如何在Swift中旋转图像？

  • Z时代
  • 2024-01-10
  • 分类：问答

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))

回答：

这是UIImage针对

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。

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。

以上是 如何在Swift中旋转图像？ 的全部内容， 来源链接： utcz.com/qa/422633.html

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