--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/include/mupdf/fitz/shade.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,233 @@
+// Copyright (C) 2004-2025 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.
+
+#ifndef MUPDF_FITZ_SHADE_H
+#define MUPDF_FITZ_SHADE_H
+
+#include "mupdf/fitz/system.h"
+#include "mupdf/fitz/context.h"
+#include "mupdf/fitz/geometry.h"
+#include "mupdf/fitz/store.h"
+#include "mupdf/fitz/pixmap.h"
+#include "mupdf/fitz/compressed-buffer.h"
+
+/**
+ * The shading code uses gouraud shaded triangle meshes.
+ */
+
+enum
+{
+	FZ_FUNCTION_BASED = 1,
+	FZ_LINEAR = 2,
+	FZ_RADIAL = 3,
+	FZ_MESH_TYPE4 = 4,
+	FZ_MESH_TYPE5 = 5,
+	FZ_MESH_TYPE6 = 6,
+	FZ_MESH_TYPE7 = 7
+};
+
+/**
+	Structure is public to allow derived classes. Do not
+	access the members directly.
+*/
+typedef struct
+{
+	fz_storable storable;
+
+	fz_rect bbox;		/* can be fz_infinite_rect */
+	fz_colorspace *colorspace;
+
+	fz_matrix matrix;	/* matrix from pattern dict */
+	int use_background;	/* background color for fills but not 'sh' */
+	float background[FZ_MAX_COLORS];
+
+	/* Just to be confusing, PDF Shadings of Type 1 (Function Based
+	 * Shadings), do NOT use function, but all the others do. This
+	 * is because Type 1 shadings take 2 inputs, whereas all the
+	 * others (when used with a function take 1 input. The type 1
+	 * data is in the 'f' field of the union below. */
+	/* If function_stride = 0, then function is not used. Otherwise
+	 * function points to 256*function_stride entries. */
+	int function_stride;
+	float *function;
+
+	int type; /* function, linear, radial, mesh */
+	union
+	{
+		struct
+		{
+			int extend[2];
+			float coords[2][3]; /* (x,y,r) twice */
+		} l_or_r;
+		struct
+		{
+			int vprow;
+			int bpflag;
+			int bpcoord;
+			int bpcomp;
+			float x0, x1;
+			float y0, y1;
+			float c0[FZ_MAX_COLORS];
+			float c1[FZ_MAX_COLORS];
+		} m;
+		struct
+		{
+			fz_matrix matrix;
+			int xdivs;
+			int ydivs;
+			float domain[2][2];
+			float *fn_vals;
+		} f;
+	} u;
+
+	fz_compressed_buffer *buffer;
+} fz_shade;
+
+/**
+	Increment the reference count for the shade structure. The
+	same pointer is returned.
+
+	Never throws exceptions.
+*/
+fz_shade *fz_keep_shade(fz_context *ctx, fz_shade *shade);
+
+/**
+	Decrement the reference count for the shade structure. When
+	the reference count hits zero, the structure is freed.
+
+	Never throws exceptions.
+*/
+void fz_drop_shade(fz_context *ctx, fz_shade *shade);
+
+/**
+	Bound a given shading.
+
+	shade: The shade to bound.
+
+	ctm: The transform to apply to the shade before bounding.
+
+	r: Pointer to storage to put the bounds in.
+
+	Returns r, updated to contain the bounds for the shading.
+*/
+fz_rect fz_bound_shade(fz_context *ctx, fz_shade *shade, fz_matrix ctm);
+
+typedef struct fz_shade_color_cache fz_shade_color_cache;
+
+void fz_drop_shade_color_cache(fz_context *ctx, fz_shade_color_cache *cache);
+
+/**
+	Render a shade to a given pixmap.
+
+	shade: The shade to paint.
+
+	override_cs: NULL, or colorspace to override the shades
+	inbuilt colorspace.
+
+	ctm: The transform to apply.
+
+	dest: The pixmap to render into.
+
+	color_params: The color rendering settings
+
+	bbox: Pointer to a bounding box to limit the rendering
+	of the shade.
+
+	eop: NULL, or pointer to overprint bitmap.
+
+	cache: *cache is used to cache color information. If *cache is NULL it
+	is set to point to a new fz_shade_color_cache. If cache is NULL it is
+	ignored.
+*/
+void fz_paint_shade(fz_context *ctx, fz_shade *shade, fz_colorspace *override_cs, fz_matrix ctm, fz_pixmap *dest, fz_color_params color_params, fz_irect bbox, const fz_overprint *eop, fz_shade_color_cache **cache);
+
+/**
+ *	Handy routine for processing mesh based shades
+ */
+typedef struct
+{
+	fz_point p;
+	float c[FZ_MAX_COLORS];
+} fz_vertex;
+
+/**
+	Callback function type for use with
+	fz_process_shade.
+
+	arg: Opaque pointer from fz_process_shade caller.
+
+	v: Pointer to a fz_vertex structure to populate.
+
+	c: Pointer to an array of floats used to populate v.
+*/
+typedef void (fz_shade_prepare_fn)(fz_context *ctx, void *arg, fz_vertex *v, const float *c);
+
+/**
+	Callback function type for use with
+	fz_process_shade.
+
+	arg: Opaque pointer from fz_process_shade caller.
+
+	av, bv, cv: Pointers to a fz_vertex structure describing
+	the corner locations and colors of a triangle to be
+	filled.
+*/
+typedef void (fz_shade_process_fn)(fz_context *ctx, void *arg, fz_vertex *av, fz_vertex *bv, fz_vertex *cv);
+
+/**
+	Process a shade, using supplied callback functions. This
+	decomposes the shading to a mesh (even ones that are not
+	natively meshes, such as linear or radial shadings), and
+	processes triangles from those meshes.
+
+	shade: The shade to process.
+
+	ctm: The transform to use
+
+	prepare: Callback function to 'prepare' each vertex.
+	This function is passed an array of floats, and populates
+	a fz_vertex structure.
+
+	process: This function is passed 3 pointers to vertex
+	structures, and actually performs the processing (typically
+	filling the area between the vertices).
+
+	process_arg: An opaque argument passed through from caller
+	to callback functions.
+*/
+void fz_process_shade(fz_context *ctx, fz_shade *shade, fz_matrix ctm, fz_rect scissor,
+			fz_shade_prepare_fn *prepare,
+			fz_shade_process_fn *process,
+			void *process_arg);
+
+
+/* Implementation details: subject to change. */
+
+/**
+	Internal function to destroy a
+	shade. Only exposed for use with the fz_store.
+
+	shade: The reference to destroy.
+*/
+void fz_drop_shade_imp(fz_context *ctx, fz_storable *shade);
+
+#endif