source/input/gesturedetector.h

   1 #ifndef MSP_INPUT_GESTUREDETECTOR_H_
   2 #define MSP_INPUT_GESTUREDETECTOR_H_
   3
   4 #include "device.h"
   5
   6 namespace Msp {
   7 namespace Input {
   8
   9 class Touchscreen;
  10
  11 enum Gesture
  12 {
  13         GESTURE_NONE,
  14         GESTURE_SWIPE_DOWN,
  15         GESTURE_SWIPE_UP,
  16         GESTURE_SWIPE_LEFT,
  17         GESTURE_SWIPE_RIGHT,
  18         GESTURE_PINCH
  19 };
  20
  21 /**
  22 Interprets events from a Touchscreen as high-level gestures.  One button is
  23 provided for each type of gesture.  Axes 0 and 1 indicate the starting position
  24 of the gesture; axis 2 tracks its progress.  The progress axis may exhibit
  25 absolute values greater than one.
  26 */
  27 class GestureDetector: public Device
  28 {
  29 private:
  30         enum
  31         {
  32                 MAX_POINTS = 3
  33         };
  34
  35         struct TouchPoint
  36         {
  37                 bool down;
  38                 float down_x;
  39                 float down_y;
  40                 float x;
  41                 float y;
  42                 bool threshold_exceeded;
  43
  44                 TouchPoint();
  45         };
  46
  47         Touchscreen &touchscreen;
  48         TouchPoint points[MAX_POINTS];
  49         Gesture current_gesture;
  50         unsigned active_points;
  51         bool invalid_gesture;
  52         float threshold_x_sq;
  53         float threshold_y_sq;
  54
  55 public:
  56         GestureDetector(Touchscreen &);
  57
  58         virtual std::string get_button_name(unsigned) const;
  59         virtual std::string get_axis_name(unsigned) const;
  60
  61 private:
  62         void touch_down(unsigned);
  63         void touch_up(unsigned);
  64         void touch_move(unsigned, float, float);
  65         void start_gesture();
  66         void update_progress();
  67         void end_gesture();
  68         void window_resized(unsigned, unsigned);
  69 };
  70
  71 } // namespace Input
  72 } // namespace Msp
  73
  74 #endif