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