Get pixel data as array from UIImage/CGImage in swift

Question

I have an app so far that allows the user to free draw (like a sketch pad) on a UIImageView element.

I want to get the raw RGB pixel data (as <

Answer 1

Please try this. This worked right for me.

func pixelValues(fromCGImage imageRef: CGImage?) -> [UInt8]?
    {
        var width = 0
        var height = 0
        var pixelValues: [UInt8]?

        if let imageRef = imageRef {
            width = imageRef.width
            height = imageRef.height
            let bitsPerComponent = imageRef.bitsPerComponent
            let bytesPerRow = imageRef.bytesPerRow
            let totalBytes = height * bytesPerRow
            let bitmapInfo = imageRef.bitmapInfo

            let colorSpace = CGColorSpaceCreateDeviceRGB()
            var intensities = [UInt8](repeating: 0, count: totalBytes)

            let contextRef = CGContext(data: &intensities,
                                      width: width,
                                     height: height,
                           bitsPerComponent: bitsPerComponent,
                                bytesPerRow: bytesPerRow,
                                      space: colorSpace,
                                 bitmapInfo: bitmapInfo.rawValue)
            contextRef?.draw(imageRef, in: CGRect(x: 0.0, y: 0.0, width: CGFloat(width), height: CGFloat(height)))

            pixelValues = intensities
        }

        return pixelValues
}