变形

变形 （transform）：
什么是变形
视图发生了 位移， 缩放， 旋转这样的变化叫做变形

如何实现视图的变形
通过修改视图对象 transform属性就能完成变形

transform属性
** 类型** CGAffineTransform （结构体类型）
** 修改transform**
1、translation 位移
2、scale 缩放
3、rotation 旋转
4、CGAffineTransformMakeTranslation //位移变化,变形是基于变形前的那个基础状态

CGAffineTransformTranslate
CGAffineTransformMakeScale
CGAffineTransformScale
CGAffineTransformMakeRotation
CGAffineTransformRotate

清除视图的所有变形
CGAffineTransformIdentity

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
//位移变化
//CGAffineTransformMakeTranslation 变形是基于变形前的那个基础状态
// self.imageView.transform = CGAffineTransformMakeTranslation(50, 50);
//变形是在 当前 变形基础上 继续变形
self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, 50, 50);

//缩放变形

// self.imageView.transform = CGAffineTransformMakeScale(1.1, 1.5);
self.imageView.transform = CGAffineTransformScale(self.imageView.transform, 1.02, 1.02);

//旋转变化

// self.imageView.transform = CGAffineTransformMakeRotation(M_PI_4);
self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, M_PI_4);//45度

NSLog(@"transform %@",NSStringFromCGAffineTransform(self.imageView.transform));

}

bounds:
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@end

@implementation ViewController

//手势代理方法 返回YES是可以同时触发
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}

• (void)viewDidLoad {
  [super viewDidLoad];
  //拖拽
  UIPanGestureRecognizer *panGR = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGR:)];
  self.imageView.userInteractionEnabled = YES;
  [self.view addGestureRecognizer:panGR];
  //捏合
  UIPinchGestureRecognizer *pinchGR = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinchGR:)];
  pinchGR.delegate = self;
  [self.view addGestureRecognizer:pinchGR];
  //旋转
  UIRotationGestureRecognizer *rotationGR = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotationGR:)];
  rotationGR.delegate = self;
  [self.view addGestureRecognizer:rotationGR];
  //点击
  UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGR:)];
  [self.view addGestureRecognizer:tapGR];

}

-(void)tapGR:(UITapGestureRecognizer*)gr {
self.imageView.transform = CGAffineTransformIdentity;
}

-(void)rotationGR:(UIRotationGestureRecognizer*)gr {
CGFloat rotation = gr.rotation;
self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotation);
gr.rotation = 0;
}

-(void)pinchGR:(UIPinchGestureRecognizer*)gr {
CGFloat scale = gr.scale;
self.imageView.transform = CGAffineTransformScale(self.imageView.transform, scale, scale);
gr.scale = 1;
}

-(void)panGR:(UIPanGestureRecognizer*)gr {
// CGPoint translation = [gr translationInView:self.view];
// CGPoint center = self.imageView.center;
// center.x += translation.x;
// center.y += translation.y;
// self.imageView.center = center;
// [gr setTranslation:CGPointZero inView:self.view];

CGPoint translation = [gr translationInView:self.view];
self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, translation.x, translation.y);
[gr setTranslation:CGPointZero inView:self.view];

}

深入坐标系：

• (void)viewDidLoad {
  [super viewDidLoad];
  [self printInfo];
  NSLog(@"============================");
  [self changeTransform];
  }
  -(void)printInfo{
  NSLog(@"\nframe:%@\nbounds:%@\ncenter:%@\ntransform:%@\n",
  NSStringFromCGRect(self.myView.frame),
  NSStringFromCGRect(self.myView.bounds),
  NSStringFromCGPoint(self.myView.center),
  NSStringFromCGAffineTransform(self.myView.transform)
  );
  }
  -(void)changeFrame {
  CGRect frame = self.myView.frame;
  frame.origin.x += 10;
  frame.origin.y += 10;
  frame.size.width += 100;
  frame.size.height += 100;
  self.myView.frame = frame;
  [self printInfo];
  }
  -(void)changeBounds {
  CGRect bounds = self.myView.bounds;
  // bounds.origin.x += 10;
  // bounds.origin.y += 10;
  bounds.size.width += 100;
  bounds.size.height += 100;
  self.myView.bounds = bounds;
  [self printInfo];
  }

-(void)changeCenter {
CGPoint center = self.myView.center;
center.x += 100;
center.y += 100;
self.myView.center = center;
[self printInfo];
}