ref: 7628681f83b663609eace87a50f8fbf68c31f40b
dir: /sys/src/libscribble/li_recognizer.c/
/*
* li_recognizer.c
*
* Copyright 2000 Compaq Computer Corporation.
* Copying or modifying this code for any purpose is permitted,
* provided that this copyright notice is preserved in its entirety
* in all copies or modifications.
* COMPAQ COMPUTER CORPORATION MAKES NO WARRANTIES, EXPRESSED OR
* IMPLIED, AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR
*
*
* Adapted from cmu_recognizer.c by Jay Kistler.
*
* Where is the CMU copyright???? Gotta track it down - Jim Gettys
*
* Credit to Dean Rubine, Jim Kempf, and Ari Rapkin.
*/
#include <u.h>
#include <libc.h>
#include <stdio.h>
#include <draw.h>
#include <scribble.h>
#include "scribbleimpl.h"
#include "hre_internal.h"
#include "li_recognizer_internal.h"
int lidebug = 0;
#define LI_MAGIC 0xACCBADDD
#define CHECK_LI_MAGIC(_a) \
((_a) != nil && ((li_recognizer*)(_a))->li_magic == LI_MAGIC)
static void lialg_initialize(rClassifier *);
static int lialg_read_classifier_digest(rClassifier *);
static int lialg_canonicalize_examples(rClassifier *);
static char *lialg_recognize_stroke(rClassifier *, point_list *);
static void lialg_compute_lpf_parameters(void);
char* li_err_msg = nil;
#define bcopy(s1,s2,n) memmove(s2,s1,n)
/*Freeing classifier*/
static void
free_rClassifier(rClassifier* rc);
/*
* Point List Support
*/
static point_list*
add_example(point_list* l,int npts,pen_point* pts)
{
pen_point* lpts = mallocz(npts*sizeof(pen_point), 1);
point_list *p = malloc(sizeof(point_list));
p->npts = npts;
p->pts = lpts;
p->next = l; /*Order doesn't matter, so we stick on end.*/
/*Copy points.*/
bcopy(pts, lpts, npts * sizeof(pen_point));
return(p);
}
static void
delete_examples(point_list* l)
{
point_list* p;
for( ; l != nil; l = p ) {
p = l->next;
free(l->pts);
free(l);
}
}
/*
* Local functions
*/
/*
* recognize_internal-Form Vector, use Classifier to classify, return char.
*/
static char*
recognize_internal(rClassifier* rec, Stroke* str, int*)
{
char *res;
point_list *stroke;
stroke = add_example(nil, str->npts, str->pts);
if (stroke == nil) return(nil);
res = lialg_recognize_stroke(rec, stroke);
delete_examples(stroke);
return(res);
}
/*
* file_path-Construct pathname, check for proper extension.
*/
static int
file_path(char* dir,char* filename,char* pathname)
{
char* dot;
/*Check for proper extension on file name.*/
dot = strrchr(filename,'.');
if( dot == nil ) {
return(-1);
}
/*Determine whether a gesture or character classifier.*/
if( strcmp(dot,LI_CLASSIFIER_EXTENSION) != 0 ) {
return(-1);
}
/*Concatenate directory and filename into pathname.*/
strcpy(pathname,dir);
strcat(pathname,"/");
strcat(pathname,filename);
return(0);
}
/*read_classifier_points-Read points so classifier can be extended.*/
static int
read_classifier_points(FILE* fd,int nclss,point_list** ex,char** cnames)
{
int i,j,k;
char buf[BUFSIZ];
int nex = 0;
char* names[MAXSCLASSES];
point_list* examples[MAXSCLASSES];
pen_point* pts;
int npts;
/*Initialize*/
for( i = 0; i < MAXSCLASSES; i++ ) {
names[i] = nil;
examples[i] = nil;
}
/*Go thru classes.*/
for( k = 0; k < nclss; k++ ) {
/*Read class name and number of examples.*/
if( fscanf(fd,"%d %s",&nex,buf) != 2 )
goto unallocate;
/*Save class name*/
names[k] = strdup(buf);
/*Read examples.*/
for( i = 0; i < nex; i++ ) {
/*Read number of points.*/
if( fscanf(fd,"%d",&npts) != 1 )
goto unallocate; /*Boy would I like exceptions!*/
/*Allocate array for points.*/
if( (pts = mallocz(npts*sizeof(pen_point), 1)) == nil )
goto unallocate;
/*Read in points.*/
for( j = 0; j < npts; j++ ) {
int x,y;
if( fscanf(fd,"%d %d",&x,&y) != 2 ) {
delete_pen_point_array(pts);
goto unallocate;
}
pts[j].Point = Pt(x, y);
}
/*Add example*/
if( (examples[k] = add_example(examples[k],npts,pts)) == nil ) {
delete_pen_point_array(pts);
goto unallocate;
}
delete_pen_point_array(pts);
}
}
/* ari -- end of list of classes */
/* fprint(2, "]\n"); */
/*Transfer to recognizer.*/
bcopy(examples,ex,sizeof(examples));
bcopy(names,cnames,sizeof(names));
return(0);
/*Error. Deallocate memory and return.*/
unallocate:
for( ; k >= 0; k-- ) {
delete_examples(examples[k]);
free(names[k]);
}
return(-1);
}
/*read_classifier-Read a classifier file.*/
static int read_classifier(FILE* fd,rClassifier* rc)
{
li_err_msg = nil;
/*Read in classifier file.*/
if(fscanf(fd, "%d", &rc->nclasses) != 1)
return -1;
/*Read in the example points, so classifier can be extended.*/
if( read_classifier_points(fd,rc->nclasses,rc->ex,rc->cnames) != 0 )
return -1;
return(0);
}
/*
* Extension Functions
*/
/* getClasses and clearState are by Ari */
static int
recognizer_getClasses (recognizer r, char ***list, int *nc)
{
int i, nclasses;
li_recognizer* rec;
char **ret;
rec = (li_recognizer*)r->recognizer_specific;
/*Check for LI recognizer.*/
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return(-1);
}
*nc = nclasses = rec->li_rc.nclasses;
ret = malloc(nclasses*sizeof(char*));
for (i = 0; i < nclasses; i++)
ret[i] = rec->li_rc.cnames[i]; /* only the 1st char of the cname */
*list = ret;
return 0;
}
static int
recognizer_clearState (recognizer)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Clearing state is not supported by the LI recognizer";
return(-1);
}
static bool isa_li(recognizer r)
{ return(CHECK_LI_MAGIC(r)); }
static int
recognizer_train(recognizer, rc*, uint, Stroke*, rec_element*, bool)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Training is not supported by the LI recognizer";
return(-1);
}
int
li_recognizer_get_example (recognizer r,
int class,
int instance,
char **name,
pen_point **points,
int *npts)
{
li_recognizer *rec = (li_recognizer*)r->recognizer_specific;
int nclasses = rec->li_rc.nclasses;
point_list *pl;
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return(-1);
}
if (class > nclasses)
return -1;
pl = rec->li_rc.canonex[class];
while (instance && pl)
{
pl = pl->next;
instance--;
}
if (!pl)
return -1;
*name = rec->li_rc.cnames[class];
*points = pl->pts;
*npts = pl->npts;
return pl->npts; /* I hope [sjm] */
}
/*
* API Functions
*/
/*li_recognizer_load-Load a classifier file.*/
static int li_recognizer_load(recognizer r, char* dir, char* filename)
{
FILE *fd;
char* pathname;
li_recognizer* rec;
rClassifier* rc;
rec = (li_recognizer*)r->recognizer_specific;
/*Make sure recognizer's OK*/
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return(-1);
}
rc = &(rec->li_rc);
/*Check parameters.*/
if( filename == nil ) {
li_err_msg = "Invalid parameters";
return(-1);
}
/*We let the directory be null.*/
if( dir == nil || (int)strlen(dir) <= 0 ) {
dir = ".";
}
if(0)fprint(2, "dir = %s, filename = %s\n",
dir, filename);
/*Make full pathname and check filename*/
pathname = malloc((strlen(dir) + strlen(filename) + 2)*sizeof(char));
if( file_path(dir, filename, pathname) == -1 ) {
free(pathname);
li_err_msg = "Not a LI recognizer classifier file";
return -1;
}
/* Try to short-circuit the full classifier-file processing. */
rc->file_name = pathname;
if (lialg_read_classifier_digest(rc) == 0)
return(0);
rc->file_name = nil;
/*Open the file*/
if( (fd = fopen(pathname,"r")) == nil ) {
li_err_msg = "Can't open classifier file";
if(0)fprint(2, "Can't open %s.\n", pathname);
free(pathname);
return(-1);
}
/*If rClassifier is OK, then delete it first.*/
if( rc->file_name != nil ) {
free_rClassifier(rc);
}
/*Read classifier.*/
if( read_classifier(fd,rc) < 0 ) {
free(pathname);
return(-1);
}
/*Close file.*/
fclose(fd);
/*Add classifier name.*/
rc->file_name = pathname;
/* Canonicalize examples. */
if (lialg_canonicalize_examples(rc) != 0) {
free(pathname);
rc->file_name = nil;
return -1;
}
return(0);
}
/*li_recognizer_save-Save a classifier file.*/
static int li_recognizer_save(recognizer, char*, char*)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Saving is not supported by the LI recognizer";
return -1;
}
static wordset
li_recognizer_load_dictionary(recognizer, char*, char*)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Dictionaries are not supported by the LI recognizer";
return nil;
}
static int
li_recognizer_save_dictionary(recognizer, char*, char*, wordset)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Dictionaries are not supported by the LI recognizer";
return -1;
}
static int
li_recognizer_free_dictionary(recognizer, wordset)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Dictionaries are not supported by the LI recognizer";
return -1;
}
static int
li_recognizer_add_to_dictionary(recognizer, letterset*, wordset)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Dictionaries are not supported by the LI recognizer";
return -1;
}
static int
li_recognizer_delete_from_dictionary(recognizer, letterset*, wordset)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Dictionaries are not supported by the LI recognizer";
return -1;
}
static char*
li_recognizer_error(recognizer rec)
{
char* ret = li_err_msg;
/*Check for LI recognizer.*/
if( !CHECK_LI_MAGIC(rec->recognizer_specific) ) {
li_err_msg = "Not a LI recognizer";
return nil;
}
li_err_msg = nil;
return ret;
}
static int
li_recognizer_clear(recognizer r, bool)
{
li_recognizer* rec;
rec = (li_recognizer*)r->recognizer_specific;
/*Check for LI recognizer.*/
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return 0;
}
return 0;
}
static int
li_recognizer_set_context(recognizer, rc*)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Contexts are not supported by the LI recognizer";
return -1;
}
static rc*
li_recognizer_get_context(recognizer)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Contexts are not supported by the LI recognizer";
return nil;
}
static int
li_recognizer_get_buffer(recognizer, uint*, Stroke**)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Buffer get/set are not supported by the LI recognizer";
return -1;
}
static int
li_recognizer_set_buffer(recognizer, uint, Stroke*)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Buffer get/set are not supported by the LI recognizer";
return -1;
}
static int
li_recognizer_translate(recognizer r, uint ncs, Stroke* tps, bool, int* nret, rec_alternative** ret)
{
char* clss;
li_recognizer* rec;
int conf;
rClassifier* rc;
rec = (li_recognizer*)r->recognizer_specific;
*nret = 0;
*ret = nil;
/*Check for LI recognizer.*/
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return(-1);
}
rc = &(rec->li_rc);
/*Check for valid parameters.*/
if (ncs < 1) {
li_err_msg = "Invalid parameters: ncs";
return(-1);
}
if( tps == nil) {
li_err_msg = "Invalid parameters: tps";
return(-1);
}
if( nret == nil) {
li_err_msg = "Invalid parameters: nret";
return(-1);
}
if( ret == nil) {
li_err_msg = "Invalid parameters: ret";
return(-1);
}
/*
* Go through the stroke array and recognize. Since this is a single
* stroke recognizer, each stroke is treated as a separate
* character or gesture. We allow only characters or gestures
* to be recognized at one time, since otherwise, handling
* the display of segmentation would be difficult.
*/
clss = recognize_internal(rc,tps,&conf);
if (clss == nil) {
*nret = 1;
return(0);
}
/*Return values.*/
*nret = 1;
return(*clss);
}
static rec_fn*
li_recognizer_get_extension_functions(recognizer rec)
{
rec_fn* ret;
/*Check for LI recognizer.*/
if( !CHECK_LI_MAGIC(rec->recognizer_specific) ) {
li_err_msg = "Not a LI recognizer";
return(nil);
}
ret = make_rec_fn_array(LI_NUM_EX_FNS);
/* ari -- clearState & getClasses are mine */
ret[LI_GET_CLASSES] = (rec_fn)recognizer_getClasses;
ret[LI_CLEAR] = (rec_fn)recognizer_clearState;
ret[LI_ISA_LI] = (rec_fn)isa_li;
ret[LI_TRAIN] = (rec_fn)recognizer_train;
return(ret);
}
static char**
li_recognizer_get_gesture_names(recognizer)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Gestures are not supported by the LI recognizer";
return nil;
}
static xgesture
li_recognizer_set_gesture_action(recognizer, char*, xgesture, void*)
{
/*This operation isn't supported by the LI recognizer.*/
li_err_msg = "Gestures are not supported by the LI recognizer";
return nil;
}
/*
* Exported Functions
*/
/*RECOGNIZER_INITIALIZE-Initialize the recognizer.*/
/* note from ari: this expands via pre-processor to
*
* recognizer __recognizer_internal_initialize(rec_info* ri)
*/
RECOGNIZER_INITIALIZE(ri)
{
recognizer r;
li_recognizer* rec;
int i;
/*Check that locale matches.*/
if( strcmp(ri->ri_locale,LI_SUPPORTED_LOCALE) != 0 ) {
li_err_msg = "Not a supported locale";
/* fprint(2, "Locale error.\n");*/
return(nil);
}
/*
* Check that character sets match. Note that this is only approximate,
* since the classifier file will have more information.
*/
if( ri->ri_subset != nil ) {
for(i = 0; ri->ri_subset[i] != nil; i++ ) {
if( strcmp(ri->ri_subset[i],UPPERCASE) != 0 &&
strcmp(ri->ri_subset[i],LOWERCASE) != 0 &&
strcmp(ri->ri_subset[i],DIGITS) != 0 &&
strcmp(ri->ri_subset[i],GESTURE) != 0 ) {
li_err_msg = "Not a supported character set";
/* fprint(2, "charset error.\n"); */
return(nil);
}
}
}
/* ari */
r = make_recognizer(ri);
/* fprint(2, "past make_recognizer.\n"); */
if( r == nil ) {
li_err_msg = "Can't allocate storage";
return(nil);
}
/*Make a LI recognizer structure.*/
/* rec = (li_recognizer*)safe_malloc(sizeof(li_recognizer))) == nil ); */
rec = malloc(sizeof(li_recognizer));
r->recognizer_specific = rec;
rec->li_rc.file_name = nil;
rec->li_rc.nclasses = 0;
/*Initialize the recognizer struct.*/
r->recognizer_load_state = li_recognizer_load;
r->recognizer_save_state = li_recognizer_save;
r->recognizer_load_dictionary = li_recognizer_load_dictionary;
r->recognizer_save_dictionary = li_recognizer_save_dictionary;
r->recognizer_free_dictionary = li_recognizer_free_dictionary;
r->recognizer_add_to_dictionary = li_recognizer_add_to_dictionary;
r->recognizer_delete_from_dictionary = li_recognizer_delete_from_dictionary;
r->recognizer_error = li_recognizer_error;
r->recognizer_translate = li_recognizer_translate;
r->recognizer_get_context = li_recognizer_get_context;
r->recognizer_set_context = li_recognizer_set_context;
r->recognizer_get_buffer = li_recognizer_get_buffer;
r->recognizer_set_buffer = li_recognizer_set_buffer;
r->recognizer_clear = li_recognizer_clear;
r->recognizer_get_extension_functions =
li_recognizer_get_extension_functions;
r->recognizer_get_gesture_names = li_recognizer_get_gesture_names;
r->recognizer_set_gesture_action =
li_recognizer_set_gesture_action;
/*Initialize LI Magic Number.*/
rec->li_magic = LI_MAGIC;
/*Initialize rClassifier.*/
rec->li_rc.file_name = nil;
for( i = 0; i < MAXSCLASSES; i++ ) {
rec->li_rc.ex[i] = nil;
rec->li_rc.cnames[i] = nil;
}
lialg_initialize(&rec->li_rc);
/*Get rid of error message. Not needed here.*/
li_err_msg = nil;
return(r);
}
/*free_rClassifier-Free the rClassifier.*/
static void
free_rClassifier(rClassifier* rc)
{
int i;
if( rc->file_name != nil) {
free(rc->file_name);
}
for( i = 0; rc->ex[i] != nil; i++) {
delete_examples(rc->ex[i]);
free(rc->cnames[i]);
}
}
/*RECOGNIZER_FINALIZE-Deallocate the recognizer, finalize.*/
RECOGNIZER_FINALIZE(r)
{
li_recognizer* rec = (li_recognizer*)r->recognizer_specific;
/*Make sure this is a li_recognizer first*/
if( !CHECK_LI_MAGIC(rec) ) {
li_err_msg = "Not a LI recognizer";
return(-1);
}
/*Deallocate rClassifier resources.*/
free_rClassifier(&(rec->li_rc));
/*Deallocate the li_recognizer struct.*/
free(rec);
/*Deallocate the recognizer*/
delete_recognizer(r);
return(0);
}
/* **************************************************
Implementation of the Li/Yeung recognition algorithm
************************************************** */
#define WORST_SCORE 0x7fffffff
/* Dynamic programming parameters */
#define DP_BAND 3
#define MIN_SIM 0
#define MAX_DIST 0x7fffffff
#define SIM_THLD 60 /* x 100 */
#define DIST_THLD 3200 /* x 100 */
/* Low-pass filter parameters -- empirically derived */
#define LP_FILTER_WIDTH 6
#define LP_FILTER_ITERS 8
#define LP_FILTER_THLD 250 /* x 100 */
#define LP_FILTER_MIN 5
/* Pseudo-extrema parameters -- empirically derived */
#define PE_AL_THLD 1500 /* x 100 */
#define PE_ATCR_THLD 135 /* x 100 */
/* Contour-angle derivation parameters */
#define T_ONE 1
#define T_TWO 20
/* Pre-processing and canonicalization parameters */
#define CANONICAL_X 108
#define CANONICAL_Y 128
#define DIST_SQ_THRESHOLD (3*3) /* copied from fv.h */
#define NCANONICAL 50
/* Tap-handling parameters */
#define TAP_CHAR "."
#define TAP_TIME_THLD 150 /* msec */
#define TAP_DIST_THLD 75 /* dx * dx + dy * dy */
#define TAP_PATHLEN 1000 /* x 100 */
/* region types */
#define RGN_CONVEX 0
#define RGN_CONCAVE 1
#define RGN_PLAIN 2
#define RGN_PSEUDO 3
typedef struct RegionList {
int start;
int end;
int type;
struct RegionList *next;
} region_list;
/* direction-code table; indexed by dx, dy */
static int lialg_dctbl[3][3] = {{1, 0, 7}, {2, 0x7FFFFFFF, 6}, {3, 4, 5}};
/* low-pass filter weights */
static int lialg_lpfwts[2 * LP_FILTER_WIDTH + 1];
static int lialg_lpfconst = -1;
static int lialg_preprocess_stroke(point_list *);
static point_list *lialg_compute_dominant_points(point_list *);
static point_list *lialg_interpolate_points(point_list *);
static void lialg_bresline(pen_point *, pen_point *, point_list *, int *);
static void lialg_compute_chain_code(point_list *);
static void lialg_compute_unit_chain_code(point_list *);
static region_list *lialg_compute_regions(point_list *);
static point_list *lialg_compute_dompts(point_list *, region_list *);
static int *lialg_compute_contour_angle_set(point_list *, region_list *);
static void lialg_score_stroke(point_list *, point_list *, int *, int *);
static int lialg_compute_similarity(point_list *, point_list *);
static int lialg_compute_distance(point_list *, point_list *);
static int lialg_read_classifier_digest(rClassifier *);
static int lialg_canonicalize_examples(rClassifier *);
static int lialg_canonicalize_example_stroke(point_list *);
static int lialg_compute_equipoints(point_list *);
static int lialg_compute_pathlen(point_list *);
static int lialg_compute_pathlen_subset(point_list *, int, int);
static int lialg_filter_points(point_list *);
static int lialg_translate_points(point_list *, int, int, int, int);
static void lialg_get_bounding_box(point_list *, int *, int *, int *, int *);
static void lialg_compute_lpf_parameters();
static int isqrt(int);
static int likeatan(int, int);
static int quadr(int);
/*************************************************************
Core routines for the Li/Yeung recognition algorithm
*************************************************************/
static void lialg_initialize(rClassifier *rec) {
int i;
/* Initialize the dompts arrays. */
for (i = 0; i < MAXSCLASSES; i++) {
rec->dompts[i] = nil;
}
}
/*
* Main recognition routine -- called by HRE API.
*/
static char *lialg_recognize_stroke(rClassifier *rec, point_list *stroke) {
int i;
char *name = nil;
point_list *input_dompts = nil;
char *best_name = nil;
int best_score = WORST_SCORE;
char *curr_name;
point_list *curr_dompts;
/* (void)gettimeofday(&stv, nil);*/
if (stroke->npts < 1) goto done;
/* Check for tap. */
/* First thing is to filter out ``close points.'' */
if (lialg_filter_points(stroke) != 0) return(nil);
/* Unfortunately, we don't have the actual time that each point */
/* was recorded (i.e., dt is invalid). Hence, we have to use a */
/* heuristic based on total distance and the number of points. */
if (stroke->npts == 1 || lialg_compute_pathlen(stroke) < TAP_PATHLEN)
return(TAP_CHAR);
/* Pre-process input stroke. */
if (lialg_preprocess_stroke(stroke) != 0) goto done;
/* Compute its dominant points. */
input_dompts = lialg_compute_dominant_points(stroke);
if (input_dompts == nil) goto done;
/* Score input stroke against every class in classifier. */
for (i = 0, curr_name = rec->cnames[i], curr_dompts = rec->dompts[i];
i < MAXSCLASSES && curr_name != nil && curr_dompts != nil;
i++, curr_name = rec->cnames[i], curr_dompts = rec->dompts[i]) {
int sim;
int dist;
int curr_score;
lialg_score_stroke(input_dompts, curr_dompts, &sim, &dist);
curr_score = dist;
if (lidebug && curr_score < DIST_THLD)
fprint(2, "(%s, %d, %d) ", curr_name, sim, dist);
/* Is it the best so far? */
if (curr_score < best_score && curr_score <= DIST_THLD) {
best_score = curr_score;
best_name = curr_name;
}
}
if (lidebug)
fprint(2, "\n");
/* No errors. */
name = best_name;
done:
delete_examples(input_dompts);
return(name);
}
static int lialg_preprocess_stroke(point_list *points) {
int minx, miny, maxx, maxy, xrange, yrange, scale, xoff, yoff;
/* Filter out points that are too close. */
/* We did this earlier, when we checked for a tap. */
/*
if (lialg_filter_points(points) != 0) return(-1);
*/
/* assert(points->npts > 0);*/
/* Scale up to avoid conversion errors. */
lialg_get_bounding_box(points, &minx, &miny, &maxx, &maxy);
xrange = maxx - minx;
yrange = maxy - miny;
scale = ( ((100 * xrange + CANONICAL_X / 2) / CANONICAL_X) >
((100 * yrange + CANONICAL_Y / 2) / CANONICAL_Y))
? (100 * CANONICAL_X + xrange / 2) / xrange
: (100 * CANONICAL_Y + yrange / 2) / yrange;
if (lialg_translate_points(points, minx, miny, scale, scale) != 0)
return(-1);
/* Center the stroke. */
lialg_get_bounding_box(points, &minx, &miny, &maxx, &maxy);
xrange = maxx - minx;
yrange = maxy - miny;
xoff = -((CANONICAL_X - xrange + 1) / 2);
yoff = -((CANONICAL_Y - yrange + 1) / 2);
if (lialg_translate_points(points, xoff, yoff, 100, 100) != 0) return(-1);
/* Store the x and y ranges in the point list. */
xrange = maxx - minx;
yrange = maxy - miny;
points->xrange = xrange;
points->yrange = yrange;
if (lidebug) {
int i;
fprint(2, "After pre-processing: %d %d %d %d\n",
minx, miny, maxx, maxy);
for (i = 0; i < points->npts; i++)
fprint(2, " (%P)\n", points->pts[i].Point);
fflush(stderr);
}
return(0);
}
static point_list *lialg_compute_dominant_points(point_list *points) {
point_list *ipts;
region_list *regions;
point_list *dpts;
/* Interpolate points. */
ipts = lialg_interpolate_points(points);
if (ipts == nil) return(nil);
if (lidebug) {
int j;
fprint(2, "After interpolation: %d ipts\n", ipts->npts);
for (j = 0; j < ipts->npts; j++) {
fprint(2, " (%P), %lud\n", ipts->pts[j].Point, ipts->pts[j].chaincode);
}
fflush(stderr);
}
/* Compute regions. */
regions = lialg_compute_regions(ipts);
/* assert(regions != nil);*/
/* Compute dominant points. */
dpts = lialg_compute_dompts(ipts, regions);
if (lidebug) {
int j;
fprint(2, "Dominant points: ");
for (j = 0; j < dpts->npts; j++) {
fprint(2, "%P (%lud) ", dpts->pts[j].Point, dpts->pts[j].chaincode);
}
fprint(2, "\n");
fflush(stderr);
}
/* Delete region data structure. */
{
region_list *curr, *next;
for (curr = regions; curr != nil; ) {
next = curr->next;
free(curr);
curr = next;
}
}
delete_examples(ipts);
return(dpts);
}
/* Input points are assumed to be integer-valued! */
static point_list *lialg_interpolate_points(point_list *points) {
int i, j;
int maxpts;
point_list *newpts;
/* Compute an upper-bound on the number of interpolated points. */
maxpts = 0;
for (i = 0; i < (points->npts - 1); i++) {
pen_point *pta = &(points->pts[i]);
pen_point *ptb = &(points->pts[i+1]);
maxpts += abs(pta->x - ptb->x) + abs(pta->y - ptb->y);
}
/* Allocate an array of the requisite size. */
maxpts += points->npts;
/* newpts = (point_list *)safe_malloc(sizeof(point_list)); */
newpts = malloc(sizeof(point_list));
newpts->pts = mallocz(maxpts*sizeof(pen_point), 1);
if (newpts->pts == nil) {
free(newpts);
return(nil);
}
newpts->npts = maxpts;
newpts->next = nil;
/* Interpolate each of the segments. */
j = 0;
for (i = 0; i < (points->npts - 1); i++) {
pen_point *startpt = &(points->pts[i]);
pen_point *endpt = &(points->pts[i+1]);
lialg_bresline(startpt, endpt, newpts, &j);
j--; /* end point gets recorded as start point of next segment! */
}
/* Add-in last point. */
newpts->pts[j++] = points->pts[points->npts - 1];
newpts->npts = j;
/* Compute the chain code for P (the list of points). */
lialg_compute_unit_chain_code(newpts);
return(newpts);
}
/* This implementation is due to Kenny Hoff. */
static void lialg_bresline(pen_point *startpt, pen_point *endpt,
point_list *newpts, int *j) {
int Ax, Ay, Bx, By, dX, dY, Xincr, Yincr;
Ax = startpt->x;
Ay = startpt->y;
Bx = endpt->x;
By = endpt->y;
/* INITIALIZE THE COMPONENTS OF THE ALGORITHM THAT ARE NOT AFFECTED */
/* BY THE SLOPE OR DIRECTION OF THE LINE */
dX = abs(Bx-Ax); /* store the change in X and Y of the line endpoints */
dY = abs(By-Ay);
/* DETERMINE "DIRECTIONS" TO INCREMENT X AND Y (REGARDLESS OF DECISION) */
if (Ax > Bx) { Xincr=-1; } else { Xincr=1; } /* which direction in X? */
if (Ay > By) { Yincr=-1; } else { Yincr=1; } /* which direction in Y? */
/* DETERMINE INDEPENDENT VARIABLE (ONE THAT ALWAYS INCREMENTS BY 1 (OR -1) ) */
/* AND INITIATE APPROPRIATE LINE DRAWING ROUTINE (BASED ON FIRST OCTANT */
/* ALWAYS). THE X AND Y'S MAY BE FLIPPED IF Y IS THE INDEPENDENT VARIABLE. */
if (dX >= dY) { /* if X is the independent variable */
int dPr = dY<<1; /* amount to increment decision if right is chosen (always) */
int dPru = dPr - (dX<<1); /* amount to increment decision if up is chosen */
int P = dPr - dX; /* decision variable start value */
/* process each point in the line one at a time (just use dX) */
for (; dX>=0; dX--) {
newpts->pts[*j].x = Ax;
newpts->pts[*j].y = Ay;
(*j)++;
if (P > 0) { /* is the pixel going right AND up? */
Ax+=Xincr; /* increment independent variable */
Ay+=Yincr; /* increment dependent variable */
P+=dPru; /* increment decision (for up) */
} else { /* is the pixel just going right? */
Ax+=Xincr; /* increment independent variable */
P+=dPr; /* increment decision (for right) */
}
}
} else { /* if Y is the independent variable */
int dPr = dX<<1; /* amount to increment decision if right is chosen (always) */
int dPru = dPr - (dY<<1); /* amount to increment decision if up is chosen */
int P = dPr - dY; /* decision variable start value */
/* process each point in the line one at a time (just use dY) */
for (; dY>=0; dY--) {
newpts->pts[*j].x = Ax;
newpts->pts[*j].y = Ay;
(*j)++;
if (P > 0) { /* is the pixel going up AND right? */
Ax+=Xincr; /* increment dependent variable */
Ay+=Yincr; /* increment independent variable */
P+=dPru; /* increment decision (for up) */
} else { /* is the pixel just going up? */
Ay+=Yincr; /* increment independent variable */
P+=dPr; /* increment decision (for right) */
}
}
}
}
static void lialg_compute_chain_code(point_list *pts) {
int i;
for (i = 0; i < (pts->npts - 1); i++) {
pen_point *startpt = &(pts->pts[i]);
pen_point *endpt = &(pts->pts[i+1]);
int dx = endpt->x - startpt->x;
int dy = endpt->y - startpt->y;
int tmp = quadr(likeatan(dy, dx));
int dircode = (12 - tmp) % 8;
startpt->chaincode = dircode;
}
}
static void lialg_compute_unit_chain_code(point_list *pts) {
int i;
for (i = 0; i < (pts->npts - 1); i++) {
pen_point *startpt = &(pts->pts[i]);
pen_point *endpt = &(pts->pts[i+1]);
int dx = endpt->x - startpt->x;
int dy = endpt->y - startpt->y;
int dircode = lialg_dctbl[dx+1][dy+1];
startpt->chaincode = dircode;
}
}
static region_list *lialg_compute_regions(point_list *pts) {
region_list *regions;
region_list *curr_reg;
int *R[2 + LP_FILTER_ITERS];
int *junk;
int *curr, *next;
int i, j;
/* Initialize low-pass filter parameters if necessary. */
if (lialg_lpfconst == -1)
lialg_compute_lpf_parameters();
/* Allocate a 2 x pts->npts array for use in computing the (filtered) Angle set, A_n. */
junk = malloc((2 + LP_FILTER_ITERS) * pts->npts*sizeof(int));
for (i = 0; i < (2 + LP_FILTER_ITERS); i++)
R[i] = junk + (i * pts->npts);
curr = R[0];
/* Compute the Angle set, A, in the first element of array R. */
/* Values in R are in degrees, x 100. */
curr[0] = 18000; /* a_0 */
for (i = 1; i < (pts->npts - 1); i++) {
int d_i = pts->pts[i].chaincode;
int d_iminusone = pts->pts[i-1].chaincode;
int a_i;
if (d_iminusone < d_i)
d_iminusone += 8;
a_i = (d_iminusone - d_i) % 8;
/* convert to degrees, x 100 */
curr[i] = ((12 - a_i) % 8) * 45 * 100;
}
curr[pts->npts - 1] = 18000; /* a_L-1 */
/* Perform a number of filtering iterations. */
next = R[1];
for (j = 0; j < LP_FILTER_ITERS; j++, curr = R[j], next = R[j+1]) {
for (i = 0; i < pts->npts; i++) {
int k;
next[i] = 0;
for (k = i - LP_FILTER_WIDTH; k <= i + LP_FILTER_WIDTH; k++) {
int oldval = (k < 0 || k >= pts->npts) ? 18000 : curr[k];
next[i] += oldval * lialg_lpfwts[k - (i - LP_FILTER_WIDTH)]; /* overflow? */
}
next[i] /= lialg_lpfconst;
}
}
/* Do final thresholding around PI. */
/* curr and next are set-up correctly at end of previous loop! */
for (i = 0; i < pts->npts; i++)
next[i] = (abs(curr[i] - 18000) < LP_FILTER_THLD) ? 18000 : curr[i];
curr = next;
/* Debugging. */
if (lidebug > 1) {
for (i = 0; i < pts->npts; i++) {
fprint(2, "%3d: (%P) %lud ",
i, pts->pts[i].Point, pts->pts[i].chaincode);
for (j = 0; j < 2 + LP_FILTER_ITERS; j++)
fprint(2, "%d ", R[j][i]);
fprint(2, "\n");
}
}
/* Do the region segmentation. */
{
int start, end;
int currtype;
#define RGN_TYPE(val) (((val)==18000)?RGN_PLAIN:((val)<18000?RGN_CONCAVE:RGN_CONVEX))
start = 0;
currtype = RGN_TYPE(curr[0]);
regions = malloc(sizeof(region_list));
curr_reg = regions;
curr_reg->start = start;
curr_reg->end = 0;
curr_reg->type = currtype;
curr_reg->next = nil;
for (i = 1; i < pts->npts; i++) {
int nexttype = RGN_TYPE(curr[i]);
if (nexttype != currtype) {
region_list *next_reg;
end = i - 1;
curr_reg->end = end;
if (lidebug > 1)
fprint(2, " (%d, %d), %d\n", start, end, currtype);
start = i;
currtype = nexttype;
next_reg = malloc(sizeof(region_list));
next_reg->start = start;
next_reg->end = 0;
next_reg->type = nexttype;
next_reg->next = nil;
curr_reg->next = next_reg;
curr_reg = next_reg;
}
}
end = i - 1;
curr_reg->end = end;
if (lidebug > 1)
fprint(2, " (%d, %d), %d\n", start, end, currtype);
/* Filter out convex/concave regions that are too short. */
for (curr_reg = regions; curr_reg; curr_reg = curr_reg->next)
if (curr_reg->type == RGN_PLAIN) {
region_list *next_reg;
for (next_reg = curr_reg->next;
next_reg != nil &&
(next_reg->end - next_reg->start) < LP_FILTER_MIN;
next_reg = curr_reg->next) {
/* next_reg must not be plain, and it must be followed by a plain */
/* assert(next_reg->type != RGN_PLAIN); */
/* assert(next_reg->next != nil && (next_reg->next)->type == RGN_PLAIN); */
curr_reg->next = (next_reg->next)->next;
curr_reg->end = (next_reg->next)->end;
free(next_reg->next);
free(next_reg);
}
}
/* Add-in pseudo-extremes. */
{
region_list *tmp, *prev_reg;
tmp = regions;
regions = nil;
prev_reg = nil;
for (curr_reg = tmp; curr_reg; curr_reg = curr_reg->next) {
if (curr_reg->type == RGN_PLAIN) {
int arclen = lialg_compute_pathlen_subset(pts,
curr_reg->start,
curr_reg->end);
int dx = pts->pts[curr_reg->end].x -
pts->pts[curr_reg->start].x;
int dy = pts->pts[curr_reg->end].y -
pts->pts[curr_reg->start].y;
int chordlen = isqrt(10000 * (dx * dx + dy * dy));
int atcr = (chordlen == 0) ? 0 : (100 * arclen + chordlen / 2) / chordlen;
if (lidebug)
fprint(2, "%d, %d, %d\n", arclen, chordlen, atcr);
/* Split region if necessary. */
if (arclen >= PE_AL_THLD && atcr >= PE_ATCR_THLD) {
int mid = curr_reg->start + (curr_reg->end - curr_reg->start) / 2;
int end = curr_reg->end;
region_list *saved_next = curr_reg->next;
curr_reg->end = mid - 1;
if (prev_reg == nil)
regions = curr_reg;
else
prev_reg->next = curr_reg;
prev_reg = curr_reg;
/* curr_reg = (region_list *)safe_malloc(sizeof(region_list));*/
curr_reg = malloc(sizeof(region_list));
curr_reg->start = mid;
curr_reg->end = mid;
curr_reg->type = RGN_PSEUDO;
curr_reg->next = nil;
prev_reg->next = curr_reg;
prev_reg = curr_reg;
/* curr_reg = (region_list *)malloc(sizeof(region_list)); */
curr_reg = malloc(sizeof(region_list));
curr_reg->start = mid + 1;
curr_reg->end = end;
curr_reg->type = RGN_PLAIN;
curr_reg->next = nil;
prev_reg->next = curr_reg;
prev_reg = curr_reg;
curr_reg->next = saved_next;
continue;
}
}
if (prev_reg == nil)
regions = curr_reg;
else
prev_reg->next = curr_reg;
prev_reg = curr_reg;
}
}
}
free(junk);
return(regions);
}
static point_list *lialg_compute_dompts(point_list *pts, region_list *regions) {
point_list *dpts;
int ndpts;
int *cas;
int nonplain;
region_list *r;
region_list *curr;
int dp;
int previx;
int currix;
/* Compute contour angle set. */
cas = lialg_compute_contour_angle_set(pts, regions);
/* Dominant points include: start_pt, end_pt, extrema_of_non_plain_regions, midpts of the preceding. */
nonplain = 0;
for (r = regions; r != nil; r = r->next)
if (r->type != RGN_PLAIN)
nonplain++;
ndpts = 2 * (2 + nonplain) - 1;
/* dpts = (point_list *)safe_malloc(sizeof(point_list)); */
dpts = malloc(sizeof(point_list));
dpts->pts = mallocz(ndpts*sizeof(pen_point), 1);
if (dpts->pts == nil) {
free(dpts);
return(nil);
}
dpts->npts = ndpts;
dpts->next = nil;
/* Pick out dominant points. */
/* Record start point. */
dp = 0;
previx = 0;
dpts->pts[dp++] = pts->pts[previx];
for (curr = regions; curr != nil; curr = curr->next)
if (curr->type != RGN_PLAIN) {
int max_v = 0;
int min_v = 0x7fffffff; /* maxint */
int max_ix = -1;
int min_ix = -1;
int i;
for (i = curr->start; i <= curr->end; i++) {
int v = cas[i];
if (v > max_v) { max_v = v; max_ix = i; }
if (v < min_v) { min_v = v; min_ix = i; }
if (lidebug > 1)
fprint(2, " %d\n", v);
}
currix = (curr->type == RGN_CONVEX ? max_ix : min_ix);
/* Record midpoint. */
dpts->pts[dp++] = pts->pts[previx + (currix - previx) / 2];
/* Record extreme point. */
dpts->pts[dp++] = pts->pts[currix];
previx = currix;
}
/* Record last mid-point and end point. */
currix = pts->npts - 1;
dpts->pts[dp++] = pts->pts[previx + (currix - previx) / 2];
dpts->pts[dp] = pts->pts[currix];
/* Compute chain-code. */
lialg_compute_chain_code(dpts);
free(cas);
return(dpts);
}
static int *lialg_compute_contour_angle_set(point_list *pts,
region_list *regions) {
int *V;
region_list *curr_reg;
int i;
V = malloc(pts->npts*sizeof(int));
V[0] = 18000;
for (curr_reg = regions; curr_reg != nil; curr_reg = curr_reg->next) {
for (i = curr_reg->start; i <= curr_reg->end; i++) {
if (curr_reg->type == RGN_PLAIN) {
V[i] = 18000;
} else {
/* For now, simply choose the mid-point. */
int isMidPt = i == (curr_reg->start +
(curr_reg->end - curr_reg->start) / 2);
V[i] = (curr_reg->type == RGN_CONVEX)
? (isMidPt ? 18000 : 0)
: (isMidPt ? 0 : 18000);
}
}
}
V[pts->npts - 1] = 18000;
return(V);
}
/*
* First compute the similarity between the two strings.
* If it's above a threshold, compute the distance between
* the two and return it as the ``score.''
* Otherwise, return the constant WORST_SCORE.
*
*/
static void lialg_score_stroke(point_list *input_dompts, point_list *curr_dompts, int *sim, int *dist) {
*sim = MIN_SIM;
*dist = MAX_DIST;
*sim = lialg_compute_similarity(input_dompts, curr_dompts);
if (*sim < SIM_THLD) goto done;
*dist = lialg_compute_distance(input_dompts, curr_dompts);
done:
if (lidebug)
fprint(2, "%d, %d\n", *sim, *dist);
}
static int lialg_compute_similarity(point_list *input_dompts, point_list *curr_dompts) {
int sim;
point_list *A, *B;
int N, M;
int **G;
int *junk;
int i, j;
/* A is the longer sequence, length N. */
/* B is the shorter sequence, length M. */
if (input_dompts->npts >= curr_dompts->npts) {
A = input_dompts;
N = input_dompts->npts;
B = curr_dompts;
M = curr_dompts->npts;
} else {
A = curr_dompts;
N = curr_dompts->npts;
B = input_dompts;
M = input_dompts->npts;
}
/* Allocate and initialize the Gain matrix, G. */
/* The size of G is M x (N + 1). */
/* Note that row 0 is unused. */
/* Similarities are x 10. */
G = malloc(M*sizeof(int *));
junk = malloc(M * (N + 1) * sizeof(int));
for (i = 0; i < M; i++)
G[i] = junk + (i * (N + 1));
for (i = 1; i < M; i++) {
int bval = B->pts[i-1].chaincode;
/* Source column. */
G[i][0] = 0;
for (j = 1; j < N; j++) {
int aval = A->pts[j-1].chaincode;
int diff = abs(bval - aval);
if (diff > 4) diff = 8 - diff;
G[i][j] = (diff == 0)
? 10
: (diff == 1)
? 6
: 0;
}
/* Sink column. */
G[i][N] = 0;
}
/* Do the DP algorithm. */
/* Proceed in column order, from highest column to the lowest. */
/* Within each column, proceed from the highest row to the lowest. */
/* Skip the highest column. */
for (j = N - 1; j >= 0; j--)
for (i = M - 1; i > 0; i--) {
int max = G[i][j + 1];
if (i < (M - 1)) {
int tmp = G[i + 1][j + 1];
if (tmp > max) max = tmp;
}
G[i][j] += max;
}
sim = (10 * G[1][0] + (N - 1) / 2) / (N - 1);
if (G != nil)
free(G);
if (junk != nil)
free(junk);
return(sim);
}
static int lialg_compute_distance(point_list *input_dompts,
point_list *curr_dompts) {
int dist;
point_list *A, *B;
int N, M;
int **C;
int *junk;
int *BE;
int *TE;
int i, j;
/* A is the longer sequence, length N. */
/* B is the shorter sequence, length M. */
if (input_dompts->npts >= curr_dompts->npts) {
A = input_dompts;
N = input_dompts->npts;
B = curr_dompts;
M = curr_dompts->npts;
}
else {
A = curr_dompts;
N = curr_dompts->npts;
B = input_dompts;
M = input_dompts->npts;
}
/* Construct the helper vectors, BE and TE, which say for each column */
/* what are the ``bottom'' and ``top'' rows of interest. */
BE = malloc((N + 1)*sizeof(int));
TE = malloc((N + 1)*sizeof(int));
for (j = 1; j <= N; j++) {
int bot, top;
bot = j + (M - DP_BAND);
if (bot > M) bot = M;
BE[j] = bot;
top = j - (N - DP_BAND);
if (top < 1) top = 1;
TE[j] = top;
}
/* Allocate and initialize the Cost matrix, C. */
/* The size of C is (M + 1) x (N + 1). */
/* Note that row and column 0 are unused. */
/* Costs are x 100. */
/* C = (int **)safe_malloc((M + 1) * sizeof(int *)); */
C = malloc((M + 1)*sizeof( int *));
junk = malloc((M + 1) * (N + 1)*sizeof(int));
for (i = 0; i <= M; i++)
C[i] = junk + (i * (N + 1));
for (i = 1; i <= M; i++) {
int bx = B->pts[i-1].x;
int by = B->pts[i-1].y;
for (j = 1; j <= N; j++) {
int ax = A->pts[j-1].x;
int ay = A->pts[j-1].y;
int dx = bx - ax;
int dy = by - ay;
int dist = isqrt(10000 * (dx * dx + dy * dy));
C[i][j] = dist;
}
}
/* Do the DP algorithm. */
/* Proceed in column order, from highest column to the lowest. */
/* Within each column, proceed from the highest row to the lowest. */
for (j = N; j > 0; j--)
for (i = M; i > 0; i--) {
int min = MAX_DIST;
if (i > BE[j] || i < TE[j] || (j == N && i == M))
continue;
if (j < N) {
if (i >= TE[j+1]) {
int tmp = C[i][j+1];
if (tmp < min)
min = tmp;
}
if (i < M) {
int tmp = C[i+1][j+1];
if (tmp < min)
min = tmp;
}
}
if (i < BE[j]) {
int tmp = C[i+1][j];
if (tmp < min) min = tmp;
}
C[i][j] += min;
}
dist = (C[1][1] + N / 2) / N;
if (C != nil) free(C);
if (junk != nil) free(junk);
if (BE != nil) free(BE);
if (TE != nil) free(TE);
return(dist);
}
/*************************************************************
Digest-processing routines
*************************************************************/
static int lialg_read_classifier_digest(rClassifier *rec) {
int nclasses;
FILE *fp;
/* Try to open the corresponding digest file. */
{
char *clx_path;
char *dot;
/* Get a copy of the filename, with some room on the end. */
/* clx_path = safe_malloc(strlen(rec->file_name) + 5); */
clx_path = malloc((strlen(rec->file_name) + 5) *sizeof(char));
strcpy(clx_path, rec->file_name);
/* Truncate the path after the last dot. */
dot = strrchr(clx_path, '.');
if (dot == nil) { free(clx_path); return(-1); }
*(dot + 1) = 0;
/* Append the classifier-digest extension. */
strcat(clx_path, "clx");
fp = fopen(clx_path, "r");
if (fp == nil) {
free(clx_path);
return(-1);
}
free(clx_path);
}
/* Read-in the name and dominant points for each class. */
for (nclasses = 0; !feof(fp); nclasses++) {
point_list *dpts = nil;
char class[BUFSIZ];
int npts;
int j;
if (fscanf(fp, "%s %d", class, &npts) != 2) {
if (feof(fp)) break;
goto failed;
}
rec->cnames[nclasses] = strdup(class);
/* Allocate a dominant-points list. */
/* dpts = (point_list *)safe_malloc(sizeof(point_list)); */
dpts = malloc(sizeof(point_list));
dpts->pts = mallocz(npts*sizeof(pen_point), 1);
if (dpts->pts == nil) goto failed;
dpts->npts = npts;
dpts->next = nil;
/* Read in each point. */
for (j = 0; j < npts; j++) {
int x, y;
if (fscanf(fp, "%d %d", &x, &y) != 2) goto failed;
dpts->pts[j].x = x;
dpts->pts[j].y = y;
}
/* Compute the chain-code. */
lialg_compute_chain_code(dpts);
/* Store the list in the rec data structure. */
rec->dompts[nclasses] = dpts;
continue;
failed:
fprint(2, "read_classifier_digest failed...\n");
for (; nclasses >= 0; nclasses--) {
if (rec->cnames[nclasses] != nil) {
free(rec->cnames[nclasses]);
rec->cnames[nclasses] = nil;
}
if (rec->dompts[nclasses] != nil) {
delete_examples(rec->dompts[nclasses]);
rec->dompts[nclasses] = nil;
}
}
if (dpts != nil)
delete_examples(dpts);
fclose(fp);
return(-1);
}
fclose(fp);
return(0);
}
/*************************************************************
Canonicalization routines
*************************************************************/
static int lialg_canonicalize_examples(rClassifier *rec) {
int i;
int nclasses;
if (lidebug) {
fprint(2, "lialg_canonicalize_examples working on %s\n",
rec->file_name);
}
/* Initialize canonical-example arrays. */
for (i = 0; i < MAXSCLASSES; i++) {
rec->canonex[i] = nil;
}
/* Figure out number of classes. */
for (nclasses = 0;
nclasses < MAXSCLASSES && rec->cnames[nclasses] != nil;
nclasses++)
;
/* Canonicalize the examples for each class. */
for (i = 0; i < nclasses; i++) {
int j, k;
int nex;
point_list *pts, *tmp, *avg;
int maxxrange, maxyrange;
int minx, miny, maxx, maxy;
int avgxrange, avgyrange, avgxoff, avgyoff, avgscale;
if (lidebug) {
fprint(2, "lialg_canonicalize_examples working on class %s\n",
rec->cnames[i]);
}
/* Make a copy of the examples. */
pts = nil;
tmp = rec->ex[i];
for (nex = 0; tmp != nil; nex++, tmp = tmp->next) {
if ((pts = add_example(pts, tmp->npts, tmp->pts)) == nil) {
delete_examples(pts);
return(-1);
}
}
/* Canonicalize each example, and derive the max x and y ranges. */
maxxrange = 0;
maxyrange = 0;
for (j = 0, tmp = pts; j < nex; j++, tmp = tmp->next) {
if (lialg_canonicalize_example_stroke(tmp) != 0) {
if (lidebug) {
fprint(2, "lialg_canonicalize_example_stroke returned error\n");
}
return(-1);
}
if (tmp->xrange > maxxrange) maxxrange = tmp->xrange;
if (tmp->yrange > maxyrange) maxyrange = tmp->yrange;
}
/* Normalize max ranges. */
if (((100 * maxxrange + CANONICAL_X / 2) / CANONICAL_X) >
((100 * maxyrange + CANONICAL_Y / 2) / CANONICAL_Y)) {
maxyrange = (maxyrange * CANONICAL_X + maxxrange / 2) / maxxrange;
maxxrange = CANONICAL_X;
}
else {
maxxrange = (maxxrange * CANONICAL_Y + maxyrange / 2) / maxyrange;
maxyrange = CANONICAL_Y;
}
/* Re-scale each example to max ranges. */
for (j = 0, tmp = pts; j < nex; j++, tmp = tmp->next) {
int scalex = (tmp->xrange == 0) ? 100 : (100 * maxxrange + tmp->xrange / 2) / tmp->xrange;
int scaley = (tmp->yrange == 0) ? 100 : (100 * maxyrange + tmp->yrange / 2) / tmp->yrange;
if (lialg_translate_points(tmp, 0, 0, scalex, scaley) != 0) {
delete_examples(pts);
return(-1);
}
}
/* Average the examples; leave average in first example. */
avg = pts; /* careful aliasing!! */
for (k = 0; k < NCANONICAL; k++) {
int xsum = 0;
int ysum = 0;
for (j = 0, tmp = pts; j < nex; j++, tmp = tmp->next) {
xsum += tmp->pts[k].x;
ysum += tmp->pts[k].y;
}
avg->pts[k].x = (xsum + j / 2) / j;
avg->pts[k].y = (ysum + j / 2) / j;
}
/* Compute BB of averaged stroke and re-scale. */
lialg_get_bounding_box(avg, &minx, &miny, &maxx, &maxy);
avgxrange = maxx - minx;
avgyrange = maxy - miny;
avgscale = (((100 * avgxrange + CANONICAL_X / 2) / CANONICAL_X) >
((100 * avgyrange + CANONICAL_Y / 2) / CANONICAL_Y))
? (100 * CANONICAL_X + avgxrange / 2) / avgxrange
: (100 * CANONICAL_Y + avgyrange / 2) / avgyrange;
if (lialg_translate_points(avg, minx, miny, avgscale, avgscale) != 0) {
delete_examples(pts);
return(-1);
}
/* Re-compute the x and y ranges and center the stroke. */
lialg_get_bounding_box(avg, &minx, &miny, &maxx, &maxy);
avgxrange = maxx - minx;
avgyrange = maxy - miny;
avgxoff = -((CANONICAL_X - avgxrange + 1) / 2);
avgyoff = -((CANONICAL_Y - avgyrange + 1) / 2);
if (lialg_translate_points(avg, avgxoff, avgyoff, 100, 100) != 0) {
delete_examples(pts);
return(-1);
}
/* Create a point list to serve as the ``canonical representation. */
if ((rec->canonex[i] = add_example(nil, avg->npts, avg->pts)) == nil) {
delete_examples(pts);
return(-1);
}
(rec->canonex[i])->xrange = maxx - minx;
(rec->canonex[i])->yrange = maxy - miny;
if (lidebug) {
fprint(2, "%s, avgpts = %d\n", rec->cnames[i], avg->npts);
for (j = 0; j < avg->npts; j++) {
fprint(2, " (%P)\n", avg->pts[j].Point);
}
}
/* Compute dominant points of canonical representation. */
rec->dompts[i] = lialg_compute_dominant_points(avg);
/* Clean up. */
delete_examples(pts);
}
/* Sanity check. */
for (i = 0; i < nclasses; i++) {
char *best_name = lialg_recognize_stroke(rec, rec->canonex[i]);
if (best_name != rec->cnames[i])
fprint(2, "%s, best = %s\n", rec->cnames[i], best_name);
}
return(0);
}
static int lialg_canonicalize_example_stroke(point_list *points) {
int minx, miny, maxx, maxy, xrange, yrange, scale;
/* Filter out points that are too close. */
if (lialg_filter_points(points) != 0) return(-1);
/* Must be at least two points! */
if (points->npts < 2) {
if (lidebug) {
fprint(2, "lialg_canonicalize_example_stroke: npts=%d\n",
points->npts);
}
return(-1);
}
/* Scale up to avoid conversion errors. */
lialg_get_bounding_box(points, &minx, &miny, &maxx, &maxy);
xrange = maxx - minx;
yrange = maxy - miny;
scale = (((100 * xrange + CANONICAL_X / 2) / CANONICAL_X) >
((100 * yrange + CANONICAL_Y / 2) / CANONICAL_Y))
? (100 * CANONICAL_X + xrange / 2) / xrange
: (100 * CANONICAL_Y + yrange / 2) / yrange;
if (lialg_translate_points(points, minx, miny, scale, scale) != 0) {
if (lidebug) {
fprint(2, "lialg_translate_points (minx=%d,miny=%d,scale=%d) returned error\n", minx, miny, scale);
}
return(-1);
}
/* Compute an equivalent stroke with equi-distant points. */
if (lialg_compute_equipoints(points) != 0) return(-1);
/* Re-translate the points to the origin. */
lialg_get_bounding_box(points, &minx, &miny, &maxx, &maxy);
if (lialg_translate_points(points, minx, miny, 100, 100) != 0) {
if (lidebug) {
fprint(2, "lialg_translate_points (minx=%d,miny=%d) returned error\n", minx, miny);
}
return(-1);
}
/* Store the x and y ranges in the point list. */
xrange = maxx - minx;
yrange = maxy - miny;
points->xrange = xrange;
points->yrange = yrange;
if (lidebug) {
int i;
fprint(2, "Canonicalized: %d, %d, %d, %d\n", minx, miny, maxx, maxy);
for (i = 0; i < points->npts; i++)
fprint(2, " (%P)\n", points->pts[i].Point);
fflush(stderr);
}
return(0);
}
static int lialg_compute_equipoints(point_list *points) {
pen_point *equipoints = mallocz(NCANONICAL*sizeof(pen_point), 1);
int nequipoints = 0;
int pathlen = lialg_compute_pathlen(points);
int equidist = (pathlen + (NCANONICAL - 1) / 2) / (NCANONICAL - 1);
int i;
int dist_since_last_eqpt;
int remaining_seglen;
int dist_to_next_eqpt;
if (equipoints == nil) {
fprint(2, "can't allocate memory in lialg_compute_equipoints");
return(-1);
}
if (lidebug) {
fprint(2, "compute_equipoints: npts = %d, pathlen = %d, equidist = %d\n",
points->npts, pathlen, equidist);
fflush(stderr);
}
/* First original point is an equipoint. */
equipoints[0] = points->pts[0];
nequipoints++;
dist_since_last_eqpt = 0;
for (i = 1; i < points->npts; i++) {
int dx1 = points->pts[i].x - points->pts[i-1].x;
int dy1 = points->pts[i].y - points->pts[i-1].y;
int endx = 100 * points->pts[i-1].x;
int endy = 100 * points->pts[i-1].y;
remaining_seglen = isqrt(10000 * (dx1 * dx1 + dy1 * dy1));
dist_to_next_eqpt = equidist - dist_since_last_eqpt;
while (remaining_seglen >= dist_to_next_eqpt) {
if (dx1 == 0) {
/* x-coordinate stays the same */
if (dy1 >= 0)
endy += dist_to_next_eqpt;
else
endy -= dist_to_next_eqpt;
}
else {
int slope = (100 * dy1 + dx1 / 2) / dx1;
int tmp = isqrt(10000 + slope * slope);
int dx = (100 * dist_to_next_eqpt + tmp / 2) / tmp;
int dy = (slope * dx + 50) / 100;
if (dy < 0) dy = -dy;
if (dx1 >= 0)
endx += dx;
else
endx -= dx;
if (dy1 >= 0)
endy += dy;
else
endy -= dy;
}
equipoints[nequipoints].x = (endx + 50) / 100;
equipoints[nequipoints].y = (endy + 50) / 100;
nequipoints++;
/* assert(nequipoints <= NCANONICAL);*/
dist_since_last_eqpt = 0;
remaining_seglen -= dist_to_next_eqpt;
dist_to_next_eqpt = equidist;
}
dist_since_last_eqpt += remaining_seglen;
}
/* Take care of last equipoint. */
if (nequipoints == NCANONICAL) {
/* Good. */
} else if (nequipoints == (NCANONICAL - 1)) {
/* Make last original point the last equipoint. */
equipoints[nequipoints] = points->pts[points->npts - 1];
} else {
if (lidebug) {
fprint(2,"lialg_compute_equipoints: nequipoints = %d\n",
nequipoints);
}
/* assert(false);*/
return(-1);
}
points->npts = NCANONICAL;
delete_pen_point_array(points->pts);
points->pts = equipoints;
return(0);
}
/*************************************************************
Utility routines
*************************************************************/
/* Result is x 100. */
static int lialg_compute_pathlen(point_list *points) {
return(lialg_compute_pathlen_subset(points, 0, points->npts - 1));
}
/* Result is x 100. */
static int lialg_compute_pathlen_subset(point_list *points,
int start, int end) {
int pathlen;
int i;
pathlen = 0;
for (i = start + 1; i <= end; i++) {
int dx = points->pts[i].x - points->pts[i-1].x;
int dy = points->pts[i].y - points->pts[i-1].y;
int dist = isqrt(10000 * (dx * dx + dy * dy));
pathlen += dist;
}
return(pathlen);
}
/* Note that this does NOT update points->xrange and points->yrange! */
static int lialg_filter_points(point_list *points) {
int filtered_npts;
pen_point *filtered_pts = mallocz(points->npts*sizeof(pen_point), 1);
int i;
if (filtered_pts == nil) {
fprint(2, "can't allocate memory in lialg_filter_points");
return(-1);
}
filtered_pts[0] = points->pts[0];
filtered_npts = 1;
for (i = 1; i < points->npts; i++) {
int j = filtered_npts - 1;
int dx = points->pts[i].x - filtered_pts[j].x;
int dy = points->pts[i].y - filtered_pts[j].y;
int magsq = dx * dx + dy * dy;
if (magsq >= DIST_SQ_THRESHOLD) {
filtered_pts[filtered_npts] = points->pts[i];
filtered_npts++;
}
}
points->npts = filtered_npts;
delete_pen_point_array(points->pts);
points->pts = filtered_pts;
return(0);
}
/* scalex and scaley are x 100. */
/* Note that this does NOT update points->xrange and points->yrange! */
static int lialg_translate_points(point_list *points,
int minx, int miny,
int scalex, int scaley) {
int i;
for (i = 0; i < points->npts; i++) {
points->pts[i].x = ((points->pts[i].x - minx) * scalex + 50) / 100;
points->pts[i].y = ((points->pts[i].y - miny) * scaley + 50) / 100;
}
return(0);
}
static void lialg_get_bounding_box(point_list *points,
int *pminx, int *pminy,
int *pmaxx, int *pmaxy) {
int minx, miny, maxx, maxy;
int i;
minx = maxx = points->pts[0].x;
miny = maxy = points->pts[0].y;
for (i = 1; i < points->npts; i++) {
pen_point *pt = &(points->pts[i]);
if (pt->x < minx) minx = pt->x;
else if (pt->x > maxx) maxx = pt->x;
if (pt->y < miny) miny = pt->y;
else if (pt->y > maxy) maxy = pt->y;
}
*pminx = minx;
*pminy = miny;
*pmaxx = maxx;
*pmaxy = maxy;
}
int wtvals[] = {100, 104, 117, 143, 189, 271, 422};
static void lialg_compute_lpf_parameters(void) {
int i;
for (i = LP_FILTER_WIDTH; i >= 0; i--) {
// double x = 0.04 * (i * i);
// double tmp = 100.0 * exp(x);
// int wt = floor((double)tmp);
int wt = wtvals[i];
lialg_lpfwts[LP_FILTER_WIDTH - i] = wt;
lialg_lpfwts[LP_FILTER_WIDTH + i] = wt;
}
lialg_lpfconst = 0;
for (i = 0; i < (2 * LP_FILTER_WIDTH + 1); i++) {
lialg_lpfconst += lialg_lpfwts[i];
}
}
/* Code from Joseph Hall (jnhall@sat.mot.com). */
static int isqrt(int n) {
register int i;
register long k0, k1, nn;
for (nn = i = n, k0 = 2; i > 0; i >>= 2, k0 <<= 1)
;
nn <<= 2;
for (;;) {
k1 = (nn / k0 + k0) >> 1;
if (((k0 ^ k1) & ~1) == 0)
break;
k0 = k1;
}
return (int) ((k1 + 1) >> 1);
}
/* Helper routines from Mark Hayter. */
static int likeatan(int tantop, int tanbot) {
int t;
/* Use tan(theta)=top/bot --> order for t */
/* t in range 0..0x40000 */
if ((tantop == 0) && (tanbot == 0))
t = 0;
else
{
t = (tantop << 16) / (abs(tantop) + abs(tanbot));
if (tanbot < 0)
t = 0x20000 - t;
else
if (tantop < 0) t = 0x40000 + t;
}
return t;
}
static int quadr(int t) {
return (8 - (((t + 0x4000) >> 15) & 7)) & 7;
}