test/text-rotate.c

   1 /*
   2  * Copyright © 2004 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 /* Bug history
  27  *
  28  * 2004-11-03 Steve Chaplin <stevech1097@yahoo.com.au>
  29  *
  30  *   Reported bug on mailing list:
  31  *
  32  *      From: Steve Chaplin <stevech1097@yahoo.com.au>
  33  *      To: cairo@cairographics.org
  34  *      Date: Thu, 04 Nov 2004 00:00:17 +0800
  35  *      Subject: [cairo] Rotated text bug on drawable target
  36  *
  37  *      The attached file draws text rotated 90 degrees first to a PNG file and
  38  *      then to a drawable. The PNG file looks fine, the text on the drawable is
  39  *      unreadable.
  40  *
  41  *      Steve
  42  *
  43  * 2004-11-03 Carl Worth <cworth@cworth.org>
  44  *
  45  *   Looks like the major problems with this bug appeared in the great
  46  *   font rework between 0.1.23 and 0.2.0. And it looks like we need
  47  *   to fix the regression test suite to test the xlib target (since
  48  *   the bug does not show up in the png backend).
  49  *
  50  *   Hmm... Actually, things don't look perfect even in the PNG
  51  *   output. Look at how that 'o' moves around. It's particularly off
  52  *   in the case where it's rotated by PI.
  53  *
  54  *   And I'm still not sure about what to do for test cases with
  55  *   text--a new version of freetype will change everything. We may
  56  *   need to add a simple backend for stroked fonts and add a simple
  57  *   builtin font to cairo for pixel-perfect tests with text.
  58  *
  59  * 2005-08-23
  60  *
  61  *   It appears that the worst placement and glyph selection problems
  62  *   have now been resolved. In the past some letters were noticeably
  63  *   of a different size at some rotations, and there was a lot of
  64  *   drift away from the baseline. These problems do not appear
  65  *   anymore.
  66  *
  67  *   Another thing that helps is that we now have font options which
  68  *   we can use to disable hinting in order to get more repeatable
  69  *   results. I'm doing that in this test now.
  70  *
  71  *   There are still some subtle positioning problems which I'm
  72  *   assuming are due to the lack of finer-than-whole-pixel glyph
  73  *   positioning. I'm generating a reference image now by replacing
  74  *   cairo_show_text with cairo_text_path; cairo_fill. This will let
  75  *   us look more closely at the remaining positioning problems. (In
  76  *   particular, I want to make sure we're rounding as well as
  77  *   possible).
  78  *
  79  * 2007-02-21
  80  *
  81  *   Seems like all the "bugs" have been fixed and all remainint is
  82  *   missing support for subpixel glyph positioning.  Removing from
  83  *   XFAIL now.
  84  */
  85
  86 #include "cairo-test.h"
  87
  88 #define WIDTH  150
  89 #define HEIGHT 150
  90 #define NUM_TEXT 20
  91 #define TEXT_SIZE 12
  92
  93 static cairo_test_draw_function_t draw;
  94
  95 cairo_test_t test = {
  96     "text-rotate",
  97     "Tests show_text under various rotations",
  98     WIDTH, HEIGHT,
  99     draw
 100 };
 101
 102 /* Draw the word cairo at NUM_TEXT different angles */
 103 static cairo_test_status_t
 104 draw (cairo_t *cr, int width, int height)
 105 {
 106     int i, x_off, y_off;
 107     cairo_text_extents_t extents;
 108     cairo_font_options_t *font_options;
 109     static char text[] = "cairo";
 110
 111     /* paint white so we don't need separate ref images for
 112      * RGB24 and ARGB32 */
 113     cairo_set_source_rgb (cr, 1., 1., 1.);
 114     cairo_paint (cr);
 115
 116     cairo_select_font_face (cr, "Bitstream Vera Sans",
 117                             CAIRO_FONT_SLANT_NORMAL,
 118                             CAIRO_FONT_WEIGHT_NORMAL);
 119     cairo_set_font_size (cr, TEXT_SIZE);
 120
 121     font_options = cairo_font_options_create ();
 122
 123     cairo_get_font_options (cr, font_options);
 124     cairo_font_options_set_hint_metrics (font_options, CAIRO_HINT_METRICS_OFF);
 125
 126     cairo_set_font_options (cr, font_options);
 127     cairo_font_options_destroy (font_options);
 128
 129     cairo_set_source_rgb (cr, 0, 0, 0);
 130
 131     cairo_translate (cr, WIDTH/2.0, HEIGHT/2.0);
 132
 133     cairo_text_extents (cr, text, &extents);
 134
 135     if (NUM_TEXT == 1) {
 136         x_off = y_off = 0;
 137     } else {
 138         y_off = - floor (0.5 + extents.height / 2.0);
 139         x_off = floor (0.5 + (extents.height+1) / (2 * tan (M_PI/NUM_TEXT)));
 140     }
 141
 142     for (i=0; i < NUM_TEXT; i++) {
 143         cairo_save (cr);
 144         cairo_rotate (cr, 2*M_PI*i/NUM_TEXT);
 145         cairo_set_line_width (cr, 1.0);
 146         cairo_rectangle (cr, x_off - 0.5, y_off - 0.5, extents.width + 1, extents.height + 1);
 147         cairo_set_source_rgb (cr, 1, 0, 0);
 148         cairo_stroke (cr);
 149         cairo_move_to (cr, x_off - extents.x_bearing, y_off - extents.y_bearing);
 150         cairo_set_source_rgb (cr, 0, 0, 0);
 151 #if CAIRO_TEST_GENERATE_REFERENCE_IMAGE
 152         cairo_text_path (cr, text);
 153         cairo_fill (cr);
 154 #else
 155         cairo_show_text (cr, text);
 156 #endif
 157         cairo_restore (cr);
 158     }
 159
 160     return CAIRO_TEST_SUCCESS;
 161 }
 162
 163 int
 164 main (void)
 165 {
 166     return cairo_test (&test);
 167 }