如何裁剪图像3:4?斯威夫特

Question

我试图在互联网上查找答案，但没有找到，也许我在互联网上键入了错误的查询。

你能告诉我如何裁剪一张3:4的照片吗？我找不到裁剪它的函数。请分享？

Answer 1

您可以使用此函数以任何AspectRatio(例如3:4(裁剪图像。您必须将Image和所需的AspectRatio作为参数传递给函数，它将返回裁剪图像。

func crop(image: UIImage, to aspectRatio: CGFloat) -> UIImage {
let originalAspectRatio = image.size.height/image.size.width
var newImagesize = image.size
if originalAspectRatio > aspectRatio {
newImagesize.height = image.size.width * aspectRatio
} else if originalAspectRatio < aspectRatio {
newImagesize.width = image.size.height / aspectRatio
} else {
return image
}
let center = CGPoint(x: image.size.width/2, y: image.size.height/2)
let origin = CGPoint(x: center.x - newImagesize.width/2, y: center.y - newImagesize.height/2)
let cgCroppedImage = image.cgImage!.cropping(to: CGRect(origin: origin, size: CGSize(width: newImagesize.width, height: newImagesize.height)))!
let croppedImage = UIImage(cgImage: cgCroppedImage, scale: image.scale, orientation: image.imageOrientation)
return croppedImage
}

用法：

let croppedImage = crop(image: "ImageName", to: 3/4)

Answer 2

使用以下函数。有关更多详细信息，请阅读本文。

func cropImage(_ inputImage: UIImage, toRect cropRect: CGRect, viewWidth: CGFloat, viewHeight: CGFloat) -> UIImage? 
{    
let imageViewScale = max(inputImage.size.width / viewWidth,
inputImage.size.height / viewHeight)
// Scale cropRect to handle images larger than shown-on-screen size
let cropZone = CGRect(x:cropRect.origin.x * imageViewScale,
y:cropRect.origin.y * imageViewScale,
width:cropRect.size.width * imageViewScale,
height:cropRect.size.height * imageViewScale)
// Perform cropping in Core Graphics
guard let cutImageRef: CGImage = inputImage.cgImage?.cropping(to:cropZone)
else {
return nil
}
// Return image to UIImage
let croppedImage: UIImage = UIImage(cgImage: cutImageRef)
return croppedImage
}