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/*
* Copyright © 2007 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Author: Carl D. Worth <cworth@cworth.org>
*/
#include "cairo-test.h"
#define SIZE 20
#define PAD 5
#define WIDTH (PAD + 3 * (PAD + SIZE) + PAD)
#define HEIGHT (PAD + SIZE + PAD)
/* We're demonstrating here a bug originally reported by Benjamin Otte
* on the cairo mailing list here, (after he ran into this problem
* with various flash animations):
*
* [cairo] Assertion `i < pen->num_vertices' failed in 1.4.10
* https://lists.cairographics.org/archives/cairo/2007-August/011282.html
*
* The problem shows up with an extreme transformation matrix that
* collapses the pen to a single line, (which means that
* _cairo_slope_compare cannot handle adjacent vertices in the pen
* since they have parallel slope).
*
* This test case tests degenerate pens in several directions and uses
* round caps to force the stroking code to attempt to walk around the
* pen doing slope comparisons.
*/
static cairo_test_status_t
draw (cairo_t *cr, int width, int height)
{
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
cairo_set_source_rgb (cr, 0, 0, 0);
cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
cairo_translate (cr, PAD, PAD);
/* First compress the pen to a vertical line. */
cairo_rectangle (cr, 0, 0, SIZE, SIZE);
cairo_curve_to (cr, SIZE / 2, 0, SIZE, SIZE / 2, SIZE, SIZE);
cairo_save (cr);
{
cairo_scale (cr, 0.000001, 1.0);
cairo_stroke (cr);
}
cairo_restore (cr);
cairo_translate (cr, PAD + SIZE, 0);
/* Then compress the pen to a horizontal line. */
cairo_rectangle (cr, 0, 0, SIZE, SIZE);
cairo_curve_to (cr, SIZE / 2, 0, SIZE, SIZE / 2, SIZE, SIZE);
cairo_save (cr);
{
cairo_scale (cr, 1.0, 0.000001);
cairo_stroke (cr);
}
cairo_restore (cr);
cairo_translate (cr, PAD + SIZE, 0);
/* Finally a line at an angle. */
cairo_rectangle (cr, 0, 0, SIZE, SIZE);
cairo_curve_to (cr, SIZE / 2, 0, SIZE, SIZE / 2, SIZE, SIZE);
cairo_save (cr);
{
cairo_rotate (cr, M_PI / 4.0);
cairo_scale (cr, 0.000001, 1.0);
cairo_stroke (cr);
}
cairo_restore (cr);
return CAIRO_TEST_SUCCESS;
}
CAIRO_TEST (degenerate_pen,
"Test round joins with a pen that's transformed to a line",
"degenerate", /* keywords */
NULL, /* requirements */
WIDTH, HEIGHT,
NULL, draw)
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