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UIImageResizer.swift
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UIImageResizer.swift
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import UIKit.UIImage
class UIImageResizer {
class func resize(_ image: UIImage,
contentMode: UIView.ContentMode,
forRect rect: CGRect) -> UIImage {
switch contentMode {
case .scaleAspectFit, .scaleAspectFill:
return handleAspectFit_AspectFill(image, contentMode: contentMode, forRect: rect)
case .center, .top, .bottom:
return handleCenterContent(image, contentMode: contentMode, forRect: rect)
case .left, .bottomLeft, .topLeft:
return handleLeftContent(image, contentMode: contentMode, forRect: rect)
case .right, .bottomRight, .topRight:
return handleRightContent(image, contentMode: contentMode, forRect: rect)
case .scaleToFill, .redraw:
return image
}
}
}
private extension UIImageResizer {
class func handleAspectFit_AspectFill(_ image: UIImage,
contentMode: UIView.ContentMode,
forRect rect: CGRect) -> UIImage {
let heightRatio = image.height / rect.height
let widthRatio = image.width / rect.width
let minRatio = min(heightRatio, widthRatio)
let imageRect = CGRect(x: 0, y: 0, width: image.width / minRatio, height: image.height / minRatio)
return drawImage(image, rect: rect, imageRect: imageRect)
}
class func handleCenterContent(_ image: UIImage,
contentMode: UIView.ContentMode,
forRect rect: CGRect) -> UIImage {
var imageRect = CGRect(origin: .zero, size: image.size)
switch contentMode {
case .top:
imageRect.origin.y = 0
imageRect.origin.x = (rect.width - imageRect.width) / 2
case .center:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = (rect.width - imageRect.width) / 2
imageRect.origin.y = fullHeight / 2
case .bottom:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = (rect.width - imageRect.width) / 2
imageRect.origin.y = fullHeight
default:
break
}
return drawImage(image, rect: rect, imageRect: imageRect)
}
class func handleLeftContent(_ image: UIImage,
contentMode: UIView.ContentMode,
forRect rect: CGRect) -> UIImage {
var imageRect = CGRect(origin: .zero, size: image.size)
switch contentMode {
case .topLeft:
imageRect.origin.y = 0
imageRect.origin.x = 0
case .left:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = 0
imageRect.origin.y = fullHeight / 2
case .bottomLeft:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = 0
imageRect.origin.y = fullHeight
default:
break
}
return drawImage(image, rect: rect, imageRect: imageRect)
}
class func handleRightContent(_ image: UIImage,
contentMode: UIView.ContentMode,
forRect rect: CGRect) -> UIImage {
var imageRect = CGRect(origin: .zero, size: image.size)
switch contentMode {
case .topRight:
imageRect.origin.y = 0
imageRect.origin.x = (rect.width - imageRect.width)
case .right:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = (rect.width - imageRect.width)
imageRect.origin.y = fullHeight / 2
case .bottomRight:
let fullHeight = rect.height - imageRect.height
imageRect.origin.x = (rect.width - imageRect.width)
imageRect.origin.y = fullHeight
default:
break
}
return drawImage(image, rect: rect, imageRect: imageRect)
}
class func drawImage(_ image: UIImage, rect: CGRect, imageRect: CGRect) -> UIImage {
UIGraphicsBeginImageContextWithOptions(rect.size, false, 0)
image.draw(in: imageRect)
let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resizedImage ?? image
}
}
extension CGRect {
var height: CGFloat {
return self.size.height
}
var width: CGFloat {
return self.size.width
}
}
extension UIImage {
var height: CGFloat {
return self.size.height
}
var width: CGFloat {
return self.size.width
}
}