iphone - blue - ios guidelines font

iOS Pinch Scale y Two Finger giran al mismo tiempo

Question

Aquí está mi código:

viewDidLoad:

UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinch:)];
[self.canvas addGestureRecognizer:pinch];
pinch.delegate = self;
UIRotationGestureRecognizer *twoFingersRotate = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(pinchRotate:)];
[[self canvas] addGestureRecognizer:twoFingersRotate];
twoFingersRotate.delegate = self;

Código para pellizcos y rotaciones:

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
-(void)pinchRotate:(UIRotationGestureRecognizer*)rotate
{
SMImage *selectedImage = [DataCenter sharedDataCenter].selectedImage;
switch (rotate.state)
{
case UIGestureRecognizerStateBegan:
{
selectedImage.referenceTransform = selectedImage.transform;
break;
}
case UIGestureRecognizerStateChanged:
{
selectedImage.transform = CGAffineTransformRotate(selectedImage.referenceTransform, ([rotate rotation] * 55) * M_PI/180);
break;
}
default:
break;
}
}
-(void)pinch:(UIPinchGestureRecognizer*)pinch
{
SMImage *selectedImage = [DataCenter sharedDataCenter].selectedImage;
[self itemSelected];
switch (pinch.state)
{
case UIGestureRecognizerStateBegan:
{
selectedImage.referenceTransform = selectedImage.transform;
break;
}
case UIGestureRecognizerStateChanged:
{
CGAffineTransform transform = CGAffineTransformScale(selectedImage.referenceTransform, pinch.scale, pinch.scale);
selectedImage.transform = transform;
break;
}
default:
break;
}
}

Mi rotación funciona muy bien por sí misma y mi báscula funciona muy bien por sí misma, pero no funcionarán juntas. Uno siempre funciona o el otro no. Cuando implemento shouldRecognizeSimultaneouslyWithGestureRecognizer, los dos gestos parecen luchar unos contra otros y producen resultados pobres. ¿Qué me estoy perdiendo? (Sí, he implementado <UIGestureRecognizerDelegate> )

Answer 1

Cada vez que se pinch: , simplemente calcula la transformación en función de la escala del reconocedor de pellizco. Cada vez que se pinchRotate: simplemente calcula la transformación en función de la rotación del reconocedor de rotación. Nunca combine la escala y la rotación en una sola transformación.

Aquí hay un enfoque. Date una nueva variable de instancia, _activeRecognizers :

NSMutableSet *_activeRecognizers;

viewDidLoad en viewDidLoad :

_activeRecognizers = [NSMutableSet set];

Use un método como acción para ambos reconocedores:

- (IBAction)handleGesture:(UIGestureRecognizer *)recognizer
{
SMImage *selectedImage = [DataCenter sharedDataCenter].selectedImage;
switch (recognizer.state) {
case UIGestureRecognizerStateBegan:
if (_activeRecognizers.count == 0)
selectedImage.referenceTransform = selectedImage.transform;
[_activeRecognizers addObject:recognizer];
break;
case UIGestureRecognizerStateEnded:
selectedImage.referenceTransform = [self applyRecognizer:recognizer toTransform:selectedImage.referenceTransform];
[_activeRecognizers removeObject:recognizer];
break;
case UIGestureRecognizerStateChanged: {
CGAffineTransform transform = selectedImage.referenceTransform;
for (UIGestureRecognizer *recognizer in _activeRecognizers)
transform = [self applyRecognizer:recognizer toTransform:transform];
selectedImage.transform = transform;
break;
}
default:
break;
}
}

Necesitarás este método de ayuda:

- (CGAffineTransform)applyRecognizer:(UIGestureRecognizer *)recognizer toTransform:(CGAffineTransform)transform
{
if ([recognizer respondsToSelector:@selector(rotation)])
return CGAffineTransformRotate(transform, [(UIRotationGestureRecognizer *)recognizer rotation]);
else if ([recognizer respondsToSelector:@selector(scale)]) {
CGFloat scale = [(UIPinchGestureRecognizer *)recognizer scale];
return CGAffineTransformScale(transform, scale, scale);
}
else
return transform;
}

Esto funciona si solo permite girar y escalar. (¡Incluso lo probé!)

Si desea agregar panoramización, use un método de acción separado y simplemente ajuste selectedImage.center . Intentar hacer panorámicas con rotación y escalado utilizandoImage.transform selectedImage.transform es mucho más complicado.

Answer 2

Para que esto suceda, debe implementar el delegado de gestos shouldRecognizeSimultaneouslyWithGestureRecognizer y colocar los gestos que desea reconocer simultáneamente.

// ensure that the pinch and rotate gesture recognizers on a particular view can all recognize simultaneously
// prevent other gesture recognizers from recognizing simultaneously
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
// if the gesture recognizers''s view isn''t one of our views, don''t allow simultaneous recognition
if (gestureRecognizer.view != firstView && gestureRecognizer.view != secondView)
return NO;
// 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;
}

Este código debe modificarse para la vista para la que desee reconocer los gestos de forma simultánea. El código anterior es lo que necesitas.

Answer 3

Swift 3 con Pan, Girar y Pellizcar

// MARK: - Gesturies
func transformUsingRecognizer(_ recognizer: UIGestureRecognizer, transform: CGAffineTransform) -> CGAffineTransform {
if let rotateRecognizer = recognizer as? UIRotationGestureRecognizer {
return transform.rotated(by: rotateRecognizer.rotation)
}
if let pinchRecognizer = recognizer as? UIPinchGestureRecognizer {
let scale = pinchRecognizer.scale
return transform.scaledBy(x: scale, y: scale)
}
if let panRecognizer = recognizer as? UIPanGestureRecognizer {
let deltaX = panRecognizer.translation(in: imageView).x
let deltaY = panRecognizer.translation(in: imageView).y
return transform.translatedBy(x: deltaX, y: deltaY)
}
return transform
}
var initialTransform: CGAffineTransform?
var gestures = Set<UIGestureRecognizer>(minimumCapacity: 3)
@IBAction func processTransform(_ sender: Any) {
let gesture = sender as! UIGestureRecognizer
switch gesture.state {
case .began:
if gestures.count == 0 {
initialTransform = imageView.transform
}
gestures.insert(gesture)
case .changed:
if var initial = initialTransform {
gestures.forEach({ (gesture) in
initial = transformUsingRecognizer(gesture, transform: initial)
})
imageView.transform = initial
}
case .ended:
gestures.remove(gesture)
default:
break
}
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return true
}