如何快速裁剪图​​像

Posted 2023-02-25

【中文标题】如何快速裁剪图​​像

【英文标题】：How to crop an image in swift

【发布时间】：2018-08-14 09:09:30

【问题描述】：

我想从相机中裁剪图像。相机预览中应该有一个矩形边框，结果将是裁剪后的图像，如下例：

【参考方案1】：

extension UIImage   
    // Crops an input image (self) to a specified rect
    func cropToRect(rect: CGRect!) -> UIImage? 
        // Correct rect size based on the device screen scale
        let scaledRect = CGRectMake(rect.origin.x * self.scale, rect.origin.y * self.scale, rect.size.width * self.scale, rect.size.height * self.scale);
        // New CGImage reference based on the input image (self) and the specified rect
        let imageRef = CGImageCreateWithImageInRect(self.CGImage, scaledRect);
        // Gets an UIImage from the CGImage
        let result = UIImage(CGImage: imageRef, scale: self.scale, orientation: self.imageOrientation)
        // Returns the final image, or NULL on error
        return result;
        


// Crops an image to 100x100 pixels, 150px from left and 200px from top
let exampleImage = UIImage(named: "yourImageFile")
let croppedImage = exampleImage?.cropToRect(CGRectMake(150.0, 200.0, 100.0, 100.0))
if croppedImage != nil 
    // Your image was cropped
 else 
    // Something went wrong

【参考方案2】：

将Apple's developer documentation 与Pranavan Sp 已弃用的答案结合起来，以跳过花里胡哨，你会得到：

extension UIImage 

    func cropToRect(rect: CGRect!) -> UIImage? 

        let scaledRect = CGRect(x: rect.origin.x * self.scale, y: rect.origin.y * self.scale, width: rect.size.width * self.scale, height: rect.size.height * self.scale);


        guard let imageRef: CGImage = self.cgImage?.cropping(to:scaledRect)
        else 
            return nil
        

        let croppedImage: UIImage = UIImage(cgImage: imageRef, scale: self.scale, orientation: self.imageOrientation)
        return croppedImage
    

【参考方案3】：

您好，您可以使用此代码调整图像大小。