test/mask-alpha.c

   1 /*
   2  * Copyright © 2007 Adrian Johnson
   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: Adrian Johnson <ajohnson@redneon.com>
  25  */
  26
  27 #include "cairo-test.h"
  28
  29 static cairo_test_draw_function_t draw;
  30
  31 #define SIZE 40
  32 #define PAD 2
  33 #define WIDTH (PAD + SIZE + PAD)
  34 #define HEIGHT WIDTH
  35
  36 /* This test is designed to test that PDF viewers use the correct
  37  * alpha values in an Alpha SMasks. Some viewers use the color values
  38  * instead of the alpha. The test draws a triangle and rectangle in a
  39  * group then draws the group using cairo_mask(). The mask consists of
  40  * a circle with the rgba (0.4, 0.4, 0.4, 0.8) and the background rgba
  41  * (0.8, 0.8, 0.8, 0.4).
  42  */
  43
  44 cairo_test_t test = {
  45     "mask-alpha",
  46     "A simple test painting a group through a circle mask",
  47     WIDTH, HEIGHT,
  48     draw
  49 };
  50
  51 static cairo_test_status_t
  52 draw (cairo_t *cr, int width, int height)
  53 {
  54     cairo_pattern_t *pattern;
  55
  56     cairo_translate (cr, PAD, PAD);
  57
  58     /* mask */
  59     cairo_push_group (cr);
  60     cairo_set_source_rgba (cr, 0.8, 0.8, 0.8, 0.4);
  61     cairo_paint (cr);
  62     cairo_arc (cr, SIZE / 2, SIZE / 2, SIZE / 6, 0., 2. * M_PI);
  63     cairo_set_source_rgba (cr, 0.4, 0.4, 0.4, 0.8);
  64     cairo_fill (cr);
  65     pattern = cairo_pop_group (cr);
  66
  67     /* source */
  68     cairo_push_group (cr);
  69     cairo_rectangle (cr, 0.3 * SIZE, 0.2 * SIZE, 0.5 * SIZE, 0.5 * SIZE);
  70     cairo_set_source_rgb (cr, 0, 0, 1);
  71     cairo_fill (cr);
  72     cairo_move_to     (cr,   0.0,          0.8 * SIZE);
  73     cairo_rel_line_to (cr,   0.7 * SIZE,   0.0);
  74     cairo_rel_line_to (cr, -0.375 * SIZE, -0.6 * SIZE);
  75     cairo_close_path (cr);
  76     cairo_set_source_rgb (cr, 0, 1, 0);
  77     cairo_fill (cr);
  78     cairo_pop_group_to_source (cr);
  79
  80     cairo_mask (cr, pattern);
  81     cairo_pattern_destroy (pattern);
  82
  83     return CAIRO_TEST_SUCCESS;
  84 }
  85
  86 int
  87 main (void)
  88 {
  89     return cairo_test (&test);
  90 }