/* * 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 */ /* Bug history * * 2005-01-07 Carl Worth * * Bug reported: * * From: Chris * Subject: [cairo] Render to image buffer artifacts * To: cairo@cairographics.org * Date: Fri, 07 Jan 2005 02:22:28 -0500 * * I've attached the code and image that shows this off. Scaling at * different levels seems to change the corruption. * * For some reason there are artifacts in the alpha channel. I don't know * if that's the only place, but the alpha channel looks bad. * * If you run the code and parse the attached image, directing stdout to a * file, you can see in the lower left corner there are alpha values where * it should be transparent. * [...] * * 2005-01-11 Carl Worth * * I trimmed the original test case down to the code that appears here. * */ #include "cairo-test.h" #define WIDTH 21 #define HEIGHT 21 static cairo_test_draw_function_t draw; static const cairo_test_t test = { "leaky-polygon", "Exercises a corner case in the trapezoid rasterization in which pixels outside the trapezoids received a non-zero alpha", WIDTH, HEIGHT, draw }; static cairo_test_status_t draw (cairo_t *cr, int width, int height) { /* We draw in the default black, so paint white first. */ cairo_save (cr); cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */ cairo_paint (cr); cairo_restore (cr); cairo_scale (cr, 1.0/(1<<16), 1.0/(1<<16)); cairo_move_to (cr, 131072,39321); cairo_line_to (cr, 1103072,1288088); cairo_line_to (cr, 1179648,1294990); cairo_close_path (cr); cairo_fill (cr); return CAIRO_TEST_SUCCESS; } int main (void) { return cairo_test (&test); }