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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:24:48 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:24:48 +0000
commitcca66b9ec4e494c1d919bff0f71a820d8afab1fa (patch)
tree146f39ded1c938019e1ed42d30923c2ac9e86789 /src/helper/mathfns.h
parentInitial commit. (diff)
downloadinkscape-cca66b9ec4e494c1d919bff0f71a820d8afab1fa.tar.xz
inkscape-cca66b9ec4e494c1d919bff0f71a820d8afab1fa.zip
Adding upstream version 1.2.2.upstream/1.2.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/helper/mathfns.h')
-rw-r--r--src/helper/mathfns.h83
1 files changed, 83 insertions, 0 deletions
diff --git a/src/helper/mathfns.h b/src/helper/mathfns.h
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ... some mathematical functions
+ *
+ * Authors:
+ * Johan Engelen <goejendaagh@zonnet.nl>
+ *
+ * Copyright (C) 2007 Johan Engelen
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef SEEN_INKSCAPE_UTIL_MATHFNS_H
+#define SEEN_INKSCAPE_UTIL_MATHFNS_H
+
+#include <2geom/point.h>
+
+namespace Inkscape {
+
+namespace Util {
+
+/**
+ * Returns area in triangle given by points; may be negative.
+ */
+inline double
+triangle_area (Geom::Point p1, Geom::Point p2, Geom::Point p3)
+{
+ using Geom::X;
+ using Geom::Y;
+ return (p1[X]*p2[Y] + p1[Y]*p3[X] + p2[X]*p3[Y] - p2[Y]*p3[X] - p1[Y]*p2[X] - p1[X]*p3[Y]);
+}
+
+/**
+ * \return x rounded to the nearest multiple of c1 plus c0.
+ *
+ * \note
+ * If c1==0 (and c0 is finite), then returns +/-inf. This makes grid spacing of zero
+ * mean "ignore the grid in this dimension".
+ */
+inline double round_to_nearest_multiple_plus(double x, double const c1, double const c0)
+{
+ return floor((x - c0) / c1 + .5) * c1 + c0;
+}
+
+/**
+ * \return x rounded to the lower multiple of c1 plus c0.
+ *
+ * \note
+ * If c1==0 (and c0 is finite), then returns +/-inf. This makes grid spacing of zero
+ * mean "ignore the grid in this dimension".
+ */
+inline double round_to_lower_multiple_plus(double x, double const c1, double const c0 = 0)
+{
+ return floor((x - c0) / c1) * c1 + c0;
+}
+
+/**
+ * \return x rounded to the upper multiple of c1 plus c0.
+ *
+ * \note
+ * If c1==0 (and c0 is finite), then returns +/-inf. This makes grid spacing of zero
+ * mean "ignore the grid in this dimension".
+ */
+inline double round_to_upper_multiple_plus(double x, double const c1, double const c0 = 0)
+{
+ return ceil((x - c0) / c1) * c1 + c0;
+}
+
+}
+
+}
+
+#endif
+/*
+ Local Variables:
+ mode:c++
+ c-file-style:"stroustrup"
+ c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+ indent-tabs-mode:nil
+ fill-column:99
+ End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :