--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/jbig2dec/jbig2_image_png.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,152 @@
+/* Copyright (C) 2001-2023 Artifex Software, Inc.
+   All Rights Reserved.
+
+   This software is provided AS-IS with no warranty, either express or
+   implied.
+
+   This software is distributed under license and may not be copied,
+   modified or distributed except as expressly authorized under the terms
+   of the license contained in the file LICENSE in this distribution.
+
+   Refer to licensing information at http://www.artifex.com or contact
+   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
+   CA 94129, USA, for further information.
+*/
+
+/*
+    jbig2dec
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "os_types.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <png.h>
+
+#ifndef OLD_LIB_PNG
+# if PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR < 2
+#  define OLD_LIB_PNG 1
+# else
+#  define OLD_LIB_PNG 0
+# endif
+#endif
+
+#if OLD_LIB_PNG
+#include <pngstruct.h>
+#endif
+
+#define CVT_PTR(ptr) (ptr)
+
+#include "jbig2.h"
+#include "jbig2_priv.h"
+#include "jbig2_image.h"
+
+/* take an image structure and write it out in png format */
+
+static void
+jbig2_png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+    png_size_t check;
+
+#if OLD_LIB_PNG
+    png_FILE_p f = (png_FILE_p) png_ptr->io_ptr;
+#else
+    png_FILE_p f = (png_FILE_p) png_get_io_ptr(png_ptr);
+#endif
+
+    check = fwrite(data, 1, length, f);
+    if (check != length) {
+        png_error(png_ptr, "write error");
+    }
+}
+
+static void
+jbig2_png_flush(png_structp png_ptr)
+{
+#if OLD_LIB_PNG
+    png_FILE_p f = (png_FILE_p) png_ptr->io_ptr;
+#else
+    png_FILE_p f = (png_FILE_p) png_get_io_ptr(png_ptr);
+#endif
+
+    if (f != NULL)
+        fflush(f);
+}
+
+/* write out an image struct in png format to an open file pointer */
+
+int
+jbig2_image_write_png(Jbig2Image *image, FILE *out)
+{
+    uint32_t i;
+    png_structp png;
+    png_infop info;
+    png_bytep rowpointer;
+
+    png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (png == NULL) {
+        fprintf(stderr, "unable to create png structure\n");
+        return 2;
+    }
+
+    info = png_create_info_struct(png);
+    if (info == NULL) {
+        fprintf(stderr, "unable to create png info structure\n");
+        png_destroy_write_struct(&png, (png_infopp) NULL);
+        return 3;
+    }
+
+    /* set/check error handling */
+    if (setjmp(png_jmpbuf(png))) {
+        /* we've returned here after an internal error */
+        fprintf(stderr, "internal error in libpng saving file\n");
+        png_destroy_write_struct(&png, &info);
+        return 4;
+    }
+
+    /* png_init_io() doesn't work linking dynamically to libpng on win32
+       one has to either link statically or use callbacks because of runtime
+       variations */
+    /* png_init_io(png, out); */
+    png_set_write_fn(png, (png_voidp) out, jbig2_png_write_data, jbig2_png_flush);
+
+    /* now we fill out the info structure with our format data */
+    png_set_IHDR(png, info, image->width, image->height, 1, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+    png_write_info(png, info);
+
+    /* png natively treats 0 as black. This will convert for us */
+    png_set_invert_mono(png);
+
+    /* write out each row in turn */
+    rowpointer = (png_bytep) image->data;
+    for (i = 0; i < image->height; i++) {
+        png_write_row(png, rowpointer);
+        rowpointer += image->stride;
+    }
+
+    /* finish and clean up */
+    png_write_end(png, info);
+    png_destroy_write_struct(&png, &info);
+
+    return 0;
+}
+
+int
+jbig2_image_write_png_file(Jbig2Image *image, char *filename)
+{
+    FILE *out;
+    int code;
+
+    if ((out = fopen(filename, "wb")) == NULL) {
+        fprintf(stderr, "unable to open '%s' for writing\n", filename);
+        return 1;
+    }
+
+    code = jbig2_image_write_png(image, out);
+
+    fclose(out);
+    return (code);
+}