[英]swift generate qr code with transparent background
在我的 swift 2 應用程序中,我可以生成這樣的二維碼:
let data = "1234567890".dataUsingEncoding(NSISOLatin1StringEncoding, allowLossyConversion: false)
let filter = CIFilter(name: "CIQRCodeGenerator")
filter!.setValue(data, forKey: "inputMessage")
filter!.setValue("Q", forKey: "inputCorrectionLevel")
qrcodeImage = filter!.outputImage
let transformedImage = qrcodeImage.imageByApplyingTransform(CGAffineTransformMakeScale(150, 150))
QRCodeImage.image = UIImage(CIImage: transformedImage)
但是我的二維碼得到了一個白色的背景圖像,但我想要一個透明的背景。
我試過這樣的事情:
QRCodeImage.backgroundColor = UIColor.clearColor()
但這不起作用。 任何的想法 ? :)
似乎 CIQRCodeGenerator 過濾器總是使用黑色和白色。
您可以將輸出傳遞到CIMaskToAlpha過濾器以將其轉換為透明:
首先你可能想使用CIColorInvert來交換白色和黑色。
對於透明背景,您應該(使用您的直覺並)嘗試這樣,
//Create a CIFalseColor Filter
let colorFilter: CIFilter = CIFilter(name: "CIFalseColor")!
colorFilter.setDefaults()
colorFilter.setValue(yourQRFilter.outputImage!, forKey: "inputImage")
//Then set the background colour like this,
let transparentBG: CIColor = CIColor(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)
colorFilter.setValue(qrColor, forKey: "inputColor0")
colorFilter.setValue(transparentBG, forKey: "inputColor1")
outputImage = colorFilter.outputImage!
我希望這應該會為您生成具有透明背景的 QRCode 圖像。
我認為關鍵在於背景的 alpha。 您可以設置或減少 alpha,減少或刪除透明度。 嘗試這樣的事情:
QRCodeImage.backgroundcolor = UIColor(white: 1, alpha: 0.5)
希望能幫助到你。
這是我的代碼:
func QRImageFromData(_ data: Data) -> UIImage? {
let filter = CIFilter(name: "CIQRCodeGenerator")
filter?.setValue(data, forKey: "inputMessage")
//filter?.setValue("H", forKey: "inputCorrectionLevel")
//change qrcode color : #1e3259
let filterFalseColor = CIFilter(name: "CIFalseColor")
filterFalseColor?.setDefaults()
filterFalseColor?.setValue(filter?.outputImage, forKey: "inputImage")
// convert method
let cgColor: CGColor? = UIColor(hex: "#1e3259")?.cgColor
let qrColor: CIColor = CIColor(cgColor: cgColor!)
let transparentBG: CIColor = CIColor(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)
filterFalseColor?.setValue(qrColor, forKey: "inputColor0")
filterFalseColor?.setValue(transparentBG, forKey: "inputColor1")
if let image = filterFalseColor?.outputImage {
let transform = CGAffineTransform(scaleX: 5.0, y: 5.0)
return UIImage(ciImage: image.applying(transform),
scale: 1.0,
orientation: UIImageOrientation.up)
} else {
return nil
}
}
我按照本教程獲得了一個具有透明背景的 qr。
添加這些擴展:
extension CIImage {
/// Inverts the colors and creates a transparent image by converting the mask to alpha.
/// Input image should be black and white.
var transparent: CIImage? {
return inverted?.blackTransparent
}
/// Inverts the colors.
var inverted: CIImage? {
guard let invertedColorFilter = CIFilter(name: "CIColorInvert") else { return nil }
invertedColorFilter.setValue(self, forKey: "inputImage")
return invertedColorFilter.outputImage
}
/// Converts all black to transparent.
var blackTransparent: CIImage? {
guard let blackTransparentFilter = CIFilter(name: "CIMaskToAlpha") else { return nil }
blackTransparentFilter.setValue(self, forKey: "inputImage")
return blackTransparentFilter.outputImage
}
/// Applies the given color as a tint color.
func tinted(using color: UIColor) -> CIImage?
{
guard
let transparentQRImage = transparent,
let filter = CIFilter(name: "CIMultiplyCompositing"),
let colorFilter = CIFilter(name: "CIConstantColorGenerator") else { return nil }
let ciColor = CIColor(color: color)
colorFilter.setValue(ciColor, forKey: kCIInputColorKey)
let colorImage = colorFilter.outputImage
filter.setValue(colorImage, forKey: kCIInputImageKey)
filter.setValue(transparentQRImage, forKey: kCIInputBackgroundImageKey)
return filter.outputImage!
}
}
extension URL {
func qrImage(using color: UIColor) -> UIImage? {
let ciImage = qrCIImage?.tinted(using: color)
return ciImage != nil ? UIImage(ciImage: ciImage!) : nil
}
var qrImage: UIImage? {
return UIImage(ciImage: qrCIImage!)
}
/// Creates a QR code for the current URL in the given color.
func qrCIImage(using color: UIColor) -> CIImage? {
return qrCIImage?.tinted(using: color)
}
/// Returns a black and white QR code for this URL.
var qrCIImage: CIImage? {
guard let qrFilter = CIFilter(name: "CIQRCodeGenerator") else { return nil }
let qrData = absoluteString.data(using: String.Encoding.ascii)
qrFilter.setValue(qrData, forKey: "inputMessage")
let qrTransform = CGAffineTransform(scaleX: 12, y: 12)
return qrFilter.outputImage?.transformed(by: qrTransform)
}
}
然后像這樣使用:
let myChosenColor = UIColor(red:0.93, green:0.31, blue:0.23, alpha:1.00)
let qrURLImage = URL(string: "https://stackoverflow.com")?.qrImage(using: myChosenColor)
myQrImageView.image = qrURLImage
在 myQrImageView.image 中,您將看到一個帶有透明背景的 qr 圖像:
除了@jtbandes 的回答之外,我還編寫了一些代碼,以便對其他人也有幫助
extension UIImage {
func transparentBackground() -> UIImage? {
let context = CIContext(options: nil)
let filter = CIFilter(name: "CIMaskToAlpha")
filter?.setDefaults()
filter?.setValue(self.ciImage, forKey: kCIInputImageKey)
if let output = filter?.outputImage,
let imageRef = context.createCGImage(output, from: output.extent) {
return UIImage(cgImage: imageRef)
}
return nil
}
func invertColor() -> UIImage? {
let filter = CIFilter(name: "CIColorInvert")
filter?.setDefaults()
filter?.setValue(self.ciImage, forKey: kCIInputImageKey)
if let output = filter?.outputImage {
return UIImage(ciImage: output)
}
return nil
}
}
並像這樣使用它
yourUIImage.invertColor()?.transparentBackground()
transparentBackground()
函數將刪除黑色並保留白色,而invertColor()
將用白色交換黑色
extension UIImage {
func alpha(_ value: CGFloat) -> UIImage {
UIGraphicsBeginImageContextWithOptions(size, false, scale)
draw(at: CGPoint.zero, blendMode: .normal, alpha: value)
let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return image
}
}
如果您正在尋找一個現成的解決方案:
enum GeneratorType {
case qrCode, barCode, aztecCode
var filterName: String {
switch self {
case .aztecCode:
return "CIAztecCodeGenerator"
case .barCode:
return "CICode128BarcodeGenerator"
case .qrCode:
return "CIQRCodeGenerator"
}
}
}
func generateCode(type: GeneratorType, text: String,
transform: CGAffineTransform = CGAffineTransform(scaleX: 32.0, y: 32.0),
fillColor: UIColor = UIColor.black,
backgroundColor: CIColor = CIColor(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)) -> UIImage? {
guard let filter = CIFilter(name: type.filterName) else {
return nil
}
filter.setDefaults()
guard let data = text.data(using: String.Encoding.utf8) else {
return nil
}
filter.setValue(data, forKey: "inputMessage")
let filterFalseColor = CIFilter(name: "CIFalseColor")
filterFalseColor?.setDefaults()
filterFalseColor?.setValue(filter.outputImage, forKey: "inputImage")
filterFalseColor?.setValue(CIColor(cgColor: fillColor.cgColor), forKey: "inputColor0")
filterFalseColor?.setValue(backgroundColor, forKey: "inputColor1")
guard let image = filterFalseColor?.outputImage else { return nil }
return UIImage(ciImage: image.transformed(by: transform), scale: 1.0,
orientation: UIImage.Orientation.up)
}
用法:
let qrImage = generateCode(type: .qrCode, text: "some text")
和平!
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