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copied!<p>As of iOS 4.0, the iOS SDK includes the <a href="http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Reference/CGImageSource/Reference/reference.html"><code>CGImageSource...</code> functions</a> (in the ImageIO framework). It's a very flexible API to query metadata without loading the image into memory. Getting the pixel dimensions of an image should work like this (make sure to include the ImageIO.framework in your target):</p> <pre><code>#import <ImageIO/ImageIO.h> NSURL *imageFileURL = [NSURL fileURLWithPath:...]; 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); CFRelease(imageSource); 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); } // Check orientation and flip size if required CFNumberRef orientationNum = CFDictionaryGetValue(imageProperties, kCGImagePropertyOrientation); if (orientationNum != NULL) { int orientation; CFNumberGetValue(orientationNum, kCFNumberIntType, &orientation); if (orientation > 4) { CGFloat temp = width; width = height; height = temp; } } CFRelease(imageProperties); } NSLog(@"Image dimensions: %.0f x %.0f px", width, height); </code></pre> <p>(adapted from "Programming with Quartz" by Gelphman and Laden, listing 9.5, page 228)</p>

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