diff options
Diffstat (limited to 'test/line-width-scale.c')
| -rw-r--r-- | test/line-width-scale.c | 178 |
1 files changed, 0 insertions, 178 deletions
diff --git a/test/line-width-scale.c b/test/line-width-scale.c deleted file mode 100644 index 037b887fd..000000000 --- a/test/line-width-scale.c +++ /dev/null @@ -1,178 +0,0 @@ -/* - * Copyright © 2006 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> - */ - -#include "cairo-test.h" - -/* This test exercises the various interactions between - * cairo_set_line_width and cairo_scale. Specifically it shows how - * separate transformations can affect the pen for stroking compared - * to the path itself. - * - * This was inspired by an image by Maxim Shemanarev demonstrating the - * flexible-pipeline nature of his Antigrain Geometry project: - * - * http://antigrain.com/tips/line_alignment/conv_order.gif - * - * It also uncovered some behavior in cairo that I found surprising. - * Namely, cairo_set_line_width was not transforming the width - * according the the current CTM, but instead delaying that - * transformation until the time of cairo_stroke. - * - * This delayed behavior was released in cairo 1.0 so we're going to - * document this as the way cairo_set_line_width works rather than - * considering this a bug. - */ - -#define LINE_WIDTH 13 -#define SPLINE 50.0 -#define XSCALE 0.5 -#define YSCALE 2.0 -#define WIDTH (XSCALE * SPLINE * 6.0) -#define HEIGHT (YSCALE * SPLINE * 2.0) - -static void -spline_path (cairo_t *cr) -{ - cairo_save (cr); - { - cairo_move_to (cr, - - SPLINE, 0); - cairo_curve_to (cr, - - SPLINE / 4, - SPLINE, - SPLINE / 4, SPLINE, - SPLINE, 0); - } - cairo_restore (cr); -} - -/* If we scale before setting the line width or creating the path, - * then obviously both will be scaled. */ -static void -scale_then_set_line_width_and_stroke (cairo_t *cr) -{ - cairo_scale (cr, XSCALE, YSCALE); - cairo_set_line_width (cr, LINE_WIDTH); - spline_path (cr); - cairo_stroke (cr); -} - -/* This is used to verify the results of - * scale_then_set_line_width_and_stroke. - * - * It uses save/restore pairs to isolate the scaling of the path and - * line_width and ensures that both are scaled. - */ -static void -scale_path_and_line_width (cairo_t *cr) -{ - cairo_save (cr); - { - cairo_scale (cr, XSCALE, YSCALE); - spline_path (cr); - } - cairo_restore (cr); - - cairo_save (cr); - { - cairo_scale (cr, XSCALE, YSCALE); - cairo_set_line_width (cr, LINE_WIDTH); - cairo_stroke (cr); - } - cairo_restore (cr); -} - -/* This is the case that was surprising. - * - * Setting the line width before scaling doesn't change anything. The - * line width will be interpreted under the CTM in effect at the time - * of cairo_stroke, so the line width will be scaled as well as the - * path here. - */ -static void -set_line_width_then_scale_and_stroke (cairo_t *cr) -{ - cairo_set_line_width (cr, LINE_WIDTH); - cairo_scale (cr, XSCALE, YSCALE); - spline_path (cr); - cairo_stroke (cr); -} - -/* Here then is the way to achieve the alternate result. - * - * This uses save/restore pairs to isolate the scaling of the path and - * line_width and ensures that the path is scaled while the line width - * is not. - */ -static void -scale_path_not_line_width (cairo_t *cr) -{ - cairo_save (cr); - { - cairo_scale (cr, XSCALE, YSCALE); - spline_path (cr); - } - cairo_restore (cr); - - cairo_save (cr); - { - cairo_set_line_width (cr, LINE_WIDTH); - cairo_stroke (cr); - } - cairo_restore (cr); -} - -static cairo_test_status_t -draw (cairo_t *cr, int width, int height) -{ - int i; - void (* const figures[4]) (cairo_t *cr) = { - scale_then_set_line_width_and_stroke, - scale_path_and_line_width, - set_line_width_then_scale_and_stroke, - scale_path_not_line_width - }; - - cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */ - cairo_paint (cr); - cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */ - - for (i = 0; i < 4; i++) { - cairo_save (cr); - cairo_translate (cr, - WIDTH/4 + (i % 2) * WIDTH/2, - HEIGHT/4 + (i / 2) * HEIGHT/2); - (figures[i]) (cr); - cairo_restore (cr); - } - - return CAIRO_TEST_SUCCESS; -} - -CAIRO_TEST (line_width_scale, - "Tests interaction of cairo_set_line_width with cairo_scale", - "stroke", /* keywords */ - NULL, /* requirements */ - WIDTH, HEIGHT, - NULL, draw) |