test/show-glyphs-many.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 #include <string.h>
  29
  30 /* Bug history
  31  *
  32  * 2006-01-07  Jon Hellan  <hellan@acm.org>
  33  *
  34  *   Jon opened the following bug report:
  35  *
  36  *      _XError from XRenderCompositeText8
  37  *      https://bugs.freedesktop.org/show_bug.cgi?id=5528
  38  *
  39  * 2006-03-02  Carl Worth  <cworth@cworth.org>
  40  *
  41  *   I wrote this test case to demonstrate the bug.
  42  *
  43  *   Approach:
  44  *
  45  *      Draw 65535 glyphs white-on-white all on top of each other.
  46  *
  47  *   Rationale:
  48  *
  49  *      The number 65535 comes from the original bug report.
  50  *
  51  *      I would use cairo_show_text with a long string of 'x's say,
  52  *      but then the surface would need to be enormous to contain
  53  *      them. A smaller surface could be used, but I fear that at some
  54  *      point the off-surface glyph drawing would be optimized away
  55  *      and not exercise the bug.
  56  *
  57  *      So, to keep the surface size under control, I use
  58  *      cairo_show_glyphs which allows me to place the glyphs all on
  59  *      top of each other. But, since cairo doesn't provide any
  60  *      character-to-glyphs mapping, I can't get a reliable glyph
  61  *      index (for character 'x' for example). So I just "guess" a
  62  *      glyph index and use white-on-white drawing to ignore the
  63  *      result. (I don't care what's drawn---I just want to ensure
  64  *      that things don't crash.)
  65  *
  66  *  Status: I replicated bug. The largest value of NUM_GLYPHS for
  67  *      which I saw success is 21842.
  68  */
  69
  70 #define TEXT_SIZE 12
  71 #define NUM_GLYPHS 65535
  72
  73 /* This is the index into the font for what glyph we'll draw. Since we
  74  * don't guarantee we'll get any particular font, we can't relibably
  75  * get any particular glyph. But we don't care what we draw anyway,
  76  * (see discussion of white-on-white drawing above). For what it's
  77  * worth, this appears to be giving me 'M' with Bitstream Vera
  78  * Sans Mono. */
  79 #define GLYPH_INDEX 48
  80
  81 static cairo_test_draw_function_t draw;
  82
  83 cairo_test_t test = {
  84     "show-glyphs-many",
  85     "Test that cairo_show_glyps works when handed 'many' glyphs",
  86     9, 11,
  87     draw
  88 };
  89
  90 static cairo_test_status_t
  91 draw (cairo_t *cr, int width, int height)
  92 {
  93     cairo_glyph_t glyphs[NUM_GLYPHS];
  94     int i;
  95
  96     /* Initialize our giant array of glyphs. */
  97     for (i=0; i < NUM_GLYPHS; i++) {
  98         glyphs[i].index = GLYPH_INDEX;
  99         glyphs[i].x = 1.0;
 100         glyphs[i].y = height - 1;
 101     }
 102
 103     /* Paint white background. */
 104     cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
 105     cairo_paint (cr);
 106
 107     cairo_select_font_face (cr, "Bitstream Vera Sans Mono",
 108                             CAIRO_FONT_SLANT_NORMAL,
 109                             CAIRO_FONT_WEIGHT_NORMAL);
 110     cairo_set_font_size (cr, TEXT_SIZE);
 111
 112     cairo_show_glyphs (cr, glyphs, NUM_GLYPHS);
 113
 114     return CAIRO_TEST_SUCCESS;
 115 }
 116
 117 int
 118 main (void)
 119 {
 120     return cairo_test (&test);
 121 }