--- /dev/null
+/*
+ * $Id: compact.c,v 1.6 2004/07/01 17:10:12 broeker Exp $
+ *
+ */
+
+/* GNUPLOT - compact.c */
+
+/* contains routines to compress a vector stream without modifying it */
+
+/*[
+ * Copyright 1986 - 1993, 1998, 2004 Thomas Williams, Colin Kelley
+ *
+ * Permission to use, copy, and distribute this software and its
+ * documentation for any purpose with or without fee is hereby granted,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.
+ *
+ * Permission to modify the software is granted, but not the right to
+ * distribute the complete modified source code. Modifications are to
+ * be distributed as patches to the released version. Permission to
+ * distribute binaries produced by compiling modified sources is granted,
+ * provided you
+ * 1. distribute the corresponding source modifications from the
+ * released version in the form of a patch file along with the binaries,
+ * 2. add special version identification to distinguish your version
+ * in addition to the base release version number,
+ * 3. provide your name and address as the primary contact for the
+ * support of your modified version, and
+ * 4. retain our contact information in regard to use of the base
+ * software.
+ * Permission to distribute the released version of the source code along
+ * with corresponding source modifications in the form of a patch file is
+ * granted with same provisions 2 through 4 for binary distributions.
+ *
+ * This software is provided "as is" without express or implied warranty
+ * to the extent permitted by applicable law.
+]*/
+
+#ifndef COMPACT
+
+static int compact_slope __PROTO((int xp[], int yp[], int isa_move[], int *sz, double delta));
+
+/* replaces runs of constant slope in the buffer with single vectors
+ returns the number of points eliminated */
+static int
+compact_slope(int xp[], int yp[], int isa_move[], int *sz, double delta)
+{
+ int dx, dy, old_size, new_index, i, start;
+ float slope, old_slope;
+
+ old_size = *sz;
+ new_index = 0;
+ start = 0;
+ if (xp[1] != xp[0])
+ old_slope = (float) (yp[1] - yp[0]) / (float) (xp[1] - xp[0]);
+ else
+ old_slope = (float) (yp[1] - yp[0]) / (float) (0.00001 + xp[1] - xp[0]);
+
+ for (i = 2; i < old_size; i++) {
+ dx = xp[i] - xp[i - 1];
+ dy = yp[i] - yp[i - 1];
+ if (dx != 0)
+ slope = (float) dy / (float) dx;
+ else
+ slope = (float) dy / ((float) dx + 0.00001);
+ if ((ABS(slope - old_slope) > delta) || (isa_move[i])) {
+ xp[new_index] = xp[start];
+ yp[new_index] = yp[start];
+ isa_move[new_index] = isa_move[start];
+ new_index++;
+ if (start != i - 1) {
+ xp[new_index] = xp[i - 1];
+ yp[new_index] = yp[i - 1];
+ isa_move[new_index] = isa_move[i - 1];
+ new_index++;
+ }
+ start = i;
+ /* this is the slope for the new run */
+ old_slope = slope;
+ }
+ }
+ /* copy the last point into the new array */
+ xp[new_index] = xp[old_size - 1];
+ yp[new_index] = yp[old_size - 1];
+ isa_move[new_index] = isa_move[old_size - 1];
+ new_index++;
+ *sz = new_index;
+ return (old_size - *sz);
+}
+
+
+# if 0 /* currently unused */
+static int compact_int __PROTO((int xp[], int yp[], int isa_move[], int *size));
+
+/* compacts the vector list by compressing runs of constant
+ dx&dy into one vector
+ use this if floating point is too expensive!
+ more naive than compact_slope; doesn't compact as much as possible
+ returns the number of points eliminated */
+static int
+compact_int(int xp[], int yp[], int isa_move[], int *size)
+{
+ int dx, dy, old_dx, old_dy, start, index, i, old_size;
+
+ start = index = 0;
+ old_dx = xp[1] - xp[0];
+ old_dy = yp[1] - yp[0];
+ for (i = 2; i < *size; i++) {
+ dx = xp[i] - xp[i - 1];
+ dy = yp[i] - yp[i - 1];
+ if ((ABS(dx - old_dx) + ABS(dy - old_dy) != 0) || (isa_move[i])) {
+ /* we've reached the end of a run */
+ xp[index] = xp[start];
+ yp[index] = yp[start];
+ isa_move[index] = isa_move[start];
+ index++;
+ if (start != i - 1) {
+ xp[index] = xp[i - 1];
+ yp[index] = yp[i - 1];
+ isa_move[index] = isa_move[i - 1];
+ index++;
+ }
+ start = i;
+ old_dx = dx;
+ old_dy = dy;
+ }
+ } /* end for */
+ /* include the last point */
+ xp[index] = xp[*size - 1];
+ yp[index] = yp[*size - 1];
+ isa_move[index] = isa_move[*size - 1];
+ index++;
+ old_size = *size;
+ *size = index;
+ return (old_size - *size);
+}
+# endif /* unused */
+
+#endif /* !defined(COMPACT) */
+
+#define COMPACT
projects / gnuplot / blobdiff