Get image width and height before loading it completely in iPhone

Question

I am loading an image in my UITableViewCell using

[NSData dataWithContentsOfURL:imageUrl]

For setting custom height for my tableview cell , i need the actual size of the image that am loading.

Can we get the width and height of an image before loading it completely ? Thanks in advance.

Answer 1

Try the Image I/O interface as done below. This will allow you to get the image size without having to load the entire file:

#import <ImageIO/ImageIO.h>

NSMutableString *imageURL = [NSMutableString stringWithFormat:@"http://www.myimageurl.com/image.png"];

CGImageSourceRef source = CGImageSourceCreateWithURL((CFURLRef)[NSURL URLWithString:imageURL], NULL);
NSDictionary* imageHeader = (__bridge NSDictionary*) CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
NSLog(@"Image header %@",imageHeader);
NSLog(@"PixelHeight %@",[imageHeader objectForKey:@"PixelHeight"]);

Answer 2

you can do it like this:

NSData *imageData = [NSData dataWithContentsOfURL:imageUrl];
UIImage *image = [UIImage imageWithData:imageData];
NSLog(@"image height: %f",image.size.height);
NSLog(@"image width: %f",image.size.width); 

Answer 3

Take a look at this Question How do I extract the width and height of a PNG from looking at the header in objective c which shares how is it possible to parse image Meta-data.

I have a created OpenSource project Ottran that extracts the image size and type of a remote image by downloading as little as possible, which supports PNG, JPEG , BMP and GIF formats.