source/input/gesturedetector.h

   1 #ifndef MSP_INPUT_GESTUREDETECTOR_H_
   2 #define MSP_INPUT_GESTUREDETECTOR_H_
   3
   4 #include <msp/graphics/mspgui_api.h>
   5 #include "device.h"
   6
   7 namespace Msp {
   8 namespace Input {
   9
  10 class Touchscreen;
  11
  12 enum Gesture
  13 {
  14         GESTURE_NONE,
  15         GESTURE_TAP,
  16         GESTURE_TAP_2,
  17         GESTURE_TAP_3,
  18         GESTURE_DRAG,
  19         GESTURE_DRAG_2,
  20         GESTURE_DRAG_3,
  21         GESTURE_PINCH,
  22         GESTURE_ROTATE
  23 };
  24
  25 /**
  26 Interprets events from a Touchscreen as high-level gestures.  One button is
  27 provided for each type of gesture.  Axes 0 and 1 indicate the starting position
  28 of the gesture; axes 2 and 3 track its progress.  The progress axis may exhibit
  29 absolute values greater than one.
  30 */
  31 class MSPGUI_API GestureDetector: public Device
  32 {
  33 private:
  34         static constexpr size_t MAX_POINTS = 3;
  35
  36         struct TouchPoint
  37         {
  38                 bool down;
  39                 float down_x;
  40                 float down_y;
  41                 float x;
  42                 float y;
  43                 bool threshold_exceeded;
  44
  45                 TouchPoint();
  46         };
  47
  48         Touchscreen &touchscreen;
  49         TouchPoint points[MAX_POINTS];
  50         Gesture current_gesture = GESTURE_NONE;
  51         Gesture pending_tap = GESTURE_NONE;
  52         bool invalid_gesture = false;
  53         float threshold_x_sq = 1.0f;
  54         float threshold_y_sq = 1.0f;
  55
  56 public:
  57         GestureDetector(Touchscreen &);
  58
  59         std::string get_button_name(unsigned) const override;
  60         std::string get_axis_name(unsigned) const override;
  61
  62 private:
  63         void touch_down(unsigned);
  64         void touch_up(unsigned);
  65         void touch_move(unsigned, float, float);
  66         void start_gesture();
  67         void set_gesture_location(unsigned);
  68         void set_gesture_delta(unsigned);
  69         void update_progress();
  70         void end_gesture();
  71         void window_resized(unsigned, unsigned);
  72 };
  73
  74
  75 MSPGUI_API unsigned gesture_points(Gesture);
  76
  77 } // namespace Input
  78 } // namespace Msp
  79
  80 #endif