source/input/gesturedetector.cpp

   1 #include <cmath>
   2 #include <sigc++/bind_return.h>
   3 #include "gesturedetector.h"
   4 #include "touchscreen.h"
   5
   6 using namespace std;
   7
   8 namespace Msp {
   9 namespace Input {
  10
  11 GestureDetector::GestureDetector(Touchscreen &ts):
  12         touchscreen(ts),
  13         current_gesture(GESTURE_NONE),
  14         active_points(0),
  15         invalid_gesture(false)
  16 {
  17         name = "Gesture";
  18
  19         touchscreen.signal_button_press.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_down), false));
  20         touchscreen.signal_button_release.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_up), false));
  21         touchscreen.signal_axis_motion.connect(sigc::bind_return(sigc::mem_fun(this, &GestureDetector::touch_move), false));
  22         Graphics::Window &window = touchscreen.get_window();
  23         window.signal_resize.connect(sigc::mem_fun(this, &GestureDetector::window_resized));
  24         window_resized(window.get_width(), window.get_height());
  25 }
  26
  27 string GestureDetector::get_button_name(unsigned btn) const
  28 {
  29         if(btn==GESTURE_SWIPE_DOWN)
  30                 return "Swipe down";
  31         else if(btn==GESTURE_SWIPE_UP)
  32                 return "Swipe up";
  33         else if(btn==GESTURE_SWIPE_LEFT)
  34                 return "Swipe left";
  35         else if(btn==GESTURE_SWIPE_RIGHT)
  36                 return "Swipe right";
  37         else if(btn==GESTURE_PINCH)
  38                 return "Pinch";
  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<3)
  58         {
  59                 TouchPoint &p = points[btn];
  60                 p.down = true;
  61                 p.down_x = p.x;
  62                 p.down_y = p.y;
  63         }
  64 }
  65
  66 void GestureDetector::touch_up(unsigned btn)
  67 {
  68         if(btn<3)
  69         {
  70                 TouchPoint &p = points[btn];
  71                 p.down = false;
  72
  73                 if(active_points&(1<<btn))
  74                 {
  75                         set_button_state(current_gesture, false, true);
  76                         set_axis_value(2, 0, false);
  77                         current_gesture = GESTURE_NONE;
  78                         active_points = 0;
  79                         invalid_gesture = true;
  80                 }
  81
  82                 if(invalid_gesture)
  83                 {
  84                         invalid_gesture = false;
  85                         for(unsigned i=0; i<3; ++i)
  86                                 if(points[i].down)
  87                                         invalid_gesture = true;
  88                 }
  89         }
  90 }
  91
  92 void GestureDetector::touch_move(unsigned axis, float value, float)
  93 {
  94         if(axis<6)
  95         {
  96                 unsigned i = axis>>1;
  97                 TouchPoint &p = points[i];
  98                 if(axis&1)
  99                         p.y = value;
 100                 else
 101                         p.x = value;
 102
 103                 if(p.down)
 104                 {
 105                         if(current_gesture==GESTURE_NONE && !invalid_gesture)
 106                                 start_gesture();
 107                         else if(active_points&(1<<i))
 108                                 update_progress();
 109                 }
 110         }
 111 }
 112
 113 void GestureDetector::start_gesture()
 114 {
 115         TouchPoint &p = points[0];
 116         if(!p.down)
 117                 return;
 118
 119         float dx = p.x-p.down_x;
 120         float dy = p.y-p.down_y;
 121         if(dx*dx/threshold_x_sq+dy*dy/threshold_y_sq<1)
 122                 return;
 123
 124         invalid_gesture = false;
 125         if(points[1].down)
 126         {
 127                 TouchPoint &p2 = points[1];
 128                 float dx2 = p2.x-p2.down_x;
 129                 float dy2 = p2.y-p2.down_y;
 130                 float ddx = p.down_x-p2.down_x;
 131                 float ddy = p.down_y-p2.down_y;
 132                 /* TODO Should the second point be also required to exceeded the
 133                 threshold? */
 134                 if(dx*dx2+dy*dy2<0 && (dx*ddx+dy*ddy)*(dx2*ddx+dy2*ddy)<0)
 135                 {
 136                         current_gesture = GESTURE_PINCH;
 137                         active_points = 3;
 138                 }
 139                 else
 140                         invalid_gesture = true;
 141
 142                 if(current_gesture!=GESTURE_NONE)
 143                 {
 144                         set_axis_value(0, (p.down_x+p2.down_x)/2, true);
 145                         set_axis_value(1, (p.down_y+p2.down_y)/2, true);
 146                 }
 147         }
 148         else
 149         {
 150                 active_points = 1;
 151                 if(abs(dx)>2*abs(dy))
 152                         current_gesture = (dx>0 ? GESTURE_SWIPE_RIGHT : GESTURE_SWIPE_LEFT);
 153                 else if(abs(dy)>2*abs(dx))
 154                         current_gesture = (dy>0 ? GESTURE_SWIPE_UP : GESTURE_SWIPE_DOWN);
 155                 else
 156                         invalid_gesture = true;
 157
 158                 if(current_gesture!=GESTURE_NONE)
 159                 {
 160                         set_axis_value(0, p.down_x, true);
 161                         set_axis_value(1, p.down_y, true);
 162                 }
 163         }
 164
 165         update_progress();
 166
 167         if(current_gesture!=GESTURE_NONE)
 168                 set_button_state(current_gesture, true, true);
 169 }
 170
 171 void GestureDetector::update_progress()
 172 {
 173         TouchPoint &p = points[0];
 174
 175         if(current_gesture==GESTURE_SWIPE_DOWN)
 176                 set_axis_value(2, p.down_y-p.y, true);
 177         else if(current_gesture==GESTURE_SWIPE_UP)
 178                 set_axis_value(2, p.y-p.down_y, true);
 179         else if(current_gesture==GESTURE_SWIPE_LEFT)
 180                 set_axis_value(2, p.down_x-p.x, true);
 181         else if(current_gesture==GESTURE_SWIPE_RIGHT)
 182                 set_axis_value(2, p.x-p.down_x, true);
 183         else if(current_gesture==GESTURE_PINCH)
 184         {
 185                 TouchPoint &p2 = points[1];
 186                 float dx = p.x-p2.x;
 187                 float dy = p.y-p2.y;
 188                 float ddx = p.down_x-p2.down_x;
 189                 float ddy = p.down_y-p2.down_y;
 190                 set_axis_value(2, sqrt(dx*dx+dy*dy)/sqrt(ddx*ddx+ddy*ddy)-1, true);
 191         }
 192 }
 193
 194 void GestureDetector::window_resized(unsigned w, unsigned h)
 195 {
 196         threshold_x_sq = 2500.0/(w*w);
 197         threshold_y_sq = 2500.0/(h*h);
 198 }
 199
 200
 201 GestureDetector::TouchPoint::TouchPoint():
 202         down(false),
 203         down_x(0),
 204         down_y(0),
 205         x(0),
 206         y(0)
 207 { }
 208
 209 } // namespace Input
 210 } // namespace Msp