Introduce cairo_tee_surface_t

Add a new surface type that multiplies it input onto several output
surfaces. The only limitation is that it requires a master surface that is
used whenever we need to query surface options, such as font options and
extents.

boilerplate/Makefile.win32.features

@@ -312,6 +312,14 @@ enabled_cairo_boilerplate_headers += $(cairo_boilerplate_meta_headers)
 enabled_cairo_boilerplate_private += $(cairo_boilerplate_meta_private)
 enabled_cairo_boilerplate_sources += $(cairo_boilerplate_meta_sources)
 
+supported_cairo_boilerplate_headers += $(cairo_boilerplate_tee_headers)
+all_cairo_boilerplate_headers += $(cairo_boilerplate_tee_headers)
+all_cairo_boilerplate_private += $(cairo_boilerplate_tee_private)
+all_cairo_boilerplate_sources += $(cairo_boilerplate_tee_sources)
+enabled_cairo_boilerplate_headers += $(cairo_boilerplate_tee_headers)
+enabled_cairo_boilerplate_private += $(cairo_boilerplate_tee_private)
+enabled_cairo_boilerplate_sources += $(cairo_boilerplate_tee_sources)
+
 supported_cairo_boilerplate_headers += $(cairo_boilerplate_user_headers)
 all_cairo_boilerplate_headers += $(cairo_boilerplate_user_headers)
 all_cairo_boilerplate_private += $(cairo_boilerplate_user_private)

build/Makefile.win32.features-h

@@ -91,5 +91,6 @@ ifeq ($(CAIRO_HAS_TEST_SURFACES),1)
 endif
 	@echo "#define CAIRO_HAS_IMAGE_SURFACE 1" >> src/cairo-features.h
 	@echo "#define CAIRO_HAS_META_SURFACE 1" >> src/cairo-features.h
+	@echo "#define CAIRO_HAS_TEE_SURFACE 1" >> src/cairo-features.h
 	@echo "#define CAIRO_HAS_USER_FONT 1" >> src/cairo-features.h
 	@echo "#endif" >>  src/cairo-features.h

build/configure.ac.features

@@ -358,6 +358,7 @@ AC_DEFUN([CAIRO_REPORT],
 	echo "The following surface backends:"
 	echo "  Image:         yes (always builtin)"
 	echo "  Meta:          yes (always builtin)"
+	echo "  Tee:           yes (always builtin)"
 	echo "  Xlib:          $use_xlib"
 	echo "  Xlib Xrender:  $use_xlib_xrender"
 	echo "  Qt:            $use_qt"

configure.ac

@@ -570,6 +570,7 @@ CAIRO_ENABLE_SURFACE_BACKEND(image, image, always, [
 dnl ===========================================================================
 
 CAIRO_ENABLE_SURFACE_BACKEND(meta, meta, always)
+CAIRO_ENABLE_SURFACE_BACKEND(tee, tee, always)
 
 dnl ===========================================================================
 

src/Makefile.sources

@@ -88,6 +88,7 @@ cairo_private = \
 	cairo-surface-private.h \
 	cairo-surface-clipper-private.h \
 	cairo-surface-wrapper-private.h \
+	cairo-tee-surface-private.h \
 	cairo-types-private.h \
 	cairo-user-font-private.h \
 	cairo-wideint-private.h \
@@ -146,10 +147,11 @@ cairo_sources = \
 	cairo-surface-fallback.c \
 	cairo-surface-clipper.c \
 	cairo-surface-wrapper.c \
-	cairo-tor-scan-converter.c \
 	cairo-system.c \
-	cairo-traps.c \
+	cairo-tee-surface.c \
+	cairo-tor-scan-converter.c \
 	cairo-toy-font-face.c \
+	cairo-traps.c \
 	cairo-unicode.c \
 	cairo-user-font.c \
 	cairo-version.c \

src/Makefile.win32.features

@@ -422,6 +422,14 @@ enabled_cairo_headers += $(cairo_meta_headers)
 enabled_cairo_private += $(cairo_meta_private)
 enabled_cairo_sources += $(cairo_meta_sources)
 
+supported_cairo_headers += $(cairo_tee_headers)
+all_cairo_headers += $(cairo_tee_headers)
+all_cairo_private += $(cairo_tee_private)
+all_cairo_sources += $(cairo_tee_sources)
+enabled_cairo_headers += $(cairo_tee_headers)
+enabled_cairo_private += $(cairo_tee_private)
+enabled_cairo_sources += $(cairo_tee_sources)
+
 supported_cairo_headers += $(cairo_user_headers)
 all_cairo_headers += $(cairo_user_headers)
 all_cairo_private += $(cairo_user_private)

src/cairo-surface-wrapper-private.h

@@ -142,6 +142,10 @@ cairo_private cairo_bool_t
 _cairo_surface_wrapper_get_extents (cairo_surface_wrapper_t *wrapper,
 				    cairo_rectangle_int_t   *extents);
 
+cairo_private void
+_cairo_surface_wrapper_get_font_options (cairo_surface_wrapper_t    *wrapper,
+					 cairo_font_options_t	    *options);
+
 cairo_private cairo_surface_t *
 _cairo_surface_wrapper_snapshot (cairo_surface_wrapper_t *wrapper);
 

src/cairo-surface-wrapper.c

@@ -429,6 +429,13 @@ _cairo_surface_wrapper_get_extents (cairo_surface_wrapper_t *wrapper,
     return _cairo_surface_get_extents (wrapper->target, extents);
 }
 
+void
+_cairo_surface_wrapper_get_font_options (cairo_surface_wrapper_t    *wrapper,
+					 cairo_font_options_t	    *options)
+{
+    return cairo_surface_get_font_options (wrapper->target, options);
+}
+
 cairo_surface_t *
 _cairo_surface_wrapper_snapshot (cairo_surface_wrapper_t *wrapper)
 {

src/cairo-surface.c

@@ -42,6 +42,7 @@
 #include "cairo-clip-private.h"
 #include "cairo-meta-surface-private.h"
 #include "cairo-region-private.h"
+#include "cairo-tee-surface-private.h"
 
 #define DEFINE_NIL_SURFACE(status, name)			\
 const cairo_surface_t name = {					\
@@ -1528,6 +1529,16 @@ _cairo_surface_clone_similar (cairo_surface_t  *surface,
     if (unlikely (surface->finished))
 	return _cairo_error (CAIRO_STATUS_SURFACE_FINISHED);
 
+    if (src->type == CAIRO_SURFACE_TYPE_TEE) {
+	cairo_surface_t *match;
+
+	match = _cairo_tee_surface_find_match (src,
+					       surface->backend,
+					       content);
+	if (match != NULL)
+	    src = match;
+    }
+
     if (surface->backend->clone_similar != NULL) {
 	status = surface->backend->clone_similar (surface, src,
 						  content,

src/cairo-tee-surface-private.h

@@ -0,0 +1,47 @@
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2009 Chris Wilson
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ * The Original Code is the cairo graphics library.
+ *
+ * The Initial Developer of the Original Code is University of Southern
+ * California.
+ *
+ * Contributor(s):
+ *	Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#ifndef CAIRO_TEE_SURFACE_PRIVATE_H
+#define CAIRO_TEE_SURFACE_PRIVATE_H
+
+#include "cairoint.h"
+
+cairo_private cairo_surface_t *
+_cairo_tee_surface_find_match (void *abstract_surface,
+			       const cairo_surface_backend_t *backend,
+			       cairo_content_t content);
+
+#endif /* CAIRO_TEE_SURFACE_PRIVATE_H */

src/cairo-tee-surface.c

@@ -0,0 +1,558 @@
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2005 Red Hat, Inc
+ * Copyright © 2009 Chris Wilson
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ * The Original Code is the cairo graphics library.
+ *
+ * The Initial Developer of the Original Code is Red Hat, Inc.
+ *
+ * Contributor(s):
+ *	Carl Worth <cworth@cworth.org>
+ *	Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+/* This surface supports redirecting all its input to multiple surfaces.
+ */
+
+#include "cairoint.h"
+
+#include "cairo-tee-surface-private.h"
+#include "cairo-surface-wrapper-private.h"
+
+typedef struct _cairo_tee_surface {
+    cairo_surface_t base;
+
+    cairo_surface_wrapper_t master;
+    cairo_array_t slaves;
+} cairo_tee_surface_t;
+
+slim_hidden_proto (cairo_tee_surface_create);
+slim_hidden_proto (cairo_tee_surface_append);
+
+static cairo_surface_t *
+_cairo_tee_surface_create_similar (void			*abstract_surface,
+				   cairo_content_t	 content,
+				   int			 width,
+				   int			 height)
+{
+
+    cairo_tee_surface_t *other = abstract_surface;
+    cairo_surface_t *similar;
+    cairo_surface_t *surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+
+    similar = _cairo_surface_wrapper_create_similar (&other->master,
+						     content, width, height);
+    surface = cairo_tee_surface_create (similar);
+    cairo_surface_destroy (similar);
+    if (unlikely (surface->status))
+	return surface;
+
+    num_slaves = _cairo_array_num_elements (&other->slaves);
+    slaves = _cairo_array_index (&other->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+
+	similar = _cairo_surface_wrapper_create_similar (&slaves[n],
+							 content,
+							 width, height);
+	cairo_tee_surface_append (surface, similar);
+	cairo_surface_destroy (similar);
+    }
+
+    if (unlikely (surface->status)) {
+	cairo_status_t status = surface->status;
+	cairo_surface_destroy (surface);
+	surface = _cairo_surface_create_in_error (status);
+    }
+
+    return surface;
+}
+
+static cairo_status_t
+_cairo_tee_surface_finish (void *abstract_surface)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+
+    _cairo_surface_wrapper_fini (&surface->master);
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++)
+	_cairo_surface_wrapper_fini (&slaves[n]);
+
+    _cairo_array_fini (&surface->slaves);
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_tee_surface_acquire_source_image (void	     *abstract_surface,
+					 cairo_image_surface_t **image_out,
+					 void		 **image_extra)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int num_slaves, n;
+
+    /* we prefer to use a real image surface if available */
+    if (_cairo_surface_is_image (surface->master.target)) {
+	return _cairo_surface_wrapper_acquire_source_image (&surface->master,
+							    image_out, image_extra);
+    }
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	if (_cairo_surface_is_image (slaves[n].target)) {
+	    return _cairo_surface_wrapper_acquire_source_image (&slaves[n],
+								image_out,
+								image_extra);
+	}
+    }
+
+    return _cairo_surface_wrapper_acquire_source_image (&surface->master,
+							image_out, image_extra);
+}
+
+static void
+_cairo_tee_surface_release_source_image (void	     *abstract_surface,
+					 cairo_image_surface_t	*image,
+					 void		  *image_extra)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+
+    _cairo_surface_wrapper_release_source_image (&surface->master,
+						 image, image_extra);
+}
+
+static cairo_surface_t *
+_cairo_tee_surface_snapshot (void *abstract_surface)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int num_slaves, n;
+
+    /* we prefer to use a meta surface for our snapshots */
+    if (_cairo_surface_is_meta (surface->master.target))
+	return _cairo_surface_wrapper_snapshot (&surface->master);
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	if (_cairo_surface_is_meta (slaves[n].target))
+	    return _cairo_surface_wrapper_snapshot (&slaves[n]);
+    }
+
+    return _cairo_surface_wrapper_snapshot (&surface->master);
+}
+
+static cairo_bool_t
+_cairo_tee_surface_get_extents (void			*abstract_surface,
+				cairo_rectangle_int_t	*rectangle)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+
+    return _cairo_surface_wrapper_get_extents (&surface->master, rectangle);
+}
+
+static void
+_cairo_tee_surface_get_font_options (void                  *abstract_surface,
+				     cairo_font_options_t  *options)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+
+    _cairo_surface_wrapper_get_font_options (&surface->master, options);
+}
+
+static cairo_int_status_t
+_cairo_tee_surface_paint (void			*abstract_surface,
+			  cairo_operator_t	 op,
+			  const cairo_pattern_t	*source,
+			  cairo_clip_t		*clip)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+    cairo_status_t status;
+
+    status = _cairo_surface_wrapper_paint (&surface->master, op, source, clip);
+    if (unlikely (status))
+	return status;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	status = _cairo_surface_wrapper_paint (&slaves[n], op, source, clip);
+	if (unlikely (status))
+	    return status;
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_int_status_t
+_cairo_tee_surface_mask (void			*abstract_surface,
+			 cairo_operator_t	 op,
+			 const cairo_pattern_t	*source,
+			 const cairo_pattern_t	*mask,
+			 cairo_clip_t		*clip)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+    cairo_status_t status;
+
+    status = _cairo_surface_wrapper_mask (&surface->master,
+					  op, source, mask, clip);
+    if (unlikely (status))
+	return status;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	status = _cairo_surface_wrapper_mask (&slaves[n],
+					      op, source, mask, clip);
+	if (unlikely (status))
+	    return status;
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_int_status_t
+_cairo_tee_surface_stroke (void				*abstract_surface,
+			   cairo_operator_t		 op,
+			   const cairo_pattern_t	*source,
+			   cairo_path_fixed_t		*path,
+			   cairo_stroke_style_t		*style,
+			   cairo_matrix_t		*ctm,
+			   cairo_matrix_t		*ctm_inverse,
+			   double			 tolerance,
+			   cairo_antialias_t		 antialias,
+			   cairo_clip_t			*clip)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+    cairo_status_t status;
+
+    status = _cairo_surface_wrapper_stroke (&surface->master,
+					    op, source,
+					    path, style,
+					    ctm, ctm_inverse,
+					    tolerance, antialias,
+					    clip);
+    if (unlikely (status))
+	return status;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	status = _cairo_surface_wrapper_stroke (&slaves[n],
+						op, source,
+						path, style,
+						ctm, ctm_inverse,
+						tolerance, antialias,
+						clip);
+	if (unlikely (status))
+	    return status;
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_int_status_t
+_cairo_tee_surface_fill (void				*abstract_surface,
+			 cairo_operator_t		 op,
+			 const cairo_pattern_t		*source,
+			 cairo_path_fixed_t		*path,
+			 cairo_fill_rule_t		 fill_rule,
+			 double				 tolerance,
+			 cairo_antialias_t		 antialias,
+			 cairo_clip_t			*clip)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+    cairo_status_t status;
+
+    status = _cairo_surface_wrapper_fill (&surface->master,
+					  op, source,
+					  path, fill_rule,
+					  tolerance, antialias,
+					  clip);
+    if (unlikely (status))
+	return status;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	status = _cairo_surface_wrapper_fill (&slaves[n],
+					      op, source,
+					      path, fill_rule,
+					      tolerance, antialias,
+					      clip);
+	if (unlikely (status))
+	    return status;
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_bool_t
+_cairo_tee_surface_has_show_text_glyphs (void *abstract_surface)
+{
+    return TRUE;
+}
+
+static cairo_int_status_t
+_cairo_tee_surface_show_text_glyphs (void		    *abstract_surface,
+				     cairo_operator_t	     op,
+				     const cairo_pattern_t  *source,
+				     const char		    *utf8,
+				     int		     utf8_len,
+				     cairo_glyph_t	    *glyphs,
+				     int		     num_glyphs,
+				     const cairo_text_cluster_t *clusters,
+				     int		     num_clusters,
+				     cairo_text_cluster_flags_t cluster_flags,
+				     cairo_scaled_font_t    *scaled_font,
+				     cairo_clip_t	    *clip)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int n, num_slaves;
+    cairo_status_t status;
+    cairo_glyph_t *glyphs_copy;
+
+    /* XXX: This copying is ugly. */
+    glyphs_copy = _cairo_malloc_ab (num_glyphs, sizeof (cairo_glyph_t));
+    if (unlikely (glyphs_copy == NULL))
+	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+
+    memcpy (glyphs_copy, glyphs, sizeof (cairo_glyph_t) * num_glyphs);
+    status = _cairo_surface_wrapper_show_text_glyphs (&surface->master, op,
+						      source,
+						      utf8, utf8_len,
+						      glyphs_copy, num_glyphs,
+						      clusters, num_clusters,
+						      cluster_flags,
+						      scaled_font,
+						      clip);
+    if (unlikely (status))
+	goto CLEANUP;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	memcpy (glyphs_copy, glyphs, sizeof (cairo_glyph_t) * num_glyphs);
+	status = _cairo_surface_wrapper_show_text_glyphs (&slaves[n], op,
+							  source,
+							  utf8, utf8_len,
+							  glyphs_copy, num_glyphs,
+							  clusters, num_clusters,
+							  cluster_flags,
+							  scaled_font,
+							  clip);
+	if (unlikely (status))
+	    goto CLEANUP;
+    }
+
+  CLEANUP:
+    free (glyphs_copy);
+    return status;
+}
+
+static const cairo_surface_backend_t cairo_tee_surface_backend = {
+    CAIRO_SURFACE_TYPE_TEE,
+    _cairo_tee_surface_create_similar,
+    _cairo_tee_surface_finish,
+    _cairo_tee_surface_acquire_source_image,
+    _cairo_tee_surface_release_source_image,
+    NULL, NULL, /* dest_image */
+    NULL, /* clone_similar */
+    NULL, /* composite */
+    NULL, /* fill_rectangles */
+    NULL, /* composite_trapezoids */
+    NULL, /* create_span_renderer */
+    NULL, /* check_span_renderer */
+    NULL, /* copy_page */
+    NULL, /* show_page */
+    _cairo_tee_surface_get_extents,
+    NULL, /* old_show_glyphs */
+    _cairo_tee_surface_get_font_options,
+    NULL, /* flush */
+    NULL, /* mark_dirty_rectangle */
+    NULL, /* scaled_font_fini */
+    NULL, /* scaled_glyph_fini */
+
+    _cairo_tee_surface_paint,
+    _cairo_tee_surface_mask,
+    _cairo_tee_surface_stroke,
+    _cairo_tee_surface_fill,
+    NULL, /* replaced by show_text_glyphs */
+
+    _cairo_tee_surface_snapshot,
+    NULL, /* is_similar */
+    NULL, /* fill_stroke */
+    NULL, /* create_solid_pattern_surface */
+    NULL, /* can_repaint_solid_pattern_surface */
+
+    _cairo_tee_surface_has_show_text_glyphs,
+    _cairo_tee_surface_show_text_glyphs
+};
+
+cairo_surface_t *
+cairo_tee_surface_create (cairo_surface_t *master)
+{
+    cairo_tee_surface_t *surface;
+
+    if (unlikely (master->status))
+	return _cairo_surface_create_in_error (master->status);
+
+    surface = malloc (sizeof (cairo_tee_surface_t));
+    if (unlikely (surface == NULL))
+	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
+
+    _cairo_surface_init (&surface->base,
+			 &cairo_tee_surface_backend,
+			 master->content);
+
+    _cairo_surface_wrapper_init (&surface->master, master);
+    /* we trust that these are already set and remain constant */
+    surface->base.device_transform = master->device_transform;
+    surface->base.device_transform_inverse = master->device_transform_inverse;
+
+    _cairo_array_init (&surface->slaves, sizeof (cairo_surface_wrapper_t));
+
+    return &surface->base;
+}
+slim_hidden_def (cairo_tee_surface_create);
+
+void
+cairo_tee_surface_append (cairo_surface_t *abstract_surface,
+			  cairo_surface_t *target)
+{
+    cairo_tee_surface_t *surface;
+    cairo_surface_wrapper_t slave;
+    cairo_status_t status;
+
+    if (unlikely (abstract_surface->status))
+	return;
+
+    if (abstract_surface->backend != &cairo_tee_surface_backend) {
+	status = _cairo_surface_set_error (abstract_surface,
+					   _cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));
+	return;
+    }
+
+    if (unlikely (target->status)) {
+	status = _cairo_surface_set_error (abstract_surface, target->status);
+	return;
+    }
+
+    surface = (cairo_tee_surface_t *) abstract_surface;
+
+    _cairo_surface_wrapper_init (&slave, target);
+    status = _cairo_array_append (&surface->slaves, &slave);
+    if (unlikely (status)) {
+	_cairo_surface_wrapper_fini (&slave);
+	status = _cairo_surface_set_error (&surface->base, status);
+    }
+}
+slim_hidden_def (cairo_tee_surface_append);
+
+cairo_surface_t *
+cairo_tee_surface_index (cairo_surface_t *abstract_surface,
+			 int index)
+{
+    cairo_tee_surface_t *surface;
+
+    if (unlikely (abstract_surface->status))
+	return _cairo_surface_create_in_error (abstract_surface->status);
+
+    if (abstract_surface->backend != &cairo_tee_surface_backend)
+	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_TYPE_MISMATCH));
+
+    surface = (cairo_tee_surface_t *) abstract_surface;
+    if (index == 0) {
+	return surface->master.target;
+    } else {
+	cairo_surface_wrapper_t *slave;
+
+	index--;
+
+	if (index >= _cairo_array_num_elements (&surface->slaves))
+	    return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_INDEX));
+
+	slave = _cairo_array_index (&surface->slaves, index);
+	return slave->target;
+    }
+}
+
+cairo_surface_t *
+_cairo_tee_surface_find_match (void *abstract_surface,
+			       const cairo_surface_backend_t *backend,
+			       cairo_content_t content)
+{
+    cairo_tee_surface_t *surface = abstract_surface;
+    cairo_surface_wrapper_t *slaves;
+    int num_slaves, n;
+
+    /* exact match first */
+    if (surface->master.target->backend == backend &&
+	surface->master.target->content == content)
+    {
+	return surface->master.target;
+    }
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	if (slaves[n].target->backend == backend &&
+	    slaves[n].target->content == content)
+	{
+	    return slaves[n].target;
+	}
+    }
+
+    /* matching backend? */
+    if (surface->master.target->backend == backend)
+	return surface->master.target;
+
+    num_slaves = _cairo_array_num_elements (&surface->slaves);
+    slaves = _cairo_array_index (&surface->slaves, 0);
+    for (n = 0; n < num_slaves; n++) {
+	if (slaves[n].target->backend == backend)
+	    return slaves[n].target;
+    }
+
+    return NULL;
+}

src/cairo.h

@@ -1948,6 +1948,7 @@ cairo_surface_status (cairo_surface_t *surface);
  * @CAIRO_SURFACE_TYPE_VG: The surface is a OpenVG surface, since 1.10
  * @CAIRO_SURFACE_TYPE_GL: The surface is of type OpenGL, since 1.10
  * @CAIRO_SURFACE_TYPE_DRM: The surface is of type Direct Render Manager, since 1.10
+ * @CAIRO_SURFACE_TYPE_TEE: The surface is of type 'tee' (a multiplexing surface), since 1.10
  *
  * #cairo_surface_type_t is used to describe the type of a given
  * surface. The surface types are also known as "backends" or "surface
@@ -1992,7 +1993,8 @@ typedef enum _cairo_surface_type {
     CAIRO_SURFACE_TYPE_META,
     CAIRO_SURFACE_TYPE_VG,
     CAIRO_SURFACE_TYPE_GL,
-    CAIRO_SURFACE_TYPE_DRM
+    CAIRO_SURFACE_TYPE_DRM,
+    CAIRO_SURFACE_TYPE_TEE
 } cairo_surface_type_t;
 
 cairo_public cairo_surface_type_t
@@ -2187,6 +2189,15 @@ cairo_public cairo_status_t
 cairo_meta_surface_replay (cairo_surface_t *surface,
 			   cairo_surface_t *target);
 
+/* Tee-surface functions */
+
+cairo_public cairo_surface_t *
+cairo_tee_surface_create (cairo_surface_t *master);
+
+cairo_public void
+cairo_tee_surface_append (cairo_surface_t *surface,
+			  cairo_surface_t *target);
+
 /* Pattern creation functions */
 
 cairo_public cairo_pattern_t *