recovery: ui: Minor cleanup for touch code

 * Better naming for some touch vars and funcs

 * Introduce Point class

Change-Id: Idfcab54ac356face52efd69fdfdc0a6f4633a3f3

minui/events.cpp

@@ -325,7 +325,7 @@ int ev_sync_key_state(const ev_set_key_callback& set_key_cb) {
   return 0;
 }
 
-void ev_iterate_available_keys(const std::function<void(int)>& f) {
+void ev_iterate_available_keys(const std::function<void(int)>& key_detected) {
   // Use unsigned long to match ioctl's parameter type.
   unsigned long ev_bits[BITS_TO_LONGS(EV_MAX)];    // NOLINT
   unsigned long key_bits[BITS_TO_LONGS(KEY_MAX)];  // NOLINT
@@ -348,13 +348,13 @@ void ev_iterate_available_keys(const std::function<void(int)>& f) {
 
     for (int key_code = 0; key_code <= KEY_MAX; ++key_code) {
       if (test_bit(key_code, key_bits)) {
-        f(key_code);
+        key_detected(key_code);
       }
     }
   }
 }
 
-void ev_iterate_touch_inputs(const std::function<void(int)>& action) {
+void ev_iterate_touch_inputs(const std::function<void(int)>& key_detected) {
   for (size_t i = 0; i < g_ev_dev_count; ++i) {
     // Use unsigned long to match ioctl's parameter type.
     unsigned long ev_bits[BITS_TO_LONGS(EV_MAX)] = {};  // NOLINT
@@ -372,7 +372,7 @@ void ev_iterate_touch_inputs(const std::function<void(int)>& action) {
 
     for (int key_code = 0; key_code <= KEY_MAX; ++key_code) {
       if (test_bit(key_code, key_bits)) {
-        action(key_code);
+        key_detected(key_code);
       }
     }
   }

minui/include/minui/minui.h

@@ -172,8 +172,8 @@ using ev_set_sw_callback = std::function<int(int code, int value)>;
 int ev_init(ev_callback input_cb, bool allow_touch_inputs = false);
 void ev_exit();
 int ev_add_fd(android::base::unique_fd&& fd, ev_callback cb);
-void ev_iterate_available_keys(const std::function<void(int)>& f);
-void ev_iterate_touch_inputs(const std::function<void(int)>& action);
+void ev_iterate_available_keys(const std::function<void(int)>& key_detected);
+void ev_iterate_touch_inputs(const std::function<void(int)>& key_detected);
 int ev_sync_key_state(const ev_set_key_callback& set_key_cb);
 int ev_sync_sw_state(const ev_set_sw_callback& set_sw_cb);
 

recovery_ui/include/recovery_ui/ui.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2011 The Android Open Source Project
+ * Copyright (C) 2019 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +30,51 @@
 
 static constexpr const char* DEFAULT_LOCALE = "en-US";
 
+/*
+ * Simple representation of a (x,y) coordinate with convenience operators
+ */
+class Point {
+ public:
+  Point() : x_(0), y_(0) {}
+  Point(int x, int y) : x_(x), y_(y) {}
+  int x() const {
+    return x_;
+  }
+  int y() const {
+    return y_;
+  }
+  void x(int x) {
+    x_ = x;
+  }
+  void y(int y) {
+    y_ = y;
+  }
+
+  bool operator==(const Point& rhs) const {
+    return (x() == rhs.x() && y() == rhs.y());
+  }
+  bool operator!=(const Point& rhs) const {
+    return !(*this == rhs);
+  }
+
+  Point operator+(const Point& rhs) const {
+    Point tmp;
+    tmp.x_ = x_ + rhs.x_;
+    tmp.y_ = y_ + rhs.y_;
+    return tmp;
+  }
+  Point operator-(const Point& rhs) const {
+    Point tmp;
+    tmp.x_ = x_ - rhs.x_;
+    tmp.y_ = y_ - rhs.y_;
+    return tmp;
+  }
+
+ private:
+  int x_;
+  int y_;
+};
+
 // Abstract class for controlling the user interface during recovery.
 class RecoveryUI {
  public:
@@ -227,7 +273,7 @@ class RecoveryUI {
   const int touch_high_threshold_;
 
   void OnKeyDetected(int key_code);
-  void OnTouchDetected(int dx, int dy);
+  void OnTouchEvent();
   int OnInputEvent(int fd, uint32_t epevents);
   void ProcessKey(int key_code, int updown);
   void TimeKey(int key_code, int count);
@@ -261,10 +307,8 @@ class RecoveryUI {
 
   // Touch event related variables. See the comments in RecoveryUI::OnInputEvent().
   int touch_slot_;
-  int touch_X_;
-  int touch_Y_;
-  int touch_start_X_;
-  int touch_start_Y_;
+  Point touch_pos_;
+  Point touch_start_;
   bool touch_finger_down_;
   bool touch_swiping_;
   bool is_bootreason_recovery_ui_;

recovery_ui/ui.cpp

@@ -212,18 +212,19 @@ static SwipeDirection FlipSwipeDirection(SwipeDirection direction) {
   }
 }
 
-void RecoveryUI::OnTouchDetected(int dx, int dy) {
+void RecoveryUI::OnTouchEvent() {
+  Point delta = touch_pos_ - touch_start_;
   SwipeDirection direction;
 
   // We only consider a valid swipe if:
   // - the delta along one axis is below touch_low_threshold_;
   // - and the delta along the other axis is beyond touch_high_threshold_.
-  if (abs(dy) < touch_low_threshold_ && abs(dx) > touch_high_threshold_) {
-    direction = dx < 0 ? SwipeDirection::LEFT : SwipeDirection::RIGHT;
-  } else if (abs(dx) < touch_low_threshold_ && abs(dy) > touch_high_threshold_) {
-    direction = dy < 0 ? SwipeDirection::UP : SwipeDirection::DOWN;
+  if (abs(delta.y()) < touch_low_threshold_ && abs(delta.x()) > touch_high_threshold_) {
+    direction = delta.x() < 0 ? SwipeDirection::LEFT : SwipeDirection::RIGHT;
+  } else if (abs(delta.x()) < touch_low_threshold_ && abs(delta.y()) > touch_high_threshold_) {
+    direction = delta.y() < 0 ? SwipeDirection::UP : SwipeDirection::DOWN;
   } else {
-    LOG(DEBUG) << "Ignored " << dx << " " << dy << " (low: " << touch_low_threshold_
+    LOG(DEBUG) << "Ignored " << delta.x() << " " << delta.y() << " (low: " << touch_low_threshold_
                << ", high: " << touch_high_threshold_ << ")";
     return;
   }
@@ -290,12 +291,11 @@ int RecoveryUI::OnInputEvent(int fd, uint32_t epevents) {
       // There might be multiple SYN_REPORT events. We should only detect a swipe after lifting the
       // contact.
       if (touch_finger_down_ && !touch_swiping_) {
-        touch_start_X_ = touch_X_;
-        touch_start_Y_ = touch_Y_;
+        touch_start_ = touch_pos_;
         touch_swiping_ = true;
       } else if (!touch_finger_down_ && touch_swiping_) {
         touch_swiping_ = false;
-        OnTouchDetected(touch_X_ - touch_start_X_, touch_Y_ - touch_start_Y_);
+        OnTouchEvent();
       }
     }
     return 0;
@@ -331,12 +331,12 @@ int RecoveryUI::OnInputEvent(int fd, uint32_t epevents) {
 
     switch (ev.code) {
       case ABS_MT_POSITION_X:
-        touch_X_ = ev.value;
+        touch_pos_.x(ev.value);
         touch_finger_down_ = true;
         break;
 
       case ABS_MT_POSITION_Y:
-        touch_Y_ = ev.value;
+        touch_pos_.y(ev.value);
         touch_finger_down_ = true;
         break;