Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/DrawingUI/Sources/DrawingGesture.swift

@@ -0,0 +1,103 @@
+import Foundation
+import UIKit
+
+class DrawingGestureRecognizer: UIPanGestureRecognizer {
+    var shouldBegin: (CGPoint) -> Bool = { _ in return true }
+    
+    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
+        if touches.count == 1, let touch = touches.first, self.shouldBegin(touch.location(in: self.view)) {
+            super.touchesBegan(touches, with: event)
+            self.state = .began
+        }
+    }
+    
+    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent) {
+        if touches.count > 1 {
+            self.state = .cancelled
+        } else {
+            super.touchesMoved(touches, with: event)
+        }
+    }
+}
+
+struct DrawingPoint {
+    let location: CGPoint
+    let velocity: CGFloat
+    
+    var x: CGFloat {
+        return self.location.x
+    }
+    
+    var y: CGFloat {
+        return self.location.y
+    }
+}
+
+final class DrawingGesturePipeline: NSObject, UIGestureRecognizerDelegate {
+    enum DrawingGestureState {
+        case began
+        case changed
+        case ended
+        case cancelled
+    }
+    
+    var onDrawing: (DrawingGestureState, DrawingPoint) -> Void = { _, _ in }
+    
+    var gestureRecognizer: DrawingGestureRecognizer?
+    var transform: CGAffineTransform = .identity
+        
+    var enabled: Bool = true
+    
+    weak var drawingView: DrawingView?
+    
+    init(drawingView: DrawingView, gestureView: UIView) {
+        self.drawingView = drawingView
+        
+        super.init()
+    
+        let gestureRecognizer = DrawingGestureRecognizer(target: self, action: #selector(self.handleGesture(_:)))
+        gestureRecognizer.delegate = self
+        self.gestureRecognizer = gestureRecognizer
+        gestureView.addGestureRecognizer(gestureRecognizer)
+    }
+    
+    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
+        return self.enabled
+    }
+    
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+        if otherGestureRecognizer is UIPinchGestureRecognizer {
+            return true
+        }
+        return false
+    }
+    
+    var previousPoint: DrawingPoint?
+    @objc private func handleGesture(_ gestureRecognizer: DrawingGestureRecognizer) {
+        let state: DrawingGestureState
+        switch gestureRecognizer.state {
+        case .began:
+            state = .began
+        case .changed:
+            state = .changed
+        case .ended:
+            state = .ended
+        case .cancelled:
+            state = .cancelled
+        case .failed:
+            state = .cancelled
+        case .possible:
+            state = .cancelled
+        @unknown default:
+            state = .cancelled
+        }
+        
+        let originalLocation = gestureRecognizer.location(in: self.drawingView)
+        let location = originalLocation.applying(self.transform)
+        let velocity = gestureRecognizer.velocity(in: self.drawingView).applying(self.transform)
+        let velocityValue = velocity.length
+        
+        let point = DrawingPoint(location: location, velocity: velocityValue)
+        self.onDrawing(state, point)
+    }
+}