--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/leptonica/src/pixafunc2.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,2716 @@
+/*====================================================================*
+ -  Copyright (C) 2001 Leptonica.  All rights reserved.
+ -
+ -  Redistribution and use in source and binary forms, with or without
+ -  modification, are permitted provided that the following conditions
+ -  are met:
+ -  1. Redistributions of source code must retain the above copyright
+ -     notice, this list of conditions and the following disclaimer.
+ -  2. Redistributions in binary form must reproduce the above
+ -     copyright notice, this list of conditions and the following
+ -     disclaimer in the documentation and/or other materials
+ -     provided with the distribution.
+ -
+ -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY
+ -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *====================================================================*/
+
+/*!
+ * \file  pixafunc2.c
+ * <pre>
+ *
+ *      Pixa display (render into a pix)
+ *           PIX      *pixaDisplay()
+ *           PIX      *pixaDisplayRandomCmap()
+ *           PIX      *pixaDisplayLinearly()
+ *           PIX      *pixaDisplayOnLattice()
+ *           PIX      *pixaDisplayUnsplit()
+ *           PIX      *pixaDisplayTiled()
+ *           PIX      *pixaDisplayTiledInRows()
+ *           PIX      *pixaDisplayTiledInColumns()
+ *           PIX      *pixaDisplayTiledAndScaled()
+ *           PIX      *pixaDisplayTiledWithText()
+ *           PIX      *pixaDisplayTiledByIndex()
+ *
+ *      Pixa pair display (render into a pix)
+ *           PIX      *pixaDisplayPairTiledInColumns()
+ *
+ *      Pixaa display (render into a pix)
+ *           PIX      *pixaaDisplay()
+ *           PIX      *pixaaDisplayByPixa()
+ *           PIXA     *pixaaDisplayTiledAndScaled()
+ *
+ *      Conversion of all pix to specified type (e.g., depth)
+ *           PIXA     *pixaConvertTo1()
+ *           PIXA     *pixaConvertTo8()
+ *           PIXA     *pixaConvertTo8Colormap()
+ *           PIXA     *pixaConvertTo32()
+ *
+ *      Pixa constrained selection and pdf generation
+ *           PIXA     *pixaConstrainedSelect()
+ *           l_int32   pixaSelectToPdf()
+ *
+ *      Generate pixa from tiled images
+ *           PIXA     *pixaMakeFromTiledPixa()
+ *           PIXA     *pixaMakeFromTiledPix()
+ *           l_int32   pixGetTileCount()
+ *
+ *      Pixa display into multiple tiles
+ *           PIXA     *pixaDisplayMultiTiled()
+ *
+ *      Split pixa into files
+ *           l_int32   pixaSplitIntoFiles()
+ *
+ *      Tile N-Up
+ *           l_int32   convertToNUpFiles()
+ *           PIXA     *convertToNUpPixa()
+ *           PIXA     *pixaConvertToNUpPixa()
+ *
+ *      Render two pixa side-by-side for comparison                   *
+ *           l_int32   pixaCompareInPdf()
+ *
+ *  We give twelve pixaDisplay*() methods for tiling a pixa in a pix.
+ *  Some work for 1 bpp input; others for any input depth.
+ *  Some give an output depth that depends on the input depth;
+ *  others give a different output depth or allow you to choose it.
+ *  Some use a boxes to determine where each pix goes; others tile
+ *  onto a regular lattice; others tile onto an irregular lattice;
+ *  one uses an associated index array to determine which column
+ *  each pix goes into.
+ *
+ *  Here is a brief description of what the pixa display functions do.
+ *
+ *    pixaDisplay()
+ *        This uses the boxes in the pixa to lay out each pix.  This
+ *        can be used to reconstruct a pix that has been broken into
+ *        components, if the boxes represents the positions of the
+ *        components in the original image.
+ *    pixaDisplayRandomCmap()
+ *        This also uses the boxes to lay out each pix.  However, it creates
+ *        a colormapped dest, where each 1 bpp pix is given a randomly
+ *        generated color (up to 256 are used).
+ *    pixaDisplayLinearly()
+ *        This puts each pix, sequentially, in a line, either horizontally
+ *        or vertically.
+ *    pixaDisplayOnLattice()
+ *        This puts each pix, sequentially, onto a regular lattice,
+ *        omitting any pix that are too big for the lattice size.
+ *        This is useful, for example, to store bitmapped fonts,
+ *        where all the characters are stored in a single image.
+ *    pixaDisplayUnsplit()
+ *        This lays out a mosaic of tiles (the pix in the pixa) that
+ *        are all of equal size.  (Don't use this for unequal sized pix!)
+ *        For example, it can be used to invert the action of
+ *        pixaSplitPix().
+ *    pixaDisplayTiled()
+ *        Like pixaDisplayOnLattice(), this places each pix on a regular
+ *        lattice, but here the lattice size is determined by the
+ *        largest component, and no components are omitted.  This is
+ *        dangerous if there are thousands of small components and
+ *        one or more very large one, because the size of the resulting
+ *        pix can be huge!
+ *    pixaDisplayTiledInRows()
+ *        This puts each pix down in a series of rows, where the upper
+ *        edges of each pix in a row are aligned and there is a uniform
+ *        spacing between the pix.  The height of each row is determined
+ *        by the tallest pix that was put in the row.  This function
+ *        is a reasonably efficient way to pack the subimages.
+ *        A boxa of the locations of each input pix is stored in the output.
+ *    pixaDisplayTiledInColumns()
+ *        This puts each pix down in a series of rows, each row having
+ *        a specified number of pix.  The upper edges of each pix in a
+ *        row are aligned and there is a uniform spacing between the pix.
+ *        The height of each row is determined by the tallest pix that
+ *        was put in the row.  A boxa of the locations of each input
+ *        pix is stored in the output.
+ *    pixaDisplayTiledAndScaled()
+ *        This scales each pix to a given width and output depth, and then
+ *        tiles them in rows with a given number placed in each row.
+ *        This is useful for presenting a sequence of images that can be
+ *        at different resolutions, but which are derived from the same
+ *        initial image.
+ *    pixaDisplayTiledWithText()
+ *        This is a version of pixaDisplayTiledInRows() that prints, below
+ *        each pix, the text in the pix text field.  It renders a pixa
+ *        to an image with white background that does not exceed a
+ *        given value in width.
+ *    pixaDisplayTiledByIndex()
+ *        This scales each pix to a given width and output depth,
+ *        and then tiles them in columns corresponding to the value
+ *        in an associated numa.  All pix with the same index value are
+ *        rendered in the same column.  Text in the pix text field are
+ *        rendered below the pix.
+ *
+ *  To render mosaics of images in a pixaa, display functions are
+ *  provided that handle situations where the images are all scaled to
+ *  the same size, or the number of images on each row needs to vary.
+ * </pre>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config_auto.h>
+#endif  /* HAVE_CONFIG_H */
+
+#include <string.h>
+#include <math.h>   /* for sqrt() */
+#include "allheaders.h"
+
+/*---------------------------------------------------------------------*
+ *                               Pixa Display                          *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaDisplay()
+ *
+ * \param[in]    pixa
+ * \param[in]    w, h    if set to 0, the size is determined from the
+ *                       bounding box of the components in pixa
+ * \return  pix, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This uses the boxes to place each pix in the rendered composite.
+ *      (2) Set w = h = 0 to use the b.b. of the components to determine
+ *          the size of the returned pix.
+ *      (3) Uses the first pix in pixa to determine the depth.
+ *      (4) The background is written "white".  On 1 bpp, each successive
+ *          pix is "painted" (adding foreground), whereas for grayscale
+ *          or color each successive pix is blitted with just the src.
+ *      (5) If the pixa is empty, returns an empty 1 bpp pix.
+ * </pre>
+ */
+PIX *
+pixaDisplay(PIXA    *pixa,
+            l_int32  w,
+            l_int32  h)
+{
+l_int32  i, n, d, xb, yb, wb, hb, res;
+BOXA    *boxa;
+PIX     *pix1, *pixd;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+
+    n = pixaGetCount(pixa);
+    if (n == 0 && w == 0 && h == 0)
+        return (PIX *)ERROR_PTR("no components; no size", __func__, NULL);
+    if (n == 0) {
+        L_WARNING("no components; returning empty 1 bpp pix\n", __func__);
+        return pixCreate(w, h, 1);
+    }
+
+        /* If w and h not input, determine the minimum size required
+         * to contain the origin and all c.c. */
+    if (w == 0 || h == 0) {
+        boxa = pixaGetBoxa(pixa, L_CLONE);
+        boxaGetExtent(boxa, &w, &h, NULL);
+        boxaDestroy(&boxa);
+        if (w == 0 || h == 0)
+            return (PIX *)ERROR_PTR("no associated boxa", __func__, NULL);
+    }
+
+        /* Use the first pix in pixa to determine depth and resolution  */
+    pix1 = pixaGetPix(pixa, 0, L_CLONE);
+    d = pixGetDepth(pix1);
+    res = pixGetXRes(pix1);
+    pixDestroy(&pix1);
+
+    if ((pixd = pixCreate(w, h, d)) == NULL)
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    pixSetResolution(pixd, res, res);
+    if (d > 1)
+        pixSetAll(pixd);
+    for (i = 0; i < n; i++) {
+        if (pixaGetBoxGeometry(pixa, i, &xb, &yb, &wb, &hb)) {
+            L_WARNING("no box found!\n", __func__);
+            continue;
+        }
+        pix1 = pixaGetPix(pixa, i, L_CLONE);
+        if (d == 1)
+            pixRasterop(pixd, xb, yb, wb, hb, PIX_PAINT, pix1, 0, 0);
+        else
+            pixRasterop(pixd, xb, yb, wb, hb, PIX_SRC, pix1, 0, 0);
+        pixDestroy(&pix1);
+    }
+
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayRandomCmap()
+ *
+ * \param[in]    pixa    1 bpp regions, with boxa delineating those regions
+ * \param[in]    w, h    if set to 0, the size is determined from the
+ *                       bounding box of the components in pixa
+ * \return  pix   8 bpp, cmapped, with random colors assigned to each region,
+ *                or NULL on error.
+ *
+ * <pre>
+ * Notes:
+ *      (1) This uses the boxes to place each pix in the rendered composite.
+ *          The fg of each pix in %pixa, such as a single connected
+ *          component or a line of text, is given a random color.
+ *      (2) By default, the background color is black (cmap index 0).
+ *          This can be changed by pixcmapResetColor()
+ * </pre>
+ */
+PIX *
+pixaDisplayRandomCmap(PIXA    *pixa,
+                      l_int32  w,
+                      l_int32  h)
+{
+l_int32   i, n, same, maxd, index, xb, yb, wb, hb, res;
+BOXA     *boxa;
+PIX      *pixs, *pix1, *pixd;
+PIXCMAP  *cmap;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    pixaVerifyDepth(pixa, &same, &maxd);
+    if (maxd > 1)
+        return (PIX *)ERROR_PTR("not all components are 1 bpp", __func__, NULL);
+
+        /* If w and h are not input, determine the minimum size required
+         * to contain the origin and all c.c. */
+    if (w == 0 || h == 0) {
+        boxa = pixaGetBoxa(pixa, L_CLONE);
+        boxaGetExtent(boxa, &w, &h, NULL);
+        boxaDestroy(&boxa);
+    }
+
+        /* Set up an 8 bpp dest pix, with a colormap with 254 random colors */
+    if ((pixd = pixCreate(w, h, 8)) == NULL)
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    cmap = pixcmapCreateRandom(8, 1, 1);
+    pixSetColormap(pixd, cmap);
+
+        /* Color each component and blit it in */
+    for (i = 0; i < n; i++) {
+        index = 1 + (i % 254);
+        pixaGetBoxGeometry(pixa, i, &xb, &yb, &wb, &hb);
+        pixs = pixaGetPix(pixa, i, L_CLONE);
+        if (i == 0) res = pixGetXRes(pixs);
+        pix1 = pixConvert1To8(NULL, pixs, 0, index);
+        pixRasterop(pixd, xb, yb, wb, hb, PIX_PAINT, pix1, 0, 0);
+        pixDestroy(&pixs);
+        pixDestroy(&pix1);
+    }
+
+    pixSetResolution(pixd, res, res);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayLinearly()
+ *
+ * \param[in]    pixas
+ * \param[in]    direction    L_HORIZ or L_VERT
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    background   0 for white, 1 for black; this is the color
+ *                            of the spacing between the images
+ * \param[in]    spacing      between images, and on outside
+ * \param[in]    border       width of black border added to each image;
+ *                            use 0 for no border
+ * \param[out]   pboxa        [optional] location of images in output pix
+ * \return  pix of composite images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This puts each pix, sequentially, in a line, either horizontally
+ *          or vertically.
+ *      (2) If any pix has a colormap, all pix are rendered in rgb.
+ *      (3) The boxa gives the location of each image.
+ * </pre>
+ */
+PIX *
+pixaDisplayLinearly(PIXA      *pixas,
+                    l_int32    direction,
+                    l_float32  scalefactor,
+                    l_int32    background,  /* not used */
+                    l_int32    spacing,
+                    l_int32    border,
+                    BOXA     **pboxa)
+{
+l_int32  i, n, x, y, w, h, depth, bordval;
+BOX     *box;
+PIX     *pix1, *pix2, *pix3, *pixd;
+PIXA    *pixa1, *pixa2;
+
+    if (pboxa) *pboxa = NULL;
+    if (!pixas)
+        return (PIX *)ERROR_PTR("pixas not defined", __func__, NULL);
+    if (direction != L_HORIZ && direction != L_VERT)
+        return (PIX *)ERROR_PTR("invalid direction", __func__, NULL);
+
+        /* Make sure all pix are at the same depth */
+    pixa1 = pixaConvertToSameDepth(pixas);
+    pixaGetDepthInfo(pixa1, &depth, NULL);
+
+        /* Scale and add border if requested */
+    n = pixaGetCount(pixa1);
+    pixa2 = pixaCreate(n);
+    bordval = (depth == 1) ? 1 : 0;
+    x = y = 0;
+    for (i = 0; i < n; i++) {
+        if ((pix1 = pixaGetPix(pixa1, i, L_CLONE)) == NULL) {
+            L_WARNING("missing pix at index %d\n", __func__, i);
+            continue;
+        }
+
+        if (scalefactor != 1.0)
+            pix2 = pixScale(pix1, scalefactor, scalefactor);
+        else
+            pix2 = pixClone(pix1);
+        if (border)
+            pix3 = pixAddBorder(pix2, border, bordval);
+        else
+            pix3 = pixClone(pix2);
+
+        pixGetDimensions(pix3, &w, &h, NULL);
+        box = boxCreate(x, y, w, h);
+        if (direction == L_HORIZ)
+            x += w + spacing;
+        else  /* vertical */
+            y += h + spacing;
+        pixaAddPix(pixa2, pix3, L_INSERT);
+        pixaAddBox(pixa2, box, L_INSERT);
+        pixDestroy(&pix1);
+        pixDestroy(&pix2);
+    }
+    pixd = pixaDisplay(pixa2, 0, 0);
+
+    if (pboxa)
+        *pboxa = pixaGetBoxa(pixa2, L_COPY);
+    pixaDestroy(&pixa1);
+    pixaDestroy(&pixa2);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayOnLattice()
+ *
+ * \param[in]    pixa
+ * \param[in]    cellw    lattice cell width
+ * \param[in]    cellh    lattice cell height
+ * \param[out]   pncols   [optional] number of columns in output lattice
+ * \param[out]   pboxa    [optional] location of images in lattice
+ * \return  pix of composite images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This places each pix on sequentially on a regular lattice
+ *          in the rendered composite.  If a pix is too large to fit in the
+ *          allocated lattice space, it is not rendered.
+ *      (2) If any pix has a colormap, all pix are rendered in rgb.
+ *      (3) This is useful when putting bitmaps of components,
+ *          such as characters, into a single image.
+ *      (4) Save the number of tiled images in the text field of the pix,
+ *          in the format: n = %d.  This survives write/read into png files,
+ *          for example.
+ *      (5) The boxa gives the location of each image.  The UL corner
+ *          of each image is on a lattice cell corner.  Omitted images
+ *          (due to size) are assigned an invalid width and height of 0.
+ * </pre>
+ */
+PIX *
+pixaDisplayOnLattice(PIXA     *pixa,
+                     l_int32   cellw,
+                     l_int32   cellh,
+                     l_int32  *pncols,
+                     BOXA    **pboxa)
+{
+char     buf[16];
+l_int32  n, nw, nh, w, h, d, wt, ht, res, samedepth;
+l_int32  index, i, j, hascmap;
+BOX     *box;
+BOXA    *boxa;
+PIX     *pix1, *pix2, *pixd;
+PIXA    *pixa1;
+
+    if (pncols) *pncols = 0;
+    if (pboxa) *pboxa = NULL;
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+
+        /* If any pix have colormaps, or if the depths differ, generate rgb */
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    pixaAnyColormaps(pixa, &hascmap);
+    pixaVerifyDepth(pixa, &samedepth, NULL);
+    if (hascmap || !samedepth) {
+        pixa1 = pixaCreate(n);
+        for (i = 0; i < n; i++) {
+            pix1 = pixaGetPix(pixa, i, L_CLONE);
+            pix2 = pixConvertTo32(pix1);
+            pixaAddPix(pixa1, pix2, L_INSERT);
+            pixDestroy(&pix1);
+        }
+    } else {
+        pixa1 = pixaCopy(pixa, L_CLONE);
+    }
+
+        /* Have number of rows and columns approximately equal */
+    nw = (l_int32)sqrt((l_float64)n);
+    nh = (n + nw - 1) / nw;
+    w = cellw * nw;
+    h = cellh * nh;
+
+        /* Use the first pix to determine output depth and resolution  */
+    pix1 = pixaGetPix(pixa1, 0, L_CLONE);
+    d = pixGetDepth(pix1);
+    res = pixGetXRes(pix1);
+    pixDestroy(&pix1);
+    if ((pixd = pixCreate(w, h, d)) == NULL) {
+        pixaDestroy(&pixa1);
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    }
+    pixSetBlackOrWhite(pixd, L_SET_WHITE);
+    pixSetResolution(pixd, res, res);
+    boxa = boxaCreate(n);
+
+        /* Tile the output */
+    index = 0;
+    for (i = 0; i < nh; i++) {
+        for (j = 0; j < nw && index < n; j++, index++) {
+            pix1 = pixaGetPix(pixa1, index, L_CLONE);
+            pixGetDimensions(pix1, &wt, &ht, NULL);
+            if (wt > cellw || ht > cellh) {
+                L_INFO("pix(%d) omitted; size %dx%x\n", __func__, index,
+                       wt, ht);
+                box = boxCreate(0, 0, 0, 0);
+                boxaAddBox(boxa, box, L_INSERT);
+                pixDestroy(&pix1);
+                continue;
+            }
+            pixRasterop(pixd, j * cellw, i * cellh, wt, ht,
+                        PIX_SRC, pix1, 0, 0);
+            box = boxCreate(j * cellw, i * cellh, wt, ht);
+            boxaAddBox(boxa, box, L_INSERT);
+            pixDestroy(&pix1);
+        }
+    }
+
+        /* Save the number of tiles in the text field */
+    snprintf(buf, sizeof(buf), "n = %d", boxaGetCount(boxa));
+    pixSetText(pixd, buf);
+
+    if (pncols) *pncols = nw;
+    if (pboxa)
+        *pboxa = boxa;
+    else
+        boxaDestroy(&boxa);
+    pixaDestroy(&pixa1);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayUnsplit()
+ *
+ * \param[in]    pixa
+ * \param[in]    nx           number of mosaic cells horizontally
+ * \param[in]    ny           number of mosaic cells vertically
+ * \param[in]    borderwidth  of added border on all sides
+ * \param[in]    bordercolor  in our RGBA format: 0xrrggbbaa
+ * \return  pix of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This is a logical inverse of pixaSplitPix().  It
+ *          constructs a pix from a mosaic of tiles, all of equal size.
+ *      (2) For added generality, a border of arbitrary color can
+ *          be added to each of the tiles.
+ *      (3) In use, pixa will typically have either been generated
+ *          from pixaSplitPix() or will derived from a pixa that
+ *          was so generated.
+ *      (4) All pix in the pixa must be of equal depth, and, if
+ *          colormapped, have the same colormap.
+ * </pre>
+ */
+PIX *
+pixaDisplayUnsplit(PIXA     *pixa,
+                   l_int32   nx,
+                   l_int32   ny,
+                   l_int32   borderwidth,
+                   l_uint32  bordercolor)
+{
+l_int32  w, h, d, wt, ht;
+l_int32  i, j, k, x, y, n;
+PIX     *pix1, *pixd;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    if (nx <= 0 || ny <= 0)
+        return (PIX *)ERROR_PTR("nx and ny must be > 0", __func__, NULL);
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    if (n != nx * ny)
+        return (PIX *)ERROR_PTR("n != nx * ny", __func__, NULL);
+    borderwidth = L_MAX(0, borderwidth);
+
+    pixaGetPixDimensions(pixa, 0, &wt, &ht, &d);
+    w = nx * (wt + 2 * borderwidth);
+    h = ny * (ht + 2 * borderwidth);
+
+    if ((pixd = pixCreate(w, h, d)) == NULL)
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    pix1 = pixaGetPix(pixa, 0, L_CLONE);
+    pixCopyColormap(pixd, pix1);
+    pixDestroy(&pix1);
+    if (borderwidth > 0)
+        pixSetAllArbitrary(pixd, bordercolor);
+
+    y = borderwidth;
+    for (i = 0, k = 0; i < ny; i++) {
+        x = borderwidth;
+        for (j = 0; j < nx; j++, k++) {
+            pix1 = pixaGetPix(pixa, k, L_CLONE);
+            pixRasterop(pixd, x, y, wt, ht, PIX_SRC, pix1, 0, 0);
+            pixDestroy(&pix1);
+            x += wt + 2 * borderwidth;
+        }
+        y += ht + 2 * borderwidth;
+    }
+
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiled()
+ *
+ * \param[in]    pixa
+ * \param[in]    maxwidth     of output image
+ * \param[in]    background   0 for white, 1 for black
+ * \param[in]    spacing
+ * \return  pix of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pixa to a single image of width not to
+ *          exceed maxwidth, with background color either white or black,
+ *          and with each subimage spaced on a regular lattice.
+ *      (2) The lattice size is determined from the largest width and height,
+ *          separately, of all pix in the pixa.
+ *      (3) All pix in the pixa must be of equal depth.
+ *      (4) If any pix has a colormap, all pix are rendered in rgb.
+ *      (5) Careful: because no components are omitted, this is
+ *          dangerous if there are thousands of small components and
+ *          one or more very large one, because the size of the
+ *          resulting pix can be huge!
+ * </pre>
+ */
+PIX *
+pixaDisplayTiled(PIXA    *pixa,
+                 l_int32  maxwidth,
+                 l_int32  background,
+                 l_int32  spacing)
+{
+l_int32  wmax, hmax, wd, hd, d, hascmap, res, same;
+l_int32  i, j, n, ni, ncols, nrows;
+l_int32  ystart, xstart, wt, ht;
+PIX     *pix1, *pix2, *pixd;
+PIXA    *pixa1;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    spacing = L_MAX(spacing, 0);
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* If any pix have colormaps, generate rgb */
+    pixaAnyColormaps(pixa, &hascmap);
+    if (hascmap) {
+        pixa1 = pixaCreate(n);
+        for (i = 0; i < n; i++) {
+            pix1 = pixaGetPix(pixa, i, L_CLONE);
+            pix2 = pixConvertTo32(pix1);
+            pixaAddPix(pixa1, pix2, L_INSERT);
+            pixDestroy(&pix1);
+        }
+    } else {
+        pixa1 = pixaCopy(pixa, L_CLONE);
+    }
+
+        /* Find the max dimensions and depth subimages */
+    pixaGetDepthInfo(pixa1, &d, &same);
+    if (!same) {
+        pixaDestroy(&pixa1);
+        return (PIX *)ERROR_PTR("depths not equal", __func__, NULL);
+    }
+    pixaSizeRange(pixa1, NULL, NULL, &wmax, &hmax);
+
+        /* Get the number of rows and columns and the output image size */
+    ncols = (l_int32)((l_float32)(maxwidth - spacing) /
+                      (l_float32)(wmax + spacing));
+    ncols = L_MAX(ncols, 1);
+    nrows = (n + ncols - 1) / ncols;
+    wd = wmax * ncols + spacing * (ncols + 1);
+    hd = hmax * nrows + spacing * (nrows + 1);
+    if ((pixd = pixCreate(wd, hd, d)) == NULL) {
+        pixaDestroy(&pixa1);
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    }
+
+        /* Reset the background color if necessary */
+    if ((background == 1 && d == 1) || (background == 0 && d != 1))
+        pixSetAll(pixd);
+
+        /* Blit the images to the dest */
+    for (i = 0, ni = 0; i < nrows; i++) {
+        ystart = spacing + i * (hmax + spacing);
+        for (j = 0; j < ncols && ni < n; j++, ni++) {
+            xstart = spacing + j * (wmax + spacing);
+            pix1 = pixaGetPix(pixa1, ni, L_CLONE);
+            if (ni == 0) res = pixGetXRes(pix1);
+            pixGetDimensions(pix1, &wt, &ht, NULL);
+            pixRasterop(pixd, xstart, ystart, wt, ht, PIX_SRC, pix1, 0, 0);
+            pixDestroy(&pix1);
+        }
+    }
+    pixSetResolution(pixd, res, res);
+
+    pixaDestroy(&pixa1);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiledInRows()
+ *
+ * \param[in]    pixa
+ * \param[in]    outdepth     output depth: 1, 8 or 32 bpp
+ * \param[in]    maxwidth     of output image
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    background   0 for white, 1 for black; this is the color
+ *                            of the spacing between the images
+ * \param[in]    spacing      between images, and on outside
+ * \param[in]    border       width of black border added to each image;
+ *                            use 0 for no border
+ * \return  pixd of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pixa to a single image of width not to
+ *          exceed maxwidth, with background color either white or black,
+ *          and with each row tiled such that the top of each pix is
+ *          aligned and separated by 'spacing' from the next one.
+ *          A black border can be added to each pix.
+ *      (2) All pix are converted to outdepth; existing colormaps are removed.
+ *      (3) This does a reasonably spacewise-efficient job of laying
+ *          out the individual pix images into a tiled composite.
+ *      (4) A serialized boxa giving the location in pixd of each input
+ *          pix (without added border) is stored in the text string of pixd.
+ *          This allows, e.g., regeneration of a pixa from pixd, using
+ *          pixaCreateFromBoxa().  If there is no scaling and the depth of
+ *          each input pix in the pixa is the same, this tiling operation
+ *          can be inverted using the boxa (except for loss of text in
+ *          each of the input pix):
+ *            pix1 = pixaDisplayTiledInRows(pixa1, 1, 1500, 1.0, 0, 30, 0);
+ *            char *boxatxt = pixGetText(pix1);
+ *            boxa1 = boxaReadMem((l_uint8 *)boxatxt, strlen(boxatxt));
+ *            pixa2 = pixaCreateFromBoxa(pix1, boxa1, 0, 0, NULL);
+ * </pre>
+ */
+PIX *
+pixaDisplayTiledInRows(PIXA      *pixa,
+                       l_int32    outdepth,
+                       l_int32    maxwidth,
+                       l_float32  scalefactor,
+                       l_int32    background,
+                       l_int32    spacing,
+                       l_int32    border)
+{
+l_int32   h;  /* cumulative height over all the rows */
+l_int32   w;  /* cumulative height in the current row */
+l_int32   bordval, wtry, wt, ht;
+l_int32   irow;  /* index of current pix in current row */
+l_int32   wmaxrow;  /* width of the largest row */
+l_int32   maxh;  /* max height in row */
+l_int32   i, j, index, n, x, y, nrows, ninrow, res;
+size_t    size;
+l_uint8  *data;
+BOXA     *boxa;
+NUMA     *nainrow;  /* number of pix in the row */
+NUMA     *namaxh;  /* height of max pix in the row */
+PIX      *pix, *pixn, *pix1, *pixd;
+PIXA     *pixan;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    if (outdepth != 1 && outdepth != 8 && outdepth != 32)
+        return (PIX *)ERROR_PTR("outdepth not in {1, 8, 32}", __func__, NULL);
+    spacing = L_MAX(spacing, 0);
+    border = L_MAX(border, 0);
+    if (scalefactor <= 0.0) scalefactor = 1.0;
+
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* Normalize depths, scale, remove colormaps; optionally add border */
+    pixan = pixaCreate(n);
+    bordval = (outdepth == 1) ? 1 : 0;
+    for (i = 0; i < n; i++) {
+        if ((pix = pixaGetPix(pixa, i, L_CLONE)) == NULL)
+            continue;
+
+        if (outdepth == 1)
+            pixn = pixConvertTo1(pix, 128);
+        else if (outdepth == 8)
+            pixn = pixConvertTo8(pix, FALSE);
+        else  /* outdepth == 32 */
+            pixn = pixConvertTo32(pix);
+        pixDestroy(&pix);
+
+        if (scalefactor != 1.0)
+            pix1 = pixScale(pixn, scalefactor, scalefactor);
+        else
+            pix1 = pixClone(pixn);
+        if (border)
+            pixd = pixAddBorder(pix1, border, bordval);
+        else
+            pixd = pixClone(pix1);
+        pixDestroy(&pixn);
+        pixDestroy(&pix1);
+
+        pixaAddPix(pixan, pixd, L_INSERT);
+    }
+    if (pixaGetCount(pixan) != n) {
+        n = pixaGetCount(pixan);
+        L_WARNING("only got %d components\n", __func__, n);
+        if (n == 0) {
+            pixaDestroy(&pixan);
+            return (PIX *)ERROR_PTR("no components", __func__, NULL);
+        }
+    }
+
+        /* Compute parameters for layout */
+    nainrow = numaCreate(0);
+    namaxh = numaCreate(0);
+    wmaxrow = 0;
+    w = h = spacing;
+    maxh = 0;  /* max height in row */
+    for (i = 0, irow = 0; i < n; i++, irow++) {
+        pixaGetPixDimensions(pixan, i, &wt, &ht, NULL);
+        wtry = w + wt + spacing;
+        if (wtry > maxwidth) {  /* end the current row and start next one */
+            numaAddNumber(nainrow, irow);
+            numaAddNumber(namaxh, maxh);
+            wmaxrow = L_MAX(wmaxrow, w);
+            h += maxh + spacing;
+            irow = 0;
+            w = wt + 2 * spacing;
+            maxh = ht;
+        } else {
+            w = wtry;
+            maxh = L_MAX(maxh, ht);
+        }
+    }
+
+        /* Enter the parameters for the last row */
+    numaAddNumber(nainrow, irow);
+    numaAddNumber(namaxh, maxh);
+    wmaxrow = L_MAX(wmaxrow, w);
+    h += maxh + spacing;
+
+    if ((pixd = pixCreate(wmaxrow, h, outdepth)) == NULL) {
+        numaDestroy(&nainrow);
+        numaDestroy(&namaxh);
+        pixaDestroy(&pixan);
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    }
+
+        /* Reset the background color if necessary */
+    if ((background == 1 && outdepth == 1) ||
+        (background == 0 && outdepth != 1))
+        pixSetAll(pixd);
+
+        /* Blit the images to the dest, and save the boxa identifying
+         * the image regions that do not include the borders. */
+    nrows = numaGetCount(nainrow);
+    y = spacing;
+    boxa = boxaCreate(n);
+    for (i = 0, index = 0; i < nrows; i++) {  /* over rows */
+        numaGetIValue(nainrow, i, &ninrow);
+        numaGetIValue(namaxh, i, &maxh);
+        x = spacing;
+        for (j = 0; j < ninrow; j++, index++) {   /* over pix in row */
+            pix = pixaGetPix(pixan, index, L_CLONE);
+            if (index == 0) {
+                res = pixGetXRes(pix);
+                pixSetResolution(pixd, res, res);
+            }
+            pixGetDimensions(pix, &wt, &ht, NULL);
+            boxaAddBox(boxa, boxCreate(x + border, y + border,
+                wt - 2 * border, ht - 2 *border), L_INSERT);
+            pixRasterop(pixd, x, y, wt, ht, PIX_SRC, pix, 0, 0);
+            pixDestroy(&pix);
+            x += wt + spacing;
+        }
+        y += maxh + spacing;
+    }
+    if (boxaWriteMem(&data, &size, boxa) == 0)
+        pixSetText(pixd, (char *)data);  /* data is ascii */
+    LEPT_FREE(data);
+    boxaDestroy(&boxa);
+
+    numaDestroy(&nainrow);
+    numaDestroy(&namaxh);
+    pixaDestroy(&pixan);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiledInColumns()
+ *
+ * \param[in]    pixas
+ * \param[in]    nx           number of columns in output image
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    spacing      between images, and on outside; can be < 0
+ * \param[in]    border       width of black border added to each image;
+ *                            use 0 for no border
+ * \return  pixd of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pixa to a single image with &nx columns of
+ *          subimages.  The background color is white, and each row
+ *          is tiled such that the top of each pix is aligned and
+ *          each pix is separated by 'spacing' from the next one.
+ *          A black border can be added to each pix.
+ *      (2) The output depth is determined by the largest depth
+ *          required by the pix in the pixa.  Colormaps are removed.
+ *      (3) A serialized boxa giving the location in pixd of each input
+ *          pix (without added border) is stored in the text string of pixd.
+ *          This allows, e.g., regeneration of a pixa from pixd, using
+ *          pixaCreateFromBoxa().  If there is no scaling and the depth of
+ *          each input pix in the pixa is the same, this tiling operation
+ *          can be inverted using the boxa (except for loss of text in
+ *          each of the input pix):
+ *            pix1 = pixaDisplayTiledInColumns(pixa1, 3, 1.0, 0, 30, 2);
+ *            char *boxatxt = pixGetText(pix1);
+ *            boxa1 = boxaReadMem((l_uint8 *)boxatxt, strlen(boxatxt));
+ *            pixa2 = pixaCreateFromBoxa(pix1, boxa1, NULL);
+ * </pre>
+ */
+PIX *
+pixaDisplayTiledInColumns(PIXA      *pixas,
+                          l_int32    nx,
+                          l_float32  scalefactor,
+                          l_int32    spacing,
+                          l_int32    border)
+{
+l_int32   i, j, index, n, x, y, nrows, wb, hb, w, h, maxd, maxh, bordval, res;
+size_t    size;
+l_uint8  *data;
+BOX      *box;
+BOXA     *boxa;
+PIX      *pix1, *pix2, *pix3, *pixd;
+PIXA     *pixa1, *pixa2;
+
+    if (!pixas)
+        return (PIX *)ERROR_PTR("pixas not defined", __func__, NULL);
+    border = L_MAX(border, 0);
+    if (scalefactor <= 0.0) scalefactor = 1.0;
+    if ((n = pixaGetCount(pixas)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* Convert to same depth, if necessary */
+    pixa1 = pixaConvertToSameDepth(pixas);
+    pixaGetDepthInfo(pixa1, &maxd, NULL);
+
+        /* Scale and optionally add border */
+    pixa2 = pixaCreate(n);
+    bordval = (maxd == 1) ? 1 : 0;
+    for (i = 0; i < n; i++) {
+        if ((pix1 = pixaGetPix(pixa1, i, L_CLONE)) == NULL)
+            continue;
+        if (scalefactor != 1.0)
+            pix2 = pixScale(pix1, scalefactor, scalefactor);
+        else
+            pix2 = pixClone(pix1);
+        if (border)
+            pix3 = pixAddBorder(pix2, border, bordval);
+        else
+            pix3 = pixClone(pix2);
+        if (i == 0) res = pixGetXRes(pix3);
+        pixaAddPix(pixa2, pix3, L_INSERT);
+        pixDestroy(&pix1);
+        pixDestroy(&pix2);
+    }
+    pixaDestroy(&pixa1);
+    if (pixaGetCount(pixa2) != n) {
+        n = pixaGetCount(pixa2);
+        L_WARNING("only got %d components\n", __func__, n);
+        if (n == 0) {
+            pixaDestroy(&pixa2);
+            return (PIX *)ERROR_PTR("no components", __func__, NULL);
+        }
+    }
+
+        /* Compute layout parameters and save as a boxa */
+    boxa = boxaCreate(n);
+    nrows = (n + nx - 1) / nx;
+    y = spacing;
+    for (i = 0, index = 0; i < nrows; i++) {
+        x = spacing;
+        maxh = 0;
+        for (j = 0; j < nx && index < n; j++) {
+            pixaGetPixDimensions(pixa2, index, &wb, &hb, NULL);
+            box = boxCreate(x, y, wb, hb);
+            boxaAddBox(boxa, box, L_INSERT);
+            maxh = L_MAX(maxh, hb + spacing);
+            x += wb + spacing;
+            index++;
+        }
+        y += maxh;
+    }
+    pixaSetBoxa(pixa2, boxa, L_INSERT);
+
+        /* Render the output pix */
+    boxaGetExtent(boxa, &w, &h, NULL);
+    pixd = pixaDisplay(pixa2, w + spacing, h + spacing);
+    pixSetResolution(pixd, res, res);
+
+        /* Save the boxa in the text field of the output pix */
+    if (boxaWriteMem(&data, &size, boxa) == 0)
+        pixSetText(pixd, (char *)data);  /* data is ascii */
+    LEPT_FREE(data);
+
+    pixaDestroy(&pixa2);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiledAndScaled()
+ *
+ * \param[in]    pixa
+ * \param[in]    outdepth    output depth: 1, 8 or 32 bpp
+ * \param[in]    tilewidth   each pix is scaled to this width
+ * \param[in]    ncols       number of tiles in each row
+ * \param[in]    background  0 for white, 1 for black; this is the color
+ *                           of the spacing between the images
+ * \param[in]    spacing     between images, and on outside
+ * \param[in]    border      width of additional black border on each image;
+ *                           use 0 for no border
+ * \return  pix of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This can be used to tile a number of renderings of
+ *          an image that are at different scales and depths.
+ *      (2) Each image, after scaling and optionally adding the
+ *          black border, has width 'tilewidth'.  Thus, the border does
+ *          not affect the spacing between the image tiles.  The
+ *          maximum allowed border width is tilewidth / 5.
+ * </pre>
+ */
+PIX *
+pixaDisplayTiledAndScaled(PIXA    *pixa,
+                          l_int32  outdepth,
+                          l_int32  tilewidth,
+                          l_int32  ncols,
+                          l_int32  background,
+                          l_int32  spacing,
+                          l_int32  border)
+{
+l_int32    x, y, w, h, wd, hd, d, res;
+l_int32    i, n, nrows, maxht, ninrow, irow, bordval;
+l_int32   *rowht;
+l_float32  scalefact;
+PIX       *pix, *pixn, *pix1, *pixb, *pixd;
+PIXA      *pixan;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    if (outdepth != 1 && outdepth != 8 && outdepth != 32)
+        return (PIX *)ERROR_PTR("outdepth not in {1, 8, 32}", __func__, NULL);
+    if (ncols <= 0)
+        return (PIX *)ERROR_PTR("ncols must be > 0", __func__, NULL);
+    spacing = L_MAX(spacing, 0);
+    if (border < 0 || border > tilewidth / 5)
+        border = 0;
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* Normalize scale and depth for each pix; optionally add border */
+    pixan = pixaCreate(n);
+    bordval = (outdepth == 1) ? 1 : 0;
+    for (i = 0; i < n; i++) {
+        if ((pix = pixaGetPix(pixa, i, L_CLONE)) == NULL)
+            continue;
+
+        pixGetDimensions(pix, &w, &h, &d);
+        scalefact = (l_float32)(tilewidth - 2 * border) / (l_float32)w;
+        if (d == 1 && outdepth > 1 && scalefact < 1.0)
+            pix1 = pixScaleToGray(pix, scalefact);
+        else
+            pix1 = pixScale(pix, scalefact, scalefact);
+
+        if (outdepth == 1)
+            pixn = pixConvertTo1(pix1, 128);
+        else if (outdepth == 8)
+            pixn = pixConvertTo8(pix1, FALSE);
+        else  /* outdepth == 32 */
+            pixn = pixConvertTo32(pix1);
+        pixDestroy(&pix1);
+
+        if (border)
+            pixb = pixAddBorder(pixn, border, bordval);
+        else
+            pixb = pixClone(pixn);
+
+        pixaAddPix(pixan, pixb, L_INSERT);
+        pixDestroy(&pix);
+        pixDestroy(&pixn);
+    }
+    if ((n = pixaGetCount(pixan)) == 0) { /* should not have changed! */
+        pixaDestroy(&pixan);
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    }
+
+        /* Determine the size of each row and of pixd */
+    wd = tilewidth * ncols + spacing * (ncols + 1);
+    nrows = (n + ncols - 1) / ncols;
+    if ((rowht = (l_int32 *)LEPT_CALLOC(nrows, sizeof(l_int32))) == NULL) {
+        pixaDestroy(&pixan);
+        return (PIX *)ERROR_PTR("rowht array not made", __func__, NULL);
+    }
+    maxht = 0;
+    ninrow = 0;
+    irow = 0;
+    for (i = 0; i < n; i++) {
+        pix = pixaGetPix(pixan, i, L_CLONE);
+        ninrow++;
+        pixGetDimensions(pix, &w, &h, NULL);
+        maxht = L_MAX(h, maxht);
+        if (ninrow == ncols) {
+            rowht[irow] = maxht;
+            maxht = ninrow = 0;  /* reset */
+            irow++;
+        }
+        pixDestroy(&pix);
+    }
+    if (ninrow > 0) {   /* last fencepost */
+        rowht[irow] = maxht;
+        irow++;  /* total number of rows */
+    }
+    nrows = irow;
+    hd = spacing * (nrows + 1);
+    for (i = 0; i < nrows; i++)
+        hd += rowht[i];
+
+    pixd = pixCreate(wd, hd, outdepth);
+    if ((background == 1 && outdepth == 1) ||
+        (background == 0 && outdepth != 1))
+        pixSetAll(pixd);
+
+        /* Now blit images to pixd */
+    x = y = spacing;
+    irow = 0;
+    for (i = 0; i < n; i++) {
+        pix = pixaGetPix(pixan, i, L_CLONE);
+        if (i == 0) {
+            res = pixGetXRes(pix);
+            pixSetResolution(pixd, res, res);
+        }
+        pixGetDimensions(pix, &w, &h, NULL);
+        if (i && ((i % ncols) == 0)) {  /* start new row */
+            x = spacing;
+            y += spacing + rowht[irow];
+            irow++;
+        }
+        pixRasterop(pixd, x, y, w, h, PIX_SRC, pix, 0, 0);
+        x += tilewidth + spacing;
+        pixDestroy(&pix);
+    }
+
+    pixaDestroy(&pixan);
+    LEPT_FREE(rowht);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiledWithText()
+ *
+ * \param[in]    pixa
+ * \param[in]    maxwidth     of output image
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    spacing      between images, and on outside
+ * \param[in]    border       width of black border added to each image;
+ *                            use 0 for no border
+ * \param[in]    fontsize     4, 6, ... 20
+ * \param[in]    textcolor    0xrrggbb00
+ * \return  pixd of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This is a version of pixaDisplayTiledInRows() that prints, below
+ *          each pix, the text in the pix text field.  Up to 127 chars
+ *          of text in the pix text field are rendered below each pix.
+ *      (2) It renders a pixa to a single image of width not to
+ *          exceed %maxwidth, with white background color, with each row
+ *          tiled such that the top of each pix is aligned and separated
+ *          by %spacing from the next one.
+ *      (3) All pix are converted to 32 bpp.
+ *      (4) This does a reasonably spacewise-efficient job of laying
+ *          out the individual pix images into a tiled composite.
+ * </pre>
+ */
+PIX *
+pixaDisplayTiledWithText(PIXA      *pixa,
+                         l_int32    maxwidth,
+                         l_float32  scalefactor,
+                         l_int32    spacing,
+                         l_int32    border,
+                         l_int32    fontsize,
+                         l_uint32   textcolor)
+{
+char      buf[128];
+char     *textstr;
+l_int32   i, n, maxw;
+L_BMF    *bmf;
+PIX      *pix1, *pix2, *pix3, *pix4, *pixd;
+PIXA     *pixad;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    if (maxwidth <= 0)
+        return (PIX *)ERROR_PTR("invalid maxwidth", __func__, NULL);
+    spacing = L_MAX(spacing, 0);
+    border = L_MAX(border, 0);
+    if (scalefactor <= 0.0) scalefactor = 1.0;
+    if (fontsize < 4 || fontsize > 20 || (fontsize & 1)) {
+        l_int32 fsize = L_MAX(L_MIN(fontsize, 20), 4);
+        if (fsize & 1) fsize--;
+        L_WARNING("changed fontsize from %d to %d\n", __func__,
+                  fontsize, fsize);
+        fontsize = fsize;
+    }
+
+        /* Be sure the width can accommodate a single column of images */
+    pixaSizeRange(pixa, NULL, NULL, &maxw, NULL);
+    maxwidth = L_MAX(maxwidth, scalefactor * (maxw + 2 * spacing + 2 * border));
+
+    bmf = bmfCreate(NULL, fontsize);
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pix1 = pixaGetPix(pixa, i, L_CLONE);
+        pix2 = pixConvertTo32(pix1);
+        pix3 = pixAddBorderGeneral(pix2, spacing / 2, spacing / 2, spacing / 2,
+                                   spacing / 2, 0xffffff00);
+        textstr = pixGetText(pix1);
+        if (textstr && strlen(textstr) > 0) {
+            snprintf(buf, sizeof(buf), "%s", textstr);
+            pix4 = pixAddSingleTextblock(pix3, bmf, buf, textcolor,
+                                     L_ADD_BELOW, NULL);
+        } else {
+            pix4 = pixClone(pix3);
+        }
+        pixaAddPix(pixad, pix4, L_INSERT);
+        pixDestroy(&pix1);
+        pixDestroy(&pix2);
+        pixDestroy(&pix3);
+    }
+    bmfDestroy(&bmf);
+
+    pixd = pixaDisplayTiledInRows(pixad, 32, maxwidth, scalefactor,
+                                  0, spacing, border);
+    pixaDestroy(&pixad);
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaDisplayTiledByIndex()
+ *
+ * \param[in]    pixa
+ * \param[in]    na         numa with indices corresponding to the pix in pixa
+ * \param[in]    width      each pix is scaled to this width
+ * \param[in]    spacing    between images, and on outside
+ * \param[in]    border     width of black border added to each image;
+ *                          use 0 for no border
+ * \param[in]    fontsize   4, 6, ... 20
+ * \param[in]    textcolor  0xrrggbb00
+ * \return  pixd of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pixa to a single image with white
+ *          background color, where the pix are placed in columns
+ *          given by the index value in the numa.  Each pix
+ *          is separated by %spacing from the adjacent ones, and
+ *          an optional border is placed around them.
+ *      (2) Up to 127 chars of text in the pix text field are rendered
+ *          below each pix.  Use newlines in the text field to write
+ *          the text in multiple lines that fit within the pix width.
+ *      (3) To avoid having empty columns, if there are N different
+ *          index values, they should be in [0 ... N-1].
+ *      (4) All pix are converted to 32 bpp.
+ * </pre>
+ */
+PIX *
+pixaDisplayTiledByIndex(PIXA     *pixa,
+                        NUMA     *na,
+                        l_int32   width,
+                        l_int32   spacing,
+                        l_int32   border,
+                        l_int32   fontsize,
+                        l_uint32  textcolor)
+{
+char      buf[128];
+char     *textstr;
+l_int32    i, n, x, y, w, h, yval, index;
+l_float32  maxindex;
+L_BMF     *bmf;
+BOX       *box;
+NUMA      *nay;  /* top of the next pix to add in that column */
+PIX       *pix1, *pix2, *pix3, *pix4, *pix5, *pixd;
+PIXA      *pixad;
+
+    if (!pixa)
+        return (PIX *)ERROR_PTR("pixa not defined", __func__, NULL);
+    if (!na)
+        return (PIX *)ERROR_PTR("na not defined", __func__, NULL);
+    if ((n = pixaGetCount(pixa)) == 0)
+        return (PIX *)ERROR_PTR("no pixa components", __func__, NULL);
+    if (n != numaGetCount(na))
+        return (PIX *)ERROR_PTR("pixa and na counts differ", __func__, NULL);
+    if (width <= 0)
+        return (PIX *)ERROR_PTR("invalid width", __func__, NULL);
+    if (width < 20)
+        L_WARNING("very small width: %d\n", __func__, width);
+    spacing = L_MAX(spacing, 0);
+    border = L_MAX(border, 0);
+    if (fontsize < 4 || fontsize > 20 || (fontsize & 1)) {
+        l_int32 fsize = L_MAX(L_MIN(fontsize, 20), 4);
+        if (fsize & 1) fsize--;
+        L_WARNING("changed fontsize from %d to %d\n", __func__,
+                  fontsize, fsize);
+        fontsize = fsize;
+    }
+
+        /* The pix will be rendered in the order they occupy in pixa. */
+    bmf = bmfCreate(NULL, fontsize);
+    pixad = pixaCreate(n);
+    numaGetMax(na, &maxindex, NULL);
+    nay = numaMakeConstant(spacing, lept_roundftoi(maxindex) + 1);
+    for (i = 0; i < n; i++) {
+        numaGetIValue(na, i, &index);
+        numaGetIValue(nay, index, &yval);
+        pix1 = pixaGetPix(pixa, i, L_CLONE);
+        pix2 = pixConvertTo32(pix1);
+        pix3 = pixScaleToSize(pix2, width, 0);
+        pix4 = pixAddBorderGeneral(pix3, border, border, border, border, 0);
+        textstr = pixGetText(pix1);
+        if (textstr && strlen(textstr) > 0) {
+            snprintf(buf, sizeof(buf), "%s", textstr);
+            pix5 = pixAddTextlines(pix4, bmf, textstr, textcolor, L_ADD_BELOW);
+        } else {
+            pix5 = pixClone(pix4);
+        }
+        pixaAddPix(pixad, pix5, L_INSERT);
+        x = spacing + border + index * (2 * border + width + spacing);
+        y = yval;
+        pixGetDimensions(pix5, &w, &h, NULL);
+        yval += h + spacing;
+        numaSetValue(nay, index, yval);
+        box = boxCreate(x, y, w, h);
+        pixaAddBox(pixad, box, L_INSERT);
+        pixDestroy(&pix1);
+        pixDestroy(&pix2);
+        pixDestroy(&pix3);
+        pixDestroy(&pix4);
+    }
+    numaDestroy(&nay);
+    bmfDestroy(&bmf);
+
+    pixd = pixaDisplay(pixad, 0, 0);
+    pixaDestroy(&pixad);
+    return pixd;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                         Pixa pair display                           *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaDisplayPairTiledInColumns()
+ *
+ * \param[in]    pixas1
+ * \param[in]    pixas2
+ * \param[in]    nx           number of columns in output image
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    spacing1     between images within a pair
+ * \param[in]    spacing2     between image pairs, and on outside
+ * \param[in]    border1      width of black border added to each image;
+ *                            use 0 for no border
+ * \param[in]    border2      width of black border added to each image pair.
+ *                            use 0 for no border
+ * \param[in]    fontsize     to print index below each pair. Valid set is
+ *                            {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \param[in]    startindex   index for the first pair; ignore if %fontsize= 0
+ * \param[in]    sa           [optional] array of text strings to display
+ * \return  pixd of tiled images, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pair of pixa in a single image with &nx columns of
+ *          tiled pairs.  The background color is white, and each row
+ *          is tiled such that the top of each pix is aligned.
+ *          The pix are displayed in pairs, taken from the input pixas.
+ *          Input %pixas1 and %pixas2 must have the same count of pix.
+ *      (2) If %fontsize != 0, text is displayed below each pair, and the
+ *          output depth is 32 bpp.  If %sa is defined, the text is taken
+ *          sequentially from %sa; otherwise, an integer is displayed with
+ *          numbers chosen consecutively starting with %startindex.
+ *      (3) If %fontsize == 0, the output depth is determined by the largest
+ *          depth required by the pix in the pixa.  Colormaps are removed.
+ *      (4) Start with these values and tune for aesthetics:
+ *            %nx = 5, %spacing1 = %spacing2 = 15, %border1 = %border2 = 2,
+ *            %fontsize = 8.
+ * </pre>
+ */
+PIX *
+pixaDisplayPairTiledInColumns(PIXA      *pixas1,
+                              PIXA      *pixas2,
+                              l_int32    nx,
+                              l_float32  scalefactor,
+                              l_int32    spacing1,
+                              l_int32    spacing2,
+                              l_int32    border1,
+                              l_int32    border2,
+                              l_int32    fontsize,
+                              l_int32    startindex,
+                              SARRAY    *sa)
+{
+l_int32  i, n, w, maxd, maxd1, maxd2, text;
+NUMA    *na;
+PIX     *pixs1, *pixs2, *pix1, *pix2, *pix3, *pix4;
+PIX     *pix5, *pix6, *pix7, *pix8, *pix9;
+PIXA    *pixa1, *pixa2;
+SARRAY  *sa1;
+
+    if (!pixas1)
+        return (PIX *)ERROR_PTR("pixas1 not defined", __func__, NULL);
+    if (!pixas2)
+        return (PIX *)ERROR_PTR("pixas2 not defined", __func__, NULL);
+    spacing1 = L_MAX(spacing1, 0);
+    spacing2 = L_MAX(spacing2, 0);
+    border1 = L_MAX(border1, 0);
+    border2 = L_MAX(border2, 0);
+    if (scalefactor <= 0.0) scalefactor = 1.0;
+    if ((n = pixaGetCount(pixas1)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+    if (n != pixaGetCount(pixas2))
+        return (PIX *)ERROR_PTR("pixa sizes differ", __func__, NULL);
+    text = (fontsize <= 0) ? 0 : 1;
+    if (text && (fontsize < 4 || fontsize > 20 || (fontsize & 1))) {
+        l_int32 fsize = L_MAX(L_MIN(fontsize, 20), 4);
+        if (fsize & 1) fsize--;
+        L_WARNING("changed fontsize from %d to %d\n", __func__,
+                  fontsize, fsize);
+        fontsize = fsize;
+    }
+
+        /* Convert to same depth, if necessary */
+    if (text) {  /* adding color text; convert to 32 bpp */
+        maxd = 32;
+    } else {
+        pixaGetRenderingDepth(pixas1, &maxd1);
+        pixaGetRenderingDepth(pixas2, &maxd2);
+        maxd = L_MAX(maxd1, maxd2);
+    }
+
+        /* Optionally scale and add borders to each pair;
+           then combine the pairs and add outer border.  */
+    pixa1 = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pixs1 = pixaGetPix(pixas1, i, L_CLONE);
+        pixs2 = pixaGetPix(pixas2, i, L_CLONE);
+        if (!pixs1 || !pixs2) continue;
+        if (maxd == 1) {
+            pix1 = pixClone(pixs1);
+            pix2 = pixClone(pixs2);
+        } else if (maxd == 8) {
+            pix1 = pixConvertTo8(pixs1, 0);
+            pix2 = pixConvertTo8(pixs2, 0);
+        } else {  /* maxd == 32 */
+            pix1 = pixConvertTo32(pixs1);
+            pix2 = pixConvertTo32(pixs2);
+        }
+        pixDestroy(&pixs1);
+        pixDestroy(&pixs2);
+        if (scalefactor != 1.0) {
+            pix3 = pixScale(pix1, scalefactor, scalefactor);
+            pix4 = pixScale(pix2, scalefactor, scalefactor);
+        } else {
+            pix3 = pixClone(pix1);
+            pix4 = pixClone(pix2);
+        }
+        pixDestroy(&pix1);
+        pixDestroy(&pix2);
+        if (border1) {
+            pix5 = pixAddBlackOrWhiteBorder(pix3, border1, border1, border1,
+                                            border1, L_GET_BLACK_VAL);
+            pix6 = pixAddBlackOrWhiteBorder(pix4, border1, border1, border1,
+                                            border1, L_GET_BLACK_VAL);
+        } else {
+            pix5 = pixClone(pix3);
+            pix6 = pixClone(pix4);
+        }
+        pixDestroy(&pix3);
+        pixDestroy(&pix4);
+        if (spacing1) {  /* white border */
+            pix7 = pixAddBlackOrWhiteBorder(pix5, spacing1 / 2, spacing1 / 2,
+                                spacing1 / 2, spacing1 / 2, L_GET_WHITE_VAL);
+            pix8 = pixAddBlackOrWhiteBorder(pix6, spacing1 / 2, spacing1 / 2,
+                                spacing1 / 2, spacing1 / 2, L_GET_WHITE_VAL);
+        } else {
+            pix7 = pixClone(pix5);
+            pix8 = pixClone(pix6);
+        }
+        pixDestroy(&pix5);
+        pixDestroy(&pix6);
+        pixa2 = pixaCreate(2);
+        pixaAddPix(pixa2, pix7, L_INSERT);
+        pixaAddPix(pixa2, pix8, L_INSERT);
+        pix9 = pixaDisplayTiledInColumns(pixa2, 2, 1.0, 0, 0);
+        pixaAddPix(pixa1, pix9, L_INSERT);
+        pixaDestroy(&pixa2);
+    }
+
+    if (!text) {
+        pix1 = pixaDisplayTiledInColumns(pixa1, nx, 1.0, spacing2, border2);
+    } else {
+        if (sa) {
+            pixaSetText(pixa1, NULL, sa);
+        } else {
+            n = pixaGetCount(pixa1);
+            na = numaMakeSequence(startindex, 1, n);
+            sa1 = numaConvertToSarray(na, 4, 0, 0, L_INTEGER_VALUE);
+            pixaSetText(pixa1, NULL, sa1);
+            numaDestroy(&na);
+            sarrayDestroy(&sa1);
+        }
+        pixaSizeRange(pixa1, NULL, NULL, &w, NULL);
+        pix1 = pixaDisplayTiledWithText(pixa1, w * (nx + 1), 1.0, spacing2,
+                                        border2, fontsize, 0xff000000);
+    }
+    pixaDestroy(&pixa1);
+    return pix1;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                              Pixaa Display                          *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaaDisplay()
+ *
+ * \param[in]    paa
+ * \param[in]    w, h   if set to 0, the size is determined from the
+ *                      bounding box of the components in pixa
+ * \return  pix, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) Each pix of the paa is displayed at the location given by
+ *          its box, translated by the box of the containing pixa
+ *          if it exists.
+ * </pre>
+ */
+PIX *
+pixaaDisplay(PIXAA   *paa,
+             l_int32  w,
+             l_int32  h)
+{
+l_int32  i, j, n, nbox, na, d, wmax, hmax, x, y, xb, yb, wb, hb;
+BOXA    *boxa1;  /* top-level boxa */
+BOXA    *boxa;
+PIX     *pix1, *pixd;
+PIXA    *pixa;
+
+    if (!paa)
+        return (PIX *)ERROR_PTR("paa not defined", __func__, NULL);
+
+    n = pixaaGetCount(paa, NULL);
+    if (n == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* If w and h not input, determine the minimum size required
+         * to contain the origin and all c.c. */
+    boxa1 = pixaaGetBoxa(paa, L_CLONE);
+    nbox = boxaGetCount(boxa1);
+    if (w == 0 || h == 0) {
+        if (nbox == n) {
+            boxaGetExtent(boxa1, &w, &h, NULL);
+        } else {  /* have to use the lower-level boxa for each pixa */
+            wmax = hmax = 0;
+            for (i = 0; i < n; i++) {
+                pixa = pixaaGetPixa(paa, i, L_CLONE);
+                boxa = pixaGetBoxa(pixa, L_CLONE);
+                boxaGetExtent(boxa, &w, &h, NULL);
+                wmax = L_MAX(wmax, w);
+                hmax = L_MAX(hmax, h);
+                pixaDestroy(&pixa);
+                boxaDestroy(&boxa);
+            }
+            w = wmax;
+            h = hmax;
+        }
+    }
+
+        /* Get depth from first pix */
+    pixa = pixaaGetPixa(paa, 0, L_CLONE);
+    pix1 = pixaGetPix(pixa, 0, L_CLONE);
+    d = pixGetDepth(pix1);
+    pixaDestroy(&pixa);
+    pixDestroy(&pix1);
+
+    if ((pixd = pixCreate(w, h, d)) == NULL) {
+        boxaDestroy(&boxa1);
+        return (PIX *)ERROR_PTR("pixd not made", __func__, NULL);
+    }
+
+    x = y = 0;
+    for (i = 0; i < n; i++) {
+        pixa = pixaaGetPixa(paa, i, L_CLONE);
+        if (nbox == n)
+            boxaGetBoxGeometry(boxa1, i, &x, &y, NULL, NULL);
+        na = pixaGetCount(pixa);
+        for (j = 0; j < na; j++) {
+            pixaGetBoxGeometry(pixa, j, &xb, &yb, &wb, &hb);
+            pix1 = pixaGetPix(pixa, j, L_CLONE);
+            pixRasterop(pixd, x + xb, y + yb, wb, hb, PIX_PAINT, pix1, 0, 0);
+            pixDestroy(&pix1);
+        }
+        pixaDestroy(&pixa);
+    }
+    boxaDestroy(&boxa1);
+
+    return pixd;
+}
+
+
+/*!
+ * \brief   pixaaDisplayByPixa()
+ *
+ * \param[in]    paa
+ * \param[in]    maxnx        maximum number of columns for rendering each pixa
+ * \param[in]    scalefactor  applied to every pix; use 1.0 for no scaling
+ * \param[in]    hspacing     between images on a row (in the pixa)
+ * \param[in]    vspacing     between tiles rows, each corresponding to a pixa
+ * \param[in]    border       width of black border added to each image;
+ *                            use 0 for no border
+ * \return  pixd of images in %paa, tiled by pixa in row-major order
+ *
+ * <pre>
+ * Notes:
+ *      (1) This renders a pixaa into a single image.  The pix from each pixa
+ *          are rendered on a row.  If the number of pix in the pixa is
+ *          larger than %maxnx, the pix will be rendered into more than 1 row.
+ *          To insure that each pixa is rendered into one row, use %maxnx
+ *          at least as large as the max number of pix in the pixa.
+ *      (2) Each row is tiled such that the top of each pix is aligned and
+ *          each pix is separated by %hspacing from the next one.
+ *          A black border can be added to each pix.
+ *      (3) The resulting pix from each row are then rendered vertically,
+ *          separated by %vspacing from each other.
+ *      (4) The output depth is determined by the largest depth of all
+ *          the pix in %paa. Colormaps are removed.
+ * </pre>
+ */
+PIX *
+pixaaDisplayByPixa(PIXAA     *paa,
+                   l_int32    maxnx,
+                   l_float32  scalefactor,
+                   l_int32    hspacing,
+                   l_int32    vspacing,
+                   l_int32    border)
+{
+l_int32  i, n, vs;
+PIX     *pix1, *pix2;
+PIXA    *pixa1, *pixa2;
+
+    if (!paa)
+        return (PIX *)ERROR_PTR("paa not defined", __func__, NULL);
+    if (scalefactor <= 0.0) scalefactor = 1.0;
+    if (hspacing < 0) hspacing = 0;
+    if (vspacing < 0) vspacing = 0;
+    if (border < 0) border = 0;
+
+    if ((n = pixaaGetCount(paa, NULL)) == 0)
+        return (PIX *)ERROR_PTR("no components", __func__, NULL);
+
+        /* Vertical spacing of amount %hspacing is also added at this step */
+    pixa2 = pixaCreate(0);
+    for (i = 0; i < n; i++) {
+        pixa1 = pixaaGetPixa(paa, i, L_CLONE);
+        pix1 = pixaDisplayTiledInColumns(pixa1, maxnx, scalefactor,
+                                         hspacing, border);
+        pixaAddPix(pixa2, pix1, L_INSERT);
+        pixaDestroy(&pixa1);
+    }
+
+    vs = vspacing - 2 * hspacing;
+    pix2 = pixaDisplayTiledInColumns(pixa2, 1, scalefactor, vs, 0);
+    pixaDestroy(&pixa2);
+    return pix2;
+}
+
+
+/*!
+ * \brief   pixaaDisplayTiledAndScaled()
+ *
+ * \param[in]    paa
+ * \param[in]    outdepth    output depth: 1, 8 or 32 bpp
+ * \param[in]    tilewidth   each pix is scaled to this width
+ * \param[in]    ncols       number of tiles in each row
+ * \param[in]    background  0 for white, 1 for black; this is the color
+ *                           of the spacing between the images
+ * \param[in]    spacing     between images, and on outside
+ * \param[in]    border      width of additional black border on each image;
+ *                           use 0 for no border
+ * \return  pixa of tiled images, one image for each pixa in
+ *                    the paa, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) For each pixa, this generates from all the pix a
+ *          tiled/scaled output pix, and puts it in the output pixa.
+ *      (2) See comments in pixaDisplayTiledAndScaled().
+ * </pre>
+ */
+PIXA *
+pixaaDisplayTiledAndScaled(PIXAA   *paa,
+                           l_int32  outdepth,
+                           l_int32  tilewidth,
+                           l_int32  ncols,
+                           l_int32  background,
+                           l_int32  spacing,
+                           l_int32  border)
+{
+l_int32  i, n;
+PIX     *pix;
+PIXA    *pixa, *pixad;
+
+    if (!paa)
+        return (PIXA *)ERROR_PTR("paa not defined", __func__, NULL);
+    if (outdepth != 1 && outdepth != 8 && outdepth != 32)
+        return (PIXA *)ERROR_PTR("outdepth not in {1, 8, 32}", __func__, NULL);
+    if (ncols <= 0)
+        return (PIXA *)ERROR_PTR("ncols must be > 0", __func__, NULL);
+    if (border < 0 || border > tilewidth / 5)
+        border = 0;
+
+    if ((n = pixaaGetCount(paa, NULL)) == 0)
+        return (PIXA *)ERROR_PTR("no components", __func__, NULL);
+
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pixa = pixaaGetPixa(paa, i, L_CLONE);
+        pix = pixaDisplayTiledAndScaled(pixa, outdepth, tilewidth, ncols,
+                                        background, spacing, border);
+        pixaAddPix(pixad, pix, L_INSERT);
+        pixaDestroy(&pixa);
+    }
+
+    return pixad;
+}
+
+
+/*---------------------------------------------------------------------*
+ *         Conversion of all pix to specified type (e.g., depth)       *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaConvertTo1()
+ *
+ * \param[in]    pixas
+ * \param[in]    thresh    threshold for final binarization from 8 bpp gray
+ * \return  pixad, or NULL on error
+ */
+PIXA *
+pixaConvertTo1(PIXA    *pixas,
+               l_int32  thresh)
+{
+l_int32  i, n;
+BOXA    *boxa;
+PIX     *pix1, *pix2;
+PIXA    *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+
+    n = pixaGetCount(pixas);
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pix1 = pixaGetPix(pixas, i, L_CLONE);
+        pix2 = pixConvertTo1(pix1, thresh);
+        pixaAddPix(pixad, pix2, L_INSERT);
+        pixDestroy(&pix1);
+    }
+
+    boxa = pixaGetBoxa(pixas, L_COPY);
+    pixaSetBoxa(pixad, boxa, L_INSERT);
+    return pixad;
+}
+
+
+/*!
+ * \brief   pixaConvertTo8()
+ *
+ * \param[in]    pixas
+ * \param[in]    cmapflag   1 to give pixd a colormap; 0 otherwise
+ * \return  pixad each pix is 8 bpp, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) See notes for pixConvertTo8(), applied to each pix in pixas.
+ * </pre>
+ */
+PIXA *
+pixaConvertTo8(PIXA    *pixas,
+               l_int32  cmapflag)
+{
+l_int32  i, n;
+BOXA    *boxa;
+PIX     *pix1, *pix2;
+PIXA    *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+
+    n = pixaGetCount(pixas);
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pix1 = pixaGetPix(pixas, i, L_CLONE);
+        pix2 = pixConvertTo8(pix1, cmapflag);
+        pixaAddPix(pixad, pix2, L_INSERT);
+        pixDestroy(&pix1);
+    }
+
+    boxa = pixaGetBoxa(pixas, L_COPY);
+    pixaSetBoxa(pixad, boxa, L_INSERT);
+    return pixad;
+}
+
+
+/*!
+ * \brief   pixaConvertTo8Colormap()
+ *
+ * \param[in]    pixas
+ * \param[in]    dither   1 to dither if necessary; 0 otherwise
+ * \return  pixad each pix is 8 bpp, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) See notes for pixConvertTo8Colormap(), applied to each pix in pixas.
+ * </pre>
+ */
+PIXA *
+pixaConvertTo8Colormap(PIXA    *pixas,
+                       l_int32  dither)
+{
+l_int32  i, n;
+BOXA    *boxa;
+PIX     *pix1, *pix2;
+PIXA    *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+
+    n = pixaGetCount(pixas);
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pix1 = pixaGetPix(pixas, i, L_CLONE);
+        pix2 = pixConvertTo8Colormap(pix1, dither);
+        pixaAddPix(pixad, pix2, L_INSERT);
+        pixDestroy(&pix1);
+    }
+
+    boxa = pixaGetBoxa(pixas, L_COPY);
+    pixaSetBoxa(pixad, boxa, L_INSERT);
+    return pixad;
+}
+
+
+/*!
+ * \brief   pixaConvertTo32()
+ *
+ * \param[in]    pixas
+ * \return  pixad 32 bpp rgb, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) See notes for pixConvertTo32(), applied to each pix in pixas.
+ *      (2) This can be used to allow 1 bpp pix in a pixa to be displayed
+ *          with color.
+ * </pre>
+ */
+PIXA *
+pixaConvertTo32(PIXA  *pixas)
+{
+l_int32  i, n;
+BOXA    *boxa;
+PIX     *pix1, *pix2;
+PIXA    *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+
+    n = pixaGetCount(pixas);
+    pixad = pixaCreate(n);
+    for (i = 0; i < n; i++) {
+        pix1 = pixaGetPix(pixas, i, L_CLONE);
+        pix2 = pixConvertTo32(pix1);
+        pixaAddPix(pixad, pix2, L_INSERT);
+        pixDestroy(&pix1);
+    }
+
+    boxa = pixaGetBoxa(pixas, L_COPY);
+    pixaSetBoxa(pixad, boxa, L_INSERT);
+    return pixad;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                        Pixa constrained selection                   *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaConstrainedSelect()
+ *
+ * \param[in]    pixas
+ * \param[in]    first      first index to choose; >= 0
+ * \param[in]    last       biggest possible index to reach;
+ *                          use -1 to go to the end; otherwise, last >= first
+ * \param[in]    nmax       maximum number of pix to select; > 0
+ * \param[in]    use_pairs  1 = select pairs of adjacent pix;
+ *                          0 = select individual pix
+ * \param[in]    copyflag   L_COPY, L_CLONE
+ * \return  pixad if OK, NULL on error
+ *
+ * <pre>
+ * Notes:
+ *     (1) See notes in genConstrainedNumaInRange() for how selection
+ *         is made.
+ *     (2) This returns a selection of the pix in the input pixa.
+ *     (3) Use copyflag == L_COPY if you don't want changes in the pix
+ *         in the returned pixa to affect those in the input pixa.
+ * </pre>
+ */
+PIXA *
+pixaConstrainedSelect(PIXA    *pixas,
+                      l_int32  first,
+                      l_int32  last,
+                      l_int32  nmax,
+                      l_int32  use_pairs,
+                      l_int32  copyflag)
+{
+l_int32  i, n, nselect, index;
+NUMA    *na;
+PIX     *pix1;
+PIXA    *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+    n = pixaGetCount(pixas);
+    first = L_MAX(0, first);
+    last = (last < 0) ? n - 1 : L_MIN(n - 1, last);
+    if (last < first)
+        return (PIXA *)ERROR_PTR("last < first!", __func__, NULL);
+    if (nmax < 1)
+        return (PIXA *)ERROR_PTR("nmax < 1!", __func__, NULL);
+
+    na = genConstrainedNumaInRange(first, last, nmax, use_pairs);
+    nselect = numaGetCount(na);
+    pixad = pixaCreate(nselect);
+    for (i = 0; i < nselect; i++) {
+        numaGetIValue(na, i, &index);
+        pix1 = pixaGetPix(pixas, index, copyflag);
+        pixaAddPix(pixad, pix1, L_INSERT);
+    }
+    numaDestroy(&na);
+    return pixad;
+}
+
+
+/*!
+ * \brief   pixaSelectToPdf()
+ *
+ * \param[in]    pixas
+ * \param[in]    first     first index to choose; >= 0
+ * \param[in]    last      biggest possible index to reach;
+ *                         use -1 to go to the end; otherwise, last >= first
+ * \param[in]    res       override the resolution of each input image, in ppi;
+ *                         use 0 to respect the resolution embedded in the input
+ * \param[in]    scalefactor   scaling factor applied to each image; > 0.0
+ * \param[in]    type      encoding type (L_JPEG_ENCODE, L_G4_ENCODE,
+ *                         L_FLATE_ENCODE, or 0 for default
+ * \param[in]    quality   used for JPEG only; 0 for default (75)
+ * \param[in]    color     of numbers added to each image (e.g., 0xff000000)
+ * \param[in]    fontsize  to print number below each image.  The valid set
+ *                         is {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \param[in]    fileout   pdf file of all images
+ * \return  0 if OK, 1 on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This writes a pdf of the selected images from %pixas, one to
+ *          a page.  They are optionally scaled and annotated with the
+ *          index printed to the left of the image.
+ *      (2) If the input images are 1 bpp and you want the numbers to be
+ *          in color, first promote each pix to 8 bpp with a colormap:
+ *                pixa1 = pixaConvertTo8(pixas, 1);
+ *          and then call this function with the specified color
+ * </pre>
+ */
+l_ok
+pixaSelectToPdf(PIXA        *pixas,
+                l_int32      first,
+                l_int32      last,
+                l_int32      res,
+                l_float32    scalefactor,
+                l_int32      type,
+                l_int32      quality,
+                l_uint32     color,
+                l_int32      fontsize,
+                const char  *fileout)
+{
+l_int32  n;
+L_BMF   *bmf;
+NUMA    *na;
+PIXA    *pixa1, *pixa2;
+
+    if (!pixas)
+        return ERROR_INT("pixas not defined", __func__, 1);
+    if (type < 0 || type > L_FLATE_ENCODE) {
+        L_WARNING("invalid compression type; using default\n", __func__);
+        type = 0;
+    }
+    if (!fileout)
+        return ERROR_INT("fileout not defined", __func__, 1);
+
+        /* Select from given range */
+    n = pixaGetCount(pixas);
+    first = L_MAX(0, first);
+    last = (last < 0) ? n - 1 : L_MIN(n - 1, last);
+    if (first > last) {
+        L_ERROR("first = %d > last = %d\n", __func__, first, last);
+        return 1;
+    }
+    pixa1 = pixaSelectRange(pixas, first, last, L_CLONE);
+
+        /* Optionally add index numbers */
+    bmf = (fontsize <= 0) ? NULL : bmfCreate(NULL, fontsize);
+    if (bmf) {
+        na = numaMakeSequence(first, 1.0, last - first + 1);
+        pixa2 = pixaAddTextNumber(pixa1, bmf, na, color, L_ADD_LEFT);
+        numaDestroy(&na);
+    } else {
+        pixa2 = pixaCopy(pixa1, L_CLONE);
+    }
+    pixaDestroy(&pixa1);
+    bmfDestroy(&bmf);
+
+    pixaConvertToPdf(pixa2, res, scalefactor, type, quality, NULL, fileout);
+    pixaDestroy(&pixa2);
+    return 0;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                    Generate pixa from tiled images                  *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaMakeFromTiledPixa()
+ *
+ * \param[in]    pixas    of mosaiced templates, one for each digit
+ * \param[in]    w        width of samples (use 0 for default = 20)
+ * \param[in]    h        height of samples (use 0 for default = 30)
+ * \param[in]    nsamp    number of requested samples (use 0 for default = 100)
+ * \return  pixa of individual, scaled templates, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This converts from a compressed representation of 1 bpp digit
+ *          templates to a pixa where each pix has a single labeled template.
+ *      (2) The mosaics hold 100 templates each, and the number of templates
+ *          %nsamp selected for each digit can be between 1 and 100.
+ *      (3) Each mosaic has the number of images written in the text field,
+ *          and the i-th pix contains samples of the i-th digit.  That value
+ *          is written into the text field of each template in the output.
+ * </pre>
+ */
+PIXA *
+pixaMakeFromTiledPixa(PIXA    *pixas,
+                      l_int32  w,
+                      l_int32  h,
+                      l_int32  nsamp)
+{
+char     buf[8];
+l_int32  ntiles, i;
+PIX     *pix1;
+PIXA    *pixad, *pixa1;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+    if (nsamp > 1000)
+        return (PIXA *)ERROR_PTR("nsamp too large; typ. 100", __func__, NULL);
+
+    if (w <= 0) w = 20;
+    if (h <= 0) h = 30;
+    if (nsamp <= 0) nsamp = 100;
+
+        /* pixas has 10 pix of mosaic'd digits.  Each of these images
+         * must be extracted into a pixa of templates, where each template
+         * is labeled with the digit value, and then selectively
+         * concatenated into an output pixa. */
+    pixad = pixaCreate(10 * nsamp);
+    for (i = 0; i < 10; i++) {
+        pix1 = pixaGetPix(pixas, i, L_CLONE);
+        pixGetTileCount(pix1, &ntiles);
+        if (nsamp > ntiles)
+            L_WARNING("requested %d; only %d tiles\n", __func__, nsamp, ntiles);
+        pixa1 = pixaMakeFromTiledPix(pix1, w, h, 0, nsamp, NULL);
+        snprintf(buf, sizeof(buf), "%d", i);
+        pixaSetText(pixa1, buf, NULL);
+        pixaJoin(pixad, pixa1, 0, -1);
+        pixaDestroy(&pixa1);
+        pixDestroy(&pix1);
+    }
+    return pixad;
+}
+
+
+/*!
+ * \brief   pixaMakeFromTiledPix()
+ *
+ * \param[in]    pixs        any depth; colormap OK
+ * \param[in]    w           width of each tile
+ * \param[in]    h           height of each tile
+ * \param[in]    start       first tile to use
+ * \param[in]    num         number of tiles; use 0 to go to the end
+ * \param[in]    boxa        [optional] location of rectangular regions
+ *                           to be extracted
+ * \return  pixa if OK, NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) Operations that generate a pix by tiling from a pixa, and
+ *          the inverse that generate a pixa from tiles of a pix,
+ *          are useful.  One such pair is pixaDisplayUnsplit() and
+ *          pixaSplitPix().  This function is a very simple one that
+ *          generates a pixa from tiles of a pix. There are two cases:
+ *            - the tiles can all be the same size (the inverse of
+ *              pixaDisplayOnLattice(), or
+ *            - the tiles can differ in size, where there is an
+ *              associated boxa (the inverse of pixaCreateFromBoxa().
+ *      (2) If all tiles are the same size, %w by %h, use %boxa = NULL.
+ *          If the tiles differ in size, use %boxa to extract the
+ *          individual images (%w and %h are then ignored).
+ *      (3) If the pix was made by pixaDisplayOnLattice(), the number
+ *          of tiled images is written into the text field, in the format
+ *               n = <number>.
+ *      (4) Typical usage: a set of character templates all scaled to
+ *          the same size can be stored on a lattice of that size in
+ *          a pix, and this function can regenerate the pixa.  If the
+ *          templates differ in size, a boxa generated when the tiled
+ *          pix was made can be used to indicate the location of
+ *          the templates.
+ * </pre>
+ */
+PIXA *
+pixaMakeFromTiledPix(PIX     *pixs,
+                     l_int32  w,
+                     l_int32  h,
+                     l_int32  start,
+                     l_int32  num,
+                     BOXA    *boxa)
+{
+l_int32   i, j, k, ws, hs, d, nx, ny, n, n_isvalid, ntiles, nmax;
+PIX      *pix1;
+PIXA     *pixa1;
+PIXCMAP  *cmap;
+
+    if (!pixs)
+        return (PIXA *)ERROR_PTR("pixs not defined", __func__, NULL);
+    if (!boxa && (w <= 0 || h <= 0))
+        return (PIXA *)ERROR_PTR("w and h must be > 0", __func__, NULL);
+
+    if (boxa)  /* general case */
+       return pixaCreateFromBoxa(pixs, boxa, start, num, NULL);
+
+        /* All tiles are the same size */
+    pixGetDimensions(pixs, &ws, &hs, &d);
+    nx = ws / w;
+    ny = hs / h;
+    if (nx < 1 || ny < 1)
+        return (PIXA *)ERROR_PTR("invalid dimensions", __func__, NULL);
+    if (nx * w != ws || ny * h != hs)
+        L_WARNING("some tiles will be clipped\n", __func__);
+
+        /* Check the text field of the pix.  It may tell how many
+         * tiles hold valid data.  If a valid value is not found,
+         * assume all (nx * ny) tiles are valid.  */
+    pixGetTileCount(pixs, &n);
+    n_isvalid = (n <= nx * ny && n > nx * (ny - 1)) ? TRUE : FALSE;
+    ntiles = (n_isvalid) ? n : nx * ny;
+    nmax = ntiles - start;  /* max available from start */
+    num = (num == 0) ? nmax : L_MIN(num, nmax);
+
+        /* Extract the tiles */
+    if ((pixa1 = pixaCreate(num)) == NULL) {
+        return (PIXA *)ERROR_PTR("pixa1 not made", __func__, NULL);
+    }
+    cmap = pixGetColormap(pixs);
+    for (i = 0, k = 0; i < ny; i++) {
+        for (j = 0; j < nx; j++, k++) {
+            if (k < start) continue;
+            if (k >= start + num) break;
+            pix1 = pixCreate(w, h, d);
+            if (cmap) pixSetColormap(pix1, pixcmapCopy(cmap));
+            pixRasterop(pix1, 0, 0, w, h, PIX_SRC, pixs, j * w, i * h);
+            pixaAddPix(pixa1, pix1, L_INSERT);
+        }
+    }
+    return pixa1;
+}
+
+
+/*!
+ * \brief   pixGetTileCount()
+ *
+ * \param[in]    pix
+ * \param[out]  *pn     number embedded in pix text field
+ * \return  0 if OK, 1 on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) If the pix was made by pixaDisplayOnLattice(), the number
+ *          of tiled images is written into the text field, in the format
+ *               n = <number>.
+ *      (2) This returns 0 if the data is not in the text field, or on error.
+ * </pre>
+ */
+l_ok
+pixGetTileCount(PIX      *pix,
+                l_int32  *pn)
+{
+char    *text;
+l_int32  n;
+
+    if (!pn)
+        return ERROR_INT("&n not defined", __func__, 1);
+    *pn = 0;
+    if (!pix)
+        return ERROR_INT("pix not defined", __func__, 1);
+
+    text = pixGetText(pix);
+    if (text && strlen(text) > 4) {
+        if (sscanf(text, "n = %d", &n) == 1)
+            *pn = n;
+    }
+    return 0;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                    Pixa display into multiple tiles                 *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaDisplayMultiTiled()
+ *
+ * \param[in]    pixas
+ * \param[in]    nx, ny       in [1, ... 50], tiling factors in each direction
+ * \param[in]    maxw, maxh   max sizes to keep
+ * \param[in]    scalefactor  scale each image by this
+ * \param[in]    spacing      between images, and on outside
+ * \param[in]    border       width of additional black border on each image;
+ *                            use 0 for no border
+ * \return  pixad if OK, NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) Each set of %nx * %ny images is optionally scaled and saved
+ *          into a new pix, and then aggregated.
+ *      (2) Set %maxw = %maxh = 0 if you want to include all pix from %pixs.
+ *      (3) This is useful for generating a pdf from the output pixa, where
+ *          each page is a tile of (%nx * %ny) images from the input pixa.
+ * </pre>
+ */
+PIXA *
+pixaDisplayMultiTiled(PIXA      *pixas,
+                      l_int32    nx,
+                      l_int32    ny,
+                      l_int32    maxw,
+                      l_int32    maxh,
+                      l_float32  scalefactor,
+                      l_int32    spacing,
+                      l_int32    border)
+{
+l_int32  n, i, j, ntile, nout, index;
+PIX     *pix1, *pix2;
+PIXA    *pixa1, *pixa2, *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+    if (nx < 1 || ny < 1 || nx > 50 || ny > 50)
+        return (PIXA *)ERROR_PTR("invalid tiling factor(s)", __func__, NULL);
+    if ((n = pixaGetCount(pixas)) == 0)
+        return (PIXA *)ERROR_PTR("pixas is empty", __func__, NULL);
+
+        /* Filter out large ones if requested */
+    if (maxw == 0 && maxh == 0) {
+        pixa1 = pixaCopy(pixas, L_CLONE);
+    } else {
+        maxw = (maxw == 0) ? 1000000 : maxw;
+        maxh = (maxh == 0) ? 1000000 : maxh;
+        pixa1 = pixaSelectBySize(pixas, maxw, maxh, L_SELECT_IF_BOTH,
+                                 L_SELECT_IF_LTE, NULL);
+        n = pixaGetCount(pixa1);
+    }
+
+    ntile = nx * ny;
+    nout = L_MAX(1, (n + ntile - 1) / ntile);
+    pixad = pixaCreate(nout);
+    for (i = 0, index = 0; i < nout; i++) {  /* over tiles */
+        pixa2 = pixaCreate(ntile);
+        for (j = 0; j < ntile && index < n; j++, index++) {
+            pix1 = pixaGetPix(pixa1, index, L_COPY);
+            pixaAddPix(pixa2, pix1, L_INSERT);
+        }
+        pix2 = pixaDisplayTiledInColumns(pixa2, nx, scalefactor, spacing,
+                                         border);
+        pixaAddPix(pixad, pix2, L_INSERT);
+        pixaDestroy(&pixa2);
+    }
+    pixaDestroy(&pixa1);
+
+    return pixad;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                       Split pixa into files                         *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaSplitIntoFiles()
+ *
+ * \param[in]    pixas
+ * \param[in]    nsplit       split pixas into this number of pixa; >= 2
+ * \param[in]    scale        scalefactor applied to each pix
+ * \param[in]    outwidth     the maxwidth parameter of tiled images
+ *                            for write_pix
+ * \param[in]    write_pixa  1 to write the split pixa as separate files
+ * \param[in]    write_pix   1 to write tiled images of the split pixa
+ * \param[in]    write_pdf   1 to write pdfs of the split pixa
+ * \return  0 if OK, 1 on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) For each requested output, %nsplit files are written into
+ *          directory /tmp/lept/split/.
+ *      (2) This is useful when a pixa is so large that the images
+ *          are not conveniently displayed as a single tiled image at
+ *          full resolution.
+ * </pre>
+ */
+l_ok
+pixaSplitIntoFiles(PIXA      *pixas,
+                   l_int32    nsplit,
+                   l_float32  scale,
+                   l_int32    outwidth,
+                   l_int32    write_pixa,
+                   l_int32    write_pix,
+                   l_int32    write_pdf)
+{
+char     buf[64];
+l_int32  i, j, index, n, nt;
+PIX     *pix1, *pix2;
+PIXA    *pixa1;
+
+    if (!pixas)
+        return ERROR_INT("pixas not defined", __func__, 1);
+    if (nsplit <= 1)
+        return ERROR_INT("nsplit must be >= 2", __func__, 1);
+    if ((nt = pixaGetCount(pixas)) == 0)
+        return ERROR_INT("pixas is empty", __func__, 1);
+    if (!write_pixa && !write_pix && !write_pdf)
+        return ERROR_INT("no output is requested", __func__, 1);
+
+    lept_mkdir("lept/split");
+    n = (nt + nsplit - 1) / nsplit;
+    lept_stderr("nt = %d, n = %d, nsplit = %d\n", nt, n, nsplit);
+    for (i = 0, index = 0; i < nsplit; i++) {
+        pixa1 = pixaCreate(n);
+        for (j = 0; j < n && index < nt; j++, index++) {
+            pix1 = pixaGetPix(pixas, index, L_CLONE);
+            pix2 = pixScale(pix1, scale, scale);
+            pixaAddPix(pixa1, pix2, L_INSERT);
+            pixDestroy(&pix1);
+        }
+        if (write_pixa) {
+            snprintf(buf, sizeof(buf), "/tmp/lept/split/split%d.pa", i + 1);
+            pixaWriteDebug(buf, pixa1);
+        }
+        if (write_pix) {
+            snprintf(buf, sizeof(buf), "/tmp/lept/split/split%d.tif", i + 1);
+            pix1 = pixaDisplayTiledInRows(pixa1, 1, outwidth, 1.0, 0, 20, 2);
+            pixWriteDebug(buf, pix1, IFF_TIFF_G4);
+            pixDestroy(&pix1);
+        }
+        if (write_pdf) {
+            snprintf(buf, sizeof(buf), "/tmp/lept/split/split%d.pdf", i + 1);
+            pixaConvertToPdf(pixa1, 0, 1.0, L_G4_ENCODE, 0, buf, buf);
+        }
+        pixaDestroy(&pixa1);
+    }
+
+    return 0;
+}
+
+
+/*---------------------------------------------------------------------*
+ *                               Tile N-Up                             *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   convertToNUpFiles()
+ *
+ * \param[in]    dir        full path to directory of images
+ * \param[in]    substr     [optional] can be null
+ * \param[in]    nx, ny     in [1, ... 50], tiling factors in each direction
+ * \param[in]    tw         target width, in pixels; must be >= 20
+ * \param[in]    spacing    between images, and on outside
+ * \param[in]    border     width of additional black border on each image;
+ *                          use 0 for no border
+ * \param[in]    fontsize   to print tail of filename with image.  Valid set is
+ *                          {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \param[in]    outdir     subdirectory of /tmp to put N-up tiled images
+ * \return  0 if OK, 1 on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) Each set of %nx * %ny images is scaled and tiled into a single
+ *          image, that is written out to %outdir.
+ *      (2) All images in each %nx * %ny set are scaled to the same
+ *          width, %tw.  This is typically used when all images are
+ *          roughly the same size.
+ *      (3) This is useful for generating a pdf from the set of input
+ *          files, where each page is a tile of (%nx * %ny) input images.
+ *          Typical values for %nx and %ny are in the range [2 ... 5].
+ *      (4) If %fontsize != 0, each image has the tail of its filename
+ *          rendered below it.
+ * </pre>
+ */
+l_ok
+convertToNUpFiles(const char  *dir,
+                  const char  *substr,
+                  l_int32      nx,
+                  l_int32      ny,
+                  l_int32      tw,
+                  l_int32      spacing,
+                  l_int32      border,
+                  l_int32      fontsize,
+                  const char  *outdir)
+{
+l_int32  d, format;
+char     rootpath[256];
+PIXA    *pixa;
+
+    if (!dir)
+        return ERROR_INT("dir not defined", __func__, 1);
+    if (nx < 1 || ny < 1 || nx > 50 || ny > 50)
+        return ERROR_INT("invalid tiling N-factor", __func__, 1);
+    if (fontsize < 0 || fontsize > 20 || fontsize & 1 || fontsize == 2)
+        return ERROR_INT("invalid fontsize", __func__, 1);
+    if (!outdir)
+        return ERROR_INT("outdir not defined", __func__, 1);
+
+    pixa = convertToNUpPixa(dir, substr, nx, ny, tw, spacing, border,
+                            fontsize);
+    if (!pixa)
+        return ERROR_INT("pixa not made", __func__, 1);
+
+    lept_rmdir(outdir);
+    lept_mkdir(outdir);
+    pixaGetRenderingDepth(pixa, &d);
+    format = (d == 1) ? IFF_TIFF_G4 : IFF_JFIF_JPEG;
+    makeTempDirname(rootpath, 256, outdir);
+    modifyTrailingSlash(rootpath, 256, L_ADD_TRAIL_SLASH);
+    pixaWriteFiles(rootpath, pixa, format);
+    pixaDestroy(&pixa);
+    return 0;
+}
+
+
+/*!
+ * \brief   convertToNUpPixa()
+ *
+ * \param[in]    dir       full path to directory of images
+ * \param[in]    substr    [optional] can be null
+ * \param[in]    nx, ny    in [1, ... 50], tiling factors in each direction
+ * \param[in]    tw        target width, in pixels; must be >= 20
+ * \param[in]    spacing   between images, and on outside
+ * \param[in]    border    width of additional black border on each image;
+ *                         use 0 for no border
+ * \param[in]    fontsize  to print tail of filename with image.  Valid set is
+ *                         {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \return  pixad, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) See notes for convertToNUpFiles()
+ * </pre>
+ */
+PIXA *
+convertToNUpPixa(const char  *dir,
+                 const char  *substr,
+                 l_int32      nx,
+                 l_int32      ny,
+                 l_int32      tw,
+                 l_int32      spacing,
+                 l_int32      border,
+                 l_int32      fontsize)
+{
+l_int32  i, n;
+char    *fname, *tail;
+PIXA    *pixa1, *pixa2;
+SARRAY  *sa1, *sa2;
+
+    if (!dir)
+        return (PIXA *)ERROR_PTR("dir not defined", __func__, NULL);
+    if (nx < 1 || ny < 1 || nx > 50 || ny > 50)
+        return (PIXA *)ERROR_PTR("invalid tiling N-factor", __func__, NULL);
+    if (tw < 20)
+        return (PIXA *)ERROR_PTR("tw must be >= 20", __func__, NULL);
+    if (fontsize < 0 || fontsize > 20 || fontsize & 1 || fontsize == 2)
+        return (PIXA *)ERROR_PTR("invalid fontsize", __func__, NULL);
+
+    sa1 = getSortedPathnamesInDirectory(dir, substr, 0, 0);
+    pixa1 = pixaReadFilesSA(sa1);
+    n = sarrayGetCount(sa1);
+    sa2 = sarrayCreate(n);
+    for (i = 0; i < n; i++) {
+        fname = sarrayGetString(sa1, i, L_NOCOPY);
+        splitPathAtDirectory(fname, NULL, &tail);
+        sarrayAddString(sa2, tail, L_INSERT);
+    }
+    sarrayDestroy(&sa1);
+    pixa2 = pixaConvertToNUpPixa(pixa1, sa2, nx, ny, tw, spacing,
+                                 border, fontsize);
+    pixaDestroy(&pixa1);
+    sarrayDestroy(&sa2);
+    return pixa2;
+}
+
+
+/*!
+ * \brief   pixaConvertToNUpPixa()
+ *
+ * \param[in]    pixas
+ * \param[in]    sa        [optional] array of strings associated with each pix
+ * \param[in]    nx, ny    in [1, ... 50], tiling factors in each direction
+ * \param[in]    tw        target width, in pixels; must be >= 20
+ * \param[in]    spacing   between images, and on outside
+ * \param[in]    border    width of additional black border on each image;
+ *                         use 0 for no border
+ * \param[in]    fontsize  to print string with each image.  Valid set is
+ *                         {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \return  pixad, or NULL on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This takes an input pixa and an optional array of strings, and
+ *          generates a pixa of NUp tiles from the input, labeled with
+ *          the strings if they exist and %fontsize != 0.
+ *      (2) See notes for convertToNUpFiles()
+ * </pre>
+ */
+PIXA *
+pixaConvertToNUpPixa(PIXA    *pixas,
+                     SARRAY  *sa,
+                     l_int32  nx,
+                     l_int32  ny,
+                     l_int32  tw,
+                     l_int32  spacing,
+                     l_int32  border,
+                     l_int32  fontsize)
+{
+l_int32    i, j, k, nt, n2, nout, d;
+char      *str;
+L_BMF     *bmf;
+PIX       *pix1, *pix2, *pix3, *pix4;
+PIXA      *pixa1, *pixad;
+
+    if (!pixas)
+        return (PIXA *)ERROR_PTR("pixas not defined", __func__, NULL);
+    if (nx < 1 || ny < 1 || nx > 50 || ny > 50)
+        return (PIXA *)ERROR_PTR("invalid tiling N-factor", __func__, NULL);
+    if (tw < 20)
+        return (PIXA *)ERROR_PTR("tw must be >= 20", __func__, NULL);
+    if (fontsize < 0 || fontsize > 20 || fontsize & 1 || fontsize == 2)
+        return (PIXA *)ERROR_PTR("invalid fontsize", __func__, NULL);
+
+    nt = pixaGetCount(pixas);
+    if (sa && (sarrayGetCount(sa) != nt)) {
+        L_WARNING("pixa size %d not equal to sarray size %d\n", __func__,
+                  nt, sarrayGetCount(sa));
+    }
+
+    n2 = nx * ny;
+    nout = (nt + n2 - 1) / n2;
+    pixad = pixaCreate(nout);
+    bmf = (fontsize == 0) ? NULL : bmfCreate(NULL, fontsize);
+    for (i = 0, j = 0; i < nout; i++) {
+        pixa1 = pixaCreate(n2);
+        for (k = 0; k < n2 && j < nt; j++, k++) {
+            pix1 = pixaGetPix(pixas, j, L_CLONE);
+            pix2 = pixScaleToSize(pix1, tw, 0);  /* all images have width tw */
+            if (bmf && sa) {
+                str = sarrayGetString(sa, j, L_NOCOPY);
+                pix3 = pixAddTextlines(pix2, bmf, str, 0xff000000,
+                                       L_ADD_BELOW);
+            } else {
+                pix3 = pixClone(pix2);
+            }
+            pixaAddPix(pixa1, pix3, L_INSERT);
+            pixDestroy(&pix1);
+            pixDestroy(&pix2);
+        }
+        if (pixaGetCount(pixa1) == 0) {  /* probably won't happen */
+            pixaDestroy(&pixa1);
+            continue;
+        }
+
+            /* Add 2 * border to image width to prevent scaling */
+        pixaGetRenderingDepth(pixa1, &d);
+        pix4 = pixaDisplayTiledAndScaled(pixa1, d, tw + 2 * border, nx, 0,
+                                         spacing, border);
+        pixaAddPix(pixad, pix4, L_INSERT);
+        pixaDestroy(&pixa1);
+    }
+
+    bmfDestroy(&bmf);
+    return pixad;
+}
+
+
+/*---------------------------------------------------------------------*
+ *            Render two pixa side-by-side for comparison              *
+ *---------------------------------------------------------------------*/
+/*!
+ * \brief   pixaCompareInPdf()
+ *
+ * \param[in]    pixa1
+ * \param[in]    pixa2
+ * \param[in]    nx, ny     in [1, ... 20], tiling factors in each direction
+ * \param[in]    tw         target width, in pixels; must be >= 20
+ * \param[in]    spacing    between images, and on outside
+ * \param[in]    border     width of additional black border on each image
+ *                          and on each pair; use 0 for no border
+ * \param[in]    fontsize   to print index of each pair of images.  Valid set
+ *                          is {4,6,8,10,12,14,16,18,20}.  Use 0 to disable.
+ * \param[in]    fileout    output pdf file
+ * \return  0 if OK, 1 on error
+ *
+ * <pre>
+ * Notes:
+ *      (1) This takes two pixa and renders them interleaved, side-by-side
+ *          in a pdf.  A warning is issued if the input pixa arrays
+ *          have different lengths.
+ *      (2) %nx and %ny specify how many side-by-side pairs are displayed
+ *          on each pdf page.  For example, if %nx = 1 and %ny = 2, then
+ *          two pairs are shown, one above the other, on each page.
+ *      (3) The input pix are scaled to a target width of %tw, and
+ *          then paired with optional %spacing between and optional
+ *          black border of width %border.
+ *      (4) After a pixa is generated of these tiled images, it is
+ *          written to %fileout as a pdf.
+ *      (5) Typical numbers for the input parameters are:
+ *            %nx = small integer (1 - 4)
+ *            %ny = 2 * %nx
+ *            %tw = 200 - 500 pixels
+ *            %spacing = 10
+ *            %border = 2
+ *            %fontsize = 10
+ *      (6) If %fontsize != 0, the index of the pix pair in their pixa
+ *          is printed out below each pair.
+ * </pre>
+ */
+l_ok
+pixaCompareInPdf(PIXA        *pixa1,
+                 PIXA        *pixa2,
+                 l_int32      nx,
+                 l_int32      ny,
+                 l_int32      tw,
+                 l_int32      spacing,
+                 l_int32      border,
+                 l_int32      fontsize,
+                 const char  *fileout)
+{
+l_int32  n1, n2, npairs;
+PIXA    *pixa3, *pixa4, *pixa5;
+SARRAY  *sa;
+
+    if (!pixa1 || !pixa2)
+        return ERROR_INT("pixa1 and pixa2 not both defined", __func__, 1);
+    if (nx < 1 || ny < 1 || nx > 20 || ny > 20)
+        return ERROR_INT("invalid tiling factors", __func__, 1);
+    if (tw < 20)
+        return ERROR_INT("invalid tw; tw must be >= 20", __func__, 1);
+    if (fontsize < 0 || fontsize > 20 || fontsize & 1 || fontsize == 2)
+        return ERROR_INT("invalid fontsize", __func__, 1);
+    if (!fileout)
+        return ERROR_INT("fileout not defined", __func__, 1);
+    n1 = pixaGetCount(pixa1);
+    n2 = pixaGetCount(pixa2);
+    if (n1 == 0 || n2 == 0)
+        return ERROR_INT("at least one pixa is empty", __func__, 1);
+    if (n1 != n2)
+        L_WARNING("sizes (%d, %d) differ; using the minimum in interleave\n",
+                  __func__, n1, n2);
+
+        /* Interleave the input pixa */
+    if ((pixa3 = pixaInterleave(pixa1, pixa2, L_CLONE)) == NULL)
+        return ERROR_INT("pixa3 not made", __func__, 1);
+
+        /* Scale the images if necessary and pair them up side/by/side */
+    pixa4 = pixaConvertToNUpPixa(pixa3, NULL, 2, 1, tw, spacing, border, 0);
+    pixaDestroy(&pixa3);
+
+        /* Label the pairs and mosaic into pages without further scaling */
+    npairs = pixaGetCount(pixa4);
+    sa = (fontsize > 0) ? sarrayGenerateIntegers(npairs) : NULL;
+    pixa5 = pixaConvertToNUpPixa(pixa4, sa, nx, ny,
+                                 2 * tw + 4 * border + spacing,
+                                 spacing, border, fontsize);
+    pixaDestroy(&pixa4);
+    sarrayDestroy(&sa);
+
+        /* Output as pdf without scaling */
+    pixaConvertToPdf(pixa5, 0, 1.0, 0, 0, NULL, fileout);
+    pixaDestroy(&pixa5);
+    return 0;
+}
+
+