iOS-grayscale-sample

This sample demonstrates how to get raw pixel data as array from UIImage, make the data grayscale, and put the data back in UIImage in Swift.

このサンプルはUIImageのピクセルデータを直接操作します。一例として取得したデータをグレイスケールに変換してUIImageに戻しています。

    0.stride(to: data.width * data.height * 4, by: 4).forEach
    {
        let count = $0
        let r = Double(data.pixelValues![count + 0])
        let g = Double(data.pixelValues![count + 1])
        let b = Double(data.pixelValues![count + 2])
        let a = Double(data.pixelValues![count + 3])
        
        let gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
        
        data.pixelValues![count + 0] = UInt8(gray)
        data.pixelValues![count + 1] = UInt8(gray)
        data.pixelValues![count + 2] = UInt8(gray)
        data.pixelValues![count + 3] = UInt8(a)
    }