iOS中GIF的制作的简单版本记录 详解

http://blog.csdn.net/ioswyl88219/article/details/17641965

之前做过一个关于gif的app,一直没有来得及记录,现在记录一下学习的过程.

制作gif是基于ImageIO.framework,所以要先添加这个库

gif分解图片

[objc] view
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<span style="font-size:18px;">  

  

- (void)viewDidLoad  

{  

    [super viewDidLoad];  

  

    NSData *data = [NSData dataWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"test101" ofType:@"gif"]];  

  

    //通过data获取image的数据源  

    CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);  

      

    //获取帧数  

    size_t count = CGImageSourceGetCount(source);  

      

    NSMutableArray* tmpArray = [NSMutableArray array];  

    for (size_t i = 0; i < count; i++)  

    {  

        //获取图像  

        CGImageRef imageRef = CGImageSourceCreateImageAtIndex(source, i, NULL);  

          

        //生成image  

        UIImage *image = [UIImage imageWithCGImage:imageRef scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp];  

          

        [tmpArray addObject:image];  

          

        CGImageRelease(imageRef);  

    }  

    CFRelease(source);  

      

    int i = 0;  

    for (UIImage *img in tmpArray) {  

        //写文件  

        NSData *imageData = UIImagePNGRepresentation(img);  

          

        NSString *pathNum = [[self backPath] stringByAppendingPathComponent:[NSString stringWithFormat:@"%d.png",i]];  

        [imageData writeToFile:pathNum atomically:NO];  

        i++;  

    }  

         

}  

  

//返回保存图片的路径  

-(NSString *)backPath{  

    NSFileManager *fileManager = [NSFileManager defaultManager];  

      

    NSString *path = [UniversalMethod backDocumentDirectoryPath];  

      

    NSString *imageDirectory = [path stringByAppendingPathComponent:@"Normal"];  

      

    [fileManager createDirectoryAtPath:imageDirectory withIntermediateDirectories:YES attributes:nil error:nil];  

    return imageDirectory;  

}  

</span>  

gif的制作

制作gif需要依赖MobileCoreServices.framework

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//gif的制作  

      

    //获取源数据image  

    NSMutableArray *imgs = [[NSMutableArray alloc]initWithObjects:[UIImage imageNamed:@"bear_1"],[UIImage imageNamed:@"bear_2"], nil nil];  

      

    //图像目标  

    CGImageDestinationRef destination;  

      

    //创建输出路径  

    NSArray *document = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  

    NSString *documentStr = [document objectAtIndex:0];  

    NSFileManager *fileManager = [NSFileManager defaultManager];  

    NSString *textDirectory = [documentStr stringByAppendingPathComponent:@"gif"];  

    [fileManager createDirectoryAtPath:textDirectory withIntermediateDirectories:YES attributes:nil error:nil];  

    NSString *path = [textDirectory stringByAppendingPathComponent:@"test101.gif"];  

      

      

    NSLog(@"%@",path);  

      

    //创建CFURL对象  

    /* 

     CFURLCreateWithFileSystemPath(CFAllocatorRef allocator, CFStringRef filePath, CFURLPathStyle pathStyle, Boolean isDirectory) 

      

     allocator : 分配器,通常使用kCFAllocatorDefault 

     filePath : 路径 

     pathStyle : 路径风格,我们就填写kCFURLPOSIXPathStyle 更多请打问号自己进去帮助看 

     isDirectory : 一个布尔值,用于指定是否filePath被当作一个目录路径解决时相对路径组件 

     */  

    CFURLRef url = CFURLCreateWithFileSystemPath (  

                                                  kCFAllocatorDefault,  

                                                  (CFStringRef)path,  

                                                  kCFURLPOSIXPathStyle,  

                                                  false);  

      

    //通过一个url返回图像目标  

    destination = CGImageDestinationCreateWithURL(url, kUTTypeGIF, imgs.count, NULL);  

      

    //设置gif的信息,播放间隔时间,基本数据,和delay时间  

    NSDictionary *frameProperties = [NSDictionary  

                                     dictionaryWithObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:0.3], (NSString *)kCGImagePropertyGIFDelayTime, nil nil]  

                                     forKey:(NSString *)kCGImagePropertyGIFDictionary];  

      

    //设置gif信息  

    NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:2];  

      

    [dict setObject:[NSNumber numberWithBool:YES] forKey:(NSString*)kCGImagePropertyGIFHasGlobalColorMap];  

      

    [dict setObject:(NSString *)kCGImagePropertyColorModelRGB forKey:(NSString *)kCGImagePropertyColorModel];  

      

    [dict setObject:[NSNumber numberWithInt:8] forKey:(NSString*)kCGImagePropertyDepth];  

      

    [dict setObject:[NSNumber numberWithInt:0] forKey:(NSString *)kCGImagePropertyGIFLoopCount];  

    NSDictionary *gifProperties = [NSDictionary dictionaryWithObject:dict  

                                                              forKey:(NSString *)kCGImagePropertyGIFDictionary];  

    //合成gif  

    for (UIImage* dImg in imgs)  

    {  

        CGImageDestinationAddImage(destination, dImg.CGImage, (__bridge CFDictionaryRef)frameProperties);  

    }  

    CGImageDestinationSetProperties(destination, (__bridge CFDictionaryRef)gifProperties);  

    CGImageDestinationFinalize(destination);  

    CFRelease(destination);  

源码:GIF制作

参考文章:iOS:GIF图片的预览以及生成 iOS由ImageIO.framework实现gif的系统解码
- VicStudio CGImageSource对图像数据读取任务的抽象