I’ve a code that adjustments the colour of a sure level in a picture to clear.
func processByPixel(in picture: UIImage, byPoint: CGPoint) -> UIImage? {
guard let inputCGImage = picture.cgImage else { print("unable to get cgImage"); return nil }
let colorSpace = CGColorSpaceCreateDeviceRGB()
let width = inputCGImage.width
let top = inputCGImage.top
let bytesPerPixel = 4
let bitsPerComponent = 8
let bytesPerRow = bytesPerPixel * width
let bitmapInfo = RGBA32.bitmapInfo
guard let context = CGContext(information: nil, width: width, top: top, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, house: colorSpace, bitmapInfo: bitmapInfo) else {
print("Can not create context!"); return nil
}
context.draw(inputCGImage, in: CGRect(x: 0, y: 0, width: width, top: top))
guard let buffer = context.information else { print("Can not get context information!"); return nil }
let pixelBuffer = buffer.bindMemory(to: RGBA32.self, capability: width * top)
let offset = Int(byPoint.x) * width + Int(byPoint.y)
pixelBuffer[offset] = .clear
let outputCGImage = context.makeImage()!
let outputImage = UIImage(cgImage: outputCGImage, scale: picture.scale, orientation: picture.imageOrientation)
return outputImage
}
By tapping on the image, I calculate the purpose on which it was clicked and go it to this operate.
The issue is that the colour adjustments barely with the offset.
For instance I’ll go CGPoint(x: 0, y:0) however change shade to 0, 30
I believe that the offset variable shouldn’t be calculated accurately