cairo/test/degenerate-arc.c

   1 /*
   2  * Copyright © 2008 Chris Wilson
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software
   5  * and its documentation for any purpose is hereby granted without
   6  * fee, provided that the above copyright notice appear in all copies
   7  * and that both that copyright notice and this permission notice
   8  * appear in supporting documentation, and that the name of
   9  * Chris Wilson not be used in advertising or publicity pertaining to
  10  * distribution of the software without specific, written prior
  11  * permission. Chris Wilson makes no representations about the
  12  * suitability of this software for any purpose.  It is provided "as
  13  * is" without express or implied warranty.
  14  *
  15  * CHRIS WILSON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
  16  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  17  * FITNESS, IN NO EVENT SHALL CHRIS WILSON BE LIABLE FOR ANY SPECIAL,
  18  * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
  19  * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  20  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
  21  * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  22  *
  23  * Author: Chris Wilson <chris@chris-wilson.co.uk>
  24  */
  25
  26 /* This test case exercises a "Potential division by zero in cairo_arc"
  27  * reported by Luiz Americo Pereira Camara <luizmed@oi.com.br>,
  28  * http://lists.cairographics.org/archives/cairo/2008-May/014054.html.
  29  */
  30
  31 #include "cairo-test.h"
  32
  33 static cairo_test_draw_function_t draw;
  34
  35 static const cairo_test_t test = {
  36     "degenerate-arc",
  37     "Tests the behaviour of degenerate arcs",
  38     40, 40,
  39     draw
  40 };
  41
  42 static cairo_test_status_t
  43 draw (cairo_t *cr, int width, int height)
  44 {
  45     int n;
  46
  47     cairo_set_source_rgb (cr, 1, 1, 1);
  48     cairo_paint (cr);
  49
  50     cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
  51
  52     cairo_set_line_width (cr, 5);
  53     cairo_set_source_rgb (cr, 0, 1, 0);
  54     for (n = 0; n < 8; n++) {
  55         double theta = n * 2 * M_PI / 8;
  56         cairo_new_sub_path (cr);
  57         cairo_arc (cr, 20, 20, 15, theta, theta);
  58         cairo_close_path (cr);
  59     }
  60     cairo_stroke (cr);
  61
  62     cairo_set_line_width (cr, 2);
  63     cairo_set_source_rgb (cr, 0, 0, 1);
  64     for (n = 0; n < 8; n++) {
  65         double theta = n * 2 * M_PI / 8;
  66         cairo_move_to (cr, 20, 20);
  67         cairo_arc (cr, 20, 20, 15, theta, theta);
  68     }
  69     cairo_stroke (cr);
  70
  71     cairo_set_source_rgb (cr, 1, 0, 0);
  72     cairo_arc (cr, 20, 20, 2, 0, 2*M_PI);
  73     cairo_fill (cr);
  74
  75     return CAIRO_TEST_SUCCESS;
  76 }
  77
  78 int
  79 main (void)
  80 {
  81     return cairo_test (&test);
  82 }