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/*
* $Id: gv_quick.c,v 2.0 2004/11/09 12:32:01 bernhard Exp $
*/
/* gv_quick.c
Bill Brown, USACERL
December 1993
*/
/*
Trying some stuff to draw a quick version of a vector file, to represent
it when doing interactive translations.
*/
#include <stdio.h>
#include <stdlib.h>
#include "gstypes.h"
#include "rowcol.h"
/* target number of desired points to represent entire file */
#define TFAST_PTS 800
/* max number of lines desired */
#define MFAST_LNS 400
static geoline *copy_line(geoline *);
static geoline *thin_line(geoline *, float);
/******************************************************************/
static geoline *copy_line(geoline * gln)
{
geoline *newln;
int i, np;
if (NULL == (newln = (geoline *) malloc(sizeof(geoline)))) {
fprintf(stderr, "Can't malloc.\n");
return (NULL);
}
np = newln->npts = gln->npts;
if (2 == (newln->dims = gln->dims)) {
if (NULL == (newln->p2 = (Point2 *) calloc(np, sizeof(Point2)))) {
fprintf(stderr, "Can't calloc.\n"); /* CLEAN UP */
return (NULL);
}
for (i = 0; i < np; i++) {
newln->p2[i][X] = gln->p2[i][X];
newln->p2[i][Y] = gln->p2[i][Y];
}
}
else {
if (NULL == (newln->p3 = (Point3 *) calloc(np, sizeof(Point3)))) {
fprintf(stderr, "Can't calloc.\n"); /* CLEAN UP */
return (NULL);
}
for (i = 0; i < np; i++) {
newln->p3[i][X] = gln->p3[i][X];
newln->p3[i][Y] = gln->p3[i][Y];
newln->p3[i][Z] = gln->p3[i][Z];
}
}
newln->next = NULL;
return (newln);
}
/******************************************************************/
/* for now, just eliminate points at regular interval */
static geoline *thin_line(geoline * gln, float factor)
{
geoline *newln;
int i, nextp, targp;
if (NULL == (newln = (geoline *) malloc(sizeof(geoline)))) {
fprintf(stderr, "Can't malloc.\n");
return (NULL);
}
targp = (int) (gln->npts / factor);
if (targp < 2) {
targp = 2;
}
newln->npts = targp;
if (2 == (newln->dims = gln->dims)) {
if (NULL == (newln->p2 = (Point2 *) calloc(targp, sizeof(Point2)))) {
fprintf(stderr, "Can't calloc.\n"); /* CLEAN UP */
return (NULL);
}
for (i = 0; i < targp; i++) {
if (i == targp - 1) {
nextp = gln->npts - 1; /* avoid rounding error */
}
else {
nextp = (int) ((i * (gln->npts - 1)) / (targp - 1));
}
newln->p2[i][X] = gln->p2[nextp][X];
newln->p2[i][Y] = gln->p2[nextp][Y];
}
}
else {
if (NULL == (newln->p3 = (Point3 *) calloc(targp, sizeof(Point3)))) {
fprintf(stderr, "Can't calloc.\n"); /* CLEAN UP */
return (NULL);
}
for (i = 0; i < targp; i++) {
if (i == targp - 1) {
nextp = gln->npts - 1; /* avoid rounding error */
}
else {
nextp = (int) ((i * (gln->npts - 1)) / (targp - 1));
}
newln->p3[i][X] = gln->p3[nextp][X];
newln->p3[i][Y] = gln->p3[nextp][Y];
newln->p3[i][Z] = gln->p3[nextp][Z];
}
}
newln->next = NULL;
return (newln);
}
/******************************************************************/
float gv_line_length(geoline * gln)
{
int n;
float length = 0.0;
for (n = 0; n < gln->npts - 1; n++) {
if (gln->p2) {
length += GS_P2distance(gln->p2[n + 1], gln->p2[n]);
}
else {
length += GS_distance(gln->p3[n + 1], gln->p3[n]);
}
}
return (length);
}
/******************************************************************/
int gln_num_points(geoline * gln)
{
int np = 0;
geoline *tln;
for (tln = gln; tln; tln = tln->next) {
np += tln->npts;
}
return (np);
}
/******************************************************************/
int gv_num_points(geovect * gv)
{
return (gln_num_points(gv->lines));
}
/******************************************************************/
/* strategy here: if line has more than average number of points, decimate
by eliminating points, otherwise decimate by eliminating shorter lines */
int gv_decimate_lines(geovect * gv)
{
int T_pts, A_ppl, N_s;
float decim_factor, slength[MFAST_LNS], T_slength, A_slength;
geoline *gln, *prev;
/* should check if already exists & free if != gv->lines */
if (TFAST_PTS > (T_pts = gv_num_points(gv))) {
gv->fastlines = gv->lines;
return (1);
}
N_s = 0;
T_slength = 0.0;
decim_factor = T_pts / TFAST_PTS;
A_ppl = T_pts / gv->n_lines; /* (int) Average points per line */
prev = NULL;
for (gln = gv->lines; gln; gln = gln->next) {
if (gln->npts > A_ppl) {
if (prev) {
prev->next = thin_line(gln, decim_factor);
prev = prev->next;
}
else {
prev = gv->fastlines = thin_line(gln, decim_factor);
}
}
else if (N_s < MFAST_LNS) {
T_slength += slength[N_s++] = gv_line_length(gln);
}
}
A_slength = T_slength / N_s;
N_s = 0;
for (gln = gv->lines; gln; gln = gln->next) {
if (gln->npts <= A_ppl) {
if (N_s < MFAST_LNS) {
if (slength[N_s++] > A_slength) {
if (prev) {
prev->next = copy_line(gln);
prev = prev->next;
}
else {
prev = gv->fastlines = copy_line(gln);
}
}
}
}
}
fprintf(stderr, "Decimated lines have %d points.\n",
gln_num_points(gv->fastlines));
return (1);
}
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