54 lines
1.8 KiB
Swift
54 lines
1.8 KiB
Swift
/// A `UIImage` extension that makes it easier to resize the image and inspect its size.
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extension UIImage {
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/// Resizes an image instance.
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///
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/// :param: size The new size of the image.
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/// :returns: A new resized image instance.
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func resize(size: CGSize) -> UIImage {
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let newSize = self.size.sizeConstrainedBySize(size)
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UIGraphicsBeginImageContext(newSize)
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self.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
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let newImage = UIGraphicsGetImageFromCurrentImageContext()
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UIGraphicsEndImageContext()
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return newImage
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}
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/// Returns a new `UIImage` instance using raw image data and a size.
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///
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/// :param: data Raw image data.
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/// :param: size The size to be used to resize the new image instance.
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/// :returns: A new image instance from the passed in data.
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class func imageWithData(data: NSData, size: CGSize) -> UIImage? {
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return UIImage(data: data)?.resize(size)
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}
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/// Returns an image size from raw image data.
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///
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/// :param: data Raw image data.
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/// :returns: The size of the image contained in the data.
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class func sizeForImageData(data: NSData) -> CGSize? {
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return UIImage(data: data)?.size
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}
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}
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private extension CGSize {
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/// Finds a new size constrained by a size keeping the aspect ratio.
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///
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/// :param: size The contraining size.
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/// :returns: size A new size that fits inside the contraining size with the same aspect ratio.
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func sizeConstrainedBySize(size: CGSize) -> CGSize {
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if height == 0 { return size }
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let aspectRatio = width / height
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let aspectWidth = round(aspectRatio * size.height)
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let aspectHeight = round(size.width / aspectRatio)
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if aspectWidth > size.width {
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return CGSize(width: size.width, height: aspectHeight)
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} else {
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return CGSize(width: aspectWidth, height: size.height)
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}
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}
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}
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