¿Cómo cambiar el tamaño de la image en Swift?

Estoy haciendo una aplicación para iOS, usando Swift y Parse.com

Estoy tratando de permitir que el usuario select una image de un selector de imágenes y luego cambiar el tamaño de la image seleccionada a 200×200 píxeles antes de upload a mi server.

Parse.com tiene un tutorial para una aplicación de copy de Instagram llamada "AnyPic", que proporciona este código para cambiar el tamaño de las imágenes, pero está en Objective-C …

// Resize the image to be square (what is shown in the preview) UIImage *resizedImage = [anImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit bounds:CGSizeMake(560.0f, 560.0f) interpolationQuality:kCGInterpolationHigh]; // Create a thumbnail and add a corner radius for use in table views UIImage *thumbnailImage = [anImage thumbnailImage:86.0f transparentBorder:0.0f cornerRadius:10.0f interpolationQuality:kCGInterpolationDefault]; 

¿Cómo crearía una versión 200x200px de la image seleccionada (para luego cargarla) en Swift?

Y, ¿qué hace la function thumbnailImage?

La function de cambio de tamaño de image se muestra de forma rápida como se muestra a continuación.

 func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage { let size = image.size let widthRatio = targetSize.width / image.size.width let heightRatio = targetSize.height / image.size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSizeMake(size.width * heightRatio, size.height * heightRatio) } else { newSize = CGSizeMake(size.width * widthRatio, size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRectMake(0, 0, newSize.width, newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) image.drawInRect(rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage } 

Use la function anterior y networkingimensione la image con 200 * 200 como el código siguiente

 self.resizeImage(UIImage(named: "yourImageName")!, targetSize: CGSizeMake(200.0, 200.0)) 

Consulte mi publicación en el blog, Redimensione la image en C rápida y objetiva , para más detalles.

swift3 actualizado

  func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage { let size = image.size let widthRatio = targetSize.width / image.size.width let heightRatio = targetSize.height / image.size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio) } else { newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) image.draw(in: rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } 

Como la respuesta de @KiritModi es de 2015, esta es la versión de Swift 3.0:

 func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage { let size = image.size let widthRatio = targetSize.width / image.size.width let heightRatio = targetSize.height / image.size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio) } else { newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) image.draw(in: rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } 

También es posible usar AlamofireImage ( https://github.com/Alamofire/AlamofireImage )

 let size = CGSize(width: 30.0, height: 30.0) let aspectScaledToFitImage = image.af_imageAspectScaled(toFit: size) 

La function en la publicación anterior me dio un resultado borroso.

Versión Swift 3 y estilo de extensión

Esta respuesta proviene de @Kirit Modi.

 extension UIImage { func resizeImage(targetSize: CGSize) -> UIImage { let size = self.size let widthRatio = targetSize.width / size.width let heightRatio = targetSize.height / size.height // Figure out what our orientation is, and use that to form the rectangle var newSize: CGSize if(widthRatio > heightRatio) { newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio) } else { newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio) } // This is the rect that we've calculated out and this is what is actually used below let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height) // Actually do the resizing to the rect using the ImageContext stuff UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0) self.draw(in: rect) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } } 

Para Swift 4.0 y iOS 10

  extension UIImage { func resizeImage(_ dimension: CGFloat, opaque: Bool, contentMode: UIViewContentMode = .scaleAspectFit) -> UIImage { var width: CGFloat var height: CGFloat var newImage: UIImage let size = self.size let aspectRatio = size.width/size.height switch contentMode { case .scaleAspectFit: if aspectRatio > 1 { // Landscape image width = dimension height = dimension / aspectRatio } else { // Portrait image height = dimension width = dimension * aspectRatio } default: fatalError("UIIMage.resizeToFit(): FATAL: Unimplemented ContentMode") } if #available(iOS 10.0, *) { let renderFormat = UIGraphicsImageRendererFormat.default() renderFormat.opaque = opaque let renderer = UIGraphicsImageRenderer(size: CGSize(width: width, height: height), format: renderFormat) newImage = renderer.image { (context) in self.draw(in: CGRect(x: 0, y: 0, width: width, height: height)) } } else { UIGraphicsBeginImageContextWithOptions(CGSize(width: width, height: height), opaque, 0) self.draw(in: CGRect(x: 0, y: 0, width: width, height: height)) newImage = UIGraphicsGetImageFromCurrentImageContext()! UIGraphicsEndImageContext() } return newImage } } 

Aquí tiene dos funciones simples de la extensión UIImage :

 func scaledWithMaxWidthOrHeightValue(value: CGFloat) -> UIImage? { let width = self.size.width let height = self.size.height let ratio = width/height var newWidth = value var newHeight = value if ratio > 1 { newWidth = width * (newHeight/height) } else { newHeight = height * (newWidth/width) } UIGraphicsBeginImageContextWithOptions(CGSize(width: newWidth, height: newHeight), false, 0) draw(in: CGRect(x: 0, y: 0, width: newWidth, height: newHeight)) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return image! } func scaled(withScale scale: CGFloat) -> UIImage? { let size = CGSize(width: self.size.width * scale, height: self.size.height * scale) UIGraphicsBeginImageContextWithOptions(size, false, 0) draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height)) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return image } 

El ejemplo es para minimizar la image a 1024 y less

func resizeImage (image: UIImage) -> UIImage {

  if image.size.height >= 1024 && image.size.width >= 1024 { UIGraphicsBeginImageContext(CGSize(width:1024, height:1024)) image.draw(in: CGRect(x:0, y:0, width:1024, height:1024)) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } else if image.size.height >= 1024 && image.size.width < 1024 { UIGraphicsBeginImageContext(CGSize(width:image.size.width, height:1024)) image.draw(in: CGRect(x:0, y:0, width:image.size.width, height:1024)) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } else if image.size.width >= 1024 && image.size.height < 1024 { UIGraphicsBeginImageContext(CGSize(width:1024, height:image.size.height)) image.draw(in: CGRect(x:0, y:0, width:1024, height:image.size.height)) let newImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return newImage! } else { return image } } 

Puedes usar esto para la image de ajuste en Swift 3 ;

 extension UIImage { func resizedImage(newSize: CGSize) -> UIImage { // Guard newSize is different guard self.size != newSize else { return self } UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0); self.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)) let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()! UIGraphicsEndImageContext() return newImage } func resizedImageWithinRect(rectSize: CGSize) -> UIImage { let widthFactor = size.width / rectSize.width let heightFactor = size.height / rectSize.height var resizeFactor = widthFactor if size.height > size.width { resizeFactor = heightFactor } let newSize = CGSize(width: size.width/resizeFactor, height: size.height/resizeFactor) let resized = resizedImage(newSize: newSize) return resized } } 

Uso;

 let resizedImage = image.resizedImageWithinRect(rectSize: CGSize(width: 1900, height: 1900))