如何实现单指旋转手势识别器？

Question

我知道 UIRotateGestureRecognizer 已经成为 iOS 的一部分。但这个手势需要两根手指。如何实现仅需要一根手指的类似手势识别器？ AppStore 中有一款游戏 - Gyrotate 很好地实现了这一点。任何线索表示赞赏。谢谢。

Answer 1

Kirby Turner 在此处有一个完整的单指旋转手势识别器。

Answer 2

这是代码 - 它可以在我的模拟器上运行。马克回答说，如果这就是您所寻找的。

    // On new touch, start a new array of points
- (void) touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event
{
    self.points = [NSMutableArray array];
    CGPoint pt = [[touches anyObject] locationInView:self];
    [self.points addObject:[NSValue valueWithCGPoint:pt]];
}

// Add each point to the array
- (void) touchesMoved:(NSSet *) touches withEvent:(UIEvent *) event
{
    CGPoint pt = [[touches anyObject] locationInView:self];
    [self.points addObject:[NSValue valueWithCGPoint:pt]];
    [self setNeedsDisplay];
}

// At the end of touches, determine whether a circle was drawn
- (void) touchesEnded:(NSSet *) touches withEvent:(UIEvent *) event
{
    if (!self.points) return;
    if (self.points.count < 3) return;

    // Test 1: The start and end points must be between 60 pixels of each other
    CGRect tcircle;
    if (distance(POINT(0), POINT(self.points.count - 1)) < 60.0f)
        tcircle = [self centeredRectangle];

    // Test 2: Count the distance traveled in degrees. Must fall within 45 degrees of 2 PI
    CGPoint center = CGPointMake(CGRectGetMidX(tcircle), CGRectGetMidY(tcircle));
    float distance = ABS(acos(dotproduct(centerPoint(POINT(0), center), centerPoint(POINT(1), center))));
    for (int i = 1; i < (self.points.count - 1); i++)
        distance += ABS(acos(dotproduct(centerPoint(POINT(i), center), centerPoint(POINT(i+1), center))));
    if ((ABS(distance - 2 * M_PI) < (M_PI / 4.0f))) circle = tcircle;

    [self setNeedsDisplay];
}

Answer 3

我实现了带有 OneFingerRotation、缩放、调整大小和关闭功能的IQStickerView。

特点：-

1) 一指旋转刻度。

2) 一指调整大小。

3) 使用属性启用/禁用旋转、缩放、调整大小。

4) 自动管理多个IQStickerView。

5) 也可以与 UIScrollView 一起使用。

6）快速响应。

github 存储库在这里：- https://github.com/hackiftekhar/IQStickerView

Answer 4

尝试探索 UIGestureRecognizer 类。您应该能够使用 UIGestureRecognizerDelegate 自定义它

Answer 5

使用平移手势识别器实现，这是使用手势识别器附加到的另一个 UIView，但它应该与附加到您想要旋转的视图一起使用。

- (void) gestureRotateButtonPan:(UIPanGestureRecognizer*) gestureRecognizer {

    switch (gestureRecognizer.state) {
        case UIGestureRecognizerStatePossible:
            break;
        case UIGestureRecognizerStateBegan:
        {
            CGPoint location = [gestureRecognizer translationInView:[gestureRecognizer view]];
            _touchRotateStartPoint = [self convertPoint:location fromView:[gestureRecognizer view]];
        }
            break;
        case UIGestureRecognizerStateChanged:
        {
            CGPoint imageLocation = CGPointMake(self.mainImageView.transform.tx + self.mainImageView.center.x
                                                , self.mainImageView.transform.ty + self.mainImageView.center.y);
            CGPoint buttonLocation = [gestureRecognizer translationInView:self];
            buttonLocation.x += _touchRotateStartPoint.x;
            buttonLocation.y += _touchRotateStartPoint.y;

            CGFloat currentRotation = atan2(buttonLocation.y - imageLocation.y, buttonLocation.x - imageLocation.x)
                                        - atan2(_touchRotateStartPoint.y - imageLocation.y, _touchRotateStartPoint.x - imageLocation.x);

            CGFloat rotation = -(_lastRotation - currentRotation);
            CGAffineTransform currentTransform = self.mainImageView.transform;
            CGAffineTransform rotatedTransform = CGAffineTransformRotate(currentTransform, rotation);
            self.mainImageView.transform = rotatedTransform;

            [self setNeedsDisplay];
        }
            break;
        case UIGestureRecognizerStateCancelled:
        case UIGestureRecognizerStateEnded:
            _lastRotation = 0.0;
            break;
        case UIGestureRecognizerStateFailed:
            break;
        default:
            break;
    }
}

Answer 6

使用 PanGestureRecogniser 在 UIView 上进行一指旋转

使用 Swift5 实现全功能代码

import UIKit

class ViewController: UIViewController {
    
    //Variable for rotating
    private var deltaAngle:CGFloat = 0
    
    let squareView : UIView = {
        let anyView = UIView()
        anyView.backgroundColor = .red
        anyView.isUserInteractionEnabled = true
        anyView.isMultipleTouchEnabled = true
        return anyView
        
    }()
    
    let rotateButton : UIButton = {
        let button = UIButton()
        button.backgroundColor = .black
        button.setImage(UIImage(systemName: "rotate.right"), for: .normal)
        return button
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        squareView.frame = CGRect(x: 50, y: 50, width: 100, height: 100)
        rotateButton.frame = CGRect(x: 0, y: squareView.frame.height-30, width: 30, height: 30)
        squareView.center = view.center
        view.addSubview(squareView)
        squareView.addSubview(rotateButton)
        
        let PanToRotate = UIPanGestureRecognizer(target: self, action: #selector(handleRotateGesture(_:)))
        rotateButton.addGestureRecognizer(PanToRotate)
        
    }
    
    
    
    
    @objc func handleRotateGesture(_ recognizer : UIPanGestureRecognizer){
        let touchLocation = recognizer.location(in: squareView.superview)
        
        let center = squareView.center
        
        switch recognizer.state{
            
        case .began :
            self.deltaAngle = atan2(touchLocation.y - center.y, touchLocation.x - center.x) - atan2(squareView.transform.b, squareView.transform.a)
            
        case .changed:
            let angle = atan2(touchLocation.y - center.y, touchLocation.x - center.x)
            
            let angleDiff = self.deltaAngle - angle
            
            squareView.transform = CGAffineTransform(rotationAngle: -angleDiff)
                        
        default: break
            
        }
        
    }
    
}