Introduce a new compositor architecture

Having spent the last dev cycle looking at how we could specialize the
compositors for various backends, we once again look for the
commonalities in order to reduce the duplication. In part this is
motivated by the idea that spans is a good interface for both the
existent GL backend and pixman, and so they deserve a dedicated
compositor. xcb/xlib target an identical rendering system and so they
should be using the same compositor, and it should be possible to run
that same compositor locally against pixman to generate reference tests.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

P.S. This brings massive upheaval (read breakage) I've tried delaying in
order to fix as many things as possible but now this one patch does far,
far, far too much. Apologies in advance for breaking your favourite
backend, but trust me in that the end result will be much better. :)

1 files changed, 185 insertions, 0 deletions

diff --git a/src/cairo-tristrip.c b/src/cairo-tristrip.c
new file mode 100644
index 000000000..bb4972f50
--- /dev/null
+++ b/src/cairo-tristrip.c
@@ -0,0 +1,185 @@
+/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
+/*
+ * Copyright © 2011 Intel Corporation
+ *
+ * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, 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 Chris Wilson
+ *
+ * Contributor(s):
+ *	Chris Wilson <chris@chris-wilsonc.co.uk>
+ */
+
+#include "cairoint.h"
+
+#include "cairo-error-private.h"
+#include "cairo-tristrip-private.h"
+
+void
+_cairo_tristrip_init (cairo_tristrip_t *strip)
+{
+    VG (VALGRIND_MAKE_MEM_UNDEFINED (strip, sizeof (cairo_tristrip_t)));
+
+    strip->status = CAIRO_STATUS_SUCCESS;
+
+    strip->num_limits = 0;
+    strip->num_points = 0;
+
+    strip->size_points = ARRAY_LENGTH (strip->points_embedded);
+    strip->points = strip->points_embedded;
+}
+
+void
+_cairo_tristrip_fini (cairo_tristrip_t *strip)
+{
+    if (strip->points != strip->points_embedded)
+	free (strip->points);
+
+    VG (VALGRIND_MAKE_MEM_NOACCESS (strip, sizeof (cairo_tristrip_t)));
+}
+
+
+void
+_cairo_tristrip_limit (cairo_tristrip_t	*strip,
+		       const cairo_box_t	*limits,
+		       int			 num_limits)
+{
+    strip->limits = limits;
+    strip->num_limits = num_limits;
+}
+
+void
+_cairo_tristrip_init_with_clip (cairo_tristrip_t *strip,
+				const cairo_clip_t *clip)
+{
+    _cairo_tristrip_init (strip);
+    if (clip)
+	_cairo_tristrip_limit (strip, clip->boxes, clip->num_boxes);
+}
+
+/* make room for at least one more trap */
+static cairo_bool_t
+_cairo_tristrip_grow (cairo_tristrip_t *strip)
+{
+    cairo_point_t *points;
+    int new_size = 4 * strip->size_points;
+
+    if (CAIRO_INJECT_FAULT ()) {
+	strip->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	return FALSE;
+    }
+
+    if (strip->points == strip->points_embedded) {
+	points = _cairo_malloc_ab (new_size, sizeof (cairo_point_t));
+	if (points != NULL)
+	    memcpy (points, strip->points, sizeof (strip->points_embedded));
+    } else {
+	points = _cairo_realloc_ab (strip->points,
+	                               new_size, sizeof (cairo_trapezoid_t));
+    }
+
+    if (unlikely (points == NULL)) {
+	strip->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	return FALSE;
+    }
+
+    strip->points = points;
+    strip->size_points = new_size;
+    return TRUE;
+}
+
+void
+_cairo_tristrip_add_point (cairo_tristrip_t *strip,
+			   const cairo_point_t *p)
+{
+    if (unlikely (strip->num_points == strip->size_points)) {
+	if (unlikely (! _cairo_tristrip_grow (strip)))
+	    return;
+    }
+
+    strip->points[strip->num_points++] = *p;
+}
+
+/* Insert degenerate triangles to advance to the given point. The
+ * next point inserted must also be @p. */
+void
+_cairo_tristrip_move_to (cairo_tristrip_t *strip,
+			 const cairo_point_t *p)
+{
+    if (strip->num_points == 0)
+	return;
+
+    _cairo_tristrip_add_point (strip, &strip->points[strip->num_points-1]);
+    _cairo_tristrip_add_point (strip, p);
+#if 0
+    /* and one more for luck! (to preserve cw/ccw ordering) */
+    _cairo_tristrip_add_point (strip, p);
+#endif
+}
+
+void
+_cairo_tristrip_translate (cairo_tristrip_t *strip, int x, int y)
+{
+    cairo_fixed_t xoff, yoff;
+    cairo_point_t *p;
+    int i;
+
+    xoff = _cairo_fixed_from_int (x);
+    yoff = _cairo_fixed_from_int (y);
+
+    for (i = 0, p = strip->points; i < strip->num_points; i++, p++) {
+	p->x += xoff;
+	p->y += yoff;
+    }
+}
+
+void
+_cairo_tristrip_extents (const cairo_tristrip_t *strip,
+			 cairo_box_t *extents)
+{
+    int i;
+
+    if (strip->num_points == 0) {
+	extents->p1.x = extents->p1.y = 0;
+	extents->p2.x = extents->p2.y = 0;
+	return;
+    }
+
+    extents->p2 = extents->p1 = strip->points[0];
+    for (i = 1; i < strip->num_points; i++) {
+	const cairo_point_t *p =  &strip->points[i];
+
+	if (p->x < extents->p1.x)
+	    extents->p1.x = p->x;
+	else if (p->x > extents->p2.x)
+	    extents->p2.x = p->x;
+
+	if (p->y < extents->p1.y)
+	    extents->p1.y = p->y;
+	else if (p->y > extents->p2.y)
+	    extents->p2.y = p->y;
+    }
+}