libgstroke - a GNOME stroke interface library Copyright (c) 1996,1997,1998,1999,2000,2001 Mark F. Willey, ETLA Technical See the file COPYING for distribution information. This file contains the stroke recognition algorithm. #include "gstroke-internal.h" _gstroke_init (struct gstroke_metrics *metrics) if (metrics->pointList != NULL) { /* FIXME: does this free the data too?*/ g_slist_free (metrics->pointList); metrics->pointList = NULL; metrics->point_count = 0; /* figure out which bin the point falls in */ _gstroke_bin (p_point point_p, gint bound_x_1, gint bound_x_2, gint bound_y_1, gint bound_y_2) if (point_p->x > bound_x_1) bin_num += 1; if (point_p->x > bound_x_2) bin_num += 1; if (point_p->y > bound_y_1) bin_num += 3; if (point_p->y > bound_y_2) bin_num += 3; _gstroke_trans (gchar *sequence, struct gstroke_metrics *metrics) /* number of bins recorded in the stroke */ guint sequence_count = 0; /* points-->sequence translation scratch variables */ /* flag indicating the start of a stroke - always count it in the sequence */ /* bin boundary and size variables */ gint bound_x_1, bound_x_2; gint bound_y_1, bound_y_2; /* determine size of grid */ delta_x = metrics->max_x - metrics->min_x; delta_y = metrics->max_y - metrics->min_y; /* calculate bin boundary positions */ bound_x_1 = metrics->min_x + (delta_x / 3); bound_x_2 = metrics->min_x + 2 * (delta_x / 3); bound_y_1 = metrics->min_y + (delta_y / 3); bound_y_2 = metrics->min_y + 2 * (delta_y / 3); if (delta_x > GSTROKE_SCALE_RATIO * delta_y) { bound_y_1 = (metrics->max_y + metrics->min_y - delta_x) / 2 + (delta_x / 3); bound_y_2 = (metrics->max_y + metrics->min_y - delta_x) / 2 + 2 * (delta_x / 3); } else if (delta_y > GSTROKE_SCALE_RATIO * delta_x) { bound_x_1 = (metrics->max_x + metrics->min_x - delta_y) / 2 + (delta_y / 3); bound_x_2 = (metrics->max_x + metrics->min_x - delta_y) / 2 + 2 * (delta_y / 3); printf ("DEBUG:: point count: %d\n", metrics->point_count); printf ("DEBUG:: metrics->min_x: %d\n", metrics->min_x); printf ("DEBUG:: metrics->max_x: %d\n", metrics->max_x); printf ("DEBUG:: metrics->min_y: %d\n", metrics->min_y); printf ("DEBUG:: metrics->max_y: %d\n", metrics->max_y); printf ("DEBUG:: delta_x: %d\n", delta_x); printf ("DEBUG:: delta_y: %d\n", delta_y); printf ("DEBUG:: bound_x_1: %d\n", bound_x_1); printf ("DEBUG:: bound_x_2: %d\n", bound_x_2); printf ("DEBUG:: bound_y_1: %d\n", bound_y_1); printf ("DEBUG:: bound_y_2: %d\n", bound_y_2); build string by placing points in bins, collapsing bins and discarding those with too few points... */ crt_elem = metrics->pointList; /* figure out which bin the point falls in */ /*printf ("X = %d Y = %d\n", ((p_point)crt_elem->data)->x, ((p_point)crt_elem->data)->y); */ current_bin = _gstroke_bin ((p_point)crt_elem->data, bound_x_1, bound_x_2, bound_y_1, bound_y_2); /* if this is the first point, consider it the previous bin, too. */ /*printf ("DEBUG:: current bin: %d x=%d y = %d\n", current_bin, ((p_point)crt_elem->data)->x, ((p_point)crt_elem->data)->y); */ if (prev_bin == current_bin) /* we are moving to a new bin -- consider adding to the sequence */ if ((bin_count > (metrics->point_count * GSTROKE_BIN_COUNT_PERCENT)) || (first_bin == TRUE)) { gchar val = '0' + prev_bin; printf ("%c", val);fflush (stdout); g_string_append (&sequence, &val); sequence[sequence_count++] = '0' + prev_bin; /* printf ("DEBUG:: adding sequence: %d\n", prev_bin); */ /* restart counting points in the new bin */ /* move to next point, freeing current point from list */ crt_elem = g_slist_next (crt_elem); /* add the last run of points to the sequence */ sequence[sequence_count++] = '0' + current_bin; /* printf ("DEBUG:: adding final sequence: %d\n", current_bin); */ /* FIXME: get rid of this block gchar val = '0' + current_bin; printf ("%c\n", val);fflush (stdout); g_string_append (&sequence, '\0'); sequence[sequence_count] = '\0'; /* my plan is to make a stroke training program where you can enter all of the variations of slop that map to a canonical set of strokes. When the application calls gstroke_canonical, it gets one of the recognized strokes, or "", if it's not a recognized variation. I will probably use a hash table. Right now, it just passes the values through to gstroke_trans */ _gstroke_canonical (gchar *sequence, struct gstroke_metrics *metrics) return _gstroke_trans (sequence, metrics); _gstroke_record (gint x, gint y, struct gstroke_metrics *metrics) g_return_if_fail( metrics != NULL ); printf ("%d:%d ", x, y); fflush (stdout); if (metrics->point_count < GSTROKE_MAX_POINTS) { new_point_p = (p_point) g_malloc (sizeof (struct s_point)); if (metrics->pointList == NULL) { /* first point in list - initialize metrics */ metrics->pointList = (GSList*) g_malloc (sizeof (GSList)); metrics->pointList->data = new_point_p; metrics->pointList->next = NULL; metrics->point_count = 0; #define LAST_POINT ((p_point)(g_slist_last (metrics->pointList)->data)) /* interpolate between last and current point */ delx = x - LAST_POINT->x; dely = y - LAST_POINT->y; if (abs(delx) > abs(dely)) { /* step by the greatest delta direction */ /* go from the last point to the current, whatever direction it may be */ for (ix = LAST_POINT->x; (delx > 0) ? (ix < x) : (ix > x); ix += (delx > 0) ? 1 : -1) { /* step the other axis by the correct increment */ iy += fabs(((float) dely / (float) delx)) * (float) ((dely < 0) ? -1.0 : 1.0); /* add the interpolated point */ metrics->pointList = g_slist_append (metrics->pointList, new_point_p); if (((gint) ix) < metrics->min_x) metrics->min_x = (gint) ix; if (((gint) ix) > metrics->max_x) metrics->max_x = (gint) ix; if (((gint) iy) < metrics->min_y) metrics->min_y = (gint) iy; if (((gint) iy) > metrics->max_y) metrics->max_y = (gint) iy; new_point_p = (p_point) malloc (sizeof(struct s_point)); } else { /* same thing, but for dely larger than delx case... */ /* go from the last point to the current, whatever direction it may be for (iy = LAST_POINT->y; (dely > 0) ? (iy < y) : (iy > y); iy += (dely > 0) ? 1 : -1) { /* step the other axis by the correct increment */ ix += fabs(((float) delx / (float) dely)) * (float) ((delx < 0) ? -1.0 : 1.0); /* add the interpolated point */ metrics->pointList = g_slist_append(metrics->pointList, new_point_p); if (((gint) ix) < metrics->min_x) metrics->min_x = (gint) ix; if (((gint) ix) > metrics->max_x) metrics->max_x = (gint) ix; if (((gint) iy) < metrics->min_y) metrics->min_y = (gint) iy; if (((gint) iy) > metrics->max_y) metrics->max_y = (gint) iy; new_point_p = (p_point) malloc (sizeof(struct s_point)); /* add the sampled point */ metrics->pointList = g_slist_append(metrics->pointList, new_point_p); /* record the sampled point values */ GSList *crt = metrics->pointList; printf ("(%d,%d)", ((p_point)crt->data)->x, ((p_point)crt->data)->y); crt = g_slist_next (crt);