CGImageDestination 和文件命名问题

Question

我正在使用 AVCapture 从相机捕获图像，因为我需要速度，而标准套件的速度太慢了。 我遇到问题，正在输出的文件（动画 GIF）的文件名被 CGImageDestination 函数破坏...

当我将 NSURL（转换为 CFURLRef）输出到日志时，我得到了我想要的路径/文件名：

2011-09-04 20:40:25.914 Mover[3558:707] Path as string:.../Documents/91B2C5E8-F925-47F3-B539-15185F640828-3558-000003327A227485.gif

但是，一旦创建并保存文件，它实际上会列出文件名，如下所示：

2011-09-04 20:40:25.960 Mover[3558:707] file: .91B2C5E8-F925-47F3-B539-15185F640828-3558-000003327A227485.gif-TtNT

看到区别了吗？开头的句号和 4 个字符的后缀？ 真正奇怪的是它并不总是这样做，大约 40% 的时间它工作正常。然而，它阻止了代码进一步工作，我在表格视图中列出了它们并进行预览。

有谁知道为什么以及如何阻止它这样做？

这是代码：

- (void)exportAnimatedGif{

NSString *guidPath = [[NSProcessInfo processInfo] globallyUniqueString];
NSString *tmpPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:guidPath];
NSString *path = [tmpPath stringByAppendingPathExtension:@"gif"];
NSLog(@"Path as string:%@", path);
CGImageDestinationRef destination = CGImageDestinationCreateWithURL((CFURLRef)[NSURL fileURLWithPath:path], kUTTypeGIF, [captureArray count], NULL);

NSDictionary *frameProperties = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:testDisplay3.displayValue]                                   forKey:(NSString *)kCGImagePropertyGIFDelayTime]
                                                            forKey:(NSString *)kCGImagePropertyGIFDictionary];
NSDictionary *gifProperties = [NSDictionary dictionaryWithObject:
                               [NSDictionary dictionaryWithObjectsAndKeys:
                                [NSNumber numberWithInt:2], (NSString *)kCGImagePropertyGIFLoopCount, 
                                [NSNumber numberWithFloat:testDisplay3.displayValue], (NSString*)kCGImagePropertyGIFDelayTime, 
                                [NSNumber numberWithFloat:testDisplay3.displayValue], (NSString*)kCGImagePropertyGIFUnclampedDelayTime,
                                nil]
                                                          forKey:(NSString *)kCGImagePropertyGIFDictionary];
for (int ii = 0; ii < [captureArray count]; ii++) 
{
    UIImage *tmpImg = [[UIImage alloc] init];
    tmpImg = [captureArray objectAtIndex:ii];
    CGImageDestinationAddImage(destination, tmpImg.CGImage, (CFDictionaryRef)frameProperties);
}
CGImageDestinationSetProperties(destination, (CFDictionaryRef)gifProperties);
CGImageDestinationFinalize(destination);
CFRelease(destination);

//TEST OUTPUT GENERATED FILES
NSArray *contents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] error:nil];
for (int xx = 0; xx < [contents count]; xx++) 
{
    NSLog(@"file: %@", [contents objectAtIndex:xx]);
}
//END TEST CODE
[captureArray removeAllObjects];
}

Answer 1

AFAIK 这是 CGImageDestinationFinalize 制作的临时文件，您看到它们的原因是 CGImageDestinationFinalize 失败。我认为，如果您检查文件大小，您会发现名称损坏的文件大小为 0。

在获得这些文件后，我开始检查是否成功:)

bool success =  CGImageDestinationFinalize(destination);
CFRelease(destination);
if (success) {
    NSLog(@"animated GIF file created at %@", path);
} else {
    NSLog(@"failed to create gif at %@", path);
}