UIImageView手势（缩放、旋转）问题

Question

我想对 UIImageView 进行 2 次操作缩放、旋转，我有 2 个问题：

A. 我对前进行了缩放操作。当我尝试旋转时，UIImageView 设置为初始大小，我想知道如何保持缩放的 UIImageView 并从缩放图像进行旋转。< /p>

B.我想将缩放操作与旋转结合起来，但我不知道如何实现：

- (void)viewDidLoad 
{
    foo = [[UIImageView alloc]initWithFrame:CGRectMake(100.0, 100.0, 600, 800.0)];
    foo.userInteractionEnabled = YES;
    foo.multipleTouchEnabled  = YES;
    foo.image = [UIImage imageNamed:@"earth.jpg"];
    foo.contentMode = UIViewContentModeScaleAspectFit;
    foo.clipsToBounds = YES;
    
    [self.view addSubview:foo];
}

//---pinch gesture--- 
UIPinchGestureRecognizer *pinchGesture =
[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)];
[foo addGestureRecognizer:pinchGesture]; 
[pinchGesture release];

//---rotate gesture--- 
UIRotationGestureRecognizer *rotateGesture =
[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(handleRotateGesture:)];
[foo addGestureRecognizer:rotateGesture]; 
[rotateGesture release];

//---handle pinch gesture--- 
-(IBAction) handlePinchGesture:(UIGestureRecognizer *) sender {
    NSLog(@"Pinch");
    CGFloat factor = [(UIPinchGestureRecognizer *) sender scale];
    if (factor > 1) { 
        //---zooming in--- 
        sender.view.transform = CGAffineTransformMakeScale(
                                                           lastScaleFactor + (factor-1),
                                                           lastScaleFactor + (factor-1)); 
    } 
    else {
        //---zooming out--- 
        sender.view.transform = CGAffineTransformMakeScale(lastScaleFactor * factor, lastScaleFactor * factor);
    }
    if (sender.state == UIGestureRecognizerStateEnded) { 
        if (factor > 1) {
            lastScaleFactor += (factor-1); 
        } else {
            lastScaleFactor *= factor;
        }
    }
}

//---handle rotate gesture--- 
-(IBAction) handleRotateGesture:(UIGestureRecognizer *) sender {
    CGFloat rotation = [(UIRotationGestureRecognizer *) sender rotation]; 
    CGAffineTransform transform = CGAffineTransformMakeRotation(rotation + netRotation); 
    sender.view.transform = transform;
    if (sender.state == UIGestureRecognizerStateEnded) { 
        netRotation += rotation;
    }
}

谢谢

Answer 1

我知道这是一个相当古老的线程，我遇到了这个 imageview 子类，它非常适合缩放、旋转和平移。它在图像视图上使用手势识别器。我正在将其用于我的应用程序之一。

ZoomRotatePanImageView

Answer 2

当您使用 CGAffineTransformMakeScale 时，每次使用都会重置 Identity 的转换，并且会丢失之前的转换信息。

尝试使用 CGAffineTransformScale(view.transform,scale,scale) 进行捏缩放。不过，您需要保留原始帧大小以控制缩放。
请参阅：如何我使用捏缩放（UIPinchGestureRecognizer）来更改 UITextView 的宽度？

对于旋转类似：

   if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
        view.transform = CGAffineTransformRotate([view transform], [gestureRecognizer rotation]);
        [gestureRecognizer setRotation:0];
    }

Answer 3

我在斯坦福大学网站上找到了您可能感兴趣的内容：

http://www.stanford.edu/class/cs193p/cgi-bin/drupal/downloads-2010-winter

在此网站上，您需要向下滚动，直到看到数字14：“标题：讲座 #14 - MultiTouch”

下载：“14_MultiTouchDemo.zip”

在此示例中，您可以同时缩放和旋转每个图像。

希望我有帮助:)

Answer 4

只需实现 gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: 在您的委托中。

我设置了一个 UIPinchGestureRecognizer、一个 UIPanGestureRecognizer 和一个 UIRotationGestureRecognizer，我希望它们同时工作。我还有一个 UITapGestureRecognizer，我不希望同时被识别。我所做的只是这样：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    if (![gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]] && ![otherGestureRecognizer isKindOfClass:[UITapGestureRecognizer class]]) {
        return YES;
    }

    return NO;
}

Answer 5

希望这对你有帮助，这就是我通常实现手势识别器的方式：

UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotatePiece:)];
[piece addGestureRecognizer:rotationGesture];
[rotationGesture release];

UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scalePiece:)];
[pinchGesture setDelegate:self];
[piece addGestureRecognizer:pinchGesture];
[pinchGesture release];

旋转方法：应用后将手势识别器的旋转重置为 0，因此下一个回调是当前旋转的增量 缩放

- (void)rotatePiece:(UIRotationGestureRecognizer *)gestureRecognizer {
    [self adjustAnchorPointForGestureRecognizer:gestureRecognizer];

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
        [gestureRecognizer view].transform = CGAffineTransformRotate([[gestureRecognizer view] transform], [gestureRecognizer rotation]);
        [gestureRecognizer setRotation:0];
    }
}

方法，最后重置手势识别器的缩放应用后为 1，因此下一个回调是当前比例的增量

- (void)scalePiece:(UIPinchGestureRecognizer *)gestureRecognizer {
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
        [gestureRecognizer view].transform = CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]);
        [gestureRecognizer setScale:1];
    }
}

确保特定视图上的捏合、平移和旋转手势识别器都可以同时识别 防止其他手势识别器同时识别

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
// if the gesture recognizers are on different views, don't allow simultaneous recognition
if (gestureRecognizer.view != otherGestureRecognizer.view)
    return NO;

// if either of the gesture recognizers is the long press, don't allow simultaneous recognition
if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]] || [otherGestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]])
    return NO;

    return YES;
}

比例和旋转变换是相对于视图应用的图层的锚点此方法在用户手指之间移动手势识别器视图的锚点

- (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer {
    if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {
        UIView *piece = gestureRecognizer.view;
        CGPoint locationInView = [gestureRecognizer locationInView:piece];
        CGPoint locationInSuperview = [gestureRecognizer locationInView:piece.superview];

        piece.layer.anchorPoint = CGPointMake(locationInView.x / piece.bounds.size.width, locationInView.y / piece.bounds.size.height);
        piece.center = locationInSuperview;
    }
}