我正在使用带有Swift的Xcode 6.0.1。我有一个UIImage，并且我想使用旧图像作为源来制作另一张图像，新图像在某种方式下被旋转...例如垂直翻转。
这个问题已经在几个月前得到了回答（链接）。但是，那个解决方案对我不起作用，即使情况完全相同。
当我有
var image = UIImage(CGImage: otherImage.CGImage, scale: 1.0, orientation: .DownMirrored)
Xcode 抱怨"调用中存在额外的参数 'scale'"。在查阅了苹果文档后，这毫无意义，因为该初始化程序版本确实使用了这三个参数。虽然省略比例和方向参数可以解决问题，但会阻止我进行旋转。
我能找到的唯一其他参考资料是这位遇到了相同的问题。
你觉得呢？
我需要在这个Xcode版本上运行它，所以如果有其他方式来执行旋转（我还没有找到），那将会很有用。
我编写了Pixel SDK，它为这个问题提供了更强大的解决方案，否则这里是最简单的解决方案：
extension UIImage {
func rotate(radians: Float) -> UIImage? {
var newSize = CGRect(origin: CGPoint.zero, size: self.size).applying(CGAffineTransform(rotationAngle: CGFloat(radians))).size
// Trim off the extremely small float value to prevent core graphics from rounding it up
newSize.width = floor(newSize.width)
newSize.height = floor(newSize.height)
UIGraphicsBeginImageContextWithOptions(newSize, false, self.scale)
guard let context = UIGraphicsGetCurrentContext() else { return nil }
// Move origin to middle
context.translateBy(x: newSize.width/2, y: newSize.height/2)
// Rotate around middle
context.rotate(by: CGFloat(radians))
// Draw the image at its center
self.draw(in: CGRect(x: -self.size.width/2, y: -self.size.height/2, width: self.size.width, height: self.size.height))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
}
let image = UIImage(named: "image.png")!
let newImage = image.rotate(radians: .pi/2) // Rotate 90 degrees
.pi жШѓ 180 еЇ¶пЉМ.pi/2 жШѓ 90 еЇ¶пЉМ.pi/4 жШѓ 45 еЇ¶пЉМ...пЉМ.pi/180 жШѓ 1 еЇ¶гАВ - lenoohrotate（angle：Angle）。在函数内部，执行：let radians = angle.radians。现在，您可以使用以下方式调用该函数：image.rotate(angle: .degrees(90))或image.rotate(angle: .degrees(-90))。 - P. Ent这是一个简单的UIImage扩展:
//ImageRotation.swift
import UIKit
extension UIImage {
public func imageRotatedByDegrees(degrees: CGFloat, flip: Bool) -> UIImage {
let radiansToDegrees: (CGFloat) -> CGFloat = {
return $0 * (180.0 / CGFloat(M_PI))
}
let degreesToRadians: (CGFloat) -> CGFloat = {
return $0 / 180.0 * CGFloat(M_PI)
}
// calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox = UIView(frame: CGRect(origin: CGPointZero, size: size))
let t = CGAffineTransformMakeRotation(degreesToRadians(degrees));
rotatedViewBox.transform = t
let rotatedSize = rotatedViewBox.frame.size
// Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap = UIGraphicsGetCurrentContext()
// Move the origin to the middle of the image so we will rotate and scale around the center.
CGContextTranslateCTM(bitmap, rotatedSize.width / 2.0, rotatedSize.height / 2.0);
// // Rotate the image context
CGContextRotateCTM(bitmap, degreesToRadians(degrees));
// Now, draw the rotated/scaled image into the context
var yFlip: CGFloat
if(flip){
yFlip = CGFloat(-1.0)
} else {
yFlip = CGFloat(1.0)
}
CGContextScaleCTM(bitmap, yFlip, -1.0)
CGContextDrawImage(bitmap, CGRectMake(-size.width / 2, -size.height / 2, size.width, size.height), CGImage)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
}
(来源)
与以下内容一起使用：
rotatedPhoto = rotatedPhoto?.imageRotatedByDegrees(90, flip: false)
如果flip设置为true，则前者将旋转图像并翻转它。
UIGraphicsBeginImageContext(rotatedSize) 应该改为 UIGraphicsBeginImageContextWithOptions(rotatedSize, false, self.scale) 以保留比例。 - adrumCGContextDrawImage(bitmap, CGRectMake(-size.width / 2, -size.height / 2, size.width, size.height), CGImage)。请将其更改为bitmap?.draw(cgImage!, in: CGRect(x: -size.width / 2, y: -size.height / 2, width: size.width, height: size.height))。 - Hannyextension UIImage {
struct RotationOptions: OptionSet {
let rawValue: Int
static let flipOnVerticalAxis = RotationOptions(rawValue: 1)
static let flipOnHorizontalAxis = RotationOptions(rawValue: 2)
}
func rotated(by rotationAngle: Measurement<UnitAngle>, options: RotationOptions = []) -> UIImage? {
guard let cgImage = self.cgImage else { return nil }
let rotationInRadians = CGFloat(rotationAngle.converted(to: .radians).value)
let transform = CGAffineTransform(rotationAngle: rotationInRadians)
var rect = CGRect(origin: .zero, size: self.size).applying(transform)
rect.origin = .zero
let renderer = UIGraphicsImageRenderer(size: rect.size)
return renderer.image { renderContext in
renderContext.cgContext.translateBy(x: rect.midX, y: rect.midY)
renderContext.cgContext.rotate(by: rotationInRadians)
let x = options.contains(.flipOnVerticalAxis) ? -1.0 : 1.0
let y = options.contains(.flipOnHorizontalAxis) ? 1.0 : -1.0
renderContext.cgContext.scaleBy(x: CGFloat(x), y: CGFloat(y))
let drawRect = CGRect(origin: CGPoint(x: -self.size.width/2, y: -self.size.height/2), size: self.size)
renderContext.cgContext.draw(cgImage, in: drawRect)
}
}
}
let rotatedImage = UIImage(named: "my_amazing_image")?.rotated(by: Measurement(value: 48.0, unit: .degrees))
使用指定的翻转标志：
let flippedImage = UIImage(named: "my_amazing_image")?.rotated(by: Measurement(value: 48.0, unit: .degrees), options: [.flipOnVerticalAxis])
.applying(transform)。 - mikro098Swift 3：
向右旋转：
let image = UIImage(cgImage: otherImage.cgImage!, scale: CGFloat(1.0), orientation: .right)
在游乐场中测试：
// MyPlayground.playground
import UIKit
import PlaygroundSupport
let view = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
view.backgroundColor = UIColor.white
PlaygroundPage.current.liveView = view
let otherImage = UIImage(named: "burger.png", in: Bundle.main,
compatibleWith: nil)
let imageViewLeft = UIImageView(image: UIImage(cgImage: (otherImage?.cgImage!)!, scale: CGFloat(1.0), orientation: .left))
let imageViewRight = UIImageView(image: UIImage(cgImage: (otherImage?.cgImage!)!, scale: CGFloat(1.0), orientation: .right))
view.addSubview(imageViewLeft)
view.addSubview(imageViewRight)
view.layoutIfNeeded()
'调用中的额外参数'通常是由于其中一个输入类型不正确造成的。
您可以通过以下方法修复代码
var image = UIImage(CGImage: otherImage.CGImage, scale: CGFloat(1.0), orientation: .DownMirrored)
UIGraphicsBeginImageContext，因为它会破坏您的向量质量，请使用UIGraphicsBeginImageContextWithOptions。这是我在Swift 3/4中的实现：extension UIImage {
func rotated(degrees: CGFloat) -> UIImage? {
let degreesToRadians: (CGFloat) -> CGFloat = { (degrees: CGFloat) in
return degrees / 180.0 * CGFloat.pi
}
// Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRect(origin: .zero, size: size))
rotatedViewBox.transform = CGAffineTransform(rotationAngle: degreesToRadians(degrees))
let rotatedSize: CGSize = rotatedViewBox.frame.size
// Create the bitmap context
UIGraphicsBeginImageContextWithOptions(rotatedSize, false, 0.0)
guard let bitmap: CGContext = UIGraphicsGetCurrentContext(), let unwrappedCgImage: CGImage = cgImage else {
return nil
}
// Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width/2.0, y: rotatedSize.height/2.0)
// Rotate the image context
bitmap.rotate(by: degreesToRadians(degrees))
bitmap.scaleBy(x: CGFloat(1.0), y: -1.0)
let rect: CGRect = CGRect(
x: -size.width/2,
y: -size.height/2,
width: size.width,
height: size.height)
bitmap.draw(unwrappedCgImage, in: rect)
guard let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() else {
return nil
}
UIGraphicsEndImageContext()
return newImage
}
@confile的答案已更新至Swift 4
import UIKit
extension UIImage {
public func imageRotatedByDegrees(degrees: CGFloat, flip: Bool) -> UIImage {
let radiansToDegrees: (CGFloat) -> CGFloat = {
return $0 * (180.0 / CGFloat.pi)
}
let degreesToRadians: (CGFloat) -> CGFloat = {
return $0 / 180.0 * CGFloat.pi
}
// calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox = UIView(frame: CGRect(origin: .zero, size: size))
let t = CGAffineTransform(rotationAngle: degreesToRadians(degrees));
rotatedViewBox.transform = t
let rotatedSize = rotatedViewBox.frame.size
// Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap = UIGraphicsGetCurrentContext()
// Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap?.translateBy(x: rotatedSize.width / 2.0, y: rotatedSize.height / 2.0)
// // Rotate the image context
bitmap?.rotate(by: degreesToRadians(degrees))
// Now, draw the rotated/scaled image into the context
var yFlip: CGFloat
if(flip){
yFlip = CGFloat(-1.0)
} else {
yFlip = CGFloat(1.0)
}
bitmap?.scaleBy(x: yFlip, y: -1.0)
let rect = CGRect(x: -size.width / 2, y: -size.height / 2, width: size.width, height: size.height)
bitmap?.draw(cgImage!, in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}
试试这段代码，它对我有效：
@IBAction func btnRotateImagePressed(sender: AnyObject) {
if let originalImage = self.imageView.image {
let rotateSize = CGSize(width: originalImage.size.height, height: originalImage.size.width)
UIGraphicsBeginImageContextWithOptions(rotateSize, true, 2.0)
if let context = UIGraphicsGetCurrentContext() {
CGContextRotateCTM(context, 90.0 * CGFloat(M_PI) / 180.0)
CGContextTranslateCTM(context, 0, -originalImage.size.height)
originalImage.drawInRect(CGRectMake(0, 0, originalImage.size.width, originalImage.size.height))
self.imageView.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
}
}
使用 Swift 5 和 Xcode 13 进行测试
extension UIView{
func rotate(degrees: CGFloat) {
let degreesToRadians: (CGFloat) -> CGFloat = { (degrees: CGFloat) in
return degrees / 180.0 * CGFloat.pi
}
self.transform = CGAffineTransform(rotationAngle: degreesToRadians(degrees))
}
只需传递角度值（以度为单位）
myView.rotate(degrees : 90)
UIView 而不是一个 UIImage。 - undefined如果您需要水平翻转图像或需要原始图像的镜像图像，有一个简单的方法：
以下代码可用于翻转图像：
let originalImage = UIImage(named: "image")
let flippedImage = originalImage?.withHorizontallyFlippedOrientation()
.CGImage（如参考的github页面）时，才会出现编译器错误。 - Martin R