pranavjha/text-detector

/*====================================================================*
 -  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.
 *====================================================================*/

/*
 * cleanpdf.c
 *
 *    This program takes as input pdf files that have been constructed
 *    from poorly compressed images -- typically images that have been
 *    scanned in grayscale or color but should be rendered in black
 *    and white (1 bpp).  It cleans and compresses them, and generates
 *    a pdf composed of tiff-g4 compressed images.
 *
 *     Syntax:  cleanpdf basedir threshold resolution
 *
 *    The basedir is a directory where the input pdf files are located.
 *    The program will operate on every file in this directory with
 *    the ".pdf" extension.
 *
 *    The input threshold should be somewhere in the range [130 - 190].
 *    The result is typically not very sensitive to the value, because
 *    internally we use a pixel mapping that is adapted to the local
 *    background before thresholding to binarize the image.
 *
 *    The resolution should be the scanned resolution.  This is typically
 *    300 ppi, which for an 8.5 x 11 page would be 2550 x 3300 pixels.
 *
 *    Whenever possible, the images have been deskewed.
 *
 *    N.B.  This requires pdfimages.  For non-unix systems, this requires
 *    installation of the cygwin Poppler package:
 *       https://cygwin.com/cgi-bin2/package-cat.cgi?file=x86/poppler/
 *              poppler-0.26.5-1
 */

#ifdef _WIN32
  #ifdef _MSC_VER
  #include <direct.h>
  #else
  #include <io.h>
  #endif  /* _MSC_VER */
#endif  /* _WIN32 */

#include "string.h"
#include <sys/stat.h>
#include <sys/types.h>
#include "allheaders.h"

l_int32 main(int    argc,
             char **argv)
{
char         buf[256];
char        *basedir, *fname, *tail, *basename, *imagedir;
l_int32      thresh, res, i, n, ret;
PIX         *pixs, *pix1, *pix2, *pix3, *pix4;
SARRAY      *sa;
static char  mainName[] = "cleanpdf";

    if (argc != 4)
        return ERROR_INT(
            "Syntax: cleanpdf basedir threshold resolution", mainName, 1);

    basedir = argv[1];
    thresh = atoi(argv[2]);
    res = atoi(argv[3]);

#if 1
        /* Get the names of the pdf files */
    if ((sa = getSortedPathnamesInDirectory(basedir, "pdf", 0, 0)) == NULL)
        return ERROR_INT("files not found", mainName, 1);
    sarrayWriteStream(stderr, sa);
    n = sarrayGetCount(sa);
#endif

        /* Rasterize: pdfimages -f fname root */
    imagedir = stringJoin(basedir, "/image");
#if 1
#ifndef _WIN32
    mkdir(imagedir, 0777);
#else
    _mkdir(imagedir);
#endif  /* _WIN32 */
    for (i = 0; i < n; i++) {
        fname = sarrayGetString(sa, i, L_NOCOPY);
        splitPathAtDirectory(fname, NULL, &tail);
        splitPathAtExtension(tail, &basename, NULL);
        snprintf(buf, sizeof(buf), "pdfimages -j %s %s/%s",
                 fname, imagedir, basename);
        FREE(tail);
        FREE(basename);
        fprintf(stderr, "%s\n", buf);
        ret = system(buf);   /* pdfimages -j */
    }
    sarrayDestroy(&sa);
#endif

#if 1
        /* Clean, deskew and compress */
    sa = getSortedPathnamesInDirectory(imagedir, NULL, 0, 0);
    sarrayWriteStream(stderr, sa);
    n = sarrayGetCount(sa);
    for (i = 0; i < n; i++) {
        fname = sarrayGetString(sa, i, L_NOCOPY);
        pixs = pixRead(fname);
        pix1 = pixConvertTo8(pixs, FALSE);
        pix2 = pixFindSkewAndDeskew(pix1, 2, NULL, NULL);
        pix3 = pixBackgroundNormSimple(pix2, NULL, NULL);
        pixGammaTRC(pix3, pix3, 2.0, 50, 250);
        pix4 = pixThresholdToBinary(pix3, thresh);
        if (0) pixRotate180(pix4, pix4);  /* remove this usually!! */
        splitPathAtDirectory(fname, NULL, &tail);
        splitPathAtExtension(tail, &basename, NULL);
        snprintf(buf, sizeof(buf), "%s/%s.tif", imagedir, basename);
        fprintf(stderr, "%s\n", buf);
        pixWrite(buf, pix4, IFF_TIFF_G4);
        pixDestroy(&pixs);
        pixDestroy(&pix1);
        pixDestroy(&pix2);
        pixDestroy(&pix3);
        pixDestroy(&pix4);
        FREE(tail);
        FREE(basename);
    }
    sarrayDestroy(&sa);
#endif

#if 1
        /* Generate the pdf */
    convertFilesToPdf(imagedir, "tif", res, 1.0, L_G4_ENCODE, 0, NULL,
                      "/tmp/output.pdf");
#endif

    return 0;
}