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/spline.c | 233 ++++++++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 plug-ins/selection-to-path/spline.c (limited to 'plug-ins/selection-to-path/spline.c') diff --git a/plug-ins/selection-to-path/spline.c b/plug-ins/selection-to-path/spline.c new file mode 100644 index 0000000..1e8c2e7 --- /dev/null +++ b/plug-ins/selection-to-path/spline.c @@ -0,0 +1,233 @@ +/* spline.c: spline and spline list (represented as arrays) manipulation. + * + * 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 "global.h" +#include "bounding-box.h" +#include "spline.h" +#include "vector.h" + +/* Return a new spline structure, initialized with (recognizable) + garbage. */ + +spline_type +new_spline (void) +{ + real_coordinate_type coord = { -100.0, -100.0 }; + spline_type spline; + + START_POINT (spline) + = CONTROL1 (spline) + = CONTROL2 (spline) + = END_POINT (spline) + = coord; + SPLINE_DEGREE (spline) = -1; + SPLINE_LINEARITY (spline) = 0; + + return spline; +} + + +/* Print a spline in human-readable form. */ + +void +print_spline (FILE *f, spline_type s) +{ + if (SPLINE_DEGREE (s) == LINEAR) + fprintf (f, "(%.3f,%.3f)--(%.3f,%.3f).\n", + START_POINT (s).x, START_POINT (s).y, + END_POINT (s).x, END_POINT (s).y); + + else if (SPLINE_DEGREE (s) == CUBIC) + fprintf (f, "(%.3f,%.3f)..ctrls(%.3f,%.3f)&(%.3f,%.3f)..(%.3f,%.3f).\n", + START_POINT (s).x, START_POINT (s).y, + CONTROL1 (s).x, CONTROL1 (s).y, + CONTROL2 (s).x, CONTROL2 (s).y, + END_POINT (s).x, END_POINT (s).y); + + else + { +/* FATAL1 ("print_spline: strange degree (%d)", SPLINE_DEGREE (s)); */ + } +} + +/* Evaluate the spline S at a given T value. This is an implementation + of de Casteljau's algorithm. See Schneider's thesis (reference in + ../limn/README), p.37. The variable names are taken from there. */ + +real_coordinate_type +evaluate_spline (spline_type s, real t) +{ + spline_type V[4]; /* We need degree+1 splines, but assert degree <= 3. */ + unsigned i, j; + real one_minus_t = 1.0 - t; + polynomial_degree degree = SPLINE_DEGREE (s); + + for (i = 0; i <= degree; i++) + V[0].v[i] = s.v[i]; + + for (j = 1; j <= degree; j++) + for (i = 0; i <= degree - j; i++) + { +#if defined (__GNUC__) + real_coordinate_type t1 = Pmult_scalar (V[j - 1].v[i], one_minus_t); + real_coordinate_type t2 = Pmult_scalar (V[j - 1].v[i + 1], t); + V[j].v[i] = Padd (t1, t2); +#else + /* HB: the above is really nice, but is there any other compiler + * supporting this ?? + */ + real_coordinate_type t1; + real_coordinate_type t2; + t1.x = V[j - 1].v[i].x * one_minus_t; + t1.y = V[j - 1].v[i].y * one_minus_t; + t2.x = V[j - 1].v[i + 1].x * t; + t2.y = V[j - 1].v[i + 1].y * t; + V[j].v[i].x = t1.x + t2.x; + V[j].v[i].y = t1.y + t2.y; +#endif + } + + return V[degree].v[0]; +} + + + +/* Return a new, empty, spline list. */ + +spline_list_type * +new_spline_list (void) +{ + spline_list_type *answer = g_new (spline_list_type, 1); + + SPLINE_LIST_DATA (*answer) = NULL; + SPLINE_LIST_LENGTH (*answer) = 0; + + return answer; +} + + +/* Return a new spline list with SPLINE as the first element. */ + +spline_list_type * +init_spline_list (spline_type spline) +{ + spline_list_type *answer = g_new (spline_list_type, 1); + + SPLINE_LIST_DATA (*answer) = g_new (spline_type, 1); + SPLINE_LIST_ELT (*answer, 0) = spline; + SPLINE_LIST_LENGTH (*answer) = 1; + + return answer; +} + + +/* Free the storage in a spline list. We don't have to free the + elements, since they are arrays in automatic storage. And we don't + want to free the list if it was empty. */ + +void +free_spline_list (spline_list_type *spline_list) +{ + if (SPLINE_LIST_DATA (*spline_list) != NULL) + safe_free ((address *) &(SPLINE_LIST_DATA (*spline_list))); +} + + +/* Append the spline S to the list SPLINE_LIST. */ + +void +append_spline (spline_list_type *l, spline_type s) +{ + assert (l != NULL); + + SPLINE_LIST_LENGTH (*l)++; + SPLINE_LIST_DATA (*l) = g_realloc (SPLINE_LIST_DATA (*l), + SPLINE_LIST_LENGTH (*l) * sizeof (spline_type)); + LAST_SPLINE_LIST_ELT (*l) = s; +} + + +/* Tack the elements in the list S2 onto the end of S1. + S2 is not changed. */ + +void +concat_spline_lists (spline_list_type *s1, spline_list_type s2) +{ + unsigned this_spline; + unsigned new_length; + + assert (s1 != NULL); + + new_length = SPLINE_LIST_LENGTH (*s1) + SPLINE_LIST_LENGTH (s2); + + SPLINE_LIST_DATA (*s1) = g_realloc(SPLINE_LIST_DATA (*s1),new_length * sizeof(spline_type)); + + for (this_spline = 0; this_spline < SPLINE_LIST_LENGTH (s2); this_spline++) + SPLINE_LIST_ELT (*s1, SPLINE_LIST_LENGTH (*s1)++) + = SPLINE_LIST_ELT (s2, this_spline); +} + + +/* Return a new, empty, spline list array. */ + +spline_list_array_type +new_spline_list_array (void) +{ + spline_list_array_type answer; + + SPLINE_LIST_ARRAY_DATA (answer) = NULL; + SPLINE_LIST_ARRAY_LENGTH (answer) = 0; + + return answer; +} + + +/* Free the storage in a spline list array. We don't + want to free the list if it is empty. */ + +void +free_spline_list_array (spline_list_array_type *spline_list_array) +{ + unsigned this_list; + + for (this_list = 0; + this_list < SPLINE_LIST_ARRAY_LENGTH (*spline_list_array); + this_list++) + free_spline_list (&SPLINE_LIST_ARRAY_ELT (*spline_list_array, this_list)); + + if (SPLINE_LIST_ARRAY_DATA (*spline_list_array) != NULL) + safe_free ((address *) &(SPLINE_LIST_ARRAY_DATA (*spline_list_array))); +} + + +/* Append the spline S to the list SPLINE_LIST_ARRAY. */ + +void +append_spline_list (spline_list_array_type *l, spline_list_type s) +{ + SPLINE_LIST_ARRAY_LENGTH (*l)++; + + SPLINE_LIST_ARRAY_DATA (*l) = g_realloc(SPLINE_LIST_ARRAY_DATA (*l),(SPLINE_LIST_ARRAY_LENGTH (*l))*sizeof(spline_list_type)); + LAST_SPLINE_LIST_ARRAY_ELT (*l) = s; +} -- cgit v1.2.3