如何在Swift 3中使用CGContextDrawImage?
问题描述:
我有一个UIImage
扩展名,它使用CGContextDrawImage
。 它只是旋转一个UIImage
。 我更新到Xcode8和Swift3,无法弄清楚如何使用CGContextDrawImage
。如何在Swift 3中使用CGContextDrawImage?
我在CGContextDrawImage上出错。
CGImage.Type“无法将类型的价值 “的预期参数类型”
我的代码是 'CGImage?':
CGContextDrawImage(bitmap, CGRectMake(-size.width/2, -size.height/2, size.width, size.height), CGImage)
和全扩展:
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 rectZero = CGPoint(dictionaryRepresentation: CGRect.zero as! CFDictionary)
let rotatedViewBox = UIView(frame: CGRect(origin: rectZero!, 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)
CGContextDrawImage(bitmap, CGRectMake(-size.width/2, -size.height/2, size.width, size.height), CGImage)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}
答
在Swift 3中,许多CGContext
的函数都作为的实例方法导入,物业名称CGImage
已更名为cgImage
。并删除CGRectMake
。
试试这个:
bitmap!.draw(cgImage!, in: CGRect(x: -size.width/2, y: -size.height/2, width: size.width, height: size.height))
(希望!
将是您的使用安全。)
与 “cgcontextdrawimage swift3” 不幸的是搜索不会导致我的线程...感谢您找到它! – OOPer