cairo/test/get-group-target.c

   1 /*
   2  * Copyright © 2006 Red Hat, Inc.
   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  * Red Hat, Inc. not be used in advertising or publicity pertaining to
  10  * distribution of the software without specific, written prior
  11  * permission. Red Hat, Inc. 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  * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
  16  * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  17  * FITNESS, IN NO EVENT SHALL RED HAT, INC. 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: Carl D. Worth <cworth@cworth.org>
  24  */
  25
  26 #include "cairo-test.h"
  27
  28 #define SIZE 8
  29 #define PAD 2
  30
  31 static cairo_test_draw_function_t draw;
  32
  33 static const cairo_test_t test = {
  34     "get-group-target",
  35     "Test of both cairo_get_group_target and cairo_surface_get_device_offset",
  36     SIZE, SIZE,
  37     draw
  38 };
  39
  40 static cairo_test_status_t
  41 draw (cairo_t *cr, int width, int height)
  42 {
  43     cairo_surface_t *group;
  44     double x, y;
  45
  46     /* First paint background in blue. */
  47     cairo_set_source_rgb (cr, 0.0, 0.0, 1.0);
  48     cairo_paint (cr);
  49
  50     /* Then clip so that the group surface ends up smaller than the
  51      * original surface. */
  52     cairo_rectangle (cr, PAD, PAD, width - 2 * PAD, height - 2 * PAD);
  53     cairo_clip (cr);
  54
  55     /* Paint the clipped region in red (which should all be overwritten later). */
  56     cairo_set_source_rgb (cr, 1.0, 0.0, 0.0);
  57     cairo_paint (cr);
  58
  59     /* Redirect to a new group and get that surface. */
  60     cairo_push_group (cr);
  61     group = cairo_get_group_target (cr);
  62
  63     /* Then paint in green what we query the group surface size to be. */
  64     cairo_set_source_rgb (cr, 0.0, 1.0, 0.0);
  65     cairo_surface_get_device_offset (group, &x, &y);
  66     /* Or rather, we calculate the group surface size based on the
  67      * only thing we can query which is the device offset. Ideally,
  68      * the size would always be the minimal (width - 2 * PAD, height -
  69      * 2 * PAD) based on the clip. But currently, group targets are
  70      * created oversized for paginated surfaces, so we only subtract
  71      * anything from the size if there is a non-zero device offfset.
  72      *
  73      * The calculation below might also be less confusing if the sign
  74      * convention on the device offset were reversed, but it is what
  75      * it is. Oh well. */
  76     cairo_rectangle (cr,
  77                      -x, -y,
  78                      width + 2 * x,
  79                      height + 2 * y);
  80     cairo_fill (cr);
  81
  82     /* Finish up the group painting. */
  83     cairo_pop_group_to_source (cr);
  84     cairo_paint (cr);
  85
  86     return CAIRO_TEST_SUCCESS;
  87 }
  88
  89 int
  90 main (void)
  91 {
  92     return cairo_test (&test);
  93 }