--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/pdf/pdf-recolor.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,177 @@
+// Copyright (C) 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.
+
+#include "mupdf/pdf.h"
+
+typedef struct {
+	fz_colorspace *outcs;
+	pdf_obj *outcs_obj;
+} recolor_data;
+
+static void
+color_rewrite(fz_context *ctx, void *opaque, pdf_obj **cs_obj, int *n, float color[FZ_MAX_COLORS])
+{
+	recolor_data *rd = (recolor_data *)opaque;
+	fz_colorspace *cs;
+	float cols[4] = { 0 };
+
+	if (pdf_name_eq(ctx, *cs_obj, PDF_NAME(Pattern)))
+		return;
+	if (pdf_name_eq(ctx, pdf_dict_get(ctx, *cs_obj, PDF_NAME(Type)), PDF_NAME(Pattern)))
+		return;
+
+	if (*n != 0)
+	{
+		cs = pdf_load_colorspace(ctx, *cs_obj);
+
+		fz_try(ctx)
+		{
+			fz_convert_color(ctx, cs, color, rd->outcs, cols, NULL, fz_default_color_params);
+		}
+		fz_always(ctx)
+			fz_drop_colorspace(ctx, cs);
+		fz_catch(ctx)
+			fz_rethrow(ctx);
+		*n = rd->outcs->n;
+	}
+
+	pdf_drop_obj(ctx, *cs_obj);
+	*cs_obj = rd->outcs_obj;
+	memcpy(color, cols, sizeof(color[0])*4);
+}
+
+static void
+image_rewrite(fz_context *ctx, void *opaque, fz_image **image, fz_matrix ctm, pdf_obj *im_obj)
+{
+	recolor_data *rd = (recolor_data *)opaque;
+	fz_image *orig = *image;
+	fz_pixmap *pix = NULL;
+	fz_colorspace* dst_cs;
+
+	fz_var(pix);
+
+	if ((*image)->imagemask)
+		return;
+
+	dst_cs = rd->outcs;
+	pix = fz_get_unscaled_pixmap_from_image(ctx, orig);
+
+	fz_try(ctx)
+	{
+		if (pix->colorspace != dst_cs)
+		{
+			fz_pixmap *pix2 = fz_convert_pixmap(ctx, pix, dst_cs, NULL, NULL, fz_default_color_params, 1);
+			fz_drop_pixmap(ctx, pix);
+			pix = pix2;
+		}
+
+		*image = fz_new_image_from_pixmap(ctx, pix, orig->mask);
+		fz_drop_image(ctx, orig);
+	}
+	fz_always(ctx)
+		fz_drop_pixmap(ctx, pix);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+
+static void
+vertex_rewrite(fz_context *ctx, void *opaque, fz_colorspace *dst_cs, float *d, fz_colorspace *src_cs, const float *s)
+{
+	recolor_data *rd = (recolor_data *)opaque;
+
+	fz_convert_color(ctx, src_cs, s, rd->outcs, d, NULL, fz_default_color_params);
+}
+
+static pdf_recolor_vertex *
+shade_rewrite(fz_context *ctx, void *opaque, fz_colorspace *src_cs, fz_colorspace **dst_cs)
+{
+	recolor_data *rd = (recolor_data *)opaque;
+
+	*dst_cs = rd->outcs;
+
+	return vertex_rewrite;
+}
+
+static void
+rewrite_page_streams(fz_context *ctx, pdf_document *doc, int page_num, recolor_data *rd)
+{
+	pdf_page *page = pdf_load_page(ctx, doc, page_num);
+	pdf_filter_options options = { 0 };
+	pdf_filter_factory list[2] = { 0 };
+	pdf_color_filter_options copts = { 0 };
+	pdf_annot *annot;
+
+	copts.opaque = rd;
+	copts.color_rewrite = color_rewrite;
+	copts.image_rewrite = image_rewrite;
+	copts.shade_rewrite = shade_rewrite;
+	options.filters = list;
+	options.recurse = 1;
+	list[0].filter = pdf_new_color_filter;
+	list[0].options = &copts;
+
+	fz_try(ctx)
+	{
+		pdf_filter_page_contents(ctx, doc, page, &options);
+
+		for (annot = pdf_first_annot(ctx, page); annot != NULL; annot = pdf_next_annot(ctx, annot))
+			pdf_filter_annot_contents(ctx, doc, annot, &options);
+	}
+	fz_always(ctx)
+		fz_drop_page(ctx, &page->super);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+
+
+void pdf_recolor_page(fz_context *ctx, pdf_document *doc, int pagenum, const pdf_recolor_options *opts)
+{
+	recolor_data rd = { 0 };
+
+	if (opts == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Options must be supplied");
+
+	switch (opts->num_comp)
+	{
+	case 1:
+		rd.outcs = fz_device_gray(ctx);
+		rd.outcs_obj = PDF_NAME(DeviceGray);
+		break;
+	case 3:
+		rd.outcs = fz_device_rgb(ctx);
+		rd.outcs_obj = PDF_NAME(DeviceRGB);
+		break;
+	case 4:
+		rd.outcs = fz_device_cmyk(ctx);
+		rd.outcs_obj = PDF_NAME(DeviceCMYK);
+		break;
+	default:
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Unsupported number of components");
+	}
+
+	rewrite_page_streams(ctx, doc, pagenum, &rd);
+}
+
+void pdf_remove_output_intents(fz_context *ctx, pdf_document *doc)
+{
+	pdf_dict_del(ctx, pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root)), PDF_NAME(OutputIntents));
+}