我无法快速将图像旋转90度。我已经写了下面的代码,但是有一个错误并且无法编译
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage { //Calculate the size of the rotated view's containing box for our drawing space let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: oldImage.size.width, height: oldImage.size.height)) let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat(M_PI / 180)) rotatedViewBox.transform = t let rotatedSize: CGSize = rotatedViewBox.frame.size //Create the bitmap context UIGraphicsBeginImageContext(rotatedSize) let bitmap: CGContext = UIGraphicsGetCurrentContext()! //Move the origin to the middle of the image so we will rotate and scale around the center. bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2) //Rotate the image context bitmap.rotate(by: (degrees * CGFloat(M_PI / 180))) //Now, draw the rotated/scaled image into the context bitmap.scaleBy(x: 1.0, y: -1.0) bitmap.draw(oldImage, in: CGRect(origin: (x: -oldImage.size.width / 2, y: -oldImage.size.height / 2, width: oldImage.size.width, height: oldImage.size.height), size: oldImage.cgImage)) let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()! UIGraphicsEndImageContext() return newImage }
以下是我不确定的代码
bitmap.draw(oldImage, in: CGRect(origin: (x: -oldImage.size.width / 2, y: -oldImage.size.height / 2, width: oldImage.size.width, height: oldImage.size.height), size: oldImage.cgImage))
这是UIImage针对 Swift 4.0 的扩展,可以仅旋转图像而无需UIImageView。成功测试了图像已旋转,不仅更改了exif数据。
UIImage
UIImageView
import UIKit extension UIImage { func rotate(radians: CGFloat) -> UIImage { let rotatedSize = CGRect(origin: .zero, size: size) .applying(CGAffineTransform(rotationAngle: CGFloat(radians))) .integral.size UIGraphicsBeginImageContext(rotatedSize) if let context = UIGraphicsGetCurrentContext() { let origin = CGPoint(x: rotatedSize.width / 2.0, y: rotatedSize.height / 2.0) context.translateBy(x: origin.x, y: origin.y) context.rotate(by: radians) draw(in: CGRect(x: -origin.y, y: -origin.x, width: size.width, height: size.height)) let rotatedImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return rotatedImage ?? self } return self } }
要执行180度旋转,您可以这样命名:
let rotatedImage = image.rotate(radians: .pi)
如果由于某种原因无法旋转,则将返回原始图像。