finditalic.c

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

/*
 * finditalic.c
 *
 *      l_int32   pixItalicWords()
 *
 *    Locate italic words.  This is an example of the use of
 *    hit-miss binary morphology with binary reconstruction
 *    (filling from a seed into a mask).
 *
 *    To see how this works, run with prog/italic.png.
 */

#include "allheaders.h"

    /* ---------------------------------------------------------------  *
     * These hit-miss sels match the slanted edge of italic characters  *
     * ---------------------------------------------------------------  */
static const char *str_ital1 = "   o x"
                               "      "
                               "      "
                               "      "
                               "  o x "
                               "      "
                               "  C   "
                               "      "
                               " o x  "
                               "      "
                               "      "
                               "      "
                               "o x   ";

static const char *str_ital2 = "   o x"
                               "      "
                               "      "
                               "  o x "
                               "  C   "
                               "      "
                               " o x  "
                               "      "
                               "      "
                               "o x   ";

    /* ------------------------------------------------------------- *
     * This sel removes noise that is not oriented as a slanted edge *
     * ------------------------------------------------------------- */
static const char *str_ital3 = " x"
                               "Cx"
                               "x "
                               "x ";

l_ok
pixItalicWords(PIX     *pixs,
               BOXA    *boxaw,
               PIX     *pixw,
               BOXA   **pboxa,
               l_int32  debugflag)
{
char     opstring[32];
l_int32  size;
BOXA    *boxa;
PIX     *pixsd, *pixm, *pixd;
SEL     *sel_ital1, *sel_ital2, *sel_ital3;

    PROCNAME("pixItalicWords");

    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    if (!pboxa)
        return ERROR_INT("&boxa not defined", procName, 1);
    if (boxaw && pixw)
        return ERROR_INT("both boxaw and pixw are defined", procName, 1);

    sel_ital1 = selCreateFromString(str_ital1, 13, 6, NULL);
    sel_ital2 = selCreateFromString(str_ital2, 10, 6, NULL);
    sel_ital3 = selCreateFromString(str_ital3, 4, 2, NULL);

        /* Make the italic seed: extract with HMT; remove noise.
         * The noise removal close/open is important to exclude
         * situations where a small slanted line accidentally
         * matches sel_ital1. */
    pixsd = pixHMT(NULL, pixs, sel_ital1);
    pixClose(pixsd, pixsd, sel_ital3);
    pixOpen(pixsd, pixsd, sel_ital3);

        /* Make the word mask.  Use input boxes or mask if given. */
    size = 0;  /* init */
    if (boxaw) {
        pixm = pixCreateTemplate(pixs);
        pixMaskBoxa(pixm, pixm, boxaw, L_SET_PIXELS);
    } else if (pixw) {
        pixm = pixClone(pixw);
    } else {
        pixWordMaskByDilation(pixs, NULL, &size, NULL);
        L_INFO("dilation size = %d\n", procName, size);
        snprintf(opstring, sizeof(opstring), "d1.5 + c%d.1", size);
        pixm = pixMorphSequence(pixs, opstring, 0);
    }

        /* Binary reconstruction to fill in those word mask
         * components for which there is at least one seed pixel. */
    pixd = pixSeedfillBinary(NULL, pixsd, pixm, 8);
    boxa = pixConnComp(pixd, NULL, 8);
    *pboxa = boxa;

    if (debugflag) {
            /* Save results at at 2x reduction */
        lept_mkdir("lept/ital");
        l_int32  res, upper;
        BOXA  *boxat;
        GPLOT *gplot;
        NUMA  *na;
        PIXA  *pad;
        PIX   *pix1, *pix2, *pix3;
        pad = pixaCreate(0);
        boxat = pixConnComp(pixm, NULL, 8);
        boxaWriteDebug("/tmp/lept/ital/ital.ba", boxat);
        pixSaveTiledOutline(pixs, pad, 0.5, 1, 20, 2, 32);  /* orig */
        pixSaveTiledOutline(pixsd, pad, 0.5, 1, 20, 2, 0);  /* seed */
        pix1 = pixConvertTo32(pixm);
        pixRenderBoxaArb(pix1, boxat, 3, 255, 0, 0);
        pixSaveTiledOutline(pix1, pad, 0.5, 1, 20, 2, 0);  /* mask + outline */
        pixDestroy(&pix1);
        pixSaveTiledOutline(pixd, pad, 0.5, 1, 20, 2, 0);  /* ital mask */
        pix1 = pixConvertTo32(pixs);
        pixRenderBoxaArb(pix1, boxa, 3, 255, 0, 0);
        pixSaveTiledOutline(pix1, pad, 0.5, 1, 20, 2, 0);  /* orig + outline */
        pixDestroy(&pix1);
        pix1 = pixCreateTemplate(pixs);
        pix2 = pixSetBlackOrWhiteBoxa(pix1, boxa, L_SET_BLACK);
        pixCopy(pix1, pixs);
        pix3 = pixDilateBrick(NULL, pixs, 3, 3);
        pixCombineMasked(pix1, pix3, pix2);
        pixSaveTiledOutline(pix1, pad, 0.5, 1, 20, 2, 0);  /* ital bolded */
        pixDestroy(&pix1);
        pixDestroy(&pix2);
        pixDestroy(&pix3);
        pix2 = pixaDisplay(pad, 0, 0);
        pixWriteDebug("/tmp/lept/ital/ital.png", pix2, IFF_PNG);
        pixDestroy(&pix2);

            /* Assuming the image represents 6 inches of actual page width,
             * the pixs resolution is approximately
             *    (width of pixs in pixels) / 6
             * and the images have been saved at half this resolution.   */
        res = pixGetWidth(pixs) / 12;
        L_INFO("resolution = %d\n", procName, res);
        l_pdfSetDateAndVersion(0);
        pixaConvertToPdf(pad, res, 1.0, L_FLATE_ENCODE, 75, "Italic Finder",
                         "/tmp/lept/ital/ital.pdf");
        l_pdfSetDateAndVersion(1);
        pixaDestroy(&pad);
        boxaDestroy(&boxat);

            /* Plot histogram of horizontal white run sizes.  A small
             * initial vertical dilation removes most runs that are neither
             * inter-character nor inter-word.  The larger first peak is
             * from inter-character runs, and the smaller second peak is
             * from inter-word runs. */
        pix1 = pixDilateBrick(NULL, pixs, 1, 15);
        upper = L_MAX(30, 3 * size);
        na = pixRunHistogramMorph(pix1, L_RUN_OFF, L_HORIZ, upper);
        pixDestroy(&pix1);
        gplot = gplotCreate("/tmp/lept/ital/runhisto", GPLOT_PNG,
                "Histogram of horizontal runs of white pixels, vs length",
                "run length", "number of runs");
        gplotAddPlot(gplot, NULL, na, GPLOT_LINES, "plot1");
        gplotMakeOutput(gplot);
        gplotDestroy(&gplot);
        numaDestroy(&na);
    }

    selDestroy(&sel_ital1);
    selDestroy(&sel_ital2);
    selDestroy(&sel_ital3);
    pixDestroy(&pixsd);
    pixDestroy(&pixm);
    pixDestroy(&pixd);
    return 0;
}