summaryrefslogtreecommitdiffstats
path: root/plug-ins/selection-to-path/spline.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 03:13:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 03:13:10 +0000
commit3c57dd931145d43f2b0aef96c4d178135956bf91 (patch)
tree3de698981e9f0cc2c4f9569b19a5f3595e741f6b /plug-ins/selection-to-path/spline.c
parentInitial commit. (diff)
downloadgimp-3c57dd931145d43f2b0aef96c4d178135956bf91.tar.xz
gimp-3c57dd931145d43f2b0aef96c4d178135956bf91.zip
Adding upstream version 2.10.36.upstream/2.10.36
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'plug-ins/selection-to-path/spline.c')
-rw-r--r--plug-ins/selection-to-path/spline.c233
1 files changed, 233 insertions, 0 deletions
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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <assert.h>
+
+#include <glib.h>
+
+#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;
+}