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-rw-r--r--test/dash-offset.c83
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diff --git a/test/dash-offset.c b/test/dash-offset.c
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+/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
+/*
+ * Copyright 2009 Andrea Canciani
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Andrea Canciani <ranma42@gmail.com>
+ */
+
+#include "cairo-test.h"
+
+/* Lengths of the dashes of the dash patterns */
+static const double dashes[] = { 2, 2, 4, 4 };
+/* Dash offset in userspace units
+ * They always grow by 2, so the dash pattern is
+ * should be shifted by the same amount each time */
+static const double frac_offset[] = { 0, 2, 4, 6 };
+/* Dash offset relative to the whole dash pattern
+ * This corresponds to the non-inverted part only if
+ * the dash pattern has odd length, so the expected result
+ * is the same for every int_offset if the pattern has
+ * even length, and inverted each time (or shifted by half
+ * period, which is the same) if the pattern has odd length. */
+static const double int_offset[] = { -2, -1, 0, 1, 2 };
+
+#define PAD 6
+#define STROKE_LENGTH 32
+#define IMAGE_WIDTH (PAD + (STROKE_LENGTH + PAD) * ARRAY_LENGTH (dashes))
+#define IMAGE_HEIGHT (PAD + PAD * ARRAY_LENGTH (int_offset) + PAD * ARRAY_LENGTH (frac_offset) * ARRAY_LENGTH (int_offset))
+
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+ double total;
+ size_t i, j, k;
+
+ cairo_set_source_rgb (cr, 1, 1, 1);
+ cairo_paint (cr);
+
+ cairo_set_source_rgb (cr, 0, 0, 0);
+ cairo_set_line_width (cr, 2);
+
+ total = 0.0;
+ for (k = 0; k < ARRAY_LENGTH (dashes); ++k) {
+ total += dashes[k];
+ for (i = 0; i < ARRAY_LENGTH (frac_offset); ++i) {
+ for (j = 0; j < ARRAY_LENGTH (int_offset); ++j) {
+ cairo_set_dash (cr, dashes, k + 1, frac_offset[i] + total * int_offset[j]);
+ cairo_move_to (cr, (STROKE_LENGTH + PAD) * k + PAD, PAD * (i + j + ARRAY_LENGTH (frac_offset) * j + 1));
+ cairo_line_to (cr, (STROKE_LENGTH + PAD) * (k + 1), PAD * (i + j + ARRAY_LENGTH (frac_offset) * j + 1));
+ cairo_stroke (cr);
+ }
+ }
+ }
+
+ return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (dash_offset,
+ "Tests dashes of different length with various offsets",
+ "stroke, dash", /* keywords */
+ NULL, /* requirements */
+ IMAGE_WIDTH, IMAGE_HEIGHT,
+ NULL, draw)