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_TAP,
  15         GESTURE_TAP_2,
  16         GESTURE_TAP_3,
  17         GESTURE_DRAG,
  18         GESTURE_DRAG_2,
  19         GESTURE_DRAG_3,
  20         GESTURE_PINCH,
  21         GESTURE_ROTATE
  22 };
  23
  24 /**
  25 Interprets events from a Touchscreen as high-level gestures.  One button is
  26 provided for each type of gesture.  Axes 0 and 1 indicate the starting position
  27 of the gesture; axes 2 and 3 track its progress.  The progress axis may exhibit
  28 absolute values greater than one.
  29 */
  30 class GestureDetector: public Device
  31 {
  32 private:
  33         static constexpr size_t MAX_POINTS = 3;
  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 = GESTURE_NONE;
  50         Gesture pending_tap = GESTURE_NONE;
  51         bool invalid_gesture = false;
  52         float threshold_x_sq = 1.0f;
  53         float threshold_y_sq = 1.0f;
  54
  55 public:
  56         GestureDetector(Touchscreen &);
  57
  58         std::string get_button_name(unsigned) const override;
  59         std::string get_axis_name(unsigned) const override;
  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 set_gesture_location(unsigned);
  67         void set_gesture_delta(unsigned);
  68         void update_progress();
  69         void end_gesture();
  70         void window_resized(unsigned, unsigned);
  71 };
  72
  73
  74 unsigned gesture_points(Gesture);
  75
  76 } // namespace Input
  77 } // namespace Msp
  78
  79 #endif