[C#/WINFORM] Bitmap 클래스 : 회색조 비트맵 구하기

■ Bitmap 클래스를 사용해 회색조 비트맵을 구하는 방법을 보여준다.

 

▶ 예제 코드 (C#)

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

#region 회색조 비트맵 구하기 - GetGrayscaleBitmap(sourceImage)

/// <summary>
/// 회색조 비트맵 구하기
/// </summary>
/// <param name="sourceImage">소스 이미지</param>
/// <returns>회색조 비트맵</returns>
public Bitmap GetGrayscaleBitmap(Image sourceImage)
{
    Bitmap targetBitmap = GetBitmap(sourceImage);

    BitmapData targetBitmapData = targetBitmap.LockBits
    (
        new Rectangle(0, 0, sourceImage.Width, sourceImage.Height),
        ImageLockMode.ReadOnly,
        PixelFormat.Format32bppArgb
    );

    IntPtr sourceHandle = targetBitmapData.Scan0;

    byte[] targetByteArray = new byte[targetBitmapData.Stride * targetBitmap.Height];

    Marshal.Copy(sourceHandle, targetByteArray, 0, targetByteArray.Length);

    float rgb = 0;

    for(int i = 0; i < targetByteArray.Length; i += 4)
    {
        rgb =  targetByteArray[i    ] * 0.11f;
        rgb += targetByteArray[i + 1] * 0.59f;
        rgb += targetByteArray[i + 2] * 0.3f;

        targetByteArray[i    ] = (byte)rgb;
        targetByteArray[i + 1] = targetByteArray[i];
        targetByteArray[i + 2] = targetByteArray[i];

        targetByteArray[i + 3] = 255;
    }

    Marshal.Copy(targetByteArray, 0, sourceHandle, targetByteArray.Length);

    targetBitmap.UnlockBits(targetBitmapData);

    targetBitmapData = null;
    targetByteArray  = null;

    return targetBitmap;
}

#endregion
#region 비트맵 구하기 - GetBitmap(sourceImage)

/// <summary>
/// 비트맵 구하기
/// </summary>
/// <param name="sourceImage">소스 이미지</param>
/// <returns>비트맵</returns>
private Bitmap GetBitmap(Image sourceImage)
{
    Bitmap targetBitmap = new Bitmap
    (
        sourceImage.Width,
        sourceImage.Height,
        PixelFormat.Format32bppArgb
    );

    using(Graphics graphics = Graphics.FromImage(targetBitmap))
    {
        graphics.DrawImage
        (
            sourceImage,
            new Rectangle(0, 0, targetBitmap.Width, targetBitmap.Height),
            new Rectangle(0, 0, targetBitmap.Width, targetBitmap.Height),
            GraphicsUnit.Pixel
        );

        graphics.Flush();
    }

    return targetBitmap;
}

#endregion