イメージの透明部分を白(または他の色)にするには、描画コンテキストに塗りつぶし矩形を描画します。
スウィフト3:
extension UIImage {
func grayScaleImage() -> UIImage {
//let imageRect = CGRectMake(0, 0, self.size.width, self.size.height);
let imageRect = CGRect(origin: CGPoint.zero, size: self.size)
let colorSpace = CGColorSpaceCreateDeviceGray();
let width = Int(self.size.width)
let height = Int(self.size.height)
let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: .allZeros)
// set Fill Color to White (or some other color)
context?.setFillColor(UIColor.white.cgColor)
// Draw a white-filled rectangle before drawing your image
context?.fill(imageRect)
context?.draw(self.cgImage!, in: imageRect)
let imageRef = context?.makeImage()
let newImage = UIImage(cgImage: imageRef!)
return newImage
}
}
スウィフト2.2:
スウィフトのバージョンを使用している
extension UIImage {
func grayScaleImage() -> UIImage {
let imageRect = CGRectMake(0, 0, self.size.width, self.size.height);
let colorSpace = CGColorSpaceCreateDeviceGray();
let width = Int(self.size.width)
let height = Int(self.size.height)
let context = CGBitmapContextCreate(nil, width, height, 8, 0, colorSpace, .allZeros);
// set Fill Color to White (or some other color)
CGContextSetFillColorWithColor(context, UIColor.whiteColor().CGColor)
// Draw a white-filled rectangle before drawing your image
CGContextFillRect(context, imageRect)
CGContextDrawImage(context, imageRect, self.CGImage!);
let imageRef = CGBitmapContextCreateImage(context);
let newImage = UIImage(CGImage: imageRef!)
return newImage
}
}
? – DonMag