ref: 7c5ca77a6e4d442b4c026e2cd9e483a692f65def
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 ([email protected]). */ 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; }