esttorhe/ImageScout

ImageScout is a Swift implementation of fastimage. It allows you to find the size and type of a remote image by downloading as little as possible.

Why?

Sometimes you need to know the size of a remote image before downloading it, such as using a custom layout in a UICollectionView.

How?

ImageScout parses the image data as it is downloaded. As soon as it finds out the size and type of image, it stops the download. The downloaded data is below 60 KB in most cases.

Install

Use Git submodules. You want to add the file(s) in source to your Xcode project.

Usage

The only method you will be using is scoutImageWithURI(), with the following full signature:

func scoutImageWithURI(URI: String, completion: (NSError?, CGSize, ScoutedImageType) -> ())

Here's an example:

let scout = ImageScout()

scout.scoutImageWithURI("http://.../image-scout-logo.png") { error, size, type in
  if let unwrappedError = error {
    println(unwrappedError.code)
  } else {
    println("Size: \(size)")
    println("Type: \(type.rawValue)")
  }
}

If the image is not successfully parsed, the error will contain more info about the reason. In that case, the size is going to be CGSizeZero and the type .Unsupported.

Error code 100: Invalid URI parameter.
Error code 101: Image is corrupt or malformatted.
Error code 102: Not an image or unsopported image format URL.

Compatibility

iOS 7.0 and above.
Compiles with Xcode 6.1 and above.

License

See LICENSE.

esttorhe / ImageScout