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3cc9a6050d
This test anticipates a future optimization, (already pushed upstream but not pulled yet), with a buggy implementation of replacing curve_to with line_to.
95 lines
3.1 KiB
C
95 lines
3.1 KiB
C
/*
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* Copyright © 2005 Red Hat, Inc.
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*
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* Permission to use, copy, modify, distribute, and sell this software
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* and its documentation for any purpose is hereby granted without
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* fee, provided that the above copyright notice appear in all copies
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* and that both that copyright notice and this permission notice
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* appear in supporting documentation, and that the name of
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* Red Hat, Inc. not be used in advertising or publicity pertaining to
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* distribution of the software without specific, written prior
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* permission. Red Hat, Inc. makes no representations about the
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* suitability of this software for any purpose. It is provided "as
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* is" without express or implied warranty.
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*
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* RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
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* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL,
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* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
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* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
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* IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* Author: Carl D. Worth <cworth@cworth.org>
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*/
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#include "cairo-test.h"
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#define SIZE 30
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/* At one point, an optimization was proposed for cairo in which a
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* curve_to would be optimized as a line_to. The initial (buggy)
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* implementation verified that the slopes of several segments of the
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* spline's control polygon were identical, but left open the
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* possibility of an anti-parallel slope for one segment.
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*
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* For example, given a spline with collinear control points (A,B,C,D)
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* positioned as follows:
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*
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* C--A--B--D
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*
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* The code verified identical slopes for AB, CD, and AD. The missing
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* check for the BC segment allowed it to be anti-parallel to the
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* others as above, and hence invalid to replace this spline with the
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* AD line segment.
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*/
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static cairo_test_status_t
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draw (cairo_t *cr, int width, int height)
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{
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cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
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cairo_paint (cr);
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cairo_set_line_width (cr, 1.0);
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cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
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cairo_set_line_join (cr, CAIRO_LINE_JOIN_BEVEL);
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cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
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cairo_translate (cr, 0, 1.0);
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/* The CABD spline as described above. We ensure that the spline
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* folds over on itself outside the bounds of the image to avoid
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* the reference image having the curved portion of that fold,
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* (which would just be harder to match in all the backends than
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* we really want). */
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cairo_move_to (cr,
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10.5, 0.5);
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cairo_curve_to (cr,
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11.5, 0.5,
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-25.0, 0.5,
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31.0, 0.5);
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cairo_stroke (cr);
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cairo_translate (cr, 0, 2.0);
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/* A reflected version: DBAC */
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cairo_move_to (cr,
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19.5, 0.5);
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cairo_curve_to (cr,
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18.5, 0.5,
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55.0, 0.5,
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-1.0, 0.5);
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cairo_stroke (cr);
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return CAIRO_TEST_SUCCESS;
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}
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CAIRO_TEST (curve_to_as_line_to,
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"Test optimization treating curve_to as line_to",
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"path", /* keywords */
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NULL, /* requirements */
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30,
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5,
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NULL, draw)
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