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/*
* Copyright © 2005 Red Hat, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without
* fee, provided that the above copyright notice appear in all copies
* and that both that copyright notice and this permission notice
* appear in supporting documentation, and that the name of
* Red Hat, Inc. not be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission. Red Hat, Inc. makes no representations about the
* suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
* IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Author: Carl D. Worth <cworth@cworth.org>
*/
/* Bug history
*
* 2005-01-07 Carl Worth <cworth@cworth.org>
*
* Bug reported:
*
* From: Chris <fltk@functionalfuture.com>
* Subject: [cairo] Render to image buffer artifacts
* To: cairo@cairographics.org
* Date: Fri, 07 Jan 2005 02:22:28 -0500
*
* I've attached the code and image that shows this off. Scaling at
* different levels seems to change the corruption.
*
* For some reason there are artifacts in the alpha channel. I don't know
* if that's the only place, but the alpha channel looks bad.
*
* If you run the code and parse the attached image, directing stdout to a
* file, you can see in the lower left corner there are alpha values where
* it should be transparent.
* [...]
*
* 2005-01-11 Carl Worth <cworth@cworth.org>
*
* I trimmed the original test case down to the code that appears here.
*
*/
#include "cairo-test.h"
#define WIDTH 21
#define HEIGHT 21
static cairo_test_status_t
draw (cairo_t *cr, int width, int height)
{
/* We draw in the default black, so paint white first. */
cairo_save (cr);
cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
cairo_paint (cr);
cairo_restore (cr);
cairo_scale (cr, 1.0/(1<<16), 1.0/(1<<16));
cairo_move_to (cr, 131072,39321);
cairo_line_to (cr, 1103072,1288088);
cairo_line_to (cr, 1179648,1294990);
cairo_close_path (cr);
cairo_fill (cr);
return CAIRO_TEST_SUCCESS;
}
CAIRO_TEST (leaky_polygon,
"Exercises a corner case in the trapezoid rasterization in which pixels outside the trapezoids received a non-zero alpha",
"fill, trap", /* keywords */
NULL, /* requirements */
WIDTH, HEIGHT,
NULL, draw)
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