test/big-trap.c

   1 /*
   2  * Copyright © 2006 Mozilla Corporation
   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  * Mozilla Corporation not be used in advertising or publicity pertaining to
  10  * distribution of the software without specific, written prior
  11  * permission. Mozilla Corporation 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  * MOZILLA CORPORATION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
  16  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  17  * FITNESS, IN NO EVENT SHALL MOZILLA CORPORATION 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: Vladimir Vukicevic <vladimir@pobox.com>
  24  */
  25
  26 #include "cairo-test.h"
  27
  28 /* This test was originally written to exercise a bug in pixman in
  29  * which it would scribble all over memory when given a particular
  30  * (and bogus) trapezoid. However, a recent change to
  31  * _cairo_fixed_from_double changed the details of the bogus trapezoid
  32  * (it overflows in a different way now), so the bug is being masked.
  33  *
  34  * According to Vladimir, (http://lists.freedesktop.org/archives/cairo/2006-November/008482.html):
  35  *
  36  *      Before the change, the two trapezoids that were generated were:
  37  *
  38  *      Trap[0]: T: 0x80000000 B: 0x80000003
  39  *         L: [(0x000a0000, 0x80000000) (0x00080000, 0x00080000)]
  40  *         R: [(0x01360000, 0x80000000) (0x01380000, 0x00080000)]
  41  *      Trap[1]: T: 0x80000003 B: 0x00080000
  42  *         L: [(0x000a0000, 0x80000000) (0x00080000, 0x00080000)]
  43  *         R: [(0x01360000, 0x80000000) (0x01380000, 0x00080000)]
  44  *
  45  *      After the change, the L/R coordinates are identical for both traps, but
  46  *      the top and bottom change:
  47  *
  48  *      Trap[0]: t: 0x80000000 b: 0xfda80003
  49  *         l: [(0x000a0000, 0x80000000) (0x00080000, 0x00080000)]
  50  *         r: [(0x01360000, 0x80000000) (0x01380000, 0x00080000)]
  51  *      Trap[1]: t: 0xfda80003 b: 0x00080000
  52  *         l: [(0x000a0000, 0x80000000) (0x00080000, 0x00080000)]
  53  *         r: [(0x01360000, 0x80000000) (0x01380000, 0x00080000)]
  54  *
  55  * I think the fix we want here is to rewrite this test to call
  56  * directly into pixman with the trapezoid of interest, (which will
  57  * require adding a new way to configure cairo for "testing" which
  58  * will prevent the hiding of internal library symbols.
  59  */
  60
  61 static cairo_test_status_t
  62 draw (cairo_t *cr, int width, int height)
  63 {
  64     /* Note that without the clip, this doesn't crash... */
  65     cairo_new_path (cr);
  66     cairo_rectangle (cr, 0, 0, width, height);
  67     cairo_clip (cr);
  68
  69     cairo_new_path (cr);
  70     cairo_line_to (cr, 8.0, 8.0);
  71     cairo_line_to (cr, 312.0, 8.0);
  72     cairo_line_to (cr, 310.0, 31378756.2666666666);
  73     cairo_line_to (cr, 10.0, 31378756.2666666666);
  74     cairo_line_to (cr, 8.0, 8.0);
  75     cairo_fill (cr);
  76
  77     return CAIRO_TEST_SUCCESS;
  78 }
  79
  80 CAIRO_TEST (big_trap,
  81             "Test oversize trapezoid with a clip region"
  82             "\nTest needs to be adjusted to trigger the original bug",
  83             "XFAIL trap", /* keywords */
  84             NULL, /* requirements */
  85             100, 100,
  86             NULL, draw)