【C#】画像の輝度値の取得設定速度の比較

set_get_bright_speed_3.cs

/// <summary>
/// MarshalクラスのReadByte、WriteByteで輝度値の取得設定
/// </summary>
/// <param name="bmp"></param>
private void NegativeImage3(Bitmap bmp)
{
    var width = bmp.Width;
    var height = bmp.Height;

    // Bitmapをロック
    var bmpData = bmp.LockBits(
            new Rectangle(0, 0, width, height),
            System.Drawing.Imaging.ImageLockMode.ReadWrite,
            bmp.PixelFormat
        );

    // メモリの幅のバイト数を取得
    var stride = Math.Abs(bmpData.Stride);

    byte r, g, b;
    int lineIndex = 0;

    var ptr = bmpData.Scan0;

    for (int y = 0; y < height; y++)
    {
        for (int x = 0; x < width * 3; x += 3)
        {
            // 輝度値の取得
            r = System.Runtime.InteropServices.Marshal.ReadByte(ptr, lineIndex + x + 2);
            g = System.Runtime.InteropServices.Marshal.ReadByte(ptr, lineIndex + x + 1);
            b = System.Runtime.InteropServices.Marshal.ReadByte(ptr, lineIndex + x);

            // 輝度値の設定
            System.Runtime.InteropServices.Marshal.WriteByte(ptr, lineIndex + x + 2, (byte)(255 - r));
            System.Runtime.InteropServices.Marshal.WriteByte(ptr, lineIndex + x + 1, (byte)(255 - g));
            System.Runtime.InteropServices.Marshal.WriteByte(ptr, lineIndex + x, (byte)(255 - b));
        }
        lineIndex += stride;
    }
    // アンロック
    bmp.UnlockBits(bmpData);
}

【C#】画像の輝度値の取得設定速度の比較
https://imagingsolution.net/program/set_get_bright_speed/