test/rectilinear-miter-limit.c

   1 /*
   2  * Copyright © 2008 Red Hat, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person
   5  * obtaining a copy of this software and associated documentation
   6  * files (the "Software"), to deal in the Software without
   7  * restriction, including without limitation the rights to use, copy,
   8  * modify, merge, publish, distribute, sublicense, and/or sell copies
   9  * of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  *
  24  * Author: Carl D. Worth <cworth@cworth.org>
  25  */
  26
  27 #include "cairo-test.h"
  28
  29 #define LINE_WIDTH  10
  30 #define PAD         2
  31 #define WIDTH       (PAD + LINE_WIDTH + PAD)
  32 #define HEIGHT      (WIDTH)
  33
  34 static cairo_test_draw_function_t draw;
  35
  36 cairo_test_t test = {
  37     "rectilinear-miter-limit",
  38     "Test that the rectilinear stroke optimization doesn't break cairo_set_miter_limit",
  39     WIDTH, HEIGHT,
  40     draw
  41 };
  42
  43 static cairo_test_status_t
  44 draw (cairo_t *cr, int width, int height)
  45 {
  46     cairo_translate (cr, PAD, PAD);
  47
  48     /* Paint background white, then draw in black. */
  49     cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
  50     cairo_paint (cr);
  51     cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
  52
  53     cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
  54     cairo_set_line_width (cr, LINE_WIDTH);
  55
  56     /* The default miter limit value of 10.0 guarantees that
  57      * right-angle turns, (in fact, any angle greater than 11
  58      * degrees), gets a miter rather than a bevel join. The
  59      * rectilinear stroke optimization was originally written in a
  60      * buggy way that did not respect the miter limit, (that is,
  61      * inappropriately drawing miter joins when the miter limit would
  62      * turn them into bevels). So we draw here with a miter limit of
  63      * 1.0 to force all miter joins into bevels. */
  64     cairo_set_line_join (cr, CAIRO_LINE_JOIN_MITER);
  65     cairo_set_miter_limit (cr, 1.0);
  66
  67     cairo_move_to (cr, LINE_WIDTH / 2.0, LINE_WIDTH);
  68     cairo_rel_line_to (cr, 0, - LINE_WIDTH / 2.0);
  69     cairo_rel_line_to (cr, LINE_WIDTH / 2.0, 0);
  70
  71     cairo_stroke (cr);
  72
  73     return CAIRO_TEST_SUCCESS;
  74 }
  75
  76 int
  77 main (void)
  78 {
  79     return cairo_test (&test);
  80 }