diff options
author | Carl Worth <cworth@cworth.org> | 2005-06-01 11:03:50 +0000 |
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committer | Carl Worth <cworth@cworth.org> | 2005-06-01 11:03:50 +0000 |
commit | 48fbc201c787512076934c40f15e173dbff771c3 (patch) | |
tree | fc4fa36d869d64a0425b4839b1278d563d500fe1 | |
parent | 37a48e674c575eaf36a3d9e8d84ea21f70da9a5b (diff) |
Add self-intersecting test which demonstrates the long-standing bug with stroking self-intersecting paths.
-rw-r--r-- | ChangeLog | 9 | ||||
-rw-r--r-- | test/.cvsignore | 1 | ||||
-rw-r--r-- | test/Makefile.am | 3 | ||||
-rw-r--r-- | test/self-intersecting-ref.png | bin | 0 -> 242 bytes | |||
-rw-r--r-- | test/self-intersecting.c | 89 |
5 files changed, 102 insertions, 0 deletions
@@ -1,5 +1,14 @@ 2005-06-01 Carl Worth <cworth@cworth.org> + * test/.cvsignore: + * test/Makefile.am: + * test/self-intersecting-ref.png: + * test/self-intersecting.c: (draw), (main): Add self-intersecting + test which demonstrates the long-standing bug with stroking + self-intersecting paths. + +2005-06-01 Carl Worth <cworth@cworth.org> + * src/cairo-gstate.c (_cairo_gstate_get_clip_extents): Fix bug in converting box to rectangle that left clip_rect.height uninitialized, (leading to unpredictable, intermittent test diff --git a/test/.cvsignore b/test/.cvsignore index beaae22b7..b930cf582 100644 --- a/test/.cvsignore +++ b/test/.cvsignore @@ -29,6 +29,7 @@ rel-path scale-source-surface-paint select-font-no-show-text self-copy +self-intersecting set-source source-clip source-surface-scale-paint diff --git a/test/Makefile.am b/test/Makefile.am index 2550582a0..030ce88b1 100644 --- a/test/Makefile.am +++ b/test/Makefile.am @@ -20,6 +20,7 @@ pixman-rotate \ scale-source-surface-paint \ select-font-no-show-text \ self-copy \ +self-intersecting \ set-source \ source-clip \ source-surface-scale-paint \ @@ -67,6 +68,7 @@ path-data-ref.png \ pixman-rotate-ref.png \ romedalen.png \ self-copy-ref.png \ +self-intersecting-ref.png \ scale-source-surface-paint-ref.png \ set-source-ref.png \ source-clip-ref.png \ @@ -145,6 +147,7 @@ pixman_rotate_LDADD = $(LDADDS) scale_source_surface_paint_LDADD = $(LDADDS) select_font_no_show_text_LDADD = $(LDADDS) self_copy_LDADD = $(LDADDS) +self_intersecting_LDADD = $(LDADDS) set_source_LDADD = $(LDADDS) source_clip_LDADD = $(LDADDS) source_surface_scale_paint_LDADD = $(LDADDS) diff --git a/test/self-intersecting-ref.png b/test/self-intersecting-ref.png Binary files differnew file mode 100644 index 000000000..384b0abc0 --- /dev/null +++ b/test/self-intersecting-ref.png diff --git a/test/self-intersecting.c b/test/self-intersecting.c new file mode 100644 index 000000000..2dfd79681 --- /dev/null +++ b/test/self-intersecting.c @@ -0,0 +1,89 @@ +/* + * Copyright © 2005 Red Hat, Inc. + * + * Permission to use, copy, modify, distribute, and sell this software + * and its documentation for any purpose is hereby granted without + * fee, provided that the above copyright notice appear in all copies + * and that both that copyright notice and this permission notice + * appear in supporting documentation, and that the name of + * Red Hat, Inc. not be used in advertising or publicity pertaining to + * distribution of the software without specific, written prior + * permission. Red Hat, Inc. makes no representations about the + * suitability of this software for any purpose. It is provided "as + * is" without express or implied warranty. + * + * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS + * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL, + * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER + * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION + * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR + * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + * Author: Carl D. Worth <cworth@cworth.org> + */ + +/* Bug history + * + * 2005-06-01 Carl Worth <cworth@cworth.org> + * + * There's a long-standing bug in that self-intersecting paths give + * an incorrect result when stroked. The problem is that the + * trapezoids are generated incrementally along the stroke and as + * such, are not disjoint. The errant intersections of these + * trapezoids then leads to overfilled pixels. + * + * The test belows first creates and fills a path. Then it creates a + * second path which has a stroked boundary identical to the first + * filled path. But the results of the two operations are + * different. The most obvious difference is in the central region + * where the entire path intersects itself. But notice that every + * time the path turns there are also errors on the inside of the + * turn, (since the subsequent trapezoids along the path intersect). + */ + +#include "cairo-test.h" + +cairo_test_t test = { + "self-intersecting", + "Test strokes of self-intersecting paths", + 10, 20 +}; + +static cairo_test_status_t +draw (cairo_t *cr, int width, int height) +{ + cairo_translate (cr, 1.0, 1.0); + + cairo_set_source_rgb (cr, 1, 0, 0); /* red */ + + /* First draw the desired shape with a fill */ + cairo_rectangle (cr, 0.5, 0.5, 4.0, 4.0); + cairo_rectangle (cr, 3.5, 3.5, 4.0, 4.0); + cairo_rectangle (cr, 3.5, 1.5, -2.0, 2.0); + cairo_rectangle (cr, 6.5, 4.5, -2.0, 2.0); + + cairo_fill (cr); + + /* Then try the same thing with a stroke */ + cairo_translate (cr, 0, 10); + cairo_move_to (cr, 1.0, 1.0); + cairo_rel_line_to (cr, 3.0, 0.0); + cairo_rel_line_to (cr, 0.0, 6.0); + cairo_rel_line_to (cr, 3.0, 0.0); + cairo_rel_line_to (cr, 0.0, -3.0); + cairo_rel_line_to (cr, -6.0, 0.0); + cairo_close_path (cr); + + cairo_set_line_width (cr, 1.0); + cairo_stroke (cr); + + return CAIRO_TEST_SUCCESS; +} + +int +main (void) +{ + return cairo_test_expect_failure (&test, draw, + "Self-intersecting strokes are wrong due to incremental trapezoidization."); +} |