gesture handling

modules/GestureRecognizer.lua

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+---@class GestureRecognizer
+---@field _touches table<string, table> -- Current touch states
+---@field _gestureStates table -- Active gesture states
+---@field _config table -- Gesture configuration (thresholds, etc.)
+---@field _InputEvent table
+---@field _utils table
+local GestureRecognizer = {}
+GestureRecognizer.__index = GestureRecognizer
+
+-- Gesture types enum
+local GestureType = {
+  TAP = "tap",
+  DOUBLE_TAP = "double_tap",
+  LONG_PRESS = "long_press",
+  SWIPE = "swipe",
+  PAN = "pan",
+  PINCH = "pinch",
+  ROTATE = "rotate",
+}
+
+-- Gesture states
+local GestureState = {
+  POSSIBLE = "possible",
+  BEGAN = "began",
+  CHANGED = "changed",
+  ENDED = "ended",
+  CANCELLED = "cancelled",
+  FAILED = "failed",
+}
+
+-- Default configuration
+local defaultConfig = {
+  -- Tap gesture
+  tapMaxDuration = 0.3, -- seconds
+  tapMaxMovement = 10, -- pixels
+  
+  -- Double-tap gesture
+  doubleTapInterval = 0.3, -- seconds between taps
+  
+  -- Long-press gesture
+  longPressMinDuration = 0.5, -- seconds
+  longPressMaxMovement = 10, -- pixels
+  
+  -- Swipe gesture
+  swipeMinDistance = 50, -- pixels
+  swipeMaxDuration = 0.2, -- seconds
+  swipeMinVelocity = 200, -- pixels per second
+  
+  -- Pan gesture
+  panMinMovement = 5, -- pixels to start pan
+  
+  -- Pinch gesture
+  pinchMinScaleChange = 0.1, -- 10% scale change
+  
+  -- Rotate gesture
+  rotateMinAngleChange = 5, -- degrees
+}
+
+--- Create a new GestureRecognizer instance
+---@param config table? Optional configuration options
+---@param deps table Dependencies {InputEvent, utils}
+---@return GestureRecognizer
+function GestureRecognizer.new(config, deps)
+  config = config or {}
+  
+  local self = setmetatable({}, GestureRecognizer)
+  
+  self._InputEvent = deps.InputEvent
+  self._utils = deps.utils
+  
+  -- Merge configuration with defaults
+  self._config = {}
+  for key, value in pairs(defaultConfig) do
+    self._config[key] = config[key] or value
+  end
+  
+  self._touches = {}
+  self._gestureStates = {
+    tap = nil,
+    doubleTap = { lastTapTime = 0, tapCount = 0 },
+    longPress = {},
+    swipe = {},
+    pan = {},
+    pinch = {},
+    rotate = {},
+  }
+  
+  return self
+end
+
+--- Update gesture recognizer with touch event
+---@param event InputEvent Touch event
+function GestureRecognizer:processTouchEvent(event)
+  if not event.touchId then
+    return
+  end
+  
+  local touchId = event.touchId
+  
+  -- Update touch state
+  if event.type == "touchpress" then
+    self._touches[touchId] = {
+      startX = event.x,
+      startY = event.y,
+      x = event.x,
+      y = event.y,
+      startTime = event.timestamp,
+      lastTime = event.timestamp,
+      phase = "began",
+    }
+    
+    -- Initialize gesture detection
+    self:_detectTapBegan(touchId, event)
+    self:_detectLongPressBegan(touchId, event)
+    
+  elseif event.type == "touchmove" then
+    local touch = self._touches[touchId]
+    if touch then
+      touch.x = event.x
+      touch.y = event.y
+      touch.lastTime = event.timestamp
+      touch.phase = "moved"
+      
+      -- Update gesture detection
+      self:_detectPan(touchId, event)
+      self:_detectSwipe(touchId, event)
+      
+      -- Multi-touch gestures
+      if self:_getTouchCount() >= 2 then
+        self:_detectPinch(event)
+        self:_detectRotate(event)
+      end
+    end
+    
+  elseif event.type == "touchrelease" then
+    local touch = self._touches[touchId]
+    if touch then
+      touch.phase = "ended"
+      
+      -- Finalize gesture detection
+      self:_detectTapEnded(touchId, event)
+      self:_detectSwipeEnded(touchId, event)
+      self:_detectPanEnded(touchId, event)
+      
+      -- Cleanup touch
+      self._touches[touchId] = nil
+    end
+    
+  elseif event.type == "touchcancel" then
+    -- Cancel all active gestures for this touch
+    self._touches[touchId] = nil
+    self:_cancelAllGestures()
+  end
+end
+
+--- Get number of active touches
+---@return number
+function GestureRecognizer:_getTouchCount()
+  local count = 0
+  for _ in pairs(self._touches) do
+    count = count + 1
+  end
+  return count
+end
+
+--- Detect tap gesture began
+---@param touchId string
+---@param event InputEvent
+function GestureRecognizer:_detectTapBegan(touchId, event)
+  -- Tap detection happens on touch end
+  -- Just record the touch for now
+end
+
+--- Detect tap gesture ended
+---@param touchId string
+---@param event InputEvent
+function GestureRecognizer:_detectTapEnded(touchId, event)
+  local touch = self._touches[touchId]
+  if not touch then
+    return
+  end
+  
+  local duration = event.timestamp - touch.startTime
+  local dx = event.x - touch.startX
+  local dy = event.y - touch.startY
+  local distance = math.sqrt(dx * dx + dy * dy)
+  
+  -- Check if it's a valid tap
+  if duration < self._config.tapMaxDuration and distance < self._config.tapMaxMovement then
+    local currentTime = event.timestamp
+    local doubleTapState = self._gestureStates.doubleTap
+    
+    -- Check for double-tap
+    if currentTime - doubleTapState.lastTapTime < self._config.doubleTapInterval then
+      doubleTapState.tapCount = doubleTapState.tapCount + 1
+      
+      if doubleTapState.tapCount >= 2 then
+        -- Fire double-tap gesture
+        return {
+          type = GestureType.DOUBLE_TAP,
+          state = GestureState.ENDED,
+          x = event.x,
+          y = event.y,
+          timestamp = event.timestamp,
+        }
+      end
+    else
+      doubleTapState.tapCount = 1
+    end
+    
+    doubleTapState.lastTapTime = currentTime
+    
+    -- Fire tap gesture
+    return {
+      type = GestureType.TAP,
+      state = GestureState.ENDED,
+      x = event.x,
+      y = event.y,
+      timestamp = event.timestamp,
+    }
+  end
+end
+
+--- Detect long-press gesture began
+---@param touchId string
+---@param event InputEvent
+function GestureRecognizer:_detectLongPressBegan(touchId, event)
+  -- Long-press detection happens continuously during touch
+  self._gestureStates.longPress[touchId] = {
+    startX = event.x,
+    startY = event.y,
+    startTime = event.timestamp,
+    triggered = false,
+  }
+end
+
+--- Update long-press detection
+---@param touchId string
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_updateLongPress(touchId, event)
+  local lpState = self._gestureStates.longPress[touchId]
+  if not lpState or lpState.triggered then
+    return nil
+  end
+  
+  local duration = event.timestamp - lpState.startTime
+  local dx = event.x - lpState.startX
+  local dy = event.y - lpState.startY
+  local distance = math.sqrt(dx * dx + dy * dy)
+  
+  -- Check if long-press duration reached and movement within threshold
+  if duration >= self._config.longPressMinDuration and distance < self._config.longPressMaxMovement then
+    lpState.triggered = true
+    
+    return {
+      type = GestureType.LONG_PRESS,
+      state = GestureState.BEGAN,
+      x = event.x,
+      y = event.y,
+      timestamp = event.timestamp,
+      duration = duration,
+    }
+  end
+  
+  return nil
+end
+
+--- Detect pan gesture
+---@param touchId string
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_detectPan(touchId, event)
+  local touch = self._touches[touchId]
+  if not touch then
+    return nil
+  end
+  
+  local dx = event.x - touch.startX
+  local dy = event.y - touch.startY
+  local distance = math.sqrt(dx * dx + dy * dy)
+  
+  local panState = self._gestureStates.pan[touchId]
+  
+  if not panState then
+    -- Check if pan should begin
+    if distance >= self._config.panMinMovement then
+      self._gestureStates.pan[touchId] = {
+        active = true,
+        lastX = touch.startX,
+        lastY = touch.startY,
+      }
+      panState = self._gestureStates.pan[touchId]
+      
+      return {
+        type = GestureType.PAN,
+        state = GestureState.BEGAN,
+        x = event.x,
+        y = event.y,
+        dx = dx,
+        dy = dy,
+        timestamp = event.timestamp,
+      }
+    end
+  else
+    -- Pan is active, fire changed event
+    local panDx = event.x - panState.lastX
+    local panDy = event.y - panState.lastY
+    
+    panState.lastX = event.x
+    panState.lastY = event.y
+    
+    return {
+      type = GestureType.PAN,
+      state = GestureState.CHANGED,
+      x = event.x,
+      y = event.y,
+      dx = panDx,
+      dy = panDy,
+      totalDx = dx,
+      totalDy = dy,
+      timestamp = event.timestamp,
+    }
+  end
+  
+  return nil
+end
+
+--- Detect pan ended
+---@param touchId string
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_detectPanEnded(touchId, event)
+  local panState = self._gestureStates.pan[touchId]
+  if panState and panState.active then
+    self._gestureStates.pan[touchId] = nil
+    
+    local touch = self._touches[touchId]
+    local dx = event.x - touch.startX
+    local dy = event.y - touch.startY
+    
+    return {
+      type = GestureType.PAN,
+      state = GestureState.ENDED,
+      x = event.x,
+      y = event.y,
+      dx = dx,
+      dy = dy,
+      timestamp = event.timestamp,
+    }
+  end
+  
+  return nil
+end
+
+--- Detect swipe gesture
+---@param touchId string
+---@param event InputEvent
+function GestureRecognizer:_detectSwipe(touchId, event)
+  -- Swipe detection happens on touch end
+end
+
+--- Detect swipe ended
+---@param touchId string
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_detectSwipeEnded(touchId, event)
+  local touch = self._touches[touchId]
+  if not touch then
+    return nil
+  end
+  
+  local duration = event.timestamp - touch.startTime
+  local dx = event.x - touch.startX
+  local dy = event.y - touch.startY
+  local distance = math.sqrt(dx * dx + dy * dy)
+  
+  -- Check if it's a valid swipe
+  if distance >= self._config.swipeMinDistance and duration <= self._config.swipeMaxDuration then
+    local velocity = distance / duration
+    
+    if velocity >= self._config.swipeMinVelocity then
+      -- Determine swipe direction
+      local angle = math.atan2(dy, dx)
+      local direction = "right"
+      
+      if angle >= -math.pi / 4 and angle < math.pi / 4 then
+        direction = "right"
+      elseif angle >= math.pi / 4 and angle < 3 * math.pi / 4 then
+        direction = "down"
+      elseif angle >= -3 * math.pi / 4 and angle < -math.pi / 4 then
+        direction = "up"
+      else
+        direction = "left"
+      end
+      
+      return {
+        type = GestureType.SWIPE,
+        state = GestureState.ENDED,
+        x = event.x,
+        y = event.y,
+        dx = dx,
+        dy = dy,
+        direction = direction,
+        velocity = velocity,
+        timestamp = event.timestamp,
+      }
+    end
+  end
+  
+  return nil
+end
+
+--- Detect pinch gesture
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_detectPinch(event)
+  -- Get two touches for pinch
+  local touches = {}
+  for touchId, touch in pairs(self._touches) do
+    table.insert(touches, { id = touchId, touch = touch })
+    if #touches >= 2 then
+      break
+    end
+  end
+  
+  if #touches < 2 then
+    return nil
+  end
+  
+  local t1 = touches[1].touch
+  local t2 = touches[2].touch
+  
+  -- Calculate current distance
+  local currentDx = t2.x - t1.x
+  local currentDy = t2.y - t1.y
+  local currentDistance = math.sqrt(currentDx * currentDx + currentDy * currentDy)
+  
+  -- Calculate initial distance
+  local initialDx = t2.startX - t1.startX
+  local initialDy = t2.startY - t1.startY
+  local initialDistance = math.sqrt(initialDx * initialDx + initialDy * initialDy)
+  
+  if initialDistance == 0 then
+    return nil
+  end
+  
+  -- Calculate scale
+  local scale = currentDistance / initialDistance
+  local pinchState = self._gestureStates.pinch
+  
+  if not pinchState.active then
+    -- Check if pinch should begin
+    if math.abs(scale - 1.0) >= self._config.pinchMinScaleChange then
+      pinchState.active = true
+      pinchState.initialScale = scale
+      pinchState.lastScale = scale
+      
+      -- Calculate center point
+      local centerX = (t1.x + t2.x) / 2
+      local centerY = (t1.y + t2.y) / 2
+      
+      return {
+        type = GestureType.PINCH,
+        state = GestureState.BEGAN,
+        scale = scale,
+        centerX = centerX,
+        centerY = centerY,
+        timestamp = event.timestamp,
+      }
+    end
+  else
+    -- Pinch is active, fire changed event
+    local centerX = (t1.x + t2.x) / 2
+    local centerY = (t1.y + t2.y) / 2
+    
+    local scaleChange = scale - pinchState.lastScale
+    pinchState.lastScale = scale
+    
+    return {
+      type = GestureType.PINCH,
+      state = GestureState.CHANGED,
+      scale = scale,
+      scaleChange = scaleChange,
+      centerX = centerX,
+      centerY = centerY,
+      timestamp = event.timestamp,
+    }
+  end
+  
+  return nil
+end
+
+--- Detect rotate gesture
+---@param event InputEvent
+---@return table? Gesture event
+function GestureRecognizer:_detectRotate(event)
+  -- Get two touches for rotation
+  local touches = {}
+  for touchId, touch in pairs(self._touches) do
+    table.insert(touches, { id = touchId, touch = touch })
+    if #touches >= 2 then
+      break
+    end
+  end
+  
+  if #touches < 2 then
+    return nil
+  end
+  
+  local t1 = touches[1].touch
+  local t2 = touches[2].touch
+  
+  -- Calculate current angle
+  local currentAngle = math.atan2(t2.y - t1.y, t2.x - t1.x)
+  
+  -- Calculate initial angle
+  local initialAngle = math.atan2(t2.startY - t1.startY, t2.startX - t1.startX)
+  
+  -- Calculate rotation (in degrees)
+  local rotation = (currentAngle - initialAngle) * 180 / math.pi
+  
+  local rotateState = self._gestureStates.rotate
+  
+  if not rotateState.active then
+    -- Check if rotation should begin
+    if math.abs(rotation) >= self._config.rotateMinAngleChange then
+      rotateState.active = true
+      rotateState.initialRotation = rotation
+      rotateState.lastRotation = rotation
+      
+      -- Calculate center point
+      local centerX = (t1.x + t2.x) / 2
+      local centerY = (t1.y + t2.y) / 2
+      
+      return {
+        type = GestureType.ROTATE,
+        state = GestureState.BEGAN,
+        rotation = rotation,
+        centerX = centerX,
+        centerY = centerY,
+        timestamp = event.timestamp,
+      }
+    end
+  else
+    -- Rotation is active, fire changed event
+    local centerX = (t1.x + t2.x) / 2
+    local centerY = (t1.y + t2.y) / 2
+    
+    local rotationChange = rotation - rotateState.lastRotation
+    rotateState.lastRotation = rotation
+    
+    return {
+      type = GestureType.ROTATE,
+      state = GestureState.CHANGED,
+      rotation = rotation,
+      rotationChange = rotationChange,
+      centerX = centerX,
+      centerY = centerY,
+      timestamp = event.timestamp,
+    }
+  end
+  
+  return nil
+end
+
+--- Cancel all active gestures
+function GestureRecognizer:_cancelAllGestures()
+  for gestureType, state in pairs(self._gestureStates) do
+    if type(state) == "table" and state.active then
+      state.active = false
+    end
+  end
+end
+
+--- Reset gesture recognizer state
+function GestureRecognizer:reset()
+  self._touches = {}
+  self._gestureStates = {
+    tap = nil,
+    doubleTap = { lastTapTime = 0, tapCount = 0 },
+    longPress = {},
+    swipe = {},
+    pan = {},
+    pinch = { active = false },
+    rotate = { active = false },
+  }
+end
+
+-- Export gesture types and states
+GestureRecognizer.GestureType = GestureType
+GestureRecognizer.GestureState = GestureState
+
+return GestureRecognizer