CGAffineTransform

//移动效果
CGAffineTransform CGAffineTransformMakeTranslation (    CGFloat tx,    CGFloat ty );
 
CGAffineTransform CGAffineTransformTranslate (    CGAffineTransform t,    CGFloat tx,    CGFloat ty );
 
//旋转效果
CGAffineTransform CGAffineTransformMakeRotation (    CGFloat angle );
 
CGAffineTransform CGAffineTransformRotate (    CGAffineTransform t,    CGFloat angle );
 
//缩放效果
CGAffineTransform CGAffineTransformMakeScale (    CGFloat sx,    CGFloat sy );
 
CGAffineTransform CGAffineTransformScale (    CGAffineTransform t,    CGFloat sx,    CGFloat sy );
 
//反转效果
CGAffineTransform CGAffineTransformInvert (    CGAffineTransform t );
 
//只对局部产生效果
CGRect CGRectApplyAffineTransform (    CGRect rect,    CGAffineTransform t );
 
//判断两个AffineTrans是否相等
bool CGAffineTransformEqualToTransform (    CGAffineTransform t1,    CGAffineTransform t2 );
 
//获得Affine Transform
CGAffineTransform CGContextGetUserSpaceToDeviceSpaceTransform (    CGContextRef c );
 
//下面的函数只起到查看的效果，比如看一下这个用户空间的点，转换到设备空间去坐标是多少
 
CGPoint CGContextConvertPointToDeviceSpace (    CGContextRef c,    CGPoint point );
 
CGPoint CGContextConvertPointToUserSpace (    CGContextRef c,    CGPoint point );
 
CGSize CGContextConvertSizeToDeviceSpace (    CGContextRef c,    CGSize size );
 
CGSize CGContextConvertSizeToUserSpace (    CGContextRef c,    CGSize size );
 
CGRect CGContextConvertRectToDeviceSpace (    CGContextRef c,    CGRect rect );
 
CGRect CGContextConvertRectToUserSpace (    CGContextRef c,    CGRect rect );

了解动画需要先了解仿射变换,先在View中添加一个按钮和一个图片, 通过这演示常见的变换,直接上码：

#import "ViewController.h"
 
#define M_PI        3.14159265358979323846264338327950288
<br>#define M_PI_2      1.57079632679489661923132169163975144
<br>#define M_PI_4      0.785398163397448309615660845819875721
@interface ViewController ()
{
    UIButton *btn;
    UIImageView *imgview;
}
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    btn=[UIButton buttonWithType:UIButtonTypeSystem];
    btn.frame=CGRectMake(30, 30, 50, 50);
    btn.backgroundColor=[UIColor redColor];
   
    [btn setTitle:@"按钮" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(btnclick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
     
    imgview=[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"test.jpg"]];
    imgview.frame=CGRectMake(100, 100, 120, 120);
    [self.view addSubview:imgview];
     
}

//平移变换
  imgview.transform=CGAffineTransformMakeTranslation(10, 10); //每次移动参照点都是初始点
  imgview.transform=CGAffineTransformTranslate(imgview.transform, 20, 20);//平移参照第一个参数的点
  imgview.transform=CGAffineTransformIdentity;//初始点

//旋转
   imgview.transform=CGAffineTransformMakeRotation(M_PI/4);//旋转参照初始值 正数顺时针 负数逆时针
   imgview.transform=CGAffineTransformRotate(imgview.transform, -M_PI/4);//旋转参照第一个参数的值

// 缩放
    imgview.transform=CGAffineTransformScale(imgview.transform,0.8,0.8);//在第一个参数的基础上缩放 第二三参数1时为正常大小
    imgview.transform=CGAffineTransformMakeScale(0.5,0.5);//在原视图的基础上缩放

//翻转
   // CGAffineTransform DefaultAffineTransform =CGAffineTransformMake(1, 0, 0, 1, 0, 0);//默认
   // imgview.transform=CGAffineTransformInvert(imgview.transform); //调用此行代码并不会产生翻转效果,因为恒等矩阵＊恒等矩阵还是恒等矩阵，这样就没有变化
    CGAffineTransform AffineTransform =CGAffineTransformMake(0, 1, 1, 1, 1, 0);
    imgview.transform=CGAffineTransformInvert(AffineTransform);

//合并 将两个仿射合并成一个仿射效果
//    CGAffineTransform AffineTransform1 =CGAffineTransformMakeScale(0.5,0.5);
     CGAffineTransform AffineTransform1=CGAffineTransformScale(imgview.transform,0.8,0.8);
     CGAffineTransform AffineTransform2 =CGAffineTransformMakeRotation(M_PI/4);
     CGAffineTransform AffineTransform3=CGAffineTransformConcat(AffineTransform1,AffineTransform2);
    CGAffineTransform AffineTransform4 =CGAffineTransformMake(0, 1, 1, 1, 1, 0);
    imgview.transform=CGAffineTransformConcat(AffineTransform3,AffineTransform4);

CGAffineTransform DefaultAffineTransform =CGAffineTransformMake(1, 0, 0, 1, 0, 0);
      CGAffineTransform DefaultAffineTransform1 =CGAffineTransformMake(1, 0, 0, 1, 0, 0);
//      CGAffineTransform AffineTransform1 =CGAffineTransformMakeScale(0.5,0.5);
      bool flag=CGAffineTransformEqualToTransform(DefaultAffineTransform, DefaultAffineTransform1);
      NSLog(@"%d",flag);