source/input/gesturedetector.cpp

   1 #define _USE_MATH_DEFINES
   2 #include <cmath>
   3 #include <sigc++/bind_return.h>
   4 #include "gesturedetector.h"
   5 #include "touchscreen.h"
   6
   7 using namespace std;
   8
   9 namespace Msp {
  10 namespace Input {
  11
  12 GestureDetector::GestureDetector(Touchscreen &ts):
  13         touchscreen(ts),
  14         current_gesture(GESTURE_NONE),
  15         pending_tap(GESTURE_NONE),
  16         invalid_gesture(false)
  17 {
  18         name = "Gesture";
  19
  20         touchscreen.signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_down), false));
  21         touchscreen.signal_button_release.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_up), false));
  22         touchscreen.signal_axis_motion.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_move), false));
  23         Graphics::Window &window = touchscreen.get_window();
  24         window.signal_resize.connect(sigc::mem_fun(this, &GestureDetector::window_resized));
  25         window_resized(window.get_width(), window.get_height());
  26 }
  27
  28 string GestureDetector::get_button_name(unsigned btn) const
  29 {
  30         if(btn==GESTURE_TAP)
  31                 return "Tap";
  32         else if(btn==GESTURE_TAP_2)
  33                 return "Two-finger tap";
  34         else if(btn==GESTURE_TAP_3)
  35                 return "Three-finger tap";
  36         else if(btn==GESTURE_DRAG)
  37                 return "Drag";
  38         else if(btn==GESTURE_DRAG_2)
  39                 return "Two-finger drag";
  40         else if(btn==GESTURE_DRAG_3)
  41                 return "Three-finger drag";
  42         else if(btn==GESTURE_PINCH)
  43                 return "Pinch";
  44         else if(btn==GESTURE_ROTATE)
  45                 return "Rotate";
  46         else
  47                 return Device::get_button_name(btn);
  48 }
  49
  50 string GestureDetector::get_axis_name(unsigned axis) const
  51 {
  52         if(axis==0)
  53                 return "X";
  54         else if(axis==1)
  55                 return "Y";
  56         else if(axis==2)
  57                 return "Delta X";
  58         else if(axis==3)
  59                 return "Delta Y";
  60         else
  61                 return Device::get_axis_name(axis);
  62 }
  63
  64 void GestureDetector::touch_down(unsigned btn)
  65 {
  66         if(btn>=MAX_POINTS)
  67                 return;
  68
  69         TouchPoint &p = points[btn];
  70         p.down = true;
  71         p.down_x = p.x;
  72         p.down_y = p.y;
  73         p.x = 0;
  74         p.y = 0;
  75         p.threshold_exceeded = false;
  76
  77         if(current_gesture==GESTURE_NONE && !invalid_gesture)
  78         {
  79                 if(btn==0)
  80                         pending_tap = GESTURE_TAP;
  81                 else if(btn==1)
  82                         pending_tap = GESTURE_TAP_2;
  83                 else if(btn==2)
  84                         pending_tap = GESTURE_TAP_3;
  85         }
  86 }
  87
  88 void GestureDetector::touch_up(unsigned btn)
  89 {
  90         if(btn>=MAX_POINTS)
  91                 return;
  92
  93         TouchPoint &p = points[btn];
  94         p.x += p.down_x;
  95         p.y += p.down_y;
  96         p.down = false;
  97
  98         if(btn<gesture_points(current_gesture))
  99                 end_gesture();
 100
 101         if(current_gesture==GESTURE_NONE)
 102         {
 103                 // New gesture can't start until all points have been released.
 104                 invalid_gesture = false;
 105                 for(unsigned i=0; (i<MAX_POINTS && !invalid_gesture); ++i)
 106                         invalid_gesture = points[i].down;
 107
 108                 if(!invalid_gesture && pending_tap!=GESTURE_NONE)
 109                 {
 110                         set_gesture_location(gesture_points(pending_tap));
 111                         set_button_state(pending_tap, true, true);
 112                         set_button_state(pending_tap, false, true);
 113
 114                         pending_tap = GESTURE_NONE;
 115                 }
 116         }
 117 }
 118
 119 void GestureDetector::touch_move(unsigned axis, float value, float)
 120 {
 121         if(axis>=MAX_POINTS*2)
 122                 return;
 123
 124         unsigned i = axis>>1;
 125         TouchPoint &p = points[i];
 126         // Track relative position when pressed, absolute when not.
 127         if(axis&1)
 128                 p.y = (p.down ? value-p.down_y : value);
 129         else
 130                 p.x = (p.down ? value-p.down_x : value);
 131
 132         if(p.down)
 133         {
 134                 if(p.x*p.x/threshold_x_sq+p.y*p.y/threshold_y_sq>=1)
 135                 {
 136                         p.threshold_exceeded = true;
 137                         pending_tap = GESTURE_NONE;
 138                 }
 139
 140                 if(current_gesture==GESTURE_NONE && !invalid_gesture)
 141                         start_gesture();
 142                 else if(i<gesture_points(current_gesture))
 143                         update_progress();
 144         }
 145 }
 146
 147 void GestureDetector::start_gesture()
 148 {
 149         TouchPoint &p = points[0];
 150         if(!p.down)
 151                 return;
 152
 153         /* At least one point needs to have moved more than the threshold to start
 154         the gesture. */
 155         bool threshold_exceeded = false;
 156         for(unsigned i=0; (i<MAX_POINTS && !threshold_exceeded); ++i)
 157                 threshold_exceeded = (points[i].down && points[i].threshold_exceeded);
 158         if(!threshold_exceeded)
 159                 return;
 160
 161         invalid_gesture = false;
 162         if(points[2].down)
 163         {
 164                 bool same_direction = true;
 165                 for(unsigned i=0; (same_direction && i<2); ++i)
 166                         for(unsigned j=i+1; (same_direction && j<3); ++j)
 167                         {
 168                                 TouchPoint &pi = points[i];
 169                                 TouchPoint &pj = points[j];
 170                                 same_direction = ((pi.x*pj.x+pi.y*pj.y)>2*abs(pi.x*pj.y-pi.y*pj.x));
 171                         }
 172
 173                 if(same_direction)
 174                         current_gesture = GESTURE_DRAG_3;
 175         }
 176         else if(points[1].down)
 177         {
 178                 TouchPoint &p2 = points[1];
 179                 float ddx = p.down_x-p2.down_x;
 180                 float ddy = p.down_y-p2.down_y;
 181                 float away = p.x*ddx+p.y*ddy;
 182                 float turn = p.y*ddx-p.x*ddy;
 183                 float away2 = -(p2.x*ddx+p2.y*ddy);
 184                 float turn2 = -(p2.y*ddx-p2.x*ddy);
 185                 if(away*away2>0 && abs(away)>abs(turn) && abs(away2)>abs(turn2))
 186                         /* If the points moved away from or towards each other without rotating
 187                         significantly, it's a pinch gesture. */
 188                         current_gesture = GESTURE_PINCH;
 189                 else if(turn*turn2>0 && abs(turn)>abs(away) && abs(turn2)>abs(away2))
 190                         /* If the points both turned in the same direction without significant
 191                         changes in distance, it's a rotate gesture. */
 192                         current_gesture = GESTURE_ROTATE;
 193                 else if((p.x*p2.x+p.y*p2.y)>2*abs(p.x*p2.y-p.y*p2.x))
 194                         // If both points moved in the same direction, it's a two-finger drag.
 195                         current_gesture = GESTURE_DRAG_2;
 196         }
 197         else
 198                 current_gesture = GESTURE_DRAG;
 199
 200         if(current_gesture!=GESTURE_NONE)
 201         {
 202                 set_gesture_location(gesture_points(current_gesture));
 203                 update_progress();
 204                 set_button_state(current_gesture, true, true);
 205         }
 206         else
 207                 invalid_gesture = true;
 208 }
 209
 210 void GestureDetector::set_gesture_location(unsigned n_points)
 211 {
 212         float x = 0;
 213         float y = 0;
 214         for(unsigned i=0; i<n_points; ++i)
 215         {
 216                 x += points[i].down_x;
 217                 y += points[i].down_y;
 218         }
 219
 220         set_axis_value(0, x/n_points, true);
 221         set_axis_value(1, y/n_points, true);
 222 }
 223
 224 void GestureDetector::set_gesture_delta(unsigned n_points)
 225 {
 226         float x = 0;
 227         float y = 0;
 228         for(unsigned i=0; i<n_points; ++i)
 229         {
 230                 x += points[i].x;
 231                 y += points[i].y;
 232         }
 233
 234         set_axis_value(2, x/n_points, true);
 235         set_axis_value(3, y/n_points, true);
 236 }
 237
 238 void GestureDetector::update_progress()
 239 {
 240         if(current_gesture>=GESTURE_DRAG && current_gesture<=GESTURE_DRAG_3)
 241                 set_gesture_delta(gesture_points(current_gesture));
 242         else if(current_gesture==GESTURE_PINCH || current_gesture==GESTURE_ROTATE)
 243         {
 244                 TouchPoint &p = points[0];
 245                 TouchPoint &p2 = points[1];
 246                 /* Pinch progress is the ratio between the current distance of the points
 247                 and their distance when they were pressed. */
 248                 float ddx = p.down_x-p2.down_x;
 249                 float ddy = p.down_y-p2.down_y;
 250                 float dx = ddx+p.x-p2.x;
 251                 float dy = ddy+p.y-p2.y;
 252                 if(current_gesture==GESTURE_PINCH)
 253                 {
 254                         set_axis_value(2, sqrt(dx*dx+dy*dy)/sqrt(ddx*ddx+ddy*ddy)-1, true);
 255                         set_axis_value(3, 0, true);
 256                 }
 257                 else if(current_gesture==GESTURE_ROTATE)
 258                 {
 259                         set_axis_value(2, atan2(dy*ddx-dx*ddy, dx*ddx+dy*ddy)/M_PI/2, true);
 260                         set_axis_value(3, 0, true);
 261                 }
 262         }
 263 }
 264
 265 void GestureDetector::end_gesture()
 266 {
 267         set_button_state(current_gesture, false, true);
 268         set_axis_value(2, 0, false);
 269         current_gesture = GESTURE_NONE;
 270         pending_tap = GESTURE_NONE;
 271 }
 272
 273 void GestureDetector::window_resized(unsigned w, unsigned h)
 274 {
 275         threshold_x_sq = 2500.0/(w*w);
 276         threshold_y_sq = 2500.0/(h*h);
 277 }
 278
 279
 280 GestureDetector::TouchPoint::TouchPoint():
 281         down(false),
 282         down_x(0),
 283         down_y(0),
 284         x(0),
 285         y(0),
 286         threshold_exceeded(false)
 287 { }
 288
 289
 290 unsigned gesture_points(Gesture gesture)
 291 {
 292         switch(gesture)
 293         {
 294         case GESTURE_NONE: return 0;
 295         case GESTURE_TAP: return 1;
 296         case GESTURE_TAP_2: return 2;
 297         case GESTURE_TAP_3: return 3;
 298         case GESTURE_DRAG: return 1;
 299         case GESTURE_DRAG_2: return 2;
 300         case GESTURE_DRAG_3: return 3;
 301         case GESTURE_PINCH: return 2;
 302         case GESTURE_ROTATE: return 2;
 303         default: throw invalid_argument("gesture_points");
 304         }
 305 }
 306
 307 } // namespace Input
 308 } // namespace Msp