From 3c57dd931145d43f2b0aef96c4d178135956bf91 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 05:13:10 +0200 Subject: Adding upstream version 2.10.36. Signed-off-by: Daniel Baumann --- plug-ins/selection-to-path/math.c | 177 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 plug-ins/selection-to-path/math.c (limited to 'plug-ins/selection-to-path/math.c') diff --git a/plug-ins/selection-to-path/math.c b/plug-ins/selection-to-path/math.c new file mode 100644 index 0000000..58f3b3f --- /dev/null +++ b/plug-ins/selection-to-path/math.c @@ -0,0 +1,177 @@ +/* math.c: define some simple array operations, and other functions. + * + * Copyright (C) 1992 Free Software Foundation, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include "config.h" + +#include +#include +#include + +#include "libgimp/gimp.h" + +#include "types.h" +#include "global.h" + +/* Numerical errors sometimes make a floating point number just slightly + larger or smaller than its true value. When it matters, we need to + compare with some tolerance, REAL_EPSILON, defined in kbase.h. */ + +boolean +epsilon_equal (real v1, real v2) +{ + return + v1 == v2 /* Usually they'll be exactly equal, anyway. */ + || fabs (v1 - v2) <= REAL_EPSILON; +} + + +/* Return the Euclidean distance between P1 and P2. */ + +real +distance (real_coordinate_type p1, real_coordinate_type p2) +{ + return hypot (p1.x - p2.x, p1.y - p2.y); +} + + +/* Same thing, for integer points. */ +real +int_distance (coordinate_type p1, coordinate_type p2) +{ + return hypot ((double) p1.x - p2.x, (double) p1.y - p2.y); +} + + +/* Return the arc cosine of V, in degrees in the range zero to 180. V + is taken to be in radians. */ + +real +my_acosd (real v) +{ + real a; + + if (epsilon_equal (v, 1.0)) + v = 1.0; + else if (epsilon_equal (v, -1.0)) + v = -1.0; + + errno = 0; + a = acos (v); + if (errno == ERANGE || errno == EDOM) + FATAL_PERROR ("acosd"); + + return a * 180.0 / G_PI; +} + + +/* The slope of the line defined by COORD1 and COORD2. */ + +real +slope (real_coordinate_type coord1, real_coordinate_type coord2) +{ + g_assert (coord2.x - coord1.x != 0); + + return (coord2.y - coord1.y) / (coord2.x - coord1.x); +} + + +/* Turn an integer point into a real one, and vice versa. */ + +real_coordinate_type +int_to_real_coord (coordinate_type int_coord) +{ + real_coordinate_type real_coord; + + real_coord.x = int_coord.x; + real_coord.y = int_coord.y; + + return real_coord; +} + + +coordinate_type +real_to_int_coord (real_coordinate_type real_coord) +{ + coordinate_type int_coord; + + int_coord.x = SROUND (real_coord.x); + int_coord.y = SROUND (real_coord.y); + + return int_coord; +} + + +/* See if two points (described by their row and column) are adjacent. */ + +boolean +points_adjacent_p (int row1, int col1, int row2, int col2) +{ + int row_diff = abs (row1 - row2); + int col_diff = abs (col1 - col2); + + return + (row_diff == 1 && col_diff == 1) + || (row_diff == 0 && col_diff == 1) + || (row_diff == 1 && col_diff == 0); +} + + +/* Find the largest and smallest elements in an array of reals. */ + +void +find_bounds (real *values, unsigned value_count, real *min, real *max) +{ + unsigned this_value; + + /* We must use FLT_MAX and FLT_MIN, instead of the corresponding + values for double, because gcc uses the native atof to parse + floating point constants, and many atof's choke on the extremes. */ + *min = FLT_MAX; + *max = FLT_MIN; + + for (this_value = 0; this_value < value_count; this_value++) + { + if (values[this_value] < *min) + *min = values[this_value]; + + if (values[this_value] > *max) + *max = values[this_value]; + } +} + +/* Map a range of numbers, some positive and some negative, into all + positive, with the greatest being at one and the least at zero. + + This allocates new memory. */ + +real * +map_to_unit (real *values, unsigned value_count) +{ + real smallest, largest; + int this_value; + real *mapped_values = g_new (real, value_count); + + find_bounds (values, value_count, &smallest, &largest); + + largest -= smallest; /* We never care about largest itself. */ + + for (this_value = 0; this_value < value_count; this_value++) + mapped_values[this_value] = (values[this_value] - smallest) / largest; + + return mapped_values; +} -- cgit v1.2.3