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iOS学习笔记--gif图片合成

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gif图片合成的过程分为以下四步：

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1.获取图片数据
2.创建gif图片
3.配置gif图片
4.单帧图片添加到gif

在这之前需要在工程中添加framework：ImageIO和MobileCoreServices

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#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>
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//1.获取图片数据
NSMutableArray * imagesArray = [[NSMutableArray alloc]initWithObjects:[UIImage imageNamed:@"Documentation0.png"],[UIImage imageNamed:@"Documentation1.png"],[UIImage imageNamed:@"Documentation2.png"],[UIImage imageNamed:@"Documentation3.png"], nil];
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-(void)gifPictureSynthetic:(NSMutableArray*)imagesArray
{  
  
  //2.创建gif文件
    
    NSArray * document = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    
    NSString * doucmentStr =[document objectAtIndex:0];
    
    NSFileManager * filemanager =[NSFileManager defaultManager];
    
    NSString * textdic = [doucmentStr stringByAppendingString:@"/gif"];
    
    [filemanager createDirectoryAtPath:textdic withIntermediateDirectories:YES attributes:nil error:nil];
    
    //路径
    NSString * path = [textdic stringByAppendingString:@"test1.gif"];
    
    NSLog(@"path = %@",path);
    
    //3.配置gif属性
    CGImageDestinationRef destion;
    
    CFURLRef url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (CFStringRef)path, kCFURLPOSIXPathStyle, false);
   destion =  CGImageDestinationCreateWithURL(url, kUTTypeGIF, imagesArray.count, NULL);
    
    //相关属性
    NSDictionary * frameDic = [NSDictionary dictionaryWithObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:0.3],(NSString *)kCGImagePropertyGIFDelayTime, nil] forKey:(NSString *)kCGImagePropertyGIFDelayTime];//延时
    
    NSMutableDictionary * gifdic = [NSMutableDictionary dictionaryWithCapacity:2];
    
    [gifdic setObject:[NSNumber numberWithBool:YES] forKey:(NSString *)kCGImagePropertyGIFHasGlobalColorMap];//颜色
    
    [gifdic setObject:(NSString *)kCGImagePropertyColorModelRGB forKey:(NSString *)kCGImagePropertyColorModel];
    
    [gifdic setObject:[NSNumber numberWithInt:8] forKey:(NSString *)kCGImagePropertyDepth];//颜色深度
    
    [gifdic setObject:[NSNumber numberWithInt:0] forKey:(NSString *)kCGImagePropertyGIFLoopCount];//是否重复
    
    NSDictionary * gifproperty = [NSDictionary dictionaryWithObject:gifdic forKey:(NSString *)kCGImagePropertyGIFDictionary];
    
    //4.单帧添加到gif
    
    for (UIImage * dimage in imagesArray)
    {
        CGImageDestinationAddImage(destion, dimage.CGImage, (__bridge CFDictionaryRef)frameDic);
    }
    
    CGImageDestinationSetProperties(destion, (__bridge CFDictionaryRef)gifproperty);
    CGImageDestinationFinalize(destion);
    
    CFRelease(destion);
    
}