C++ pixGetWpl函数代码示例

/*!
 *  pixThresholdToValue()
 *
 *      Input:  pixd (<optional>; if not null, must be equal to pixs)
 *              pixs (8, 16, 32 bpp)
 *              threshval
 *              setval
 *      Return: pixd always
 *
 *  Notes:
 *    - operation can be in-place (pixs == pixd) or to a new pixd
 *    - if setval > threshval, sets pixels with a value >= threshval to setval
 *    - if setval < threshval, sets pixels with a value <= threshval to setval
 *    - if setval == threshval, no-op
 */
PIX *
pixThresholdToValue(PIX      *pixd,
                    PIX      *pixs,
                    l_int32   threshval,
                    l_int32   setval)
{
l_int32    w, h, d, wpld;
l_uint32  *datad;

    PROCNAME("pixThresholdToValue");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, pixd);
    d = pixGetDepth(pixs);
    if (d != 8 && d != 16 && d != 32)
        return (PIX *)ERROR_PTR("pixs not 8, 16 or 32 bpp", procName, pixd);
    if (pixd && (pixs != pixd))
        return (PIX *)ERROR_PTR("pixd exists and is not pixs", procName, pixd);
    if (threshval < 0 || setval < 0)
        return (PIX *)ERROR_PTR("threshval & setval not < 0", procName, pixd);
    if (d == 8 && setval > 255)
        return (PIX *)ERROR_PTR("setval > 255 for 8 bpp", procName, pixd);
    if (d == 16 && setval > 0xffff)
        return (PIX *)ERROR_PTR("setval > 0xffff for 16 bpp", procName, pixd);

    if (!pixd)
        pixd = pixCopy(NULL, pixs);
    if (setval == threshval) {
        L_WARNING("setval == threshval; no operation", procName);
        return pixd;
    }

    datad = pixGetData(pixd);
    pixGetDimensions(pixd, &w, &h, NULL);
    wpld = pixGetWpl(pixd);

    thresholdToValueLow(datad, w, h, d, wpld, threshval, setval);
    return pixd;
}

// Sends each pixel as hex value like html, e.g. #00FF00 for green.
void ScrollView::Transfer32bppImage(Pix* image) {
#ifdef HAVE_LIBLEPT
  int ppL = pixGetWidth(image);
  int h = pixGetHeight(image);
  int wpl = pixGetWpl(image);
  int transfer_size= ppL * 7 + 2;
  char* pixel_data = new char[transfer_size];
  for (int y = 0; y < h; ++y) {
    l_uint32* data = pixGetData(image) + y*wpl;
    for (int x = 0; x < ppL; ++x, ++data) {
      snprintf(&pixel_data[x*7], 7, "#%.2x%.2x%.2x",
               GET_DATA_BYTE(data, COLOR_RED),
               GET_DATA_BYTE(data, COLOR_GREEN),
               GET_DATA_BYTE(data, COLOR_BLUE));
    }
    pixel_data[transfer_size - 2] = '\n';
    pixel_data[transfer_size - 1] = '\0';
    SendRawMessage(pixel_data);
  }
  delete[] pixel_data;
#endif
}

/*!
 *  pixSetPadBits()
 *
 *      Input:  pix (1, 2, 4, 8, 16, 32 bpp)
 *              val  (0 or 1)
 *      Return: 0 if OK; 1 on error
 *
 *  Notes:
 *      (1) The pad bits are the bits that expand each scanline to a
 *          multiple of 32 bits.  They are usually not used in
 *          image processing operations.  When boundary conditions
 *          are important, as in seedfill, they must be set properly.
 *      (2) This sets the value of the pad bits (if any) in the last
 *          32-bit word in each scanline.
 *      (3) For 32 bpp pix, there are no pad bits, so this is a no-op.
 */
LEPTONICA_REAL_EXPORT l_int32
pixSetPadBits(PIX     *pix,
              l_int32  val)
{
l_int32    i, w, h, d, wpl, endbits, fullwords;
l_uint32   mask;
l_uint32  *data, *pword;

    PROCNAME("pixSetPadBits");

    if (!pix)
        return ERROR_INT("pix not defined", procName, 1);

    pixGetDimensions(pix, &w, &h, &d);
    if (d == 32)  /* no padding exists for 32 bpp */
        return 0;  

    data = pixGetData(pix);
    wpl = pixGetWpl(pix);
    endbits = 32 - ((w * d) % 32);
    if (endbits == 32)  /* no partial word */
        return 0;
    fullwords = w * d / 32;

    mask = rmask32[endbits];
    if (val == 0)
        mask = ~mask;

    for (i = 0; i < h; i++) {
        pword = data + i * wpl + fullwords;
        if (val == 0) /* clear */
            *pword = *pword & mask;
        else  /* set */
            *pword = *pword | mask;
    }

    return 0;
}

// NOTE: Opposite to SetImage for raw images, SetImage for Pix clones its
// input, so the source pix may be pixDestroyed immediately after.
void ImageThresholder::SetImage(const Pix* pix) {
  image_data_ = NULL;
  if (pix_ != NULL)
    pixDestroy(&pix_);
  Pix* src = const_cast<Pix*>(pix);
  int depth;
  pixGetDimensions(src, &image_width_, &image_height_, &depth);
  // Convert the image as necessary so it is one of binary, plain RGB, or
  // 8 bit with no colormap.
  if (depth > 1 && depth < 8) {
    pix_ = pixConvertTo8(src, false);
  } else if (pixGetColormap(src)) {
    pix_ = pixRemoveColormap(src, REMOVE_CMAP_BASED_ON_SRC);
  } else {
    pix_ = pixClone(src);
  }
  depth = pixGetDepth(pix_);
  image_bytespp_ = depth / 8;
  image_bytespl_ = pixGetWpl(pix_) * sizeof(l_uint32);
  scale_ = 1;
  estimated_res_ = yres_ = pixGetYRes(src);
  Init();
}

/*!
 *  pixMultConstantGray()
 *
 *      Input:  pixs (8, 16 or 32 bpp)
 *              val  (>= 0.0; amount to multiply by each pixel)
 *      Return: 0 if OK, 1 on error
 *
 *  Notes:
 *      (1) In-place operation; val must be >= 0.
 *      (2) No clipping for 32 bpp.
 *      (3) For 8 and 16 bpp, the result is clipped to 0xff and 0xffff, rsp.
 */
l_int32
pixMultConstantGray(PIX       *pixs,
                    l_float32  val)
{
l_int32    w, h, d, wpl;
l_uint32  *data;

    PROCNAME("pixMultConstantGray");

    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 8 && d != 16 && d != 32)
        return ERROR_INT("pixs not 8, 16 or 32 bpp", procName, 1);
    if (val < 0.0)
        return ERROR_INT("val < 0.0", procName, 1);

    data = pixGetData(pixs);
    wpl = pixGetWpl(pixs);
    multConstantGrayLow(data, w, h, d, wpl, val);

    return 0;
}

/*!
 *  pixMultConstAccumulate() 
 *
 *      Input:  pixs (32 bpp)
 *              factor
 *              offset (same as used for initialization)
 *      Return: 0 if OK; 1 on error
 *
 *  Notes:
 *      (1) The offset must be >= 0 and should not exceed 0x40000000.
 *      (2) This multiplies each pixel, relative to offset, by the input factor
 *      (3) The result is returned with the offset back in place.
 */
l_int32
pixMultConstAccumulate(PIX       *pixs,
                       l_float32  factor,
                       l_uint32   offset)
{
l_int32    w, h, wpl;
l_uint32  *data;

    PROCNAME("pixMultConstAccumulate");

    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    if (pixGetDepth(pixs) != 32)
        return ERROR_INT("pixs not 32 bpp", procName, 1);
    if (offset > 0x40000000)
        offset = 0x40000000;

    pixGetDimensions(pixs, &w, &h, NULL);
    data = pixGetData(pixs);
    wpl = pixGetWpl(pixs);

    multConstAccumulateLow(data, w, h, wpl, factor, offset);
    return 0;
}

//.........这里部分代码省略.........
        if ((1 << i) >= ncolor) {
            gif_ncolor = (1 << i);
            break;
        }
    }
    if (gif_ncolor < 1) {
        pixDestroy(&pixd);
        return ERROR_INT("number of colors is invalid", procName, 1);
    }

        /* Save the cmap colors in a gif_cmap */
    if ((gif_cmap = GifMakeMapObject(gif_ncolor, NULL)) == NULL) {
        pixDestroy(&pixd);
        return ERROR_INT("failed to create GIF color map", procName, 1);
    }
    for (i = 0; i < gif_ncolor; i++) {
        rval = gval = bval = 0;
        if (ncolor > 0) {
            if (pixcmapGetColor(cmap, i, &rval, &gval, &bval) != 0) {
                pixDestroy(&pixd);
                GifFreeMapObject(gif_cmap);
                return ERROR_INT("failed to get color from color map",
                                 procName, 1);
            }
            ncolor--;
        }
        gif_cmap->Colors[i].Red = rval;
        gif_cmap->Colors[i].Green = gval;
        gif_cmap->Colors[i].Blue = bval;
    }

    pixGetDimensions(pixd, &w, &h, NULL);
    if (EGifPutScreenDesc(gif, w, h, gif_cmap->BitsPerPixel, 0, gif_cmap)
        != GIF_OK) {
        pixDestroy(&pixd);
        GifFreeMapObject(gif_cmap);
        return ERROR_INT("failed to write screen description", procName, 1);
    }
    GifFreeMapObject(gif_cmap); /* not needed after this point */

    if (EGifPutImageDesc(gif, 0, 0, w, h, FALSE, NULL) != GIF_OK) {
        pixDestroy(&pixd);
        return ERROR_INT("failed to image screen description", procName, 1);
    }

    data = pixGetData(pixd);
    wpl = pixGetWpl(pixd);
    if (d != 1 && d != 2 && d != 4 && d != 8) {
        pixDestroy(&pixd);
        return ERROR_INT("image depth is not in {1, 2, 4, 8}", procName, 1);
    }

    if ((gif_line = (GifByteType *)LEPT_CALLOC(sizeof(GifByteType), w))
        == NULL) {
        pixDestroy(&pixd);
        return ERROR_INT("mem alloc fail for data line", procName, 1);
    }

    for (i = 0; i < h; i++) {
        line = data + i * wpl;
            /* Gif's way of setting the raster line up for compression */
        for (j = 0; j < w; j++) {
            switch(d)
            {
            case 8:
                gif_line[j] = GET_DATA_BYTE(line, j);
                break;
            case 4:
                gif_line[j] = GET_DATA_QBIT(line, j);
                break;
            case 2:
                gif_line[j] = GET_DATA_DIBIT(line, j);
                break;
            case 1:
                gif_line[j] = GET_DATA_BIT(line, j);
                break;
            }
        }

            /* Compress and save the line */
        if (EGifPutLine(gif, gif_line, w) != GIF_OK) {
            LEPT_FREE(gif_line);
            pixDestroy(&pixd);
            return ERROR_INT("failed to write data line into GIF", procName, 1);
        }
    }

        /* Write a text comment.  This must be placed after writing the
         * data (!!)  Note that because libgif does not provide a function
         * for reading comments from file, you will need another way
         * to read comments. */
    if ((text = pixGetText(pix)) != NULL) {
        if (EGifPutComment(gif, text) != GIF_OK)
            L_WARNING("gif comment not written\n", procName);
    }

    LEPT_FREE(gif_line);
    pixDestroy(&pixd);
    return 0;
}

int main(int    argc,
         char **argv)
{
l_int32       i, j, k, w, h, w2, w4, w8, w16, w32, wpl;
l_int32       count1, count2, count3;
l_uint32      val32, val1, val2;
l_uint32     *data1, *line1, *data2, *line2;
void        **lines1, **linet1, **linet2;
PIX          *pixs, *pix1, *pix2;
L_REGPARAMS  *rp;

    if (regTestSetup(argc, argv, &rp))
        return 1;

    pixs = pixRead("feyn-fract.tif");
    pixGetDimensions(pixs, &w, &h, NULL);
    data1 = pixGetData(pixs);
    wpl = pixGetWpl(pixs);
    lines1 = pixGetLinePtrs(pixs, NULL);

        /* Get timing for the 3 different methods */
    startTimer();
    for (k = 0; k < 10; k++) {
        count1 = 0;
        for (i = 0; i < h; i++) {
            for (j = 0; j < w; j++) {
                if (GET_DATA_BIT(lines1[i], j))
                    count1++;
            }
        }
    }
    fprintf(stderr, "Time with line ptrs     = %5.3f sec, count1 = %d\n",
            stopTimer(), count1);

    startTimer();
    for (k = 0; k < 10; k++) {
        count2 = 0;
        for (i = 0; i < h; i++) {
            line1 = data1 + i * wpl;
            for (j = 0; j < w; j++) {
               if (l_getDataBit(line1, j))
                    count2++;
            }
        }
    }
    fprintf(stderr, "Time with l_get*        = %5.3f sec, count2 = %d\n",
            stopTimer(), count2);

    startTimer();
    for (k = 0; k < 10; k++) {
        count3 = 0;
        for (i = 0; i < h; i++) {
            for (j = 0; j < w; j++) {
                pixGetPixel(pixs, j, i, &val32);
                count3 += val32;
            }
        }
    }
    fprintf(stderr, "Time with pixGetPixel() = %5.3f sec, count3 = %d\n",
            stopTimer(), count3);

    pix1 = pixCreateTemplate(pixs);
    linet1 = pixGetLinePtrs(pix1, NULL);
    pix2 = pixCreateTemplate(pixs);
    data2 = pixGetData(pix2);
    linet2 = pixGetLinePtrs(pix2, NULL);

        /* ------------------------------------------------- */
        /*           Test different methods for 1 bpp        */
        /* ------------------------------------------------- */
    count1 = 0;
    for (i = 0; i < h; i++) {
        for (j = 0; j < w; j++) {
            val1 = GET_DATA_BIT(lines1[i], j);
            count1 += val1;
            if (val1) SET_DATA_BIT(linet1[i], j);
        }
    }
    count2 = 0;
    for (i = 0; i < h; i++) {
        line1 = data1 + i * wpl;
        line2 = data2 + i * wpl;
        for (j = 0; j < w; j++) {
            val2 = l_getDataBit(line1, j);
            count2 += val2;
            if (val2) l_setDataBit(line2, j);
        }
    }
    CompareResults(pixs, pix1, pix2, count1, count2, "1 bpp", rp);

        /* ------------------------------------------------- */
        /*           Test different methods for 2 bpp        */
        /* ------------------------------------------------- */
    count1 = 0;
    w2 = w / 2;
    for (i = 0; i < h; i++) {
        for (j = 0; j < w2; j++) {
            val1 = GET_DATA_DIBIT(lines1[i], j);
            count1 += val1;
            val1 += 0xbbbbbbbc;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    else if (spp == 2) {
        d = 2 * bit_depth;
        L_WARNING("there shouldn't be 2 spp!", procName);
    }
    else  /* spp == 3 (rgb), spp == 4 (rgba) */
        d = 4 * bit_depth;

        /* Remove if/when this is implemented for all bit_depths */
    if (spp == 3 && bit_depth != 8) {
        fprintf(stderr, "Help: spp = 3 and depth = %d != 8\n!!", bit_depth);
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        return (PIX *)ERROR_PTR("not implemented for this depth",
            procName, NULL);
    }

    if (color_type == PNG_COLOR_TYPE_PALETTE ||
        color_type == PNG_COLOR_MASK_PALETTE) {   /* generate a colormap */
        png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette);
        cmap = pixcmapCreate(d);  /* spp == 1 */
        for (cindex = 0; cindex < num_palette; cindex++) {
            rval = palette[cindex].red;
            gval = palette[cindex].green;
            bval = palette[cindex].blue;
            pixcmapAddColor(cmap, rval, gval, bval);
        }
    }
    else
        cmap = NULL;

    if ((pix = pixCreate(w, h, d)) == NULL) {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        return (PIX *)ERROR_PTR("pix not made", procName, NULL);
    }
    wpl = pixGetWpl(pix);
    data = pixGetData(pix);
    pixSetColormap(pix, cmap);

    if (spp == 1) {   /* copy straight from buffer to pix */
        for (i = 0; i < h; i++) {
            line = data + i * wpl;
            rowptr = row_pointers[i];
            for (j = 0; j < rowbytes; j++) {
                SET_DATA_BYTE(line, j, rowptr[j]);
            }
        }
    }
    else  {   /* spp == 3 or spp == 4 */
        for (i = 0; i < h; i++) {
            ppixel = data + i * wpl;
            rowptr = row_pointers[i];
            for (j = k = 0; j < w; j++) {
                SET_DATA_BYTE(ppixel, COLOR_RED, rowptr[k++]);
                SET_DATA_BYTE(ppixel, COLOR_GREEN, rowptr[k++]);
                SET_DATA_BYTE(ppixel, COLOR_BLUE, rowptr[k++]);
                if (spp == 4)
                    SET_DATA_BYTE(ppixel, L_ALPHA_CHANNEL, rowptr[k++]);
                ppixel++;
            }
        }
    }

#if  DEBUG
    if (cmap) {
        for (i = 0; i < 16; i++) {
            fprintf(stderr, "[%d] = %d\n", i,
                   ((l_uint8 *)(cmap->array))[i]);

/*!
 * \brief   pixSeedfill8BB()
 *
 * \param[in]    pixs 1 bpp
 * \param[in]    stack for holding fillsegs
 * \param[in]    x,y   location of seed pixel
 * \return  box or NULL on error.
 *
 * <pre>
 * Notes:
 *      (1) This is Paul Heckbert's stack-based 8-cc seedfill algorithm.
 *      (2) This operates on the input 1 bpp pix to remove the fg seed
 *          pixel, at (x,y), and all pixels that are 8-connected to it.
 *          The seed pixel at (x,y) must initially be ON.
 *      (3) Returns the bounding box of the erased 8-cc component.
 *      (4) Reference: see Paul Heckbert's stack-based seed fill algorithm
 *          in "Graphic Gems", ed. Andrew Glassner, Academic
 *          Press, 1990.  The algorithm description is given
 *          on pp. 275-277; working C code is on pp. 721-722.)
 *          The code here follows Heckbert's closely, except
 *          the leak checks are changed for 8 connectivity.
 *          See comments on pixSeedfill4BB() for more details.
 * </pre>
 */
BOX *
pixSeedfill8BB(PIX      *pixs,
               L_STACK  *stack,
               l_int32   x,
               l_int32   y)
{
    l_int32    w, h, xstart, wpl, x1, x2, dy;
    l_int32    xmax, ymax;
    l_int32    minx, maxx, miny, maxy;  /* for bounding box of this c.c. */
    l_uint32  *data, *line;
    BOX       *box;

    PROCNAME("pixSeedfill8BB");

    if (!pixs || pixGetDepth(pixs) != 1)
        return (BOX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
    if (!stack)
        return (BOX *)ERROR_PTR("stack not defined", procName, NULL);
    if (!stack->auxstack)
        stack->auxstack = lstackCreate(0);

    pixGetDimensions(pixs, &w, &h, NULL);
    xmax = w - 1;
    ymax = h - 1;
    data = pixGetData(pixs);
    wpl = pixGetWpl(pixs);
    line = data + y * wpl;

    /* Check pix value of seed; must be ON */
    if (x < 0 || x > xmax || y < 0 || y > ymax || (GET_DATA_BIT(line, x) == 0))
        return NULL;

    /* Init stack to seed:
     * Must first init b.b. values to prevent valgrind from complaining;
     * then init b.b. boundaries correctly to seed.  */
    minx = miny = 100000;
    maxx = maxy = 0;
    pushFillsegBB(stack, x, x, y, 1, ymax, &minx, &maxx, &miny, &maxy);
    pushFillsegBB(stack, x, x, y + 1, -1, ymax, &minx, &maxx, &miny, &maxy);
    minx = maxx = x;
    miny = maxy = y;

    while (lstackGetCount(stack) > 0) {
        /* Pop segment off stack and fill a neighboring scan line */
        popFillseg(stack, &x1, &x2, &y, &dy);
        line = data + y * wpl;

        /* A segment of scanline y - dy for x1 <= x <= x2 was
         * previously filled.  We now explore adjacent pixels
         * in scan line y.  There are three regions: to the
         * left of x1, between x1 and x2, and to the right of x2.
         * These regions are handled differently.  Leaks are
         * possible expansions beyond the previous segment and
         * going back in the -dy direction.  These can happen
         * for x < x1 and for x > x2.  Any "leak" segments
         * are plugged with a push in the -dy (opposite) direction.
         * And any segments found anywhere are always extended
         * in the +dy direction.  */
        for (x = x1 - 1; x >= 0 && (GET_DATA_BIT(line, x) == 1); x--)
            CLEAR_DATA_BIT(line,x);
        if (x >= x1 - 1)  /* pix at x1 - 1 was off and was not cleared */
            goto skip;
        xstart = x + 1;
        if (xstart < x1)   /* leak on left? */
            pushFillsegBB(stack, xstart, x1 - 1, y, -dy,
                          ymax, &minx, &maxx, &miny, &maxy);

        x = x1;
        do {
            for (; x <= xmax && (GET_DATA_BIT(line, x) == 1); x++)
                CLEAR_DATA_BIT(line, x);
            pushFillsegBB(stack, xstart, x - 1, y, dy,
                          ymax, &minx, &maxx, &miny, &maxy);
            if (x > x2)   /* leak on right? */
                pushFillsegBB(stack, x2 + 1, x - 1, y, -dy,
                              ymax, &minx, &maxx, &miny, &maxy);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        return (PIX *)ERROR_PTR("invalid imagebytes", procName, NULL);
    cmapbytes = offset - BMP_FHBYTES - BMP_IHBYTES;
    cmapEntries = cmapbytes / sizeof(RGBA_QUAD);
    if (cmapEntries < 0 || cmapEntries == 1)
        return (PIX *)ERROR_PTR("invalid: cmap size < 0 or 1", procName, NULL);
    if (cmapEntries > L_MAX_ALLOWED_NUM_COLORS)
        return (PIX *)ERROR_PTR("invalid cmap: too large", procName,NULL);
    if (size != 1LL * offset + 1LL * fdatabpl * height)
        return (PIX *)ERROR_PTR("size incommensurate with image data",
                                procName,NULL);

        /* Handle the colormap */
    cmapBuf = NULL;
    if (cmapEntries > 0) {
        if ((cmapBuf = (l_uint8 *)LEPT_CALLOC(cmapEntries, sizeof(RGBA_QUAD)))
                 == NULL)
            return (PIX *)ERROR_PTR("cmapBuf alloc fail", procName, NULL );

            /* Read the colormap entry data from bmp. The RGBA_QUAD colormap
             * entries are used for both bmp and leptonica colormaps. */
        memcpy(cmapBuf, cdata + BMP_FHBYTES + BMP_IHBYTES,
               sizeof(RGBA_QUAD) * cmapEntries);
    }

        /* Make a 32 bpp pix if depth is 24 bpp */
    d = (depth == 24) ? 32 : depth;
    if ((pix = pixCreate(width, height, d)) == NULL) {
        LEPT_FREE(cmapBuf);
        return (PIX *)ERROR_PTR( "pix not made", procName, NULL);
    }
    pixSetXRes(pix, (l_int32)((l_float32)xres / 39.37 + 0.5));  /* to ppi */
    pixSetYRes(pix, (l_int32)((l_float32)yres / 39.37 + 0.5));  /* to ppi */
    pixSetInputFormat(pix, IFF_BMP);
    pixWpl = pixGetWpl(pix);
    pixBpl = 4 * pixWpl;

        /* Convert the bmp colormap to a pixcmap */
    cmap = NULL;
    if (cmapEntries > 0) {  /* import the colormap to the pix cmap */
        cmap = pixcmapCreate(L_MIN(d, 8));
        LEPT_FREE(cmap->array);  /* remove generated cmap array */
        cmap->array  = (void *)cmapBuf;  /* and replace */
        cmap->n = L_MIN(cmapEntries, 256);
        for (i = 0; i < cmap->n; i++)   /* set all colors opaque */
            pixcmapSetAlpha (cmap, i, 255);
    }
    pixSetColormap(pix, cmap);

        /* Acquire the image data.  Image origin for bmp is at lower right. */
    fdata = (l_uint8 *)cdata + offset;  /* start of the bmp image data */
    pixdata = pixGetData(pix);
    if (depth != 24) {  /* typ. 1 or 8 bpp */
        data = (l_uint8 *)pixdata + pixBpl * (height - 1);
        for (i = 0; i < height; i++) {
            memcpy(data, fdata, fdatabpl);
            fdata += fdatabpl;
            data -= pixBpl;
        }
    } else {  /*  24 bpp file; 32 bpp pix
             *  Note: for bmp files, pel[0] is blue, pel[1] is green,
             *  and pel[2] is red.  This is opposite to the storage
             *  in the pix, which puts the red pixel in the 0 byte,
             *  the green in the 1 byte and the blue in the 2 byte.
             *  Note also that all words are endian flipped after
             *  assignment on L_LITTLE_ENDIAN platforms.
             *

/*!
 *  pixSauvolaGetThreshold()
 *
 *      Input:  pixm (8 bpp grayscale; not colormapped)
 *              pixms (32 bpp)
 *              factor (factor for reducing threshold due to variance; >= 0)
 *              &pixsd (<optional return> local standard deviation)
 *      Return: pixd (8 bpp, sauvola threshold values), or null on error
 *
 *  Notes:
 *      (1) The Sauvola threshold is determined from the formula:
 *            t = m * (1 - k * (1 - s / 128))
 *          where:
 *            t = local threshold
 *            m = local mean
 *            k = @factor (>= 0)   [ typ. 0.35 ]
 *            s = local standard deviation, which is maximized at
 *                127.5 when half the samples are 0 and half are 255.
 *      (2) See pixSauvolaBinarize() for other details.
 *      (3) Important definitions and relations for computing averages:
 *            v == pixel value
 *            E(p) == expected value of p == average of p over some pixel set
 *            S(v) == square of v == v * v
 *            mv == E(v) == expected pixel value == mean value
 *            ms == E(S(v)) == expected square of pixel values
 *               == mean square value
 *            var == variance == expected square of deviation from mean
 *                == E(S(v - mv)) = E(S(v) - 2 * S(v * mv) + S(mv))
 *                                = E(S(v)) - S(mv)
 *                                = ms - mv * mv
 *            s == standard deviation = sqrt(var)
 *          So for evaluating the standard deviation in the Sauvola
 *          threshold, we take
 *            s = sqrt(ms - mv * mv)
 */
PIX *
pixSauvolaGetThreshold(PIX       *pixm,
                       PIX       *pixms,
                       l_float32  factor,
                       PIX      **ppixsd)
{
l_int32     i, j, w, h, tabsize, wplm, wplms, wplsd, wpld, usetab;
l_int32     mv, ms, var, thresh;
l_uint32   *datam, *datams, *datasd, *datad;
l_uint32   *linem, *linems, *linesd, *lined;
l_float32   sd;
l_float32  *tab;  /* of 2^16 square roots */
PIX        *pixsd, *pixd;

    PROCNAME("pixSauvolaGetThreshold");

    if (ppixsd) *ppixsd = NULL;
    if (!pixm || pixGetDepth(pixm) != 8)
        return (PIX *)ERROR_PTR("pixm undefined or not 8 bpp", procName, NULL);
    if (pixGetColormap(pixm))
        return (PIX *)ERROR_PTR("pixm is colormapped", procName, NULL);
    if (!pixms || pixGetDepth(pixms) != 32)
        return (PIX *)ERROR_PTR("pixms undefined or not 32 bpp",
                                procName, NULL);
    if (factor < 0.0)
        return (PIX *)ERROR_PTR("factor must be >= 0", procName, NULL);

        /* Only make a table of 2^16 square roots if there
         * are enough pixels to justify it. */
    pixGetDimensions(pixm, &w, &h, NULL);
    usetab = (w * h > 100000) ? 1 : 0;
    if (usetab) {
        tabsize = 1 << 16;
        tab = (l_float32 *)CALLOC(tabsize, sizeof(l_float32));
        for (i = 0; i < tabsize; i++)
            tab[i] = (l_float32)sqrt((l_float64)i);
    }

    pixd = pixCreate(w, h, 8);
    if (ppixsd) {
        pixsd = pixCreate(w, h, 8);
        *ppixsd = pixsd;
    }
    datam = pixGetData(pixm);
    datams = pixGetData(pixms);
    if (ppixsd) datasd = pixGetData(pixsd);
    datad = pixGetData(pixd);
    wplm = pixGetWpl(pixm);
    wplms = pixGetWpl(pixms);
    if (ppixsd) wplsd = pixGetWpl(pixsd);
    wpld = pixGetWpl(pixd);
    for (i = 0; i < h; i++) {
        linem = datam + i * wplm;
        linems = datams + i * wplms;
        if (ppixsd) linesd = datasd + i * wplsd;
        lined = datad + i * wpld;
        for (j = 0; j < w; j++) {
            mv = GET_DATA_BYTE(linem, j);
            ms = linems[j];
            var = ms - mv * mv;
            if (usetab)
                sd = tab[var];
            else
                sd = (l_float32)sqrt((l_float32)var);
            if (ppixsd) SET_DATA_BYTE(linesd, j, (l_int32)sd);
//.........这里部分代码省略.........

/*!
 *  pixFindLargestRectangle()
 *
 *      Input:  pixs  (1 bpp)
 *              polarity (0 within background, 1 within foreground)
 *              &box (<return> largest rectangle, either by area or
 *                    by perimeter)
 *              debugflag (1 to output image with rectangle drawn on it)
 *      Return: 0 if OK, 1 on error
 *
 *  Notes:
 *      (1) Why is this here?  This is a simple and elegant solution to
 *          a problem in computational geometry that at first appears
 *          quite difficult: what is the largest rectangle that can
 *          be placed in the image, covering only pixels of one polarity
 *          (bg or fg)?  The solution is O(n), where n is the number
 *          of pixels in the image, and it requires nothing more than
 *          using a simple recursion relation in a single sweep of the image.
 *      (2) In a sweep from UL to LR with left-to-right being the fast
 *          direction, calculate the largest white rectangle at (x, y),
 *          using previously calculated values at pixels #1 and #2:
 *             #1:    (x, y - 1)
 *             #2:    (x - 1, y)
 *          We also need the most recent "black" pixels that were seen
 *          in the current row and column.
 *          Consider the largest area.  There are only two possibilities:
 *             (a)  Min(w(1), horizdist) * (h(1) + 1)
 *             (b)  Min(h(2), vertdist) * (w(2) + 1)
 *          where
 *             horizdist: the distance from the rightmost "black" pixel seen
 *                        in the current row across to the current pixel
 *             vertdist: the distance from the lowest "black" pixel seen
 *                       in the current column down to the current pixel
 *          and we choose the Max of (a) and (b).
 *      (3) To convince yourself that these recursion relations are correct,
 *          it helps to draw the maximum rectangles at #1 and #2.
 *          Then for #1, you try to extend the rectangle down one line,
 *          so that the height is h(1) + 1.  Do you get the full
 *          width of #1, w(1)?  It depends on where the black pixels are
 *          in the current row.  You know the final width is bounded by w(1)
 *          and w(2) + 1, but the actual value depends on the distribution
 *          of black pixels in the current row that are at a distance
 *          from the current pixel that is between these limits.
 *          We call that value "horizdist", and the area is then given
 *          by the expression (a) above.  Using similar reasoning for #2,
 *          where you attempt to extend the rectangle to the right
 *          by 1 pixel, you arrive at (b).  The largest rectangle is
 *          then found by taking the Max.
 */
l_int32
pixFindLargestRectangle(PIX         *pixs,
                        l_int32      polarity,
                        BOX        **pbox,
                        const char  *debugfile)
{
l_int32    i, j, w, h, d, wpls, val;
l_int32    wp, hp, w1, w2, h1, h2, wmin, hmin, area1, area2;
l_int32    xmax, ymax;  /* LR corner of the largest rectangle */
l_int32    maxarea, wmax, hmax, vertdist, horizdist, prevfg;
l_int32   *lowestfg;
l_uint32  *datas, *lines;
l_uint32 **linew, **lineh;
BOX       *box;
PIX       *pixw, *pixh;  /* keeps the width and height for the largest */
                         /* rectangles whose LR corner is located there. */

    PROCNAME("pixFindLargestRectangle");

    if (!pbox)
        return ERROR_INT("&box not defined", procName, 1);
    *pbox = NULL;
    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 1)
        return ERROR_INT("pixs not 1 bpp", procName, 1);
    if (polarity != 0 && polarity != 1)
        return ERROR_INT("invalid polarity", procName, 1);

        /* Initialize lowest "fg" seen so far for each column */
    lowestfg = (l_int32 *)CALLOC(w, sizeof(l_int32));
    for (i = 0; i < w; i++)
        lowestfg[i] = -1;

        /* The combination (val ^ polarity) is the color for which we
         * are searching for the maximum rectangle.  For polarity == 0,
         * we search in the bg (white). */
    pixw = pixCreate(w, h, 32);  /* stores width */
    pixh = pixCreate(w, h, 32);  /* stores height */
    linew = (l_uint32 **)pixGetLinePtrs(pixw, NULL);
    lineh = (l_uint32 **)pixGetLinePtrs(pixh, NULL);
    datas = pixGetData(pixs);
    wpls = pixGetWpl(pixs);
    maxarea = xmax = ymax = wmax = hmax = 0;
    for (i = 0; i < h; i++) {
        lines = datas + i * wpls;
        prevfg = -1;
        for (j = 0; j < w; j++) {
            val = GET_DATA_BIT(lines, j);
            if ((val ^ polarity) == 0) {  /* bg (0) if polarity == 0, etc. */
//.........这里部分代码省略.........

/**********************************************************************
 * SetBlobStrokeWidth
 *
 * Set the horizontal and vertical stroke widths in the blob.
 **********************************************************************/
void SetBlobStrokeWidth(Pix* pix, BLOBNBOX* blob) {
  // Cut the blob rectangle into a Pix.
  int pix_height = pixGetHeight(pix);
  const TBOX& box = blob->bounding_box();
  int width = box.width();
  int height = box.height();
  Box* blob_pix_box = boxCreate(box.left(), pix_height - box.top(),
                                width, height);
  Pix* pix_blob = pixClipRectangle(pix, blob_pix_box, nullptr);
  boxDestroy(&blob_pix_box);
  Pix* dist_pix = pixDistanceFunction(pix_blob, 4, 8, L_BOUNDARY_BG);
  pixDestroy(&pix_blob);
  // Compute the stroke widths.
  uint32_t* data = pixGetData(dist_pix);
  int wpl = pixGetWpl(dist_pix);
  // Horizontal width of stroke.
  STATS h_stats(0, width + 1);
  for (int y = 0; y < height; ++y) {
    uint32_t* pixels = data + y*wpl;
    int prev_pixel = 0;
    int pixel = GET_DATA_BYTE(pixels, 0);
    for (int x = 1; x < width; ++x) {
      int next_pixel = GET_DATA_BYTE(pixels, x);
      // We are looking for a pixel that is equal to its vertical neighbours,
      // yet greater than its left neighbour.
      if (prev_pixel < pixel &&
          (y == 0 || pixel == GET_DATA_BYTE(pixels - wpl, x - 1)) &&
          (y == height - 1 || pixel == GET_DATA_BYTE(pixels + wpl, x - 1))) {
        if (pixel > next_pixel) {
          // Single local max, so an odd width.
          h_stats.add(pixel * 2 - 1, 1);
        } else if (pixel == next_pixel && x + 1 < width &&
                 pixel > GET_DATA_BYTE(pixels, x + 1)) {
          // Double local max, so an even width.
          h_stats.add(pixel * 2, 1);
        }
      }
      prev_pixel = pixel;
      pixel = next_pixel;
    }
  }
  // Vertical width of stroke.
  STATS v_stats(0, height + 1);
  for (int x = 0; x < width; ++x) {
    int prev_pixel = 0;
    int pixel = GET_DATA_BYTE(data, x);
    for (int y = 1; y < height; ++y) {
      uint32_t* pixels = data + y*wpl;
      int next_pixel = GET_DATA_BYTE(pixels, x);
      // We are looking for a pixel that is equal to its horizontal neighbours,
      // yet greater than its upper neighbour.
      if (prev_pixel < pixel &&
          (x == 0 || pixel == GET_DATA_BYTE(pixels - wpl, x - 1)) &&
          (x == width - 1 || pixel == GET_DATA_BYTE(pixels - wpl, x + 1))) {
        if (pixel > next_pixel) {
          // Single local max, so an odd width.
          v_stats.add(pixel * 2 - 1, 1);
        } else if (pixel == next_pixel && y + 1 < height &&
                 pixel > GET_DATA_BYTE(pixels + wpl, x)) {
          // Double local max, so an even width.
          v_stats.add(pixel * 2, 1);
        }
      }
      prev_pixel = pixel;
      pixel = next_pixel;
    }
  }
  pixDestroy(&dist_pix);
  // Store the horizontal and vertical width in the blob, keeping both
  // widths if there is enough information, otherwse only the one with
  // the most samples.
  // If there are insufficient samples, store zero, rather than using
  // 2*area/perimeter, as the numbers that gives do not match the numbers
  // from the distance method.
  if (h_stats.get_total() >= (width + height) / 4) {
    blob->set_horz_stroke_width(h_stats.ile(0.5f));
    if (v_stats.get_total() >= (width + height) / 4)
      blob->set_vert_stroke_width(v_stats.ile(0.5f));
    else
      blob->set_vert_stroke_width(0.0f);
  } else {
    if (v_stats.get_total() >= (width + height) / 4 ||
        v_stats.get_total() > h_stats.get_total()) {
      blob->set_horz_stroke_width(0.0f);
      blob->set_vert_stroke_width(v_stats.ile(0.5f));
    } else {
      blob->set_horz_stroke_width(h_stats.get_total() > 2 ? h_stats.ile(0.5f)
                                                          : 0.0f);
      blob->set_vert_stroke_width(0.0f);
    }
  }
}

/*!
 *  pixApplyHorizontalDisparity()
 *
 *      Input:  pixs (1, 8 or 32 bpp)
 *              fpix (horizontal disparity array)
 *              extraw (extra width added to pixd)
 *      Return: pixd (modified by fpix), or null on error
 *
 *  Notes:
 *      (1) This applies the horizontal disparity array to the specified
 *          image.
 */
PIX *
pixApplyHorizontalDisparity(PIX     *pixs,
                            FPIX    *fpix,
                            l_int32  extraw)
{
l_int32     i, j, w, h, d, wd, fw, fh, wpls, wpld, wplf, jsrc, val8;
l_uint32   *datas, *lines, *datad, *lined;
l_float32  *dataf, *linef;
PIX        *pixd;

    PROCNAME("pixApplyHorizontalDisparity");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    if (!fpix)
        return (PIX *)ERROR_PTR("fpix not defined", procName, NULL);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 1 && d != 8 && d != 32)
        return (PIX *)ERROR_PTR("pix not 1, 8 or 32 bpp", procName, NULL);
    fpixGetDimensions(fpix, &fw, &fh);
    if (fw < w + extraw || fh < h) {
        fprintf(stderr, "fw = %d, w = %d, fh = %d, h = %d\n", fw, w, fh, h);
        return (PIX *)ERROR_PTR("invalid fpix size", procName, NULL);
    }

    wd = w + extraw;
    pixd = pixCreate(wd, h, d);
    datas = pixGetData(pixs);
    datad = pixGetData(pixd);
    dataf = fpixGetData(fpix);
    wpls = pixGetWpl(pixs);
    wpld = pixGetWpl(pixd);
    wplf = fpixGetWpl(fpix);
    if (d == 1) {
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + i * wpld;
            linef = dataf + i * wplf;
            for (j = 0; j < wd; j++) {
                jsrc = (l_int32)(j - linef[j] + 0.5);
                if (jsrc < 0) jsrc = 0;
                if (jsrc > w - 1) jsrc = w - 1;
                if (GET_DATA_BIT(lines, jsrc))
                    SET_DATA_BIT(lined, j);
            }
        }
    }
    else if (d == 8) {
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + i * wpld;
            linef = dataf + i * wplf;
            for (j = 0; j < wd; j++) {
                jsrc = (l_int32)(j - linef[j] + 0.5);
                if (jsrc < 0) jsrc = 0;
                if (jsrc > w - 1) jsrc = w - 1;
                val8 = GET_DATA_BYTE(lines, jsrc);
                SET_DATA_BYTE(lined, j, val8);
            }
        }
    }
    else {  /* d == 32 */
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + i * wpld;
            linef = dataf + i * wplf;
            for (j = 0; j < wd; j++) {
                jsrc = (l_int32)(j - linef[j] + 0.5);
                if (jsrc < 0) jsrc = 0;
                if (jsrc > w - 1) jsrc = w - 1;
                lined[j] = lines[jsrc];
            }
        }
    }

    return pixd;
}