Get iOS Memory Info

- (void)refreshMemoryInfo {
    uint64_t physicalMemorySize;
    uint64_t userMemorySize;
    int mib[2];
    size_t length;
    mib[0] = CTL_HW;
    mib[1] = HW_MEMSIZE;
    length = sizeof(int64_t);
    sysctl(mib, 2, &physicalMemorySize, &length, NULL, 0);
    mib[1] = HW_USERMEM;
    length = sizeof(int64_t);
    sysctl(mib, 2, &userMemorySize, &length, NULL, 0);

iOS 截图代码

- (UIImage*)snapshot
    UIGraphicsBeginImageContextWithOptions(self.bounds.size, NO, 0.0);
    [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:NO];
    UIImage *snap = UIGraphicsGetImageFromCurrentImageContext();
    return snap;

– (BOOL)drawViewHierarchyInRect:(CGRect)rect afterScreenUpdates:(BOOL)afterUpdates是在iOS7.0才引入的,所有此方法只适合在iOS7.0及以上系统使用。

iOS Support Matrix

Alt none

Exporting the Composition and Saving it to Camera Roll

// Create a static date formatter so we only have to initialize it once.
static NSDateFormatter *kDateFormatter;
if (!kDateFormatter) {
    kDateFormatter = [[NSDateFormatter alloc] init];
    kDateFormatter.dateStyle = NSDateFormatterMediumStyle;
    kDateFormatter.timeStyle = NSDateFormatterShortStyle;
// Create the export session with the composition and set the preset to the highest quality.
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mutableComposition presetName:AVAssetExportPresetHighestQuality];
// Set the desired output URL for the file created by the export process.
exporter.outputURL = [[[[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:@YES error:nil] URLByAppendingPathComponent:[kDateFormatter stringFromDate:[NSDate date]]] URLByAppendingPathExtension:CFBridgingRelease(UTTypeCopyPreferredTagWithClass((CFStringRef)AVFileTypeQuickTimeMovie, kUTTagClassFilenameExtension))];
// Set the output file type to be a QuickTime movie.
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
exporter.videoComposition = mutableVideoComposition;
// Asynchronously export the composition to a video file and save this file to the camera roll once export completes.
[exporter exportAsynchronouslyWithCompletionHandler:^{
    dispatch_async(dispatch_get_main_queue(), ^{
        if (exporter.status == AVAssetExportSessionStatusCompleted) {
            ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
            if ([assetsLibrary videoAtPathIsCompatibleWithSavedPhotosAlbum:exporter.outputURL]) {
                [assetsLibrary writeVideoAtPathToSavedPhotosAlbum:exporter.outputURL completionBlock:NULL];

ref: Link Here

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