pidgin/plugins/gestures/stroke.c

   1 /*
   2    libgstroke - a GNOME stroke interface library
   3    Copyright (c) 1996,1997,1998,1999,2000,2001  Mark F. Willey, ETLA Technical
   4
   5    See the file COPYING for distribution information.
   6
   7    This file contains the stroke recognition algorithm.
   8 */
   9
  10 #include "config.h"
  11
  12 #include <unistd.h>
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <math.h>
  16 #include <glib.h>
  17 #include <gtk/gtk.h>
  18 #include "gstroke.h"
  19 #include "gstroke-internal.h"
  20
  21
  22 void
  23 _gstroke_init (struct gstroke_metrics *metrics)
  24 {
  25   if (metrics->pointList != NULL) {
  26     /* FIXME: does this free the data too?*/
  27     g_slist_free (metrics->pointList);
  28     metrics->pointList = NULL;
  29     metrics->point_count = 0;
  30   }
  31 }
  32
  33 /* figure out which bin the point falls in */
  34 static gint
  35 _gstroke_bin (p_point point_p, gint bound_x_1, gint bound_x_2,
  36             gint bound_y_1, gint bound_y_2)
  37 {
  38
  39   gint bin_num = 1;
  40
  41   if (point_p->x > bound_x_1) bin_num += 1;
  42   if (point_p->x > bound_x_2) bin_num += 1;
  43   if (point_p->y > bound_y_1) bin_num += 3;
  44   if (point_p->y > bound_y_2) bin_num += 3;
  45
  46   return bin_num;
  47 }
  48
  49 gint
  50 _gstroke_trans (gchar *sequence, struct gstroke_metrics *metrics)
  51 {
  52   GSList *crt_elem;
  53   /* number of bins recorded in the stroke */
  54   guint sequence_count = 0;
  55
  56   /* points-->sequence translation scratch variables */
  57   gint prev_bin = 0;
  58   gint current_bin = 0;
  59   gint bin_count = 0;
  60
  61   /* flag indicating the start of a stroke - always count it in the sequence */
  62   gint first_bin = TRUE;
  63
  64   /* bin boundary and size variables */
  65   gint delta_x, delta_y;
  66   gint bound_x_1, bound_x_2;
  67   gint bound_y_1, bound_y_2;
  68
  69
  70   /* determine size of grid */
  71   delta_x = metrics->max_x - metrics->min_x;
  72   delta_y = metrics->max_y - metrics->min_y;
  73
  74   /* calculate bin boundary positions */
  75   bound_x_1 = metrics->min_x + (delta_x / 3);
  76   bound_x_2 = metrics->min_x + 2 * (delta_x / 3);
  77
  78   bound_y_1 = metrics->min_y + (delta_y / 3);
  79   bound_y_2 = metrics->min_y + 2 * (delta_y / 3);
  80
  81   if (delta_x > GSTROKE_SCALE_RATIO * delta_y) {
  82     bound_y_1 = (metrics->max_y + metrics->min_y - delta_x) / 2 + (delta_x / 3);
  83     bound_y_2 = (metrics->max_y + metrics->min_y - delta_x) / 2 + 2 * (delta_x / 3);
  84   } else if (delta_y > GSTROKE_SCALE_RATIO * delta_x) {
  85     bound_x_1 = (metrics->max_x + metrics->min_x - delta_y) / 2 + (delta_y / 3);
  86     bound_x_2 = (metrics->max_x + metrics->min_x - delta_y) / 2 + 2 * (delta_y / 3);
  87   }
  88
  89 #if 0
  90   printf ("DEBUG:: point count: %d\n", metrics->point_count);
  91   printf ("DEBUG:: metrics->min_x: %d\n", metrics->min_x);
  92   printf ("DEBUG:: metrics->max_x: %d\n", metrics->max_x);
  93   printf ("DEBUG:: metrics->min_y: %d\n", metrics->min_y);
  94   printf ("DEBUG:: metrics->max_y: %d\n", metrics->max_y);
  95   printf ("DEBUG:: delta_x: %d\n", delta_x);
  96   printf ("DEBUG:: delta_y: %d\n", delta_y);
  97   printf ("DEBUG:: bound_x_1: %d\n", bound_x_1);
  98   printf ("DEBUG:: bound_x_2: %d\n", bound_x_2);
  99   printf ("DEBUG:: bound_y_1: %d\n", bound_y_1);
 100   printf ("DEBUG:: bound_y_2: %d\n", bound_y_2);
 101 #endif
 102
 103   /*
 104     build string by placing points in bins, collapsing bins and
 105     discarding those with too few points...  */
 106
 107   crt_elem = metrics->pointList;
 108   while (crt_elem != NULL)
 109     {
 110       /* figure out which bin the point falls in */
 111
 112       /*printf ("X = %d Y = %d\n", ((p_point)crt_elem->data)->x,
 113         ((p_point)crt_elem->data)->y); */
 114
 115
 116       current_bin = _gstroke_bin ((p_point)crt_elem->data, bound_x_1,
 117                                  bound_x_2, bound_y_1, bound_y_2);
 118
 119       /* if this is the first point, consider it the previous bin, too. */
 120       if (prev_bin == 0)
 121         prev_bin = current_bin;
 122
 123       /*printf ("DEBUG:: current bin: %d x=%d y = %d\n", current_bin,
 124               ((p_point)crt_elem->data)->x,
 125               ((p_point)crt_elem->data)->y); */
 126
 127       if (prev_bin == current_bin)
 128         bin_count++;
 129       else {
 130         /* we are moving to a new bin -- consider adding to the sequence */
 131         if ((bin_count > (metrics->point_count * GSTROKE_BIN_COUNT_PERCENT))
 132             || (first_bin == TRUE)) {
 133
 134                 /*
 135                 gchar val = '0' + prev_bin;
 136                 printf ("%c", val);fflush (stdout);
 137                 g_string_append (&sequence, &val);
 138                 */
 139
 140           first_bin = FALSE;
 141           sequence[sequence_count++] = '0' + prev_bin;
 142           /*  printf ("DEBUG:: adding sequence: %d\n", prev_bin); */
 143
 144         }
 145
 146         /* restart counting points in the new bin */
 147         bin_count=0;
 148         prev_bin = current_bin;
 149       }
 150
 151       /* move to next point, freeing current point from list */
 152
 153       free (crt_elem->data);
 154       crt_elem = g_slist_next (crt_elem);
 155     }
 156   /* add the last run of points to the sequence */
 157   sequence[sequence_count++] = '0' + current_bin;
 158   /*  printf ("DEBUG:: adding final sequence: %d\n", current_bin);  */
 159
 160   _gstroke_init (metrics);
 161
 162   {
 163     /* FIXME: get rid of this block
 164           gchar val = '0' + current_bin;
 165           printf ("%c\n", val);fflush (stdout);
 166           g_string_append (&sequence,  '\0');
 167          */
 168     sequence[sequence_count] = '\0';
 169   }
 170
 171   return TRUE;
 172 }
 173
 174 /* my plan is to make a stroke training program where you can enter all of
 175 the variations of slop that map to a canonical set of strokes.  When the
 176 application calls gstroke_canonical, it gets one of the recognized strokes,
 177 or "", if it's not a recognized variation.  I will probably use a hash
 178 table.  Right now, it just passes the values through to gstroke_trans */
 179 gint
 180 _gstroke_canonical (gchar *sequence, struct gstroke_metrics *metrics)
 181 {
 182   return _gstroke_trans (sequence, metrics);
 183 }
 184
 185
 186 void
 187 _gstroke_record (gint x, gint y, struct gstroke_metrics *metrics)
 188 {
 189   p_point new_point_p;
 190   gint delx, dely;
 191   float ix, iy;
 192
 193   g_return_if_fail( metrics != NULL );
 194
 195 #if 0
 196   printf ("%d:%d ", x, y); fflush (stdout);
 197 #endif
 198
 199   if (metrics->point_count < GSTROKE_MAX_POINTS) {
 200     new_point_p = g_malloc(sizeof (struct s_point));
 201
 202     if (metrics->pointList == NULL) {
 203
 204       /* first point in list - initialize metrics */
 205       metrics->min_x = 10000;
 206       metrics->min_y = 10000;
 207       metrics->max_x = -1;
 208       metrics->max_y = -1;
 209
 210       metrics->pointList = g_slist_prepend(metrics->pointList, new_point_p);
 211       metrics->point_count = 0;
 212
 213     } else {
 214
 215 #define LAST_POINT ((p_point)(g_slist_last (metrics->pointList)->data))
 216
 217       /* interpolate between last and current point */
 218       delx = x - LAST_POINT->x;
 219       dely = y - LAST_POINT->y;
 220
 221       if (abs(delx) > abs(dely)) {  /* step by the greatest delta direction */
 222         iy = LAST_POINT->y;
 223
 224         /* go from the last point to the current, whatever direction it may be */
 225         for (ix = LAST_POINT->x; (delx > 0) ? (ix < x) : (ix > x); ix += (delx > 0) ? 1 : -1) {
 226
 227           /* step the other axis by the correct increment */
 228           iy += fabs(((float) dely / (float) delx)) * (float) ((dely < 0) ? -1.0 : 1.0);
 229
 230           /* add the interpolated point */
 231           new_point_p->x = ix;
 232           new_point_p->y = iy;
 233           metrics->pointList = g_slist_append (metrics->pointList, new_point_p);
 234
 235           /* update metrics */
 236           if (((gint) ix) < metrics->min_x) metrics->min_x = (gint) ix;
 237           if (((gint) ix) > metrics->max_x) metrics->max_x = (gint) ix;
 238           if (((gint) iy) < metrics->min_y) metrics->min_y = (gint) iy;
 239           if (((gint) iy) > metrics->max_y) metrics->max_y = (gint) iy;
 240           metrics->point_count++;
 241
 242           new_point_p = malloc(sizeof(struct s_point));
 243         }
 244       } else {  /* same thing, but for dely larger than delx case... */
 245         ix = LAST_POINT->x;
 246
 247         /* go from the last point to the current, whatever direction it may be
 248          */
 249         for (iy = LAST_POINT->y; (dely > 0) ? (iy < y) : (iy > y); iy += (dely > 0) ? 1 : -1) {
 250
 251           /* step the other axis by the correct increment */
 252           ix += fabs(((float) delx / (float) dely)) * (float) ((delx < 0) ? -1.0 : 1.0);
 253
 254           /* add the interpolated point */
 255           new_point_p->y = iy;
 256           new_point_p->x = ix;
 257           metrics->pointList = g_slist_append(metrics->pointList, new_point_p);
 258
 259           /* update metrics */
 260           if (((gint) ix) < metrics->min_x) metrics->min_x = (gint) ix;
 261           if (((gint) ix) > metrics->max_x) metrics->max_x = (gint) ix;
 262           if (((gint) iy) < metrics->min_y) metrics->min_y = (gint) iy;
 263           if (((gint) iy) > metrics->max_y) metrics->max_y = (gint) iy;
 264           metrics->point_count++;
 265
 266           new_point_p = malloc(sizeof(struct s_point));
 267         }
 268       }
 269
 270       /* add the sampled point */
 271       metrics->pointList = g_slist_append(metrics->pointList, new_point_p);
 272     }
 273
 274     /* record the sampled point values */
 275     new_point_p->x = x;
 276     new_point_p->y = y;
 277
 278 #if 0
 279     {
 280       GSList *crt = metrics->pointList;
 281       printf ("Record ");
 282       while (crt != NULL)
 283         {
 284           printf ("(%d,%d)", ((p_point)crt->data)->x, ((p_point)crt->data)->y);
 285           crt = g_slist_next (crt);
 286         }
 287       printf ("\n");
 288     }
 289 #endif
 290   }
 291 }