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