Remove transparency from an image in swift

UIImage+Extension.swift

extension UIImage {

    func trimmed() -> UIImage {
        let newRect = cropRect()
        if let imageRef = cgImage?.cropping(to: newRect) {
            return UIImage(cgImage: imageRef)
        }
        return self
    }

    private func cropRect() -> CGRect {
        let cgImage = self.cgImage!

        let bitmapBytesPerRow = cgImage.width * 4
        let bitmapByteCount = bitmapBytesPerRow * cgImage.height
        let colorSpace = CGColorSpaceCreateDeviceRGB()
        let bitmapData = malloc(bitmapByteCount)

        if bitmapData == nil {
            return CGRect(x: 0, y: 0, width: 0, height: 0)
        }

        guard let context = CGContext(
            data: bitmapData,
            width: cgImage.width,
            height: cgImage.height,
            bitsPerComponent: 8,
            bytesPerRow: bitmapBytesPerRow,
            space: colorSpace,
            bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue
        ) else {
            return CGRect(x: 0, y: 0, width: 0, height: 0)
        }

        let height = cgImage.height
        let width = cgImage.width

        let rect = CGRect(x: 0, y: 0, width: width, height: height)
        context.clear(rect)
        context.draw(cgImage, in: rect)

        guard let data = context.data else {
            return CGRect(x: 0, y: 0, width: 0, height: 0)
        }

        var lowX = width
        var lowY = height
        var highX: Int = 0
        var highY: Int = 0

        // Filter through data and look for non-transparent pixels.
        for y in 0..<height {
            for x in 0..<width {
                let pixelIndex = (width * y + x) * 4 /* 4 for A, R, G, B */
                let color = data.load(fromByteOffset: pixelIndex, as: UInt32.self)

                if color != 0 { // Alpha value is not zero pixel is not transparent.
                    if x < lowX {
                        lowX = x
                    }
                    if x > highX {
                        highX = x
                    }
                    if y < lowY {
                        lowY = y
                    }
                    if y > highY {
                        highY = y
                    }
                }
            }
        }

        return CGRect(x: lowX, y: lowY, width: highX - lowX, height: highY - lowY)
    }
}