ios 将 UIImage 大小调整为 200x200pt/px
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Resize UIImage to 200x200pt/px
提问by swift_dan
I have been struggling resizing an image. Basically I have stumpled upon: How to scale down a UIImage and make it crispy / sharp at the same time instead of blurry?
我一直在努力调整图像大小。基本上我偶然发现：如何缩小 UIImage 并使其同时变脆 /清晰而不是模糊？
This seems to be a legit solution but somehow it is not working correctly.
这似乎是一个合法的解决方案，但不知何故它无法正常工作。
My app works with Photos from the Camera Roll. This photos should be resized to about 200x200 whereas the width is important, not the height.
我的应用程序适用于相机胶卷中的照片。这张照片应该调整到大约 200x200，而宽度很重要，而不是高度。
Unfortunetly I am not having a sample code as I discarded it in my rage about non working solution, sorry.
不幸的是，我没有示例代码，因为我对非工作解决方案的愤怒将其丢弃，抱歉。
回答by swift_dan
Here is my code. The Image is in width 850 px and not 200 px:
这是我的代码。图像的宽度为 850 像素而不是 200 像素：
func resizeImage(image: UIImage, newWidth: CGFloat) -> UIImage {
let scale = newWidth / image.size.width
let newHeight = image.size.height * scale
UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight))
image.drawInRect(CGRectMake(0, 0, newWidth, newHeight))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
@IBAction func chooseImage(sender: AnyObject) {
var myPickerController = UIImagePickerController()
myPickerController.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
myPickerController.delegate = self;
self.presentViewController(myPickerController, animated: true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject])
{
var imagenow = info[UIImagePickerControllerOriginalImage] as? UIImage
imageImage.image = resizeImage(imagenow!, newWidth: 200)
pimg2 = imageImage.image!
cidnew2 = textFieldCID!.text!
pname2 = textFieldName!.text
pmanu2 = textFieldMan!.text
pnick2 = textFieldNick!.text
podate2 = textFieldPODate!.text
pno2 = textFieldArtNo!.text
self.dismissViewControllerAnimated(true, completion: nil)
}
回答by Christoph R
Based on swift_dan's answer, an update for Swift 3
基于 swift_dan 的回答，Swift 3 的更新
func resizeImage(image: UIImage, newWidth: CGFloat) -> UIImage? {
let scale = newWidth / image.size.width
let newHeight = image.size.height * scale
UIGraphicsBeginImageContext(CGSize(width: newWidth, height: newHeight))
image.draw(in: CGRect(x: 0, y: 0, width: newWidth, height: newHeight))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
回答by Travis M.
If you're dealing with PNG images that contain transparencies, then the accepted answer function will actually convert the transparent areas to black.
如果您正在处理包含透明度的 PNG 图像，那么接受的答案函数实际上会将透明区域转换为黑色。
If you wish to scale and keep the transparencies in place, try this function:
如果您希望缩放并保持透明胶片就位，请尝试以下功能：
SWIFT 4
快速 4
extension UIImage {
func scaleImage(toSize newSize: CGSize) -> UIImage? {
var newImage: UIImage?
let newRect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height).integral
UIGraphicsBeginImageContextWithOptions(newSize, false, 0)
if let context = UIGraphicsGetCurrentContext(), let cgImage = self.cgImage {
context.interpolationQuality = .high
let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: newSize.height)
context.concatenate(flipVertical)
context.draw(cgImage, in: newRect)
if let img = context.makeImage() {
newImage = UIImage(cgImage: img)
}
UIGraphicsEndImageContext()
}
return newImage
}
}
回答by Faruk
For Swift 3.0
对于 Swift 3.0
simply add this snippet as extension to UIImage. However, remember that is not going to make the image in square form but if it was in that form, the result will be square.
只需将此代码段作为扩展名添加到UIImage. 但是，请记住，这不会使图像呈方形，但如果是这种形式，则结果将是方形的。
extension UIImage {
func resizeImage(newWidth: CGFloat) -> UIImage {
let scale = newWidth / self.size.width
let newHeight = self.size.height * scale
UIGraphicsBeginImageContext(CGSize(width: newWidth, height: newHeight))
self.draw(in: CGRect(x: 0, y: 0, width: newWidth, height: newHeight))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
} }
回答by abhimanyu jindal
Swift 4.0 -
斯威夫特 4.0 -
If you're dealing with images that contain transparencies, then the accepted answer function will actually convert the transparent areas to black.
如果您正在处理包含透明度的图像，那么接受的答案函数实际上会将透明区域转换为黑色。
If you wish to scale and keep the transparencies in place, try this function:
如果您希望缩放并保持透明胶片就位，请尝试以下功能：
func resizeImageWith(image: UIImage, newSize: CGSize) -> UIImage {
let horizontalRatio = newSize.width / image.size.width
let verticalRatio = newSize.height / image.size.height
let ratio = max(horizontalRatio, verticalRatio)
let newSize = CGSize(width: image.size.width * ratio, height: image.size.height * ratio)
var newImage: UIImage
if #available(iOS 10.0, *) {
let renderFormat = UIGraphicsImageRendererFormat.default()
renderFormat.opaque = false
let renderer = UIGraphicsImageRenderer(size: CGSize(width: newSize.width, height: newSize.height), format: renderFormat)
newImage = renderer.image {
(context) in
image.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
}
} else {
UIGraphicsBeginImageContextWithOptions(CGSize(width: newSize.width, height: newSize.height), isOpaque, 0)
image.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
newImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
}
return newImage
}
回答by rommex
This code uses UIGraphicsImageRendererintroduced in iOS 10: in my testing it was 10-40% faster than earlier samples with UIGraphicsBeginImageContext (Swift 4 / Xcode 9):
此代码使用iOS 10 中引入的UIGraphicsImageRenderer：在我的测试中，它比使用 UIGraphicsBeginImageContext (Swift 4 / Xcode 9) 的早期示例快 10-40%：
extension UIImage {
func renderResizedImage (newWidth: CGFloat) -> UIImage {
let scale = newWidth / self.size.width
let newHeight = self.size.height * scale
let newSize = CGSize(width: newWidth, height: newHeight)
let renderer = UIGraphicsImageRenderer(size: newSize)
let image = renderer.image { (context) in
self.draw(in: CGRect(origin: CGPoint(x: 0, y: 0), size: newSize))
}
return image
}
}
回答by Rashid
This function will return an image with widthyou specified:
此函数将返回具有您指定宽度的图像：
func scaleImage(image: UIImage, maximumWidth: CGFloat) -> UIImage {
let rect: CGRect = CGRectMake(0, 0, image.size.width, image.size.height)
let cgImage: CGImageRef = CGImageCreateWithImageInRect(image.CGImage!, rect)!
return UIImage(CGImage: cgImage, scale: image.size.width / maximumWidth, orientation: image.imageOrientation)
}
Swift 3.0
斯威夫特 3.0
func scaledImage(_ image: UIImage, maximumWidth: CGFloat) -> UIImage {
let rect: CGRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)
let cgImage: CGImage = image.cgImage!.cropping(to: rect)!
return UIImage(cgImage: cgImage, scale: image.size.width / maximumWidth, orientation: image.imageOrientation)
}
回答by Balázs Vincze
Further improving on @rommex's answer using a maximum size, in Swift 4.2:
在 Swift 4.2 中使用最大尺寸进一步改进@rommex的答案：
private extension UIImage {
func scaled(to maxSize: CGFloat) -> UIImage? {
let aspectRatio: CGFloat = min(maxSize / size.width, maxSize / size.height)
let newSize = CGSize(width: size.width * aspectRatio, height: size.height * aspectRatio)
let renderer = UIGraphicsImageRenderer(size: newSize)
return renderer.image { context in
draw(in: CGRect(origin: CGPoint(x: 0, y: 0), size: newSize))
}
}
}
回答by Abdul Karim
If you are using kingfisher lib for loading images in you project and want to resize it here is the way:
如果您正在使用 kingfisher lib 在您的项目中加载图像并想调整它的大小，方法如下：
let imageUrl = URL(string: "your image url")
//Size refer to the size which you want to resize your original image
let size = CGSize(width: 60, height: 60)
let processImage = ResizingImageProcessor(targetSize: size, contentMode: .aspectFit)
cell.courseTitleImage.kf.setImage(with: imageUrl! , placeholder: UIImage(named: "placeholder"), options: [.transition(ImageTransition.fade(1)), .processor(processImage)], progressBlock: nil, completionHandler: nil)
OR
Resize Local Image:- you can refer to the answer of @Christoph R
let imageUrl = URL(string: "your image url")
//Size refer to the size which you want to resize your original image
let size = CGSize(width: 60, height: 60)
let processImage = ResizingImageProcessor(targetSize: size, contentMode: .aspectFit)
cell.courseTitleImage.kf.setImage(with: imageUrl! , placeholder: UIImage(named: "placeholder"), options: [.transition(ImageTransition.fade(1)), .processor(processImage)], progressBlock: nil, completionHandler: nil)
或者
调整本地图像大小：-您可以参考@Christoph R 的回答
回答by Mohammad Razipour
func getScaledDimension(width: CGFloat, height: CGFloat,new_width: CGFloat, new_height: CGFloat)->CGPoint {
let widthAspect = (width / new_width)
let heightAspect = (height / new_height)
if widthAspect == 0 || heightAspect == 0 {
return CGPoint(x: width, y: height)
}
var width1 : CGFloat = 0
var height1 : CGFloat = 0
if widthAspect > heightAspect {
width1 = (width) / heightAspect
height1 = (height) / heightAspect
} else {
width1 = (width) / widthAspect
height1 = (height) / widthAspect
}
return CGPoint(x: width1, y: height1 )
}
func ResizeImage(image: UIImage, targetSize: CGSize) -> UIImage {
let rect = CGRectMake(0, 0, targetSize.width, targetSize.height)
UIGraphicsBeginImageContextWithOptions(targetSize, false, 1.0)
image.drawInRect(rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
let imagesize = getScaledDimension(image.size.width, height: image.size.height , new_width: Width, new_height: Hieght)
print("Image Size Scaled Dimension -> H:\(imagesize.x) W:\(imagesize.y)")
let newImage = ResizeImage(image, targetSize: CGSizeMake(imagesize.x,imagesize.y))
print("Resize Image Size -> H\(newImage.size.height) W\(newImage.size.width) ")
