Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
vImage를 사용한 이미지 리사이징 (가장 빠르고 정확)
extension UIImage {
func resizeVI(size:CGSize) -> UIImage? {
let cgImage = self.CGImage!
var format = vImage_CGImageFormat(bitsPerComponent: 8, bitsPerPixel: 32, colorSpace: nil,
bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.First.rawValue),
version: 0, decode: nil, renderingIntent: CGColorRenderingIntent.RenderingIntentDefault)
var sourceBuffer = vImage_Buffer()
defer {
sourceBuffer.data.dealloc(Int(sourceBuffer.height) * Int(sourceBuffer.height) * 4)
}
var error = vImageBuffer_InitWithCGImage(&sourceBuffer, &format, nil, cgImage, numericCast(kvImageNoFlags))
guard error == kvImageNoError else { return nil }
// create a destination buffer
let scale = self.scale
let destWidth = Int(size.width)
let destHeight = Int(size.height)
let bytesPerPixel = CGImageGetBitsPerPixel(self.CGImage) / 8
let destBytesPerRow = destWidth * bytesPerPixel
let destData = UnsafeMutablePointer<UInt8>.alloc(destHeight * destBytesPerRow)
defer {
destData.dealloc(destHeight * destBytesPerRow)
}
var destBuffer = vImage_Buffer(data: destData, height: vImagePixelCount(destHeight), width: vImagePixelCount(destWidth), rowBytes: destBytesPerRow)
// scale the image
error = vImageScale_ARGB8888(&sourceBuffer, &destBuffer, nil, numericCast(kvImageHighQualityResampling))
guard error == kvImageNoError else { return nil }
// create a CGImage from vImage_Buffer
let destCGImage = vImageCreateCGImageFromBuffer(&destBuffer, &format, nil, nil, numericCast(kvImageNoFlags), &error)?.takeRetainedValue()
guard error == kvImageNoError else { return nil }
// create a UIImage
let resizedImage = destCGImage.flatMap { UIImage(CGImage: $0, scale: 0.0, orientation: self.imageOrientation) }
return resizedImage
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment