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- /*
- * 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;
- }
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