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Annotation of OpenXM_contrib/gnuplot/term/compact.c, Revision 1.1

1.1     ! maekawa     1: /*
        !             2:  * $Id: $
        !             3:  *
        !             4:  */
        !             5:
        !             6: /* GNUPLOT - compact.c */
        !             7:
        !             8: /* contains routines to compress a vector stream without modifying it */
        !             9:
        !            10: /*[
        !            11:  * Copyright 1986 - 1993, 1998   Thomas Williams, Colin Kelley
        !            12:  *
        !            13:  * Permission to use, copy, and distribute this software and its
        !            14:  * documentation for any purpose with or without fee is hereby granted,
        !            15:  * provided that the above copyright notice appear in all copies and
        !            16:  * that both that copyright notice and this permission notice appear
        !            17:  * in supporting documentation.
        !            18:  *
        !            19:  * Permission to modify the software is granted, but not the right to
        !            20:  * distribute the complete modified source code.  Modifications are to
        !            21:  * be distributed as patches to the released version.  Permission to
        !            22:  * distribute binaries produced by compiling modified sources is granted,
        !            23:  * provided you
        !            24:  *   1. distribute the corresponding source modifications from the
        !            25:  *    released version in the form of a patch file along with the binaries,
        !            26:  *   2. add special version identification to distinguish your version
        !            27:  *    in addition to the base release version number,
        !            28:  *   3. provide your name and address as the primary contact for the
        !            29:  *    support of your modified version, and
        !            30:  *   4. retain our contact information in regard to use of the base
        !            31:  *    software.
        !            32:  * Permission to distribute the released version of the source code along
        !            33:  * with corresponding source modifications in the form of a patch file is
        !            34:  * granted with same provisions 2 through 4 for binary distributions.
        !            35:  *
        !            36:  * This software is provided "as is" without express or implied warranty
        !            37:  * to the extent permitted by applicable law.
        !            38: ]*/
        !            39:
        !            40: #ifndef COMPACT
        !            41:
        !            42: /* replaces runs of constant slope in the buffer with single vectors
        !            43:    returns the number of points eliminated */
        !            44: int compact_slope(xp, yp, isa_move, sz, delta)
        !            45: int xp[], yp[], isa_move[];
        !            46: int *sz;
        !            47: double delta;
        !            48: {
        !            49:     int dx, dy, old_size, new_index, i, start;
        !            50:     float slope, old_slope;
        !            51:
        !            52:     old_size = *sz;
        !            53:     new_index = 0;
        !            54:     start = 0;
        !            55:     if (xp[1] != xp[0])
        !            56:        old_slope = (float) (yp[1] - yp[0]) / (float) (xp[1] - xp[0]);
        !            57:     else
        !            58:        old_slope = (float) (yp[1] - yp[0]) / (float) (0.00001 + xp[1] - xp[0]);
        !            59:     for (i = 2; i < old_size; i++) {
        !            60:        dx = xp[i] - xp[i - 1];
        !            61:        dy = yp[i] - yp[i - 1];
        !            62:        if (dx != 0)
        !            63:            slope = (float) dy / (float) dx;
        !            64:        else
        !            65:            slope = (float) dy / ((float) dx + 0.00001);
        !            66:        if ((ABS(slope - old_slope) > delta) || (isa_move[i])) {
        !            67:            xp[new_index] = xp[start];
        !            68:            yp[new_index] = yp[start];
        !            69:            isa_move[new_index] = isa_move[start];
        !            70:            new_index++;
        !            71:            if (start != i - 1) {
        !            72:                xp[new_index] = xp[i - 1];
        !            73:                yp[new_index] = yp[i - 1];
        !            74:                isa_move[new_index] = isa_move[i - 1];
        !            75:                new_index++;
        !            76:            }
        !            77:            start = i;
        !            78:            /* this is the slope for the new run */
        !            79:            old_slope = slope;
        !            80:        }
        !            81:     }
        !            82:     /* copy the last point into the new array */
        !            83:     xp[new_index] = xp[old_size - 1];
        !            84:     yp[new_index] = yp[old_size - 1];
        !            85:     isa_move[new_index] = isa_move[old_size - 1];
        !            86:     new_index++;
        !            87:     *sz = new_index;
        !            88:     return (old_size - *sz);
        !            89: }
        !            90:
        !            91: /* compacts the vector list by compressing runs of constant
        !            92:    dx&dy into one vector
        !            93:    use this if floating point is too expensive!
        !            94:    more naive than compact_slope; doesn't compact as much as possible
        !            95:    returns the number of points eliminated */
        !            96: int compact_int(xp, yp, isa_move, size)
        !            97: int xp[], yp[], isa_move[], *size;
        !            98: {
        !            99:     int dx, dy, old_dx, old_dy, start, index, i, old_size;
        !           100:
        !           101:     start = index = 0;
        !           102:     old_dx = xp[1] - xp[0];
        !           103:     old_dy = yp[1] - yp[0];
        !           104:     for (i = 2; i < *size; i++) {
        !           105:        dx = xp[i] - xp[i - 1];
        !           106:        dy = yp[i] - yp[i - 1];
        !           107:        if ((ABS(dx - old_dx) + ABS(dy - old_dy) != 0) || (isa_move[i])) {
        !           108:            /*  we've reached the end of a run */
        !           109:            xp[index] = xp[start];
        !           110:            yp[index] = yp[start];
        !           111:            isa_move[index] = isa_move[start];
        !           112:            index++;
        !           113:            if (start != i - 1) {
        !           114:                xp[index] = xp[i - 1];
        !           115:                yp[index] = yp[i - 1];
        !           116:                isa_move[index] = isa_move[i - 1];
        !           117:                index++;
        !           118:            }
        !           119:            start = i;
        !           120:            old_dx = dx;
        !           121:            old_dy = dy;
        !           122:        }
        !           123:     }                          /* end for */
        !           124:     /* include the last point */
        !           125:     xp[index] = xp[*size - 1];
        !           126:     yp[index] = yp[*size - 1];
        !           127:     isa_move[index] = isa_move[*size - 1];
        !           128:     index++;
        !           129:     old_size = *size;
        !           130:     *size = index;
        !           131:     return (old_size - *size);
        !           132: }
        !           133: #endif
        !           134:
        !           135: #define COMPACT