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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:24:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:24:48 +0000 |
commit | cca66b9ec4e494c1d919bff0f71a820d8afab1fa (patch) | |
tree | 146f39ded1c938019e1ed42d30923c2ac9e86789 /src/helper/mathfns.h | |
parent | Initial commit. (diff) | |
download | inkscape-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.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/helper/mathfns.h b/src/helper/mathfns.h new file mode 100644 index 0000000..e0e321c --- /dev/null +++ b/src/helper/mathfns.h @@ -0,0 +1,83 @@ +// 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 : |