生成GIF

gif.m

- (void)makeAnimatedGif:(NSArray *)images filePath:(NSString *)filePath ration:(CGFloat)ration
{
    NSInteger count = images.count;
    CGImageDestinationRef destination;
    
    CFURLRef url = CFURLCreateWithFileSystemPath(
                                                 kCFAllocatorDefault,
                                                 (__bridge CFStringRef)filePath,
                                                 kCFURLPOSIXPathStyle,
                                                 false);
    
    destination = CGImageDestinationCreateWithURL(url, kUTTypeGIF, count, NULL);
    
    if (ration <= 0) {
        ration = count <= 5 ? 0.2 : 0.1;
    }
    
    NSDictionary *gifProperties = @{(__bridge NSString *) kCGImagePropertyGIFDictionary : @{
                                            (__bridge NSString *) kCGImagePropertyGIFLoopCount : @(0),
                                            (__bridge NSString *) kCGImagePropertyColorModel : (__bridge NSString *) kCGImagePropertyColorModelRGB,
                                            (__bridge NSString *) kCGImagePropertyDepth : @(8),
                                            (__bridge NSString *) kCGImagePropertyGIFHasGlobalColorMap : @(NO),
                                            }
                                    };
    
    NSDictionary *frameProperties = @{(__bridge NSString *) kCGImagePropertyGIFDictionary : @{
                                              (__bridge NSString *) kCGImagePropertyGIFDelayTime : @(ration),
                                              }
                                      };
    
    CGImageDestinationSetProperties(destination, (__bridge CFDictionaryRef) gifProperties);
    
    for (UIImage *srcImage in images)
    {
        
        uint8_t *colorTable =nil;
#ifdef kUseNewTableColor
        colorTable = [self createColorTableWithImage:srcImage];
#endif
        UIImage * reduceImage = [self drawImage:srcImage colorTable:colorTable];
        
#ifdef kUseNewTableColor
        free(colorTable);
#endif
        CGImageDestinationAddImage(destination, reduceImage.CGImage, (__bridge CFDictionaryRef) frameProperties);
    }
    
    CGImageDestinationFinalize(destination);
    
    CFRelease(destination);
    CFRelease(url);
    
}