图片的缩放与旋转_短视频图片不可缩放旋转-优快云博客

本文介绍了一个使用iOS手势识别实现图片缩放与旋转的功能。通过UIPinchGestureRecognizer与UIRotationGestureRecognizer来捕捉用户的捏合与旋转手势，并据此更新图片视图的变换矩阵。

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通过手势识别实现图片的缩放与旋转

#import <UIKit/UIKit.h>

@interface BIDViewController : UIViewController <UIGestureRecognizerDelegate>

@property (strong, nonatomic) UIImageView *imageView;

@end

#import "BIDViewController.h"

@interface BIDViewController ()

@end

@implementation BIDViewController {
    CGFloat scale, previousScale;
    CGFloat rotation, previousRotation;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    previousScale = 1;
    UIImage *image = [UIImage imageNamed:@"test"];
    self.imageView = [[UIImageView alloc] initWithImage:image];
    self.imageView.userInteractionEnabled = NO;
    self.imageView.center = CGPointMake(160, 160);
    [self.view addSubview:self.imageView];
    
    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(doPinch:)];
    pinchGesture.delegate = self;
    [self.view addGestureRecognizer:pinchGesture];
    
    UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(doRotate:)];
    rotationGesture.delegate = self;
    [self.view addGestureRecognizer:rotationGesture];
}

//- (void)didReceiveMemoryWarning
//{
//    [super didReceiveMemoryWarning];
//    // Dispose of any resources that can be recreated.
//}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

- (void)transfromImageView
{
    CGAffineTransform t = CGAffineTransformMakeScale(scale * previousScale, scale * previousScale);
    t = CGAffineTransformRotate(t, rotation + previousRotation);
    self.imageView.transform = t;
}

- (void)doPinch:(UIPinchGestureRecognizer *)gesture
{
    scale = gesture.scale;
    [self transfromImageView];
    if (gesture.state ==  UIGestureRecognizerStateEnded) {
        previousScale = scale * previousScale;
        scale = 1;
    }
}

- (void)doRotate:(UIRotationGestureRecognizer *)gesture
{
    rotation = gesture.rotation;
    [self transfromImageView];
    if (gesture.state == UIGestureRecognizerStateEnded) {
        previousRotation = rotation + previousRotation;
        rotation = 0;
    }
}

@end