UIImage 旋转和保存旋转 (转载)

 1 @interface ViewController ()
 2 {
 3     UIImageView * iv;
 4 }
 5 @end
 6 
 7 @implementation ViewController
 8 
 9 - (void)viewDidLoad
10 {
11     [super viewDidLoad];
12     // Do any additional setup after loading the view, typically from a nib.
13     
14     CGRect rect = [[UIScreen mainScreen] bounds];
15     
16     // 图像
17     iv = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"haha.png"]];
18     iv.frame = CGRectMake(60, 100, 200, 200);
19     [self.view addSubview:iv];
20     
21     // 旋转按扭
22     UIButton * rotateBtn = [UIButton buttonWithType:UIButtonTypeCustom];
23     rotateBtn.frame = CGRectMake(0, rect.size.height-44, rect.size.width, 44);
24     rotateBtn.backgroundColor = [UIColor greenColor];
25     [rotateBtn addTarget:self action:@selector(rotateBtnClick) forControlEvents:UIControlEventTouchUpInside];
26     [self.view addSubview:rotateBtn];
27 }
28 
29 #pragma mark - 调用图片旋转方法并保存旋转
30 - (void)rotateBtnClick
31 {
32     iv.image = [self image:iv.image rotation:UIImageOrientationRight];
33     
34     NSString * path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
35     NSString * filePath = [NSString stringWithFormat:@"%@/rotateImage.png", path];
36     NSData * data = UIImagePNGRepresentation(iv.image);
37     [data writeToFile:filePath atomically:YES];
38 }
39 
40 #pragma mark - 图片旋转方法
41 - (UIImage *)image:(UIImage *)image rotation:(UIImageOrientation)orientation
42 {
43     long double rotate = 0.0;
44     CGRect rect;
45     float translateX = 0;
46     float translateY = 0;
47     float scaleX = 1.0;
48     float scaleY = 1.0;
49     
50     switch (orientation) {
51         case UIImageOrientationLeft:
52             rotate = M_PI_2;
53             rect = CGRectMake(0, 0, image.size.height, image.size.width);
54             translateX = 0;
55             translateY = -rect.size.width;
56             scaleY = rect.size.width/rect.size.height;
57             scaleX = rect.size.height/rect.size.width;
58             break;
59         case UIImageOrientationRight:
60             rotate = 3 * M_PI_2;
61             rect = CGRectMake(0, 0, image.size.height, image.size.width);
62             translateX = -rect.size.height;
63             translateY = 0;
64             scaleY = rect.size.width/rect.size.height;
65             scaleX = rect.size.height/rect.size.width;
66             break;
67         case UIImageOrientationDown:
68             rotate = M_PI;
69             rect = CGRectMake(0, 0, image.size.width, image.size.height);
70             translateX = -rect.size.width;
71             translateY = -rect.size.height;
72             break;
73         default:
74             rotate = 0.0;
75             rect = CGRectMake(0, 0, image.size.width, image.size.height);
76             translateX = 0;
77             translateY = 0;
78             break;
79     }
80     
81     UIGraphicsBeginImageContext(rect.size);
82     CGContextRef context = UIGraphicsGetCurrentContext();
83     
84     //做CTM变换
85     CGContextTranslateCTM(context, 0.0, rect.size.height);
86     CGContextScaleCTM(context, 1.0, -1.0);
87     CGContextRotateCTM(context, rotate);
88     CGContextTranslateCTM(context, translateX, translateY);
89     CGContextScaleCTM(context, scaleX, scaleY);
90     
91     //绘制图片
92     CGContextDrawImage(context, CGRectMake(0, 0, rect.size.width, rect.size.height), image.CGImage);
93     
94     UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
95     
96     return newPic;
97 }