NSFileManager > attributesOfItemAtPath > Image Dimension

Question

How can I get dimensions of an image file saved in Documents Directory?

I'm able to get other attributes like NSFileCreationDate and NSFileSize by using the following code

NSDictionary *attributes = [[NSFileManager defaultManager] attributesOfItemAtPath:imageFile error:nil];
NSDate *date = (NSDate*)[attributes objectForKey:NSFileCreationDate];

Answer 1

As Duncan said, you can't do it this way. But yes can use ImageIO framework. Please try the code below.

NSURL *imageFileURL = [NSURL fileURLWithPath:...]; // Put your image in a URL
CGImageSourceRef imageSource = CGImageSourceCreateWithURL((CFURLRef)imageFileURL, NULL);
if (imageSource == NULL) {
// Error loading image
...
return;
}

CGFloat width = 0.0f, height = 0.0f;
CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, NULL);
if (imageProperties != NULL) {
CFNumberRef widthNum  = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelWidth);
if (widthNum != NULL) {
    CFNumberGetValue(widthNum, kCFNumberCGFloatType, &width);
}

CFNumberRef heightNum = CFDictionaryGetValue(imageProperties, kCGImagePropertyPixelHeight);
if (heightNum != NULL) {
    CFNumberGetValue(heightNum, kCFNumberCGFloatType, &height);
}

CFRelease(imageProperties);
}

NSLog(@"Image dimensions: %.0f x %.0f px", width, height);

Answer 2

You can't at the NSFileManager level. You need to read and parse the file's contents - at least the header.

How you do that depends on the file's type.

The easiest thing to do would be to load it as an image and then interrogate the image.