IOS GIF图片的解析

//加载gif   
 
02     
 
03   NSString *filePath = [[NSBundle mainBundle]pathForResource:@"bai3" ofType:@"gif"];   
 
04     
 
05     NSData *data = [NSData dataWithContentsOfFile:filePath];   
 
06     
 
07     CGImageSourceRef gif = CGImageSourceCreateWithData((CFDataRef)data, nil);   
 
08     
 
09  //获取gif的各种属性   
 
10     
 
11     CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,0,NULL));   
 
12     
 
13     NSLog(@"_______%@",gifprops);   
 
14     
 
15     
 
16     NSInteger count =CGImageSourceGetCount(gif);   
 
17     
 
18     NSLog(@"________%d",count);   
 
19     
 
20     
 
21    CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);   
 
22     
 
23  CFDictionaryRef delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);   
 
24     
 
25     NSLog(@"_______%@",delay);    
 
26     
 
27     
 
28  //[gifDic objectForKey:(NSString *)kCGImagePropertyGIFDelayTime];   
 
29     
 
30     //    NSNumber * w = CFDictionaryGetValue(gifprops, @"PixelWidth");   
 
31     
 
32     //    NSNumber * h =CFDictionaryGetValue(gifprops, @"PixelHeight");   
 
33     
 
34     //    float totalDuration = delay.doubleValue * count;   
 
35     
 
36     //    float pixelWidth = w.intValue;   
 
37     
 
38     //    float pixelHeight = h.intValue;   
 
39     
 
40   //将gif解析成UIImage类型对象，并加进images数组中     
 
41     
 
42     
 
43     NSMutableArray *images = [NSMutableArray arrayWithCapacity:count];   
 
44     
 
45     for(int index=0;index<count;index++)   
 
46     
 
47     {   
 
48     
 
49         CGImageRef ref = CGImageSourceCreateImageAtIndex(gif, index, nil);   
 
50     
 
51         UIImage *img = [UIImage imageWithCGImage:ref];   
 
52     
 
53         [images addObject:img];   
 
54     
 
55         CFRelease(ref);   
 
56     
 
57     }   
 
58     
 
59     CFRelease(gifprops);   
 
60     
 
61     CFRelease(gif);  

Gif的合成

- (void)exportAnimatedGif:(CGImageSourceRef )gif :(NSMutableArray *)images   
 
02     
 
03 {   
 
04     
 
05        NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"animated.gif"];   
 
06     
 
07     CGImageDestinationRef destination = CGImageDestinationCreateWithURL(( CFURLRef)[NSURL fileURLWithPath:path],   
 
08     
 
09                                                                         kUTTypeGIF,   
 
10     
 
11                                                                         images.count,   
 
12     
 
13                                                                         NULL);   
 
14     
 
15     UIImage *image;   
 
16     
 
17     for (int i = 0; i<images.count; i++)   
 
18     
 
19     {   
 
20     
 
21         image = images[i];   
 
22     
 
23         CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,i,NULL));   
 
24     
 
25         CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);   
 
26     
 
27         NSNumber *delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);   
 
28     
 
29         NSDictionary *gifDelay = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:delay forKey:(NSString *)kCGImagePropertyGIFDelayTime]   
 
30     
 
31                                                              forKey:(NSString *)kCGImagePropertyGIFDictionary];   
 
32     
 
33             
 
34     
 
35         CGImageDestinationAddImage(destination,image.CGImage, (CFDictionaryRef)gifDelay);   
 
36     
 
37         CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);   
 
38     
 
39     }   
 
40     
 
41         
 
42     
 
43 //    CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);   
 
44     
 
45     CGImageDestinationFinalize(destination);   
 
46     
 
47     CFRelease(destination);   
 
48     
 
49     NSLog(@"animated GIF file created at %@", path);   
 
50     
 
51     
 
52 }  

24.将一个UIView对象的内容保存为UIImage

+ (UIImage*)imageFromView:(UIView*)view{   
 
02     
 
03 UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, view.layer.contentsScale);   
 
04     
 
05 [view.layer renderInContext:UIGraphicsGetCurrentContext()];   
 
06     
 
07 UIImage *image = UIGraphicsGetImageFromCurrentImageContext();   
 
08     
 
09 UIGraphicsEndImageContext();   
 
10     
 
11 return image;   
 
12     
 
13 }  

注意：生成的图片的scale和view的scale一致，这样才可以保证图片的效果和view显示的完全一致，使用renderInContext方法可以让subviews的内容也显示的图片里。