allheaders.h"

#define L_BUF_SIZE 512                        /*!< size of filename buffer    */

static const l_int32 JB_WORDS_MIN_WIDTH = 5;  /*!< min. word width in pixels  */

static const l_int32 JB_WORDS_MIN_HEIGHT = 3; /*!< min. word height in pixels */

    /* Static comparison functions */

static l_int32 testLineAlignmentX(NUMA *na1, NUMA *na2, l_int32 shiftx,

                                  l_int32 delx, l_int32 nperline);

static l_int32 countAlignedMatches(NUMA *nai1, NUMA *nai2, NUMA *nasx,

                                   NUMA *nasy, l_int32 n1, l_int32 n2,

                                   l_int32 delx, l_int32 dely,

                                   l_int32 nreq, l_int32 *psame,

                                   l_int32 debugflag);

static void printRowIndices(l_int32 *index1, l_int32 n1,

                            l_int32 *index2, l_int32 n2);

/*------------------------------------------------------------------*

 *          Top-level jb2 correlation and rank-hausdorff            *

 *------------------------------------------------------------------*/

/*!

 * \brief   jbCorrelation()

 *

 * \param[in]    dirin        directory of input images

 * \param[in]    thresh       typically ~0.8

 * \param[in]    weight       typically ~0.6

 * \param[in]    components   JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS

 * \param[in]    rootname     for output files

 * \param[in]    firstpage    0-based

 * \param[in]    npages       use 0 for all pages in dirin

 * \param[in]    renderflag   1 to render from templates; 0 to skip

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) The images must be 1 bpp.  If they are not, you can convert

 *          them using convertFilesTo1bpp().

 *      (2) See prog/jbcorrelation for generating more output (e.g.,

 *          for debugging)

 * </pre>

 */

l_ok

jbCorrelation(const char  *dirin,

              l_float32    thresh,

              l_float32    weight,

              l_int32      components,

              const char  *rootname,

              l_int32      firstpage,

              l_int32      npages,

              l_int32      renderflag)

{

char        filename[L_BUF_SIZE];

l_int32     nfiles, i, numpages;

JBDATA     *data;

JBCLASSER  *classer;

PIX        *pix;

PIXA       *pixa;

SARRAY     *safiles;

    if (!dirin)

        return ERROR_INT("dirin not defined", __func__, 1);

    if (!rootname)

        return ERROR_INT("rootname not defined", __func__, 1);

    if (components != JB_CONN_COMPS && components != JB_CHARACTERS &&

        components != JB_WORDS)

        return ERROR_INT("components invalid", __func__, 1);

    safiles = getSortedPathnamesInDirectory(dirin, NULL, firstpage, npages);

    nfiles = sarrayGetCount(safiles);

        /* Classify components */

    classer = jbCorrelationInit(components, 0, 0, thresh, weight);

    jbAddPages(classer, safiles);

        /* Save data */

    data = jbDataSave(classer);

    jbDataWrite(rootname, data);

        /* Optionally, render pages using class templates */

    if (renderflag) {

        pixa = jbDataRender(data, FALSE);

        numpages = pixaGetCount(pixa);

        if (numpages != nfiles)

            lept_stderr("numpages = %d, nfiles = %d, not equal!\n",

                        numpages, nfiles);

        for (i = 0; i < numpages; i++) {

            pix = pixaGetPix(pixa, i, L_CLONE);

            snprintf(filename, L_BUF_SIZE, "%s.%04d", rootname, i);

            lept_stderr("filename: %s\n", filename);

            pixWrite(filename, pix, IFF_PNG);

            pixDestroy(&pix);

        }

        pixaDestroy(&pixa);

    }

    sarrayDestroy(&safiles);

    jbClasserDestroy(&classer);

    jbDataDestroy(&data);

    return 0;

}

/*!

 * \brief   jbRankHaus()

 *

 * \param[in]    dirin         directory of input images

 * \param[in]    size          of Sel used for dilation; typ. 2

 * \param[in]    rank          rank value of match; typ. 0.97

 * \param[in]    components    JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS

 * \param[in]    rootname      for output files

 * \param[in]    firstpage     0-based

 * \param[in]    npages        use 0 for all pages in dirin

 * \param[in]    renderflag    1 to render from templates; 0 to skip

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) See prog/jbrankhaus for generating more output (e.g.,

 *          for debugging)

 * </pre>

 */

l_ok

jbRankHaus(const char  *dirin,

           l_int32      size,

           l_float32    rank,

           l_int32      components,

           const char  *rootname,

           l_int32      firstpage,

           l_int32      npages,

           l_int32      renderflag)

{

char        filename[L_BUF_SIZE];

l_int32     nfiles, i, numpages;

JBDATA     *data;

JBCLASSER  *classer;

PIX        *pix;

PIXA       *pixa;

SARRAY     *safiles;

    if (!dirin)

        return ERROR_INT("dirin not defined", __func__, 1);

    if (!rootname)

        return ERROR_INT("rootname not defined", __func__, 1);

    if (components != JB_CONN_COMPS && components != JB_CHARACTERS &&

        components != JB_WORDS)

        return ERROR_INT("components invalid", __func__, 1);

    safiles = getSortedPathnamesInDirectory(dirin, NULL, firstpage, npages);

    nfiles = sarrayGetCount(safiles);

        /* Classify components */

    classer = jbRankHausInit(components, 0, 0, size, rank);

    jbAddPages(classer, safiles);

        /* Save data */

    data = jbDataSave(classer);

    jbDataWrite(rootname, data);

        /* Optionally, render pages using class templates */

    if (renderflag) {

        pixa = jbDataRender(data, FALSE);

        numpages = pixaGetCount(pixa);

        if (numpages != nfiles)

            lept_stderr("numpages = %d, nfiles = %d, not equal!\n",

                        numpages, nfiles);

        for (i = 0; i < numpages; i++) {

            pix = pixaGetPix(pixa, i, L_CLONE);

            snprintf(filename, L_BUF_SIZE, "%s.%04d", rootname, i);

            lept_stderr("filename: %s\n", filename);

            pixWrite(filename, pix, IFF_PNG);

            pixDestroy(&pix);

        }

        pixaDestroy(&pixa);

    }

    sarrayDestroy(&safiles);

    jbClasserDestroy(&classer);

    jbDataDestroy(&data);

    return 0;

}

/*------------------------------------------------------------------*

 *           Extract and classify words in textline order           *

 *------------------------------------------------------------------*/

/*!

 * \brief   jbWordsInTextlines()

 *

 * \param[in]    dirin       directory of input pages

 * \param[in]    reduction   1 for full res; 2 for half-res

 * \param[in]    maxwidth    of word mask components, to be kept

 * \param[in]    maxheight   of word mask components, to be kept

 * \param[in]    thresh      on correlation; 0.80 is reasonable

 * \param[in]    weight      for handling thick text; 0.6 is reasonable

 * \param[out]   pnatl       numa with textline index for each component

 * \param[in]    firstpage   0-based

 * \param[in]    npages      use 0 for all pages in dirin

 * \return  classer for the set of pages

 *

 * <pre>

 * Notes:

 *      (1) This is a high-level function.  See prog/jbwords for example

 *          of usage.

 *      (2) Typically, use input of 75 - 150 ppi for finding words.

 * </pre>

 */

JBCLASSER *

jbWordsInTextlines(const char  *dirin,

                   l_int32      reduction,

                   l_int32      maxwidth,

                   l_int32      maxheight,

                   l_float32    thresh,

                   l_float32    weight,

                   NUMA       **pnatl,

                   l_int32      firstpage,

                   l_int32      npages)

{

char       *fname;

l_int32     nfiles, i, w, h;

BOXA       *boxa;

JBCLASSER  *classer;

NUMA       *nai, *natl;

PIX        *pix1, *pix2;

PIXA       *pixa;

SARRAY     *safiles;

    if (!pnatl)

        return (JBCLASSER *)ERROR_PTR("&natl not defined", __func__, NULL);

    *pnatl = NULL;

    if (!dirin)

        return (JBCLASSER *)ERROR_PTR("dirin not defined", __func__, NULL);

    if (reduction != 1 && reduction != 2)

        return (JBCLASSER *)ERROR_PTR("reduction not in {1,2}", __func__, NULL);

    safiles = getSortedPathnamesInDirectory(dirin, NULL, firstpage, npages);

    nfiles = sarrayGetCount(safiles);

        /* Classify components */

    classer = jbCorrelationInit(JB_WORDS, maxwidth, maxheight, thresh, weight);

    classer->safiles = sarrayCopy(safiles);

    natl = numaCreate(0);

    *pnatl = natl;

    for (i = 0; i < nfiles; i++) {

        fname = sarrayGetString(safiles, i, L_NOCOPY);

        if ((pix1 = pixRead(fname)) == NULL) {

            L_WARNING("image file %d not read\n", __func__, i);

            continue;

        }

        if (reduction == 1)

            pix2 = pixClone(pix1);

        else  /* reduction == 2 */

            pix2 = pixReduceRankBinaryCascade(pix1, 1, 0, 0, 0);

        pixGetWordsInTextlines(pix2, JB_WORDS_MIN_WIDTH,

                               JB_WORDS_MIN_HEIGHT, maxwidth, maxheight,

                               &boxa, &pixa, &nai);

        pixGetDimensions(pix2, &w, &h, NULL);

        classer->w = w;

        classer->h = h;

        jbAddPageComponents(classer, pix2, boxa, pixa);

        numaJoin(natl, nai, 0, -1);

        pixDestroy(&pix1);

        pixDestroy(&pix2);

        numaDestroy(&nai);

        boxaDestroy(&boxa);

        pixaDestroy(&pixa);

    }

    sarrayDestroy(&safiles);

    return classer;

}

/*!

 * \brief   pixGetWordsInTextlines()

 *

 * \param[in]    pixs        1 bpp, typ. 75 - 150 ppi

 * \param[in]    minwidth    of saved components; smaller are discarded

 * \param[in]    minheight   of saved components; smaller are discarded

 * \param[in]    maxwidth    of saved components; larger are discarded

 * \param[in]    maxheight   of saved components; larger are discarded

 * \param[out]   pboxad      word boxes sorted in textline line order

 * \param[out]   ppixad      word images sorted in textline line order

 * \param[out]   pnai        index of textline for each word

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) The input should be at a resolution of between 75 and 150 ppi.

 *      (2) The four size constraints on saved components are all

 *          scaled by %reduction.

 *      (3) The result are word images (and their b.b.), extracted in

 *          textline order, at either full res or 2x reduction,

 *          and with a numa giving the textline index for each word.

 *      (4) The pixa and boxa interfaces should make this type of

 *          application simple to put together.  The steps are:

 *           ~ generate first estimate of word masks

 *           ~ get b.b. of these, and remove the small and big ones

 *           ~ extract pixa of the word images, using the b.b.

 *           ~ sort actual word images in textline order (2d)

 *           ~ flatten them to a pixa (1d), saving the textline index

 *             for each pix

 *      (5) In an actual application, it may be desirable to pre-filter

 *          the input image to remove large components, to extract

 *          single columns of text, and to deskew them.  For example,

 *          to remove both large components and small noisy components

 *          that can interfere with the statistics used to estimate

 *          parameters for segmenting by words, but still retain text lines,

 *          the following image preprocessing can be done:

 *                Pix *pixt = pixMorphSequence(pixs, "c40.1", 0);

 *                Pix *pixf = pixSelectBySize(pixt, 0, 60, 8,

 *                                     L_SELECT_HEIGHT, L_SELECT_IF_LT, NULL);

 *                pixAnd(pixf, pixf, pixs);  // the filtered image

 *          The closing turns text lines into long blobs, but does not

 *          significantly increase their height.  But if there are many

 *          small connected components in a dense texture, this is likely

 *          to generate tall components that will be eliminated in pixf.

 * </pre>

 */

l_ok

pixGetWordsInTextlines(PIX     *pixs,

                       l_int32  minwidth,

                       l_int32  minheight,

                       l_int32  maxwidth,

                       l_int32  maxheight,

                       BOXA   **pboxad,

                       PIXA   **ppixad,

                       NUMA   **pnai)

{

BOXA    *boxa1, *boxad;

BOXAA   *baa;

NUMA    *nai;

NUMAA   *naa;

PIXA    *pixa1, *pixad;

PIXAA   *paa;

    if (!pboxad || !ppixad || !pnai)

        return ERROR_INT("&boxad, &pixad, &nai not all defined", __func__, 1);

    *pboxad = NULL;

    *ppixad = NULL;

    *pnai = NULL;

    if (!pixs)

        return ERROR_INT("pixs not defined", __func__, 1);

        /* Get the bounding boxes of the words from the word mask. */

    pixWordBoxesByDilation(pixs, minwidth, minheight, maxwidth, maxheight,

                           &boxa1, NULL, NULL);

        /* Generate a pixa of the word images */

    pixa1 = pixaCreateFromBoxa(pixs, boxa1, 0, 0, NULL);

        /* Sort the bounding boxes of these words by line.  We use the

         * index mapping to allow identical sorting of the pixa. */

    baa = boxaSort2d(boxa1, &naa, -1, -1, 4);

    paa = pixaSort2dByIndex(pixa1, naa, L_CLONE);

        /* Flatten the word paa */

    pixad = pixaaFlattenToPixa(paa, &nai, L_CLONE);

    boxad = pixaGetBoxa(pixad, L_COPY);

    *pnai = nai;

    *pboxad = boxad;

    *ppixad = pixad;

    pixaDestroy(&pixa1);

    boxaDestroy(&boxa1);

    boxaaDestroy(&baa);

    pixaaDestroy(&paa);

    numaaDestroy(&naa);

    return 0;

}

/*!

 * \brief   pixGetWordBoxesInTextlines()

 *

 * \param[in]    pixs        1 bpp, typ. 75 - 150 ppi

 * \param[in]    minwidth    of saved components; smaller are discarded

 * \param[in]    minheight   of saved components; smaller are discarded

 * \param[in]    maxwidth    of saved components; larger are discarded

 * \param[in]    maxheight   of saved components; larger are discarded

 * \param[out]   pboxad      word boxes sorted in textline line order

 * \param[out]   pnai        [optional] index of textline for each word

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) The input should be at a resolution of between 75 and 150 ppi.

 *      (2) This is a special version of pixGetWordsInTextlines(), that

 *          just finds the word boxes in line order, with a numa

 *          giving the textline index for each word.

 *          See pixGetWordsInTextlines() for more details.

 * </pre>

 */

l_ok

pixGetWordBoxesInTextlines(PIX     *pixs,

                           l_int32  minwidth,

                           l_int32  minheight,

                           l_int32  maxwidth,

                           l_int32  maxheight,

                           BOXA   **pboxad,

                           NUMA   **pnai)

{

BOXA    *boxa1;

BOXAA   *baa;

NUMA    *nai;

    if (pnai) *pnai = NULL;

    if (!pboxad)

        return ERROR_INT("&boxad and &nai not both defined", __func__, 1);

    *pboxad = NULL;

    if (!pixs)

        return ERROR_INT("pixs not defined", __func__, 1);

        /* Get the bounding boxes of the words from the word mask. */

    pixWordBoxesByDilation(pixs, minwidth, minheight, maxwidth, maxheight,

                           &boxa1, NULL, NULL);

        /* 2D sort the bounding boxes of these words. */

    baa = boxaSort2d(boxa1, NULL, 3, -5, 5);

        /* Flatten the boxaa, saving the boxa index for each box */

    *pboxad = boxaaFlattenToBoxa(baa, &nai, L_CLONE);

    if (pnai)

        *pnai = nai;

    else

        numaDestroy(&nai);

    boxaDestroy(&boxa1);

    boxaaDestroy(&baa);

    return 0;

}

/*------------------------------------------------------------------*

 *             Extract word and character bounding boxes            *

 *------------------------------------------------------------------*/

/*!

 * \brief   pixFindWordAndCharacterBoxes()

 *

 * \param[in]    pixs        2, 4, 8 or 32 bpp; colormap OK; typ. 300 ppi

 * \param[in]    boxs        [optional] region to select in pixs

 * \param[in]    thresh      binarization threshold (typ. 100 - 150)

 * \param[out]   pboxaw      return the word boxes

 * \param[out]   pboxaac     return the character boxes

 * \param[in]    debugdir    [optional] for debug images; use NULL to skip

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) If %boxs == NULL, the entire input image is used.

 *      (2) Having an input pix that is not 1bpp is necessary to reduce

 *          touching characters by using a low binarization threshold.

 *          Suggested thresholds are between 100 and 150.

 *      (3) The coordinates in the output boxes are global, with respect

 *          to the input image.

 * </pre>

 */

l_ok

pixFindWordAndCharacterBoxes(PIX         *pixs,

                             BOX         *boxs,

                             l_int32      thresh,

                             BOXA       **pboxaw,

                             BOXAA      **pboxaac,

                             const char  *debugdir)

{

char      *debugfile, *subdir;

l_int32    i, xs, ys, xb, yb, nb, loc;

l_float32  scalefact;

BOX       *box1, *box2;

BOXA      *boxa1, *boxa1a, *boxa2, *boxa3, *boxa4, *boxa5, *boxaw;

BOXAA     *boxaac;

PIX       *pix1, *pix2, *pix3, *pix3a, *pix4, *pix5;

    if (pboxaw) *pboxaw = NULL;

    if (pboxaac) *pboxaac = NULL;

    if (!pboxaw || !pboxaac)

        return ERROR_INT("&boxaw and &boxaac not defined", __func__, 1);

    if (!pixs || pixGetDepth(pixs) == 1)

        return ERROR_INT("pixs not defined or 1 bpp", __func__, 1);

    if (thresh > 150)

        L_WARNING("threshold is %d; may be too high\n", __func__, thresh);

    if (boxs) {

        if ((pix1 = pixClipRectangle(pixs, boxs, NULL)) == NULL)

            return ERROR_INT("pix1 not made", __func__, 1);

        boxGetGeometry(boxs, &xs, &ys, NULL, NULL);

    } else {

        pix1 = pixClone(pixs);

        xs = ys = 0;

    }

        /* Convert pix1 to 8 bpp gray if necessary */

    pix2 = pixConvertTo8(pix1, FALSE);

        /* To find the words and letters, work with 1 bpp images and use

         * a low threshold to reduce the number of touching characters. */

    pix3 = pixConvertTo1(pix2, thresh);

        /* Work at about 120 ppi to find the word bounding boxes. */

    pix3a = pixScaleToResolution(pix3, 120.0, 300.0, &scalefact);

        /* First find the words, removing the very small things like

         * dots over the 'i' that weren't included in word boxes. */

    pixGetWordBoxesInTextlines(pix3a, 1, 4, 150, 40, &boxa1a, NULL);

    boxa1 = boxaTransform(boxa1a, 0, 0, 1.0 / scalefact, 1.0 / scalefact);

    if (debugdir) {

        loc = 0;

        subdir = stringReplaceSubstr(debugdir, "/tmp/", "", &loc, NULL);

        lept_mkdir(subdir);

        LEPT_FREE(subdir);

        pix4 = pixConvertTo32(pix2);

        pixRenderBoxaArb(pix4, boxa1, 2, 255, 0, 0);

        debugfile = stringJoin(debugdir, "/words.png");

        pixWrite(debugfile, pix4, IFF_PNG);

        pixDestroy(&pix4);

        LEPT_FREE(debugfile);

    }

        /* Now find the letters at 300 ppi */

    nb = boxaGetCount(boxa1);

    boxaw = boxaCreate(nb);

    boxaac = boxaaCreate(nb);

    *pboxaw = boxaw;

    *pboxaac = boxaac;

    for (i = 0; i < nb; i++) {

        box1 = boxaGetBox(boxa1, i, L_COPY);

        boxGetGeometry(box1, &xb, &yb, NULL, NULL);

        pix4 = pixClipRectangle(pix3, box1, NULL);

            /* Join detached parts of characters vertically */

        pix5 = pixMorphSequence(pix4, "c1.10", 0);

            /* The connected components should mostly be characters */

        boxa2 = pixConnCompBB(pix5, 4);

            /* Remove very small pieces */

        boxa3 = boxaSelectBySize(boxa2, 2, 5, L_SELECT_IF_BOTH,

                                 L_SELECT_IF_GTE, NULL);

            /* Order left to right */

        boxa4 = boxaSort(boxa3, L_SORT_BY_X, L_SORT_INCREASING, NULL);

            /* Express locations with reference to the full input image */

        boxa5 = boxaTransform(boxa4, xs + xb, ys + yb, 1.0, 1.0);

        box2 = boxTransform(box1, xs, ys, 1.0, 1.0);

            /* Ignore any boxa with no boxes after size filtering */

        if (boxaGetCount(boxa5) > 0) {

            boxaAddBox(boxaw, box2, L_INSERT);

            boxaaAddBoxa(boxaac, boxa5, L_INSERT);

        } else {

            boxDestroy(&box2);

            boxaDestroy(&boxa5);

        }

        boxDestroy(&box1);

        pixDestroy(&pix4);

        pixDestroy(&pix5);

        boxaDestroy(&boxa2);

        boxaDestroy(&boxa3);

        boxaDestroy(&boxa4);

    }

    pixDestroy(&pix1);

    pixDestroy(&pix2);

    pixDestroy(&pix3);

    pixDestroy(&pix3a);

    boxaDestroy(&boxa1);

    boxaDestroy(&boxa1a);

    if (debugdir) {

        pix4 = pixConvertTo32(pixs);

        boxa2 = boxaaFlattenToBoxa(boxaac, NULL, L_COPY);

        pixRenderBoxaArb(pix4, boxa2, 2, 255, 0, 0);

        boxa3 = boxaAdjustSides(boxaw, -2, 2, -2, 2);

        pixRenderBoxaArb(pix4, boxa3, 2, 0, 255, 0);

        debugfile = stringJoin(debugdir, "/chars.png");

        pixWrite(debugfile, pix4, IFF_PNG);

        pixDestroy(&pix4);

        boxaDestroy(&boxa2);

        boxaDestroy(&boxa3);

        LEPT_FREE(debugfile);

    }

    return 0;

}

/*------------------------------------------------------------------*

 *           Use word bounding boxes to compare page images         *

 *------------------------------------------------------------------*/

/*!

 * \brief   boxaExtractSortedPattern()

 *

 * \param[in]    boxa    typ. of word bounding boxes, in textline order

 * \param[in]    na      index of textline for each box in boxa

 * \return  naa NUMAA, where each numa represents one textline,

 *                   or NULL on error

 *

 * <pre>

 * Notes:

 *      (1) The input is expected to come from pixGetWordBoxesInTextlines().

 *      (2) Each numa in the output consists of an average y coordinate

 *          of the first box in the textline, followed by pairs of

 *          x coordinates representing the left and right edges of each

 *          of the boxes in the textline.

 * </pre>

 */

NUMAA *

boxaExtractSortedPattern(BOXA  *boxa,

                         NUMA  *na)

{

l_int32  index, nbox, row, prevrow, x, y, w, h;

BOX     *box;

NUMA    *nad = NULL;

NUMAA   *naa;

    if (!boxa)

        return (NUMAA *)ERROR_PTR("boxa not defined", __func__, NULL);

    if (!na)

        return (NUMAA *)ERROR_PTR("na not defined", __func__, NULL);

    naa = numaaCreate(0);

    nbox = boxaGetCount(boxa);

    if (nbox == 0)

        return naa;

    prevrow = -1;

    for (index = 0; index < nbox; index++) {

        box = boxaGetBox(boxa, index, L_CLONE);

        numaGetIValue(na, index, &row);

        if (row > prevrow) {

            if (index > 0)

                numaaAddNuma(naa, nad, L_INSERT);

            nad = numaCreate(0);

            prevrow = row;

            boxGetGeometry(box, NULL, &y, NULL, &h);

            numaAddNumber(nad, y + h / 2);

        }

        boxGetGeometry(box, &x, NULL, &w, NULL);

        numaAddNumber(nad, x);

        numaAddNumber(nad, x + w - 1);

        boxDestroy(&box);

    }

    numaaAddNuma(naa, nad, L_INSERT);

    return naa;

}

/*!

 * \brief   numaaCompareImagesByBoxes()

 *

 * \param[in]    naa1       for image 1, formatted by boxaExtractSortedPattern()

 * \param[in]    naa2       for image 2, formatted by boxaExtractSortedPattern()

 * \param[in]    nperline   number of box regions to be used in each textline

 * \param[in]    nreq       number of complete row matches required

 * \param[in]    maxshiftx  max allowed x shift between two patterns, in pixels

 * \param[in]    maxshifty  max allowed y shift between two patterns, in pixels

 * \param[in]    delx       max allowed difference in x data, after alignment

 * \param[in]    dely       max allowed difference in y data, after alignment

 * \param[out]   psame      1 if %nreq row matches are found; 0 otherwise

 * \param[in]    debugflag  1 for debug output

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) Each input numaa describes a set of sorted bounding boxes

 *          (sorted by textline and, within each textline, from

 *          left to right) in the images from which they are derived.

 *          See boxaExtractSortedPattern() for a description of the data

 *          format in each of the input numaa.

 *      (2) This function does an alignment between the input

 *          descriptions of bounding boxes for two images. The

 *          input parameter %nperline specifies the number of boxes

 *          to consider in each line when testing for a match, and

 *          %nreq is the required number of lines that must be well-aligned

 *          to get a match.

 *      (3) Testing by alignment has 3 steps:

 *          (a) Generating the location of word bounding boxes from the

 *              images (prior to calling this function).

 *          (b) Listing all possible pairs of aligned rows, based on

 *              tolerances in horizontal and vertical positions of

 *              the boxes.  Specifically, all pairs of rows are enumerated

 *              whose first %nperline boxes can be brought into close

 *              alignment, based on the delx parameter for boxes in the

 *              line and within the overall the %maxshiftx and %maxshifty

 *              constraints.

 *          (c) Each pair, starting with the first, is used to search

 *              for a set of %nreq - 1 other pairs that can all be aligned

 *              with a difference in global translation of not more

 *              than (%delx, %dely).

 * </pre>

 */

l_ok

numaaCompareImagesByBoxes(NUMAA    *naa1,

                          NUMAA    *naa2,

                          l_int32   nperline,

                          l_int32   nreq,

                          l_int32   maxshiftx,

                          l_int32   maxshifty,

                          l_int32   delx,

                          l_int32   dely,

                          l_int32  *psame,

                          l_int32   debugflag)

{

l_int32   n1, n2, i, j, nbox, y1, y2, xl1, xl2;

l_int32   shiftx, shifty, match;

l_int32  *line1, *line2;  /* indicator for sufficient boxes in a line */

l_int32  *yloc1, *yloc2;  /* arrays of y value for first box in a line */

l_int32  *xleft1, *xleft2;  /* arrays of x value for left side of first box */

NUMA     *na1, *na2, *nai1, *nai2, *nasx, *nasy;

    if (!psame)

        return ERROR_INT("&same not defined", __func__, 1);

    *psame = 0;

    if (!naa1)

        return ERROR_INT("naa1 not defined", __func__, 1);

    if (!naa2)

        return ERROR_INT("naa2 not defined", __func__, 1);

    if (nperline < 1)

        return ERROR_INT("nperline < 1", __func__, 1);

    if (nreq < 1)

        return ERROR_INT("nreq < 1", __func__, 1);

    n1 = numaaGetCount(naa1);

    n2 = numaaGetCount(naa2);

    if (n1 < nreq || n2 < nreq)

        return 0;

        /* Find the lines in naa1 and naa2 with sufficient boxes.

         * Also, find the y-values for each of the lines, and the

         * LH x-values of the first box in each line. */

    line1 = (l_int32 *)LEPT_CALLOC(n1, sizeof(l_int32));

    line2 = (l_int32 *)LEPT_CALLOC(n2, sizeof(l_int32));

    yloc1 = (l_int32 *)LEPT_CALLOC(n1, sizeof(l_int32));

    yloc2 = (l_int32 *)LEPT_CALLOC(n2, sizeof(l_int32));

    xleft1 = (l_int32 *)LEPT_CALLOC(n1, sizeof(l_int32));

    xleft2 = (l_int32 *)LEPT_CALLOC(n2, sizeof(l_int32));

    if (!line1 || !line2 || !yloc1 || !yloc2 || !xleft1 || !xleft2) {

        LEPT_FREE(line1);

        LEPT_FREE(line2);

        LEPT_FREE(yloc1);

        LEPT_FREE(yloc2);

        LEPT_FREE(xleft1);

        LEPT_FREE(xleft2);

        return ERROR_INT("calloc failure for an array", __func__, 1);

    }

    for (i = 0; i < n1; i++) {

        na1 = numaaGetNuma(naa1, i, L_CLONE);

        numaGetIValue(na1, 0, yloc1 + i);

        numaGetIValue(na1, 1, xleft1 + i);

        nbox = (numaGetCount(na1) - 1) / 2;

        if (nbox >= nperline)

            line1[i] = 1;

        numaDestroy(&na1);

    }

    for (i = 0; i < n2; i++) {

        na2 = numaaGetNuma(naa2, i, L_CLONE);

        numaGetIValue(na2, 0, yloc2 + i);

        numaGetIValue(na2, 1, xleft2 + i);

        nbox = (numaGetCount(na2) - 1) / 2;

        if (nbox >= nperline)

            line2[i] = 1;

        numaDestroy(&na2);

    }

        /* Enumerate all possible line matches.  A 'possible' line

         * match is one where the x and y shifts for the first box

         * in each line are within the maxshiftx and maxshifty

         * constraints, and the left and right sides of the remaining

         * (nperline - 1) successive boxes are within delx of each other.

         * The result is a set of four numas giving parameters of

         * each set of matching lines. */

    nai1 = numaCreate(0);  /* line index 1 of match */

    nai2 = numaCreate(0);  /* line index 2 of match */

    nasx = numaCreate(0);  /* shiftx for match */

    nasy = numaCreate(0);  /* shifty for match */

    for (i = 0; i < n1; i++) {

        if (line1[i] == 0) continue;

        y1 = yloc1[i];

        xl1 = xleft1[i];

        na1 = numaaGetNuma(naa1, i, L_CLONE);

        for (j = 0; j < n2; j++) {

            if (line2[j] == 0) continue;

            y2 = yloc2[j];

            if (L_ABS(y1 - y2) > maxshifty) continue;

            xl2 = xleft2[j];

            if (L_ABS(xl1 - xl2) > maxshiftx) continue;

            shiftx = xl1 - xl2;  /* shift to add to x2 values */

            shifty = y1 - y2;  /* shift to add to y2 values */

            na2 = numaaGetNuma(naa2, j, L_CLONE);

                /* Now check if 'nperline' boxes in the two lines match */

            match = testLineAlignmentX(na1, na2, shiftx, delx, nperline);

            if (match) {

                numaAddNumber(nai1, i);

                numaAddNumber(nai2, j);

                numaAddNumber(nasx, shiftx);

                numaAddNumber(nasy, shifty);

            }

            numaDestroy(&na2);

        }

        numaDestroy(&na1);

    }

        /* Determine if there are a sufficient number of mutually

         * aligned matches.  Mutually aligned matches place an additional

         * constraint on the 'possible' matches, where the relative

         * shifts must not exceed the (delx, dely) distances. */

    countAlignedMatches(nai1, nai2, nasx, nasy, n1, n2, delx, dely,

                        nreq, psame, debugflag);

    LEPT_FREE(line1);

    LEPT_FREE(line2);

    LEPT_FREE(yloc1);

    LEPT_FREE(yloc2);

    LEPT_FREE(xleft1);

    LEPT_FREE(xleft2);

    numaDestroy(&nai1);

    numaDestroy(&nai2);

    numaDestroy(&nasx);

    numaDestroy(&nasy);

    return 0;

}

static l_int32

testLineAlignmentX(NUMA    *na1,

                   NUMA    *na2,

                   l_int32  shiftx,

                   l_int32  delx,

                   l_int32  nperline)

{

l_int32  i, xl1, xr1, xl2, xr2, diffl, diffr;

    if (!na1)

        return ERROR_INT("na1 not defined", __func__, 1);

    if (!na2)

        return ERROR_INT("na2 not defined", __func__, 1);

    for (i = 0; i < nperline; i++) {

        numaGetIValue(na1, i + 1, &xl1);

        numaGetIValue(na1, i + 2, &xr1);

        numaGetIValue(na2, i + 1, &xl2);

        numaGetIValue(na2, i + 2, &xr2);

        diffl = L_ABS(xl1 - xl2 - shiftx);

        diffr = L_ABS(xr1 - xr2 - shiftx);

        if (diffl > delx || diffr > delx)

            return 0;

    }

    return 1;

}

/*

 * \brief   countAlignedMatches()

 *

 * \param[in]    nai1, nai2   numas of row pairs for matches

 * \param[in]    nasx, nasy   numas of x and y shifts for the matches

 * \param[in]    n1, n2       number of rows in images 1 and 2

 * \param[in]    delx, dely   allowed difference in shifts of the match,

 *                            compared to the reference match

 * \param[in]    nre1         number of required aligned matches

 * \param[out]   psame        return 1 if %nreq row matches are found;

 *                            0 otherwise

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) This takes 4 input arrays giving parameters of all the

 *          line matches.  It looks for the maximum set of aligned

 *          matches (matches with approximately the same overall shifts)

 *          that do not use rows from either image more than once.

 * </pre>

 */

static l_ok

countAlignedMatches(NUMA     *nai1,

                    NUMA     *nai2,

                    NUMA     *nasx,

                    NUMA     *nasy,

                    l_int32   n1,

                    l_int32   n2,

                    l_int32   delx,

                    l_int32   dely,

                    l_int32   nreq,

                    l_int32  *psame,

                    l_int32   debugflag)

{

l_int32   i, j, nm, shiftx, shifty, nmatch, diffx, diffy;

l_int32  *ia1, *ia2, *iasx, *iasy, *index1, *index2;

    if (!nai1 || !nai2 || !nasx || !nasy)

        return ERROR_INT("4 input numas not defined", __func__, 1);

    if (!psame)

        return ERROR_INT("&same not defined", __func__, 1);

    *psame = 0;

        /* Check for sufficient aligned matches, doing a double iteration

         * over the set of raw matches.  The row index arrays

         * are used to verify that the same rows in either image

         * are not used in more than one match.  Whenever there

         * is a match that is properly aligned, those rows are

         * marked in the index arrays.  */

    nm = numaGetCount(nai1);  /* number of matches */

    if (nm < nreq)

        return 0;

    ia1 = numaGetIArray(nai1);

    ia2 = numaGetIArray(nai2);

    iasx = numaGetIArray(nasx);

    iasy = numaGetIArray(nasy);

    index1 = (l_int32 *)LEPT_CALLOC(n1, sizeof(l_int32));  /* watch rows */

    index2 = (l_int32 *)LEPT_CALLOC(n2, sizeof(l_int32));

    if (!index1 || !index2)

        return ERROR_INT("calloc fail for array", __func__, 1);