// Degrade the pix as if by a print/copy/scan cycle with exposure > 0
// corresponding to darkening on the copier and <0 lighter and 0 not copied.
// Exposures in [-2,2] are most useful, with -3 and 3 being extreme.
// If rotation is NULL, rotation is skipped. If *rotation is non-zero, the pix
// is rotated by *rotation else it is randomly rotated and *rotation is
// modified.
// HOW IT WORKS:
// Most of the process is really dictated by the fact that the minimum
// available convolution is 3X3, which is too big really to simulate a
// good quality print/scan process. (2X2 would be better.)
// 1 pixel wide inputs are heavily smeared by the 3X3 convolution, making the
// images generally biased to being too light, so most of the work is to make
// them darker. 3 levels of thickening/darkening are achieved with 2 dilations,
// (using a greyscale erosion) one heavy (by being before convolution) and one
// light (after convolution).
// With no dilation, after covolution, the images are so light that a heavy
// constant offset is required to make the 0 image look reasonable. A simple
// constant offset multiple of exposure to undo this value is enough to achieve
// all the required lightening. This gives the advantage that exposure level 1
// with a single dilation gives a good impression of the broken-yet-too-dark
// problem that is often seen in scans.
// A small random rotation gives some varying greyscale values on the edges,
// and some random salt and pepper noise on top helps to realistically jaggy-up
// the edges.
// Finally a greyscale ramp provides a continuum of effects between exposure
// levels.
Pix* DegradeImage(Pix* input, int exposure, float* rotation) {
  Pix* pix = pixConvertTo8(input, false);
  pixDestroy(&input);
  input = pix;
  int width = pixGetWidth(input);
  int height = pixGetHeight(input);
  if (exposure >= 2) {
    // An erosion simulates the spreading darkening of a dark copy.
    // This is backwards to binary morphology,
    // see http://www.leptonica.com/grayscale-morphology.html
    pix = input;
    input = pixErodeGray(pix, 3, 3);
    pixDestroy(&pix);
  }
  // A convolution is essential to any mode as no scanner produces an
  // image as sharp as the electronic image.
  pix = pixBlockconv(input, 1, 1);
  pixDestroy(&input);
  // A small random rotation helps to make the edges jaggy in a realistic way.
  if (rotation != NULL) {
    float radians_clockwise;
    if (*rotation) {
      radians_clockwise = *rotation;
    } else {
      radians_clockwise = (2.0*rand_r(&random_seed)/RAND_MAX - 1.0) *
          kRotationRange;
    }

    input = pixRotate(pix, radians_clockwise,
                      L_ROTATE_AREA_MAP, L_BRING_IN_WHITE,
                      0, 0);
    // Rotate the boxes to match.
    *rotation = radians_clockwise;
    pixDestroy(&pix);
  } else {
    input = pix;
  }

  if (exposure >= 3 || exposure == 1) {
    // Erosion after the convolution is not as heavy as before, so it is
    // good for level 1 and in addition as a level 3.
    // This is backwards to binary morphology,
    // see http://www.leptonica.com/grayscale-morphology.html
    pix = input;
    input = pixErodeGray(pix, 3, 3);
    pixDestroy(&pix);
  }
  // The convolution really needed to be 2x2 to be realistic enough, but
  // we only have 3x3, so we have to bias the image darker or lose thin
  // strokes.
  int erosion_offset = 0;
  // For light and 0 exposure, there is no dilation, so compensate for the
  // convolution with a big darkening bias which is undone for lighter
  // exposures.
  if (exposure <= 0)
    erosion_offset = -3 * kExposureFactor;
  // Add in a general offset of the greyscales for the exposure level so
  // a threshold of 128 gives a reasonable binary result.
  erosion_offset -= exposure * kExposureFactor;
  // Add a gradual fade over the page and a small amount of salt and pepper
  // noise to simulate noise in the sensor/paper fibres and varying
  // illumination.
  l_uint32* data = pixGetData(input);
  for (int y = 0; y < height; ++y) {
    for (int x = 0; x < width; ++x) {
      int pixel = GET_DATA_BYTE(data, x);
      pixel += rand_r(&random_seed) % (kSaltnPepper*2 + 1) - kSaltnPepper;
      if (height + width > kMinRampSize)
        pixel -= (2*x + y) * 32 / (height + width);
      pixel += erosion_offset;
      if (pixel < 0)
        pixel = 0;
      if (pixel > 255)
        pixel = 255;
//.........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);
        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,
//.........这里部分代码省略.........

/*!
 *  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.........

//.........这里部分代码省略.........

            /* 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.
             *
             *  We can then make these assignments for little endians:
             *      SET_DATA_BYTE(pword, 1, pel[0]);      blue
             *      SET_DATA_BYTE(pword, 2, pel[1]);      green
             *      SET_DATA_BYTE(pword, 3, pel[2]);      red
             *  This looks like:
             *          3  (R)     2  (G)        1  (B)        0
             *      |-----------|------------|-----------|-----------|
             *  and after byte flipping:
             *           3          2  (B)     1  (G)        0  (R)
             *      |-----------|------------|-----------|-----------|
             *
             *  For big endians we set:
             *      SET_DATA_BYTE(pword, 2, pel[0]);      blue
             *      SET_DATA_BYTE(pword, 1, pel[1]);      green
             *      SET_DATA_BYTE(pword, 0, pel[2]);      red
             *  This looks like:
             *          0  (R)     1  (G)        2  (B)        3

/*!
 *  pixSetSelectCmap()
 *
 *      Input:  pixs (1, 2, 4 or 8 bpp, with colormap)
 *              box (<optional> region to set color; can be NULL)
 *              sindex (colormap index of pixels to be changed)
 *              rval, gval, bval (new color to paint)
 *      Return: 0 if OK, 1 on error
 *
 *  Note:
 *      (1) This is an in-place operation.
 *      (2) It sets all pixels in region that have the color specified
 *          by the colormap index 'sindex' to the new color.
 *      (3) sindex must be in the existing colormap; otherwise an
 *          error is returned.
 *      (4) If the new color exists in the colormap, it is used;
 *          otherwise, it is added to the colormap.  If it cannot be
 *          added because the colormap is full, an error is returned.
 *      (5) If box is NULL, applies function to the entire image; otherwise,
 *          clips the operation to the intersection of the box and pix.
 *      (6) An DC of use would be to set to a specific color all
 *          the light (background) pixels within a certain region of
 *          a 3-level 2 bpp image, while leaving light pixels outside
 *          this region unchanged.
 */
l_int32
pixSetSelectCmap(PIX     *pixs,
                 BOX     *box,
                 l_int32  sindex,
                 l_int32  rval,
                 l_int32  gval,
                 l_int32  bval)
{
l_int32    i, j, w, h, d, n, x1, y1, x2, y2, bw, bh, val, wpls;
l_int32    index;  /* of new color to be set */
l_uint32  *lines, *datas;
PIXCMAP   *cmap;

    PROCNAME("pixSetSelectCmap");

    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    if ((cmap = pixGetColormap(pixs)) == NULL)
        return ERROR_INT("no colormap", procName, 1);
    d = pixGetDepth(pixs);
    if (d != 1 && d != 2 && d != 4 && d != 8)
        return ERROR_INT("depth not in {1,2,4,8}", procName, 1);

        /* Add new color if necessary; get index of this color in cmap */
    n = pixcmapGetCount(cmap);
    if (sindex >= n)
        return ERROR_INT("sindex too large; no cmap entry", procName, 1);
    if (pixcmapGetIndex(cmap, rval, gval, bval, &index)) { /* not found */
        if (pixcmapAddColor(cmap, rval, gval, bval))
            return ERROR_INT("error adding cmap entry", procName, 1);
        else
            index = n;  /* we've added one color */
    }

        /* Determine the region of substitution */
    pixGetDimensions(pixs, &w, &h, NULL);
    if (!box) {
        x1 = y1 = 0;
        x2 = w;
        y2 = h;
    } else {
        boxGetGeometry(box, &x1, &y1, &bw, &bh);
        x2 = x1 + bw - 1;
        y2 = y1 + bh - 1;
    }

        /* Replace pixel value sindex by index in the region */
    datas = pixGetData(pixs);
    wpls = pixGetWpl(pixs);
    for (i = y1; i <= y2; i++) {
        if (i < 0 || i >= h)  /* clip */
            continue;
        lines = datas + i * wpls;
        for (j = x1; j <= x2; j++) {
            if (j < 0 || j >= w)  /* clip */
                continue;
            switch (d) {
            case 1:
                val = GET_DATA_BIT(lines, j);
                if (val == sindex) {
                    if (index == 0)
                        CLEAR_DATA_BIT(lines, j);
                    else
                        SET_DATA_BIT(lines, j);
                }
                break;
            case 2:
                val = GET_DATA_DIBIT(lines, j);
                if (val == sindex)
                    SET_DATA_DIBIT(lines, j, index);
                break;
            case 4:
                val = GET_DATA_QBIT(lines, j);
                if (val == sindex)
                    SET_DATA_QBIT(lines, j, index);
//.........这里部分代码省略.........

// Adds sub-pixel resolution EdgeOffsets for the outline if the supplied
// pix is 8-bit. Does nothing otherwise.
// Operation: Consider the following near-horizontal line:
// _________
//          |________
//                   |________
// At *every* position along this line, the gradient direction will be close
// to vertical. Extrapoaltion/interpolation of the position of the threshold
// that was used to binarize the image gives a more precise vertical position
// for each horizontal step, and the conflict in step direction and gradient
// direction can be used to ignore the vertical steps.
void C_OUTLINE::ComputeEdgeOffsets(int threshold, Pix* pix) {
  if (pixGetDepth(pix) != 8) return;
  const l_uint32* data = pixGetData(pix);
  int wpl = pixGetWpl(pix);
  int width = pixGetWidth(pix);
  int height = pixGetHeight(pix);
  bool negative = flag(COUT_INVERSE);
  delete [] offsets;
  offsets = new EdgeOffset[stepcount];
  ICOORD pos = start;
  ICOORD prev_gradient;
  ComputeGradient(data, wpl, pos.x(), height - pos.y(), width, height,
                  &prev_gradient);
  for (int s = 0; s < stepcount; ++s) {
    ICOORD step_vec = step(s);
    TPOINT pt1(pos);
    pos += step_vec;
    TPOINT pt2(pos);
    ICOORD next_gradient;
    ComputeGradient(data, wpl, pos.x(), height - pos.y(), width, height,
                    &next_gradient);
    // Use the sum of the prev and next as the working gradient.
    ICOORD gradient = prev_gradient + next_gradient;
    // best_diff will be manipulated to be always positive.
    int best_diff = 0;
    // offset will be the extrapolation of the location of the greyscale
    // threshold from the edge with the largest difference, relative to the
    // location of the binary edge.
    int offset = 0;
    if (pt1.y == pt2.y && abs(gradient.y()) * 2 >= abs(gradient.x())) {
      // Horizontal step. diff_sign == 1 indicates black above.
      int diff_sign = (pt1.x > pt2.x) == negative ? 1 : -1;
      int x = MIN(pt1.x, pt2.x);
      int y = height - pt1.y;
      int best_sum = 0;
      int best_y = y;
      EvaluateVerticalDiff(data, wpl, diff_sign, x, y, height,
                           &best_diff, &best_sum, &best_y);
      // Find the strongest edge.
      int test_y = y;
      do {
        ++test_y;
      } while (EvaluateVerticalDiff(data, wpl, diff_sign, x, test_y, height,
                                    &best_diff, &best_sum, &best_y));
      test_y = y;
      do {
        --test_y;
      } while (EvaluateVerticalDiff(data, wpl, diff_sign, x, test_y, height,
                                    &best_diff, &best_sum, &best_y));
      offset = diff_sign * (best_sum / 2 - threshold) +
          (y - best_y) * best_diff;
    } else if (pt1.x == pt2.x && abs(gradient.x()) * 2 >= abs(gradient.y())) {
      // Vertical step. diff_sign == 1 indicates black on the left.
      int diff_sign = (pt1.y > pt2.y) == negative ? 1 : -1;
      int x = pt1.x;
      int y = height - MAX(pt1.y, pt2.y);
      const l_uint32* line = pixGetData(pix) + y * wpl;
      int best_sum = 0;
      int best_x = x;
      EvaluateHorizontalDiff(line, diff_sign, x, width,
                             &best_diff, &best_sum, &best_x);
      // Find the strongest edge.
      int test_x = x;
      do {
        ++test_x;
      } while (EvaluateHorizontalDiff(line, diff_sign, test_x, width,
                                      &best_diff, &best_sum, &best_x));
      test_x = x;
      do {
        --test_x;
      } while (EvaluateHorizontalDiff(line, diff_sign, test_x, width,
                                      &best_diff, &best_sum, &best_x));
      offset = diff_sign * (threshold - best_sum / 2) +
          (best_x - x) * best_diff;
    }
    offsets[s].offset_numerator =
        static_cast<inT8>(ClipToRange(offset, -MAX_INT8, MAX_INT8));
    offsets[s].pixel_diff = static_cast<uinT8>(ClipToRange(best_diff, 0 ,
                                                           MAX_UINT8));
    if (negative) gradient = -gradient;
    // Compute gradient angle quantized to 256 directions, rotated by 64 (pi/2)
    // to convert from gradient direction to edge direction.
    offsets[s].direction =
        Modulo(FCOORD::binary_angle_plus_pi(gradient.angle()) + 64, 256);
    prev_gradient = next_gradient;
  }
}

//.........这里部分代码省略.........
    pixSetInputFormat(pix, IFF_JFIF_JPEG);
    if (!rowbuffer || !pix) {
        LEPT_FREE(rowbuffer);
        pixDestroy(&pix);
        return (PIX *)ERROR_PTR("rowbuffer or pix not made", procName, NULL);
    }

        /* Initialize decompression.  Set up a colormap for color
         * quantization if requested. */
    if (spp == 1) {  /* Grayscale or colormapped */
        jpeg_start_decompress(&cinfo);
    } else {        /* Color; spp == 3 or YCCK or CMYK */
        if (cmapflag == 0) {   /* 24 bit color in 32 bit pix or YCCK/CMYK */
            cinfo.quantize_colors = FALSE;
            jpeg_start_decompress(&cinfo);
        } else {      /* Color quantize to 8 bits */
            cinfo.quantize_colors = TRUE;
            cinfo.desired_number_of_colors = 256;
            jpeg_start_decompress(&cinfo);

                /* Construct a pix cmap */
            cmap = pixcmapCreate(8);
            ncolors = cinfo.actual_number_of_colors;
            for (cindex = 0; cindex < ncolors; cindex++) {
                rval = cinfo.colormap[0][cindex];
                gval = cinfo.colormap[1][cindex];
                bval = cinfo.colormap[2][cindex];
                pixcmapAddColor(cmap, rval, gval, bval);
            }
            pixSetColormap(pix, cmap);
        }
    }
    wpl  = pixGetWpl(pix);
    data = pixGetData(pix);

        /* Decompress.  Unfortunately, we cannot use the return value
         * from jpeg_read_scanlines() to determine if there was a problem
         * with the data; it always appears to return 1.  We can only
         * tell from the warnings during decoding, such as "premature
         * end of data segment".  The default behavior is to return an
         * image even if there are warnings.  However, by setting the
         * hint to have the same bit flag as L_JPEG_FAIL_ON_BAD_DATA,
         * no image will be returned if there are any warnings. */
    for (i = 0; i < h; i++) {
        if (jpeg_read_scanlines(&cinfo, &rowbuffer, (JDIMENSION)1) == 0) {
            L_ERROR("read error at scanline %d\n", procName, i);
            pixDestroy(&pix);
            jpeg_destroy_decompress(&cinfo);
            LEPT_FREE(rowbuffer);
            return (PIX *)ERROR_PTR("bad data", procName, NULL);
        }

            /* -- 24 bit color -- */
        if ((spp == 3 && cmapflag == 0) || ycck || cmyk) {
            ppixel = data + i * wpl;
            if (spp == 3) {
                for (j = k = 0; j < w; j++) {
                    SET_DATA_BYTE(ppixel, COLOR_RED, rowbuffer[k++]);
                    SET_DATA_BYTE(ppixel, COLOR_GREEN, rowbuffer[k++]);
                    SET_DATA_BYTE(ppixel, COLOR_BLUE, rowbuffer[k++]);
                    ppixel++;
                }
            } else {
                    /* This is a conversion from CMYK -> RGB that ignores
                       color profiles, and is invoked when the image header
                       claims to be in CMYK or YCCK colorspace.  If in YCCK,

//.........这里部分代码省略.........

        /* Initialize the jpeg structs for compression */
    jpeg_create_compress(&cinfo);
    jpeg_stdio_dest(&cinfo, fp);
    cinfo.image_width  = w;
    cinfo.image_height = h;

        /* Set the color space and number of components */
    d = pixGetDepth(pix);
    if (d == 8) {
        colorflag = 0;    /* 8 bpp grayscale; no cmap */
        cinfo.input_components = 1;
        cinfo.in_color_space = JCS_GRAYSCALE;
    } else {  /* d == 32 || d == 24 */
        colorflag = 1;    /* rgb */
        cinfo.input_components = 3;
        cinfo.in_color_space = JCS_RGB;
    }

    jpeg_set_defaults(&cinfo);

        /* Setting optimize_coding to TRUE seems to improve compression
         * by approx 2-4 percent, and increases comp time by approx 20%. */
    cinfo.optimize_coding = FALSE;

        /* Set resolution in pixels/in (density_unit: 1 = in, 2 = cm) */
    xres = pixGetXRes(pix);
    yres = pixGetYRes(pix);
    if ((xres != 0) && (yres != 0)) {
        cinfo.density_unit = 1;  /* designates pixels per inch */
        cinfo.X_density = xres;
        cinfo.Y_density = yres;
    }

        /* Set the quality and progressive parameters */
    jpeg_set_quality(&cinfo, quality, TRUE);
    if (progressive)
        jpeg_simple_progression(&cinfo);

        /* Set the chroma subsampling parameters.  This is done in
         * YUV color space.  The Y (intensity) channel is never subsampled.
         * The standard subsampling is 2x2 on both the U and V channels.
         * Notation on this is confusing.  For a nice illustrations, see
         *   http://en.wikipedia.org/wiki/Chroma_subsampling
         * The standard subsampling is written as 4:2:0.
         * We allow high quality where there is no subsampling on the
         * chroma channels: denoted as 4:4:4.  */
    if (pixs->special == L_NO_CHROMA_SAMPLING_JPEG) {
        cinfo.comp_info[0].h_samp_factor = 1;
        cinfo.comp_info[0].v_samp_factor = 1;
        cinfo.comp_info[1].h_samp_factor = 1;
        cinfo.comp_info[1].v_samp_factor = 1;
        cinfo.comp_info[2].h_samp_factor = 1;
        cinfo.comp_info[2].v_samp_factor = 1;
    }

    jpeg_start_compress(&cinfo, TRUE);

    if ((text = pixGetText(pix)))
        jpeg_write_marker(&cinfo, JPEG_COM, (const JOCTET *)text, strlen(text));

        /* Allocate row buffer */
    spp = cinfo.input_components;
    rowsamples = spp * w;
    if ((rowbuffer = (JSAMPROW)LEPT_CALLOC(sizeof(JSAMPLE), rowsamples))
        == NULL) {
        pixDestroy(&pix);
        return ERROR_INT("calloc fail for rowbuffer", procName, 1);
    }

    data = pixGetData(pix);
    wpl  = pixGetWpl(pix);
    for (i = 0; i < h; i++) {
        line = data + i * wpl;
        if (colorflag == 0) {        /* 8 bpp gray */
            for (j = 0; j < w; j++)
                rowbuffer[j] = GET_DATA_BYTE(line, j);
        } else {  /* colorflag == 1 */
            if (d == 24) {  /* See note 3 above; special case of 24 bpp rgb */
                jpeg_write_scanlines(&cinfo, (JSAMPROW *)&line, 1);
            } else {  /* standard 32 bpp rgb */
                ppixel = line;
                for (j = k = 0; j < w; j++) {
                    rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_RED);
                    rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_GREEN);
                    rowbuffer[k++] = GET_DATA_BYTE(ppixel, COLOR_BLUE);
                    ppixel++;
                }
            }
        }
        if (d != 24)
            jpeg_write_scanlines(&cinfo, &rowbuffer, 1);
    }
    jpeg_finish_compress(&cinfo);

    pixDestroy(&pix);
    LEPT_FREE(rowbuffer);
    jpeg_destroy_compress(&cinfo);
    return 0;
}

/*!
 *  pixProjectiveSampled()
 *
 *      Input:  pixs (all depths)
 *              vc  (vector of 8 coefficients for projective transformation)
 *              incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
 *      Return: pixd, or null on error
 *
 *  Notes:
 *      (1) Brings in either black or white pixels from the boundary.
 *      (2) Retains colormap, which you can do for a sampled transform..
 *      (3) For 8 or 32 bpp, much better quality is obtained by the
 *          somewhat slower pixProjective().  See that function
 *          for relative timings between sampled and interpolated.
 */
PIX *
pixProjectiveSampled(PIX        *pixs,
                     l_float32  *vc,
                     l_int32     incolor)
{
l_int32     i, j, w, h, d, x, y, wpls, wpld, color, cmapindex;
l_uint32    val;
l_uint32   *datas, *datad, *lines, *lined;
PIX        *pixd;
PIXCMAP    *cmap;

    PROCNAME("pixProjectiveSampled");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    if (!vc)
        return (PIX *)ERROR_PTR("vc not defined", procName, NULL);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
        return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 1 && d != 2 && d != 4 && d != 8 && d != 32)
        return (PIX *)ERROR_PTR("depth not 1, 2, 4, 8 or 16", procName, NULL);

        /* Init all dest pixels to color to be brought in from outside */
    pixd = pixCreateTemplate(pixs);
    if ((cmap = pixGetColormap(pixs)) != NULL) {
        if (incolor == L_BRING_IN_WHITE)
            color = 1;
        else
            color = 0;
        pixcmapAddBlackOrWhite(cmap, color, &cmapindex);
        pixSetAllArbitrary(pixd, cmapindex);
    }
    else {
        if ((d == 1 && incolor == L_BRING_IN_WHITE) ||
            (d > 1 && incolor == L_BRING_IN_BLACK))
            pixClearAll(pixd);
        else
            pixSetAll(pixd);
    }

        /* Scan over the dest pixels */
    datas = pixGetData(pixs);
    wpls = pixGetWpl(pixs);
    datad = pixGetData(pixd);
    wpld = pixGetWpl(pixd);
    for (i = 0; i < h; i++) {
        lined = datad + i * wpld;
        for (j = 0; j < w; j++) {
            projectiveXformSampledPt(vc, j, i, &x, &y);
            if (x < 0 || y < 0 || x >=w || y >= h)
                continue;
            lines = datas + y * wpls;
            if (d == 1) {
                val = GET_DATA_BIT(lines, x);
                SET_DATA_BIT_VAL(lined, j, val);
            }
            else if (d == 8) {
                val = GET_DATA_BYTE(lines, x);
                SET_DATA_BYTE(lined, j, val);
            }
            else if (d == 32) {
                lined[j] = lines[x];
            }
            else if (d == 2) {
                val = GET_DATA_DIBIT(lines, x);
                SET_DATA_DIBIT(lined, j, val);
            }
            else if (d == 4) {
                val = GET_DATA_QBIT(lines, x);
                SET_DATA_QBIT(lined, j, val);
            }
        }
    }

    return pixd;
}

/*!
 *  pixExpandBinaryPower2()
 *
 *      Input:  pixs (1 bpp)
 *              factor (expansion factor: 1, 2, 4, 8, 16)
 *      Return: pixd (expanded 1 bpp by replication), or null on error
 */
PIX *
pixExpandBinaryPower2(PIX     *pixs,
                      l_int32  factor)
{
l_uint8    sval;
l_uint16  *tab2;
l_int32    i, j, k, w, h, d, wd, hd, wpls, wpld, sdibits, sqbits, sbytes;
l_uint32  *datas, *datad, *lines, *lined, *tab4, *tab8;
PIX       *pixd;

    PROCNAME("pixExpandBinaryPower2");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 1)
        return (PIX *)ERROR_PTR("pixs not binary", procName, NULL);
    if (factor == 1)
        return pixCopy(NULL, pixs);
    if (factor != 2 && factor != 4 && factor != 8 && factor != 16)
        return (PIX *)ERROR_PTR("factor must be in {2,4,8,16}", procName, NULL);

    wpls = pixGetWpl(pixs);
    datas = pixGetData(pixs);
    wd = factor * w;
    hd = factor * h;
    if ((pixd = pixCreate(wd, hd, 1)) == NULL)
        return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
    pixCopyResolution(pixd, pixs);
    pixScaleResolution(pixd, (l_float32)factor, (l_float32)factor);
    wpld = pixGetWpl(pixd);
    datad = pixGetData(pixd);
    if (factor == 2) {
        if ((tab2 = makeExpandTab2x()) == NULL)
            return (PIX *)ERROR_PTR("tab2 not made", procName, NULL);
        sbytes = (w + 7) / 8;
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + 2 * i * wpld;
            for (j = 0; j < sbytes; j++) {
                sval = GET_DATA_BYTE(lines, j);
                SET_DATA_TWO_BYTES(lined, j, tab2[sval]);
            }
            memcpy((char *)(lined + wpld), (char *)lined, 4 * wpld);
        }
        FREE(tab2);
    } else if (factor == 4) {
        if ((tab4 = makeExpandTab4x()) == NULL)
            return (PIX *)ERROR_PTR("tab4 not made", procName, NULL);
        sbytes = (w + 7) / 8;
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + 4 * i * wpld;
            for (j = 0; j < sbytes; j++) {
                sval = GET_DATA_BYTE(lines, j);
                lined[j] = tab4[sval];
            }
            for (k = 1; k < 4; k++)
                memcpy((char *)(lined + k * wpld), (char *)lined, 4 * wpld);
        }
        FREE(tab4);
    } else if (factor == 8) {
        if ((tab8 = makeExpandTab8x()) == NULL)
            return (PIX *)ERROR_PTR("tab8 not made", procName, NULL);
        sqbits = (w + 3) / 4;
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + 8 * i * wpld;
            for (j = 0; j < sqbits; j++) {
                sval = GET_DATA_QBIT(lines, j);
                if (sval > 15)
                    L_WARNING("sval = %d; should be < 16\n", procName, sval);
                lined[j] = tab8[sval];
            }
            for (k = 1; k < 8; k++)
                memcpy((char *)(lined + k * wpld), (char *)lined, 4 * wpld);
        }
        FREE(tab8);
    } else {  /* factor == 16 */
        sdibits = (w + 1) / 2;
        for (i = 0; i < h; i++) {
            lines = datas + i * wpls;
            lined = datad + 16 * i * wpld;
            for (j = 0; j < sdibits; j++) {
                sval = GET_DATA_DIBIT(lines, j);
                lined[j] = expandtab16[sval];
            }
            for (k = 1; k < 16; k++)
                memcpy((char *)(lined + k * wpld), (char *)lined, 4 * wpld);
        }
    }

    return pixd;
//.........这里部分代码省略.........

/*!
 * \brief   pixAssignToNearestColor()
 *
 * \param[in]    pixd  8 bpp, colormapped
 * \param[in]    pixs  32 bpp; 24-bit color
 * \param[in]    pixm  [optional] 1 bpp
 * \param[in]    level of octcube used for finding nearest color in cmap
 * \param[in]    countarray [optional] ptr to array, in which we can store
 *                          the number of pixels found in each color in
 *                          the colormap in pixd
 * \return  0 if OK, 1 on error
 *
 * <pre>
 * Notes:
 *      (1) This is used in phase 2 of color segmentation, where pixs
 *          is the original input image to pixColorSegment(), and
 *          pixd is the colormapped image returned from
 *          pixColorSegmentCluster().  It is also used, with a mask,
 *          in phase 4.
 *      (2) This is an in-place operation.
 *      (3) The colormap in pixd is unchanged.
 *      (4) pixs and pixd must be the same size (w, h).
 *      (5) The selection mask pixm can be null.  If it exists, it must
 *          be the same size as pixs and pixd, and only pixels
 *          corresponding to fg in pixm are assigned.  Set to
 *          NULL if all pixels in pixd are to be assigned.
 *      (6) The countarray can be null.  If it exists, it is pre-allocated
 *          and of a size at least equal to the size of the colormap in pixd.
 *      (7) This does a best-fit (non-greedy) assignment of pixels to
 *          existing clusters.  Specifically, it assigns each pixel
 *          in pixd to the color index in the pixd colormap that has a
 *          color closest to the corresponding rgb pixel in pixs.
 *      (8) 'level' is the octcube level used to quickly find the nearest
 *          color in the colormap for each pixel.  For color segmentation,
 *          this parameter is set to LEVEL_IN_OCTCUBE.
 *      (9) We build a mapping table from octcube to colormap index so
 *          that this function can run in a time (otherwise) independent
 *          of the number of colors in the colormap.  This avoids a
 *          brute-force search for the closest colormap color to each
 *          pixel in the image.
 * </pre>
 */
l_ok
pixAssignToNearestColor(PIX      *pixd,
                        PIX      *pixs,
                        PIX      *pixm,
                        l_int32   level,
                        l_int32  *countarray)
{
l_int32    w, h, wpls, wpld, wplm, i, j, success;
l_int32    rval, gval, bval, index;
l_int32   *cmaptab;
l_uint32   octindex;
l_uint32  *rtab, *gtab, *btab;
l_uint32  *ppixel;
l_uint32  *datas, *datad, *datam, *lines, *lined, *linem;
PIXCMAP   *cmap;

    PROCNAME("pixAssignToNearestColor");

    if (!pixd)
        return ERROR_INT("pixd not defined", procName, 1);
    if ((cmap = pixGetColormap(pixd)) == NULL)
        return ERROR_INT("cmap not found", procName, 1);
    if (!pixs)
        return ERROR_INT("pixs not defined", procName, 1);
    if (pixGetDepth(pixs) != 32)
        return ERROR_INT("pixs not 32 bpp", procName, 1);
    if (level < 1 || level > 6)
        return ERROR_INT("level not in [1 ... 6]", procName, 1);

        /* Set up the tables to map rgb to the nearest colormap index */
    success = TRUE;
    makeRGBToIndexTables(&rtab, &gtab, &btab, level);
    cmaptab = pixcmapToOctcubeLUT(cmap, level, L_MANHATTAN_DISTANCE);
    if (!rtab || !gtab || !btab || !cmaptab) {
        L_ERROR("failure to make a table\n", procName);
        success = FALSE;
        goto cleanup_arrays;
    }

    pixGetDimensions(pixs, &w, &h, NULL);
    datas = pixGetData(pixs);
    datad = pixGetData(pixd);
    wpls = pixGetWpl(pixs);
    wpld = pixGetWpl(pixd);
    if (pixm) {
        datam = pixGetData(pixm);
        wplm = pixGetWpl(pixm);
    }
    for (i = 0; i < h; i++) {
        lines = datas + i * wpls;
        lined = datad + i * wpld;
        if (pixm)
            linem = datam + i * wplm;
        for (j = 0; j < w; j++) {
            if (pixm) {
                if (!GET_DATA_BIT(linem, j))
                    continue;
            }
//.........这里部分代码省略.........

/*!
 * \brief   pixColorSegmentTryCluster()
 *
 * \param[in]    pixd
 * \param[in]    pixs
 * \param[in]    maxdist
 * \param[in]    maxcolors
 * \param[in]    debugflag  1 for debug output; 0 otherwise
 * \return  0 if OK, 1 on error
 *
 * <pre>
 * Notes:
 *      This function should only be called from pixColorSegCluster()
 * </pre>
 */
static l_int32
pixColorSegmentTryCluster(PIX     *pixd,
                          PIX     *pixs,
                          l_int32  maxdist,
                          l_int32  maxcolors,
                          l_int32  debugflag)
{
l_int32    rmap[256], gmap[256], bmap[256];
l_int32    w, h, wpls, wpld, i, j, k, found, ret, index, ncolors;
l_int32    rval, gval, bval, dist2, maxdist2;
l_int32    countarray[256];
l_int32    rsum[256], gsum[256], bsum[256];
l_uint32  *ppixel;
l_uint32  *datas, *datad, *lines, *lined;
PIXCMAP   *cmap;

    PROCNAME("pixColorSegmentTryCluster");

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

    w = pixGetWidth(pixs);
    h = pixGetHeight(pixs);
    maxdist2 = maxdist * maxdist;
    cmap = pixGetColormap(pixd);
    pixcmapClear(cmap);
    for (k = 0; k