图片合成GIF

NSImage *img1 = [NSImage imageNamed:@"Textmate"];NSImage *img2 = [NSImage imageNamed:@"potraint"];NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"animated.gif"];NSLog(@"%@", path);NSURL *destUrl = [NSURL fileURLWithPath:path];CGImageDestinationRef imageDest;NSString *uti = @"com.compuserve.gif";NSData *img1Data = [img1 TIFFRepresentation];NSData *img2Data = [img2 TIFFRepresentation];NSDictionary *frameProperties = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:2] forKey:(NSString *)kCGImagePropertyGIFDelayTime]                                                            forKey:(NSString *)kCGImagePropertyGIFDictionary];NSDictionary *gifProperties = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:0] forKey:(NSString *)kCGImagePropertyGIFLoopCount]                                                          forKey:(NSString *)kCGImagePropertyGIFDictionary];CGImageSourceRef imageSourceRef1 = CGImageSourceCreateWithData((CFDataRef)img1Data, (CFDictionaryRef)frameProperties);CGImageSourceRef imageSourceRef2 = CGImageSourceCreateWithData((CFDataRef)img2Data, (CFDictionaryRef)frameProperties);CGImageRef imgRef1 = CGImageSourceCreateImageAtIndex(imageSourceRef1, 0, NULL);CGImageRef imgRef2 = CGImageSourceCreateImageAtIndex(imageSourceRef2, 0, NULL);imageDest = CGImageDestinationCreateWithURL((CFURLRef)destUrl, (CFStringRef)uti, 2, NULL);CGImageDestinationAddImage(imageDest, imgRef1, (CFDictionaryRef)frameProperties);CGImageDestinationAddImage(imageDest, imgRef2, (CFDictionaryRef)frameProperties);CGImageDestinationFinalize(imageDest);

上面实现了控制播放的速度，使用CoreAnimation来添加水印等功能可以查看API，还是比较简单的。