--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/tools/pdfposter.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,283 @@
+// Copyright (C) 2004-2024 Artifex Software, Inc.
+//
+// This file is part of MuPDF.
+//
+// MuPDF is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
+//
+// Alternative licensing terms are available from the licensor.
+// For commercial licensing, see <https://www.artifex.com/> or contact
+// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
+// CA 94129, USA, for further information.
+
+/*
+ * PDF posteriser; split pages within a PDF file into smaller lumps.
+ */
+
+#include "mupdf/fitz.h"
+#include "mupdf/pdf.h"
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+static int x_factor = 0;
+static int y_factor = 0;
+static float margin = 0;
+static int margin_is_percent = 0;
+static int x_dir = 1;
+
+static int usage(void)
+{
+	fprintf(stderr,
+		"usage: mutool poster [options] input.pdf [output.pdf]\n"
+		"\t-p -\tpassword\n"
+		"\t-m -\tmargin (overlap) between pages (pts, or %%)\n"
+		"\t-x\tx decimation factor\n"
+		"\t-y\ty decimation factor\n"
+		"\t-r\tsplit right-to-left\n"
+		);
+	return 1;
+}
+
+static void
+intersect_box(fz_context *ctx, pdf_document *doc, pdf_obj *page, pdf_obj *box_name, fz_rect mb)
+{
+	pdf_obj *box = pdf_dict_get(ctx, page, box_name);
+	pdf_obj *newbox;
+	fz_rect old_rect;
+
+	if (box == NULL)
+		return;
+
+	old_rect.x0 = pdf_array_get_real(ctx, box, 0);
+	old_rect.y0 = pdf_array_get_real(ctx, box, 1);
+	old_rect.x1 = pdf_array_get_real(ctx, box, 2);
+	old_rect.y1 = pdf_array_get_real(ctx, box, 3);
+
+	if (old_rect.x0 < mb.x0)
+		old_rect.x0 = mb.x0;
+	if (old_rect.y0 < mb.y0)
+		old_rect.y0 = mb.y0;
+	if (old_rect.x1 > mb.x1)
+		old_rect.x1 = mb.x1;
+	if (old_rect.y1 > mb.y1)
+		old_rect.y1 = mb.y1;
+
+	newbox = pdf_new_array(ctx, doc, 4);
+	pdf_array_push_real(ctx, newbox, old_rect.x0);
+	pdf_array_push_real(ctx, newbox, old_rect.y0);
+	pdf_array_push_real(ctx, newbox, old_rect.x1);
+	pdf_array_push_real(ctx, newbox, old_rect.y1);
+	pdf_dict_put_drop(ctx, page, box_name, newbox);
+}
+
+/*
+ * Recreate page tree with our posterised pages in.
+ */
+
+static void decimatepages(fz_context *ctx, pdf_document *doc)
+{
+	pdf_obj *oldroot, *root, *pages, *kids;
+	int num_pages = pdf_count_pages(ctx, doc);
+	int page, kidcount;
+	fz_rect mediabox, cropbox;
+	int rotate;
+
+	oldroot = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root));
+	pages = pdf_dict_get(ctx, oldroot, PDF_NAME(Pages));
+
+	root = pdf_new_dict(ctx, doc, 2);
+	pdf_dict_put(ctx, root, PDF_NAME(Type), pdf_dict_get(ctx, oldroot, PDF_NAME(Type)));
+	pdf_dict_put(ctx, root, PDF_NAME(Pages), pdf_dict_get(ctx, oldroot, PDF_NAME(Pages)));
+
+	pdf_update_object(ctx, doc, pdf_to_num(ctx, oldroot), root);
+
+	pdf_drop_obj(ctx, root);
+
+	/* Create a new kids array with our new pages in */
+	kids = pdf_new_array(ctx, doc, 1);
+
+	kidcount = 0;
+	for (page=0; page < num_pages; page++)
+	{
+		pdf_obj *page_obj = pdf_lookup_page_obj(ctx, doc, page);
+		int xf = x_factor, yf = y_factor;
+		float w, h;
+		int x, y;
+		int xd, yd, y0, y1;
+		float xmargin, ymargin;
+
+		rotate = pdf_to_int(ctx, pdf_dict_get_inheritable(ctx, page_obj, PDF_NAME(Rotate)));
+		mediabox = pdf_to_rect(ctx, pdf_dict_get_inheritable(ctx, page_obj, PDF_NAME(MediaBox)));
+		cropbox = pdf_to_rect(ctx, pdf_dict_get_inheritable(ctx, page_obj, PDF_NAME(CropBox)));
+		if (fz_is_empty_rect(mediabox))
+			mediabox = fz_make_rect(0, 0, 612, 792);
+		if (!fz_is_empty_rect(cropbox))
+			mediabox = fz_intersect_rect(mediabox, cropbox);
+
+		w = mediabox.x1 - mediabox.x0;
+		h = mediabox.y1 - mediabox.y0;
+
+		if (rotate == 90 || rotate == 270)
+		{
+			xf = y_factor;
+			yf = x_factor;
+			yd = -x_dir;
+			xd = 1;
+		}
+		else
+		{
+			xf = x_factor;
+			yf = y_factor;
+			xd = x_dir;
+			yd = -1;
+		}
+
+		if (xf == 0 && yf == 0)
+		{
+			/* Nothing specified, so split along the long edge */
+			if (w > h)
+				xf = 2, yf = 1;
+			else
+				xf = 1, yf = 2;
+		}
+		else if (xf == 0)
+			xf = 1;
+		else if (yf == 0)
+			yf = 1;
+
+		xmargin = xf == 1 ? 0 : margin * (margin_is_percent ? .001 * w/xf : 1);
+		ymargin = yf == 1 ? 0 : margin * (margin_is_percent ? .001 * h/yf : 1);
+
+		y0 = (yd > 0) ? 0 : yf-1;
+		y1 = (yd > 0) ? yf : -1;
+		for (y = y0; y != y1; y += yd)
+		{
+			int x0 = (xd > 0) ? 0 : xf-1;
+			int x1 = (xd > 0) ? xf : -1;
+			for (x = x0; x != x1; x += xd)
+			{
+				pdf_obj *newpageobj, *newpageref, *newmediabox;
+				fz_rect mb;
+
+				newpageobj = pdf_copy_dict(ctx, pdf_lookup_page_obj(ctx, doc, page));
+				pdf_flatten_inheritable_page_items(ctx, newpageobj);
+				newpageref = pdf_add_object(ctx, doc, newpageobj);
+
+				newmediabox = pdf_new_array(ctx, doc, 4);
+
+				mb.x0 = mediabox.x0 + (w/xf)*x;
+				if (x == xf-1)
+					mb.x1 = mediabox.x1;
+				else
+					mb.x1 = mb.x0 + (w/xf) + xmargin;
+				mb.y0 = mediabox.y0 + (h/yf)*y;
+				if (y == yf-1)
+					mb.y1 = mediabox.y1;
+				else
+					mb.y1 = mb.y0 + (h/yf) + ymargin;
+
+				pdf_array_push_real(ctx, newmediabox, mb.x0);
+				pdf_array_push_real(ctx, newmediabox, mb.y0);
+				pdf_array_push_real(ctx, newmediabox, mb.x1);
+				pdf_array_push_real(ctx, newmediabox, mb.y1);
+
+				pdf_dict_put(ctx, newpageobj, PDF_NAME(Parent), pages);
+				pdf_dict_put_drop(ctx, newpageobj, PDF_NAME(MediaBox), newmediabox);
+
+				intersect_box(ctx, doc, newpageobj, PDF_NAME(CropBox), mb);
+				intersect_box(ctx, doc, newpageobj, PDF_NAME(BleedBox), mb);
+				intersect_box(ctx, doc, newpageobj, PDF_NAME(TrimBox), mb);
+				intersect_box(ctx, doc, newpageobj, PDF_NAME(ArtBox), mb);
+
+				/* Store page object in new kids array */
+				pdf_drop_obj(ctx, newpageobj);
+				pdf_array_push_drop(ctx, kids, newpageref);
+
+				kidcount++;
+			}
+		}
+	}
+
+	/* Update page count and kids array */
+	pdf_dict_put_int(ctx, pages, PDF_NAME(Count), kidcount);
+	pdf_dict_put_drop(ctx, pages, PDF_NAME(Kids), kids);
+}
+
+int pdfposter_main(int argc, char **argv)
+{
+	char *infile;
+	char *outfile = "out.pdf";
+	char *password = "";
+	int c;
+	pdf_write_options opts = pdf_default_write_options;
+	pdf_document *doc;
+	fz_context *ctx;
+	int ret = 0;
+
+	while ((c = fz_getopt(argc, argv, "m:x:y:p:r")) != -1)
+	{
+		switch (c)
+		{
+		case 'p': password = fz_optarg; break;
+		case 'm': margin = atof(fz_optarg); margin_is_percent = (strchr(fz_optarg, '%') != NULL); break;
+		case 'x': x_factor = atoi(fz_optarg); break;
+		case 'y': y_factor = atoi(fz_optarg); break;
+		case 'r': x_dir = -1; break;
+		default: return usage();
+		}
+	}
+
+	if (argc - fz_optind < 1)
+		return usage();
+
+	infile = argv[fz_optind++];
+
+	if (argc - fz_optind > 0 &&
+		(strstr(argv[fz_optind], ".pdf") || strstr(argv[fz_optind], ".PDF")))
+	{
+		outfile = fz_optpath(argv[fz_optind++]);
+	}
+
+	ctx = fz_new_context(NULL, NULL, FZ_STORE_UNLIMITED);
+	if (!ctx)
+	{
+		fprintf(stderr, "cannot initialise context\n");
+		exit(1);
+	}
+
+	fz_var(doc);
+
+	fz_try(ctx)
+	{
+		doc = pdf_open_document(ctx, infile);
+		if (pdf_needs_password(ctx, doc))
+			if (!pdf_authenticate_password(ctx, doc, password))
+				fz_throw(ctx, FZ_ERROR_ARGUMENT, "cannot authenticate password: %s", infile);
+
+		decimatepages(ctx, doc);
+
+		pdf_save_document(ctx, doc, outfile, &opts);
+	}
+	fz_always(ctx)
+		pdf_drop_document(ctx, doc);
+	fz_catch(ctx)
+	{
+		fz_report_error(ctx);
+		ret = 1;
+	}
+	fz_drop_context(ctx);
+
+	return ret;
+}