iPhone: как повернуть UIImageview влево или вправо?

Я возился с этим в прошлом году. Это оказалось сложнее, чем я думал. IIRC, этот маленький класс сделал то, что вы хотели. Это UIButtonSubclass, который отображает изображение и реагирует на щелчки и перетаскивания. Обратите внимание, что это просто скретч-код. Он не выполняет никакого управления памятью, очистки и т. Д.

#import <UIKit/UIKit.h>
#import "BackgroundImageButton.h"
#import "WiggleImageView.h"

@interface StickerButton : UIButton {
    //ivars used to control selection animaiton
    CGAffineTransform startTransform;
    BOOL currentlyAnimating;
    BOOL shouldAnimate; 
    //ivars to handle touches and control events
    BOOL wasDrag;
    BOOL wasTouchDown;
  WiggleImageView * imgView;
}
//ivars used to control selection animaiton
@property CGAffineTransform startTransform;
@property(nonatomic, retain)  WiggleImageView *imgView;
@property BOOL currentlyAnimating;
@property BOOL shouldAnimate;
//ivars to handle touches and control events
@property BOOL wasDrag;
@property BOOL wasTouchDown;


#pragma mark Initialization
-(id) initWithImage:(UIImage *)anImage atCenterPoint:(CGPoint) centerPoint;

#pragma mark Selection Animation Methods
-(void) animateSelection;
-(void) animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context;

#pragma mark Self Touch Methods  //not as dirty as it sounds.
-(void) touchDragSelf:(id)sender withEvent:(UIEvent *) theEvent;
-(void) touchDownSelf:(id)sender withEvent:(UIEvent *) theEvent;
-(void) touchUpSelf:(id)sender withEvent:(UIEvent *) theEvent;

#pragma mark Graphic Edit Methods
-(void) rotateRight;
-(void) rotateLeft;
-(void) scaleUp;
-(void) scaleDown;
-(void) select;
-(void) deselect;
-(void) translateMoveByX:(CGFloat) dx andY:(CGFloat) dy; //used by self to account for translated coordinates
-(void) frameMoveByX:(CGFloat) dx andY:(CGFloat) dy; //used by external to move frame in superview    
@end

#import "StickerButton.h"

@implementation StickerButton
@synthesize startTransform;
@synthesize currentlyAnimating;
@synthesize shouldAnimate;
@synthesize wasDrag;
@synthesize wasTouchDown;
@synthesize imgView;


#pragma mark Initialization
- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        startTransform=self.transform;
        currentlyAnimating=NO;
        shouldAnimate=NO;
        wasDrag=NO;
        wasTouchDown=NO;
        self.adjustsImageWhenDisabled=NO;
        self.adjustsImageWhenHighlighted=NO;
        self.showsTouchWhenHighlighted=NO;
        [self addTarget:self action:@selector(touchDownSelf:withEvent:) forControlEvents:UIControlEventTouchDown];
        [self addTarget:self action:@selector(touchDragSelf:withEvent:) forControlEvents:UIControlEventTouchDragInside];
        [self addTarget:self action:@selector(touchUpSelf:withEvent:) forControlEvents:UIControlEventTouchUpInside];
    }
    return self;
}

-(id) initWithImage:(UIImage *)anImage atCenterPoint:(CGPoint) centerPoint{
    CGFloat xOrigin,yOrigin;
    xOrigin=centerPoint.x-(anImage.size.width/2);
    yOrigin=centerPoint.y-(anImage.size.height/2);
    [self initWithFrame:CGRectMake(xOrigin, yOrigin, anImage.size.width, anImage.size.height)];
    WiggleImageView *w=[[WiggleImageView alloc] initWithFrame:self.bounds];
    imgView=w;
    imgView.image=anImage;
    [self addSubview:imgView];
    return self;
}//------------------------------------initWithImage:atCenterPoint:------------------------------------



#pragma mark Selection Animation Methods
-(void) animateSelectedThrob{
    if (!currentlyAnimating) {
        NSLog(@"animating");
        currentlyAnimating=YES;
        //startTransform=self.transform; //this has to be saved to prevent some kind of rounding error from gradually rotating the view
        [UIView beginAnimations:@"selectionAnimation" context:nil];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.1];
        [UIView setAnimationRepeatCount:1];
        [UIView setAnimationRepeatAutoreverses:YES];
        self.transform=CGAffineTransformScale(self.transform, 1.1, 1.1);
        [UIView commitAnimations];
    } 
}//-------------------------------------(void) animateSelectedThrob------------------------------------


-(void) animateSelection{
    if (!currentlyAnimating) {
        //NSLog(@"animating");
        currentlyAnimating=YES;
        startTransform=self.transform; //this has to be saved to prevent some kind of rounding error from gradually rotating the view
        [UIView beginAnimations:@"selectionAnimation" context:nil];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.1];
        [UIView setAnimationRepeatCount:2];
        [UIView setAnimationRepeatAutoreverses:YES];
        self.transform=CGAffineTransformRotate(self.transform, (2 * M_PI / 180) );
        [UIView commitAnimations];
    } 

}//-------------------------------------(void) animateSelection------------------------------------

-(void) animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context{
    self.transform=startTransform;
    currentlyAnimating=NO;
    if (shouldAnimate) {

        [self animateSelection];
    }   
}//------------------------------------animationDidStop:finished:context:------------------------------------

#pragma mark Self Touch Methods

-(void) touchDownSelf:(id)sender withEvent:(UIEvent *) theEvent{
    NSLog(@"touchDownSelf");
    wasTouchDown=YES;
    shouldAnimate=NO;
}//------------------------------------touchDownSelf:withEvent:------------------------------------

-(void) touchDragSelf:(id)sender withEvent:(UIEvent *) theEvent{
    NSLog(@"touchDragSelf");
    if ([[theEvent touchesForView:self] count]==1) {
        UITouch *t=[[theEvent touchesForView:self] anyObject];
        CGPoint l,p;
        l=[t locationInView:self];
        p=[t previousLocationInView:self];
        [self translateMoveByX:(l.x-p.x) andY:(l.y-p.y)];
        wasDrag=YES;        
    }

}//------------------------------------touchDragSelf:withEvent:------------------------------------

-(void) touchUpSelf:(id)sender withEvent:(UIEvent *) theEvent{
    NSLog(@"touchUpSelf");
//  if (!wasDrag && wasTouchDown) {
//      [self select];
//  }
    if (wasTouchDown) {
        [self select];
    }
    wasDrag=NO;
    wasTouchDown=NO;
}//------------------------------------touchUpSelf:withEvent:------------------------------------

#pragma mark Graphic Edit Methods 
-(void) rotateRight{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.1];
    [UIView setAnimationBeginsFromCurrentState:YES];
    self.transform=CGAffineTransformRotate(self.transform, (M_PI / 180) );
    [UIView commitAnimations];  
}//-------------------------------------(void) rotateRight------------------------------------

-(void) rotateLeft{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.1];
    [UIView setAnimationBeginsFromCurrentState:YES];
    self.transform=CGAffineTransformRotate(self.transform, (-1*M_PI / 180) );
    [UIView commitAnimations];
}//-------------------------------------(void) rotateLeft------------------------------------

-(void) scaleUp{
    //todo add variable to track total scale so it doesn't get to big and cause problems
    shouldAnimate=NO;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.1];
    [UIView setAnimationBeginsFromCurrentState:YES];
    self.transform=CGAffineTransformScale(self.transform, 1.1, 1.1);
    [UIView commitAnimations];
    startTransform=self.transform;
}//-------------------------------------(void) scaleUp------------------------------------

-(void) scaleDown{
    //todo add variable to track total scale so it doesn't get to small and cause problems
    shouldAnimate=NO;
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.1];
    [UIView setAnimationBeginsFromCurrentState:YES];
    self.transform=CGAffineTransformScale(self.transform, 0.9, 0.9);
    [UIView commitAnimations];
    startTransform=self.transform;
}//-------------------------------------(void) scaleDown------------------------------------

-(void) select{ 
    [self animateSelectedThrob];
    imgView.shouldWiggle=YES;
}
//-------------------------------------(void) select------------------------------------

-(void) deselect{
    imgView.shouldWiggle=NO;
}

-(void) translateMoveByX:(CGFloat) dx andY:(CGFloat) dy{ //necessary for all points that orignate within the transformed view
    NSLog(@"dx=%f,dy=%f",dx,dy);
    shouldAnimate=NO;
    self.transform=CGAffineTransformTranslate(self.transform, dx,dy);
    startTransform=self.transform;
}//------------------------------------translateMoveByX:andY:------------------------------------

-(void) frameMoveByX:(CGFloat) dx andY:(CGFloat) dy{ //necessary for all points that originate outside the transformed view

    self.frame=CGRectMake(self.frame.origin.x+dx, self.frame.origin.y+dy, self.frame.size.width, self.frame.size.height);
}//------------------------------------frameMoveByX:andY:------------------------------------
- (void)drawRect:(CGRect)rect {
    // Drawing code
}

- (void)dealloc {
    [super dealloc];
}

@end

У вас может быть ivar в вашем контроллере для отслеживания начала перетаскивания. Когда вы получите событие «приземление», сохраните начальную точку. Когда вы получаете события «перемещено касанием», рассчитайте расстояние от текущей точки до сохраненной точки. Евклидово расстояние между ними может дать вам вращение (знак, указывающий, в каком направлении вращаться). Соответствующим образом масштабируйте поворот (т. е., возможно, половина ширины представления эквивалентна 180 градусам) и установите поворот преобразования изображения.