--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/reflow/reflow-doc.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,283 @@
+// Copyright (C) 2004-2021 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.
+
+#include "mupdf/fitz.h"
+
+#if FZ_ENABLE_HTML_ENGINE
+
+#include <assert.h>
+#include <limits.h>
+#include <string.h>
+
+#define DEF_WIDTH 612
+#define DEF_HEIGHT 792
+#define DEF_FONTSIZE 12
+
+typedef struct
+{
+	fz_document base;
+
+	fz_document *underdoc;
+	fz_stext_options opts;
+	float w;
+	float h;
+	float em;
+} reflow_document;
+
+typedef struct {
+	fz_page base;
+
+	fz_document *html_doc;
+	fz_page *html_page;
+} reflow_page;
+
+static void
+reflow_drop_document_imp(fz_context *ctx, fz_document *doc_)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	fz_defer_reap_start(ctx);
+
+	fz_drop_document(ctx, doc->underdoc);
+	fz_defer_reap_end(ctx);
+}
+
+static fz_colorspace *
+reflow_document_output_intent(fz_context *ctx, fz_document *doc_)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_document_output_intent(ctx, doc->underdoc);
+}
+
+static int
+reflow_needs_password(fz_context *ctx, fz_document *doc_)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_needs_password(ctx, doc->underdoc);
+}
+
+static int
+reflow_authenticate_password(fz_context *ctx, fz_document *doc_, const char *password)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_authenticate_password(ctx, doc->underdoc, password);
+}
+
+static int
+reflow_has_permission(fz_context *ctx, fz_document *doc_, fz_permission permission)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_has_permission(ctx, doc->underdoc, permission);
+}
+
+/* FIXME: Need to translate page targets somehow. */
+static fz_outline *
+reflow_load_outline(fz_context *ctx, fz_document *doc_)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_load_outline(ctx, doc->underdoc);
+}
+
+/* FIXME: Need to translate page targets somehow. */
+static fz_outline_iterator *
+reflow_outline_iterator(fz_context *ctx, fz_document *doc_)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_new_outline_iterator(ctx, doc->underdoc);
+}
+
+static fz_link_dest
+reflow_resolve_link_dest(fz_context *ctx, fz_document *doc_, const char *uri)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_resolve_link_dest(ctx, doc->underdoc, uri);
+}
+
+static int
+reflow_count_pages(fz_context *ctx, fz_document *doc_, int chapter)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_count_chapter_pages(ctx, doc->underdoc, chapter);
+}
+
+static fz_rect
+reflow_bound_page(fz_context *ctx, fz_page *page_, fz_box_type box)
+{
+	reflow_page *page = (reflow_page *)page_;
+
+	return fz_bound_page(ctx, page->html_page);
+}
+
+static void
+reflow_drop_page(fz_context *ctx, fz_page *page_)
+{
+	reflow_page *page = (reflow_page *)page_;
+
+	fz_drop_page(ctx, page->html_page);
+	fz_drop_document(ctx, page->html_doc);
+}
+
+static void
+reflow_run_page_contents(fz_context *ctx, fz_page *page_, fz_device *dev, fz_matrix transform, fz_cookie *cookie)
+{
+	reflow_page *page = (reflow_page *)page_;
+
+	fz_run_page_contents(ctx, page->html_page, dev, transform, cookie);
+}
+
+static void
+reflow_run_page_annots(fz_context *ctx, fz_page *page_, fz_device *dev, fz_matrix transform, fz_cookie *cookie)
+{
+	reflow_page *page = (reflow_page *)page_;
+
+	fz_run_page_annots(ctx, page->html_page, dev, transform, cookie);
+}
+
+static void
+reflow_run_page_widgets(fz_context *ctx, fz_page *page_, fz_device *dev, fz_matrix transform, fz_cookie *cookie)
+{
+	reflow_page *page = (reflow_page *)page_;
+
+	fz_run_page_widgets(ctx, page->html_page, dev, transform, cookie);
+}
+
+static fz_page *
+reflow_load_page(fz_context *ctx, fz_document *doc_, int chapter, int pagenum)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	fz_buffer *buf = NULL;
+	fz_stext_page *text = NULL;
+	fz_stext_options default_opts = { FZ_STEXT_PRESERVE_IMAGES | FZ_STEXT_DEHYPHENATE };
+	reflow_page *page = NULL;
+	fz_stream *stm = NULL;
+	fz_output *out = NULL;
+
+	page = fz_new_derived_page(ctx, reflow_page, doc_);
+	page->base.bound_page = reflow_bound_page;
+	page->base.drop_page = reflow_drop_page;
+	page->base.run_page_contents = reflow_run_page_contents;
+	page->base.run_page_annots = reflow_run_page_annots;
+	page->base.run_page_widgets = reflow_run_page_widgets;
+
+	fz_var(buf);
+	fz_var(out);
+	fz_var(text);
+	fz_var(stm);
+
+	fz_try(ctx)
+	{
+		buf = fz_new_buffer(ctx, 8192);
+		out = fz_new_output_with_buffer(ctx, buf);
+		fz_print_stext_header_as_xhtml(ctx, out);
+
+		text = fz_new_stext_page_from_chapter_page_number(ctx, doc->underdoc, chapter, pagenum, &default_opts);
+		fz_print_stext_page_as_xhtml(ctx, out, text, pagenum+1); /* pagenum is not right w.r.t chapter. */
+		fz_drop_stext_page(ctx, text);
+		text = NULL;
+
+		fz_print_stext_trailer_as_xhtml(ctx, out);
+		fz_close_output(ctx, out);
+		fz_terminate_buffer(ctx, buf);
+
+		stm = fz_open_buffer(ctx, buf);
+		page->html_doc = fz_open_document_with_stream(ctx, "application/xhtml+xml", stm);
+		fz_layout_document(ctx, page->html_doc, doc->w, 0, doc->em);
+		page->html_page = fz_load_chapter_page(ctx, page->html_doc, 0, 0);
+	}
+	fz_always(ctx)
+	{
+		fz_drop_stext_page(ctx, text);
+		fz_drop_output(ctx, out);
+		fz_drop_stream(ctx, stm);
+		fz_drop_buffer(ctx, buf);
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_page(ctx, &page->base);
+		fz_rethrow(ctx);
+	}
+
+	return &page->base;
+}
+
+static int reflow_lookup_metadata(fz_context *ctx, fz_document *doc_, const char *key, char *buf, size_t size)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	return fz_lookup_metadata(ctx, doc->underdoc, key, buf, size);
+}
+
+static void *reflow_layout_page(fz_context *ctx, fz_page *page_, void *state)
+{
+	reflow_page *page = (reflow_page *) page_;
+	reflow_document *doc = (reflow_document *) page->base.doc;
+	fz_layout_document(ctx, page->html_doc, doc->w, 0, doc->em);
+	return NULL;
+}
+
+static void reflow_layout(fz_context *ctx, fz_document *doc_, float w, float h, float em)
+{
+	reflow_document *doc = (reflow_document*)doc_;
+	if (doc->w == w && doc->h == h && doc->em == em)
+		return;
+	doc->w = w;
+	doc->h = h;
+	doc->em = em;
+
+	(void) fz_process_opened_pages(ctx, (fz_document *) doc, reflow_layout_page, NULL);
+}
+
+fz_document *
+fz_open_reflowed_document(fz_context *ctx, fz_document *underdoc, const fz_stext_options *opts)
+{
+	reflow_document *doc = fz_new_derived_document(ctx, reflow_document);
+
+	doc->base.drop_document = reflow_drop_document_imp;
+	doc->base.get_output_intent = reflow_document_output_intent;
+	doc->base.needs_password = reflow_needs_password;
+	doc->base.authenticate_password = reflow_authenticate_password;
+	doc->base.has_permission = reflow_has_permission;
+	doc->base.load_outline = reflow_load_outline;
+	doc->base.outline_iterator = reflow_outline_iterator;
+	doc->base.resolve_link_dest = reflow_resolve_link_dest;
+	doc->base.count_pages = reflow_count_pages;
+	doc->base.load_page = reflow_load_page;
+	doc->base.lookup_metadata = reflow_lookup_metadata;
+	doc->base.layout = reflow_layout;
+
+	doc->underdoc = fz_keep_document(ctx, underdoc);
+	doc->opts = *opts;
+
+	doc->w = DEF_WIDTH;
+	doc->h = DEF_HEIGHT;
+	doc->em = DEF_FONTSIZE;
+
+	return &doc->base;
+}
+
+#else
+
+fz_document *
+fz_open_reflowed_document(fz_context *ctx, fz_document *underdoc, const fz_stext_options *opts)
+{
+	fz_throw(ctx, FZ_ERROR_UNSUPPORTED, "reflowed documents require html engine");
+}
+
+#endif