Brighten Photo

Brighten Photo 

In this post, a simple function is presented to brighten/darken photos. In this function I use GDI+ and write code in unsafe mode (for efficiency).

using System.Drawing;

using System.Drawing.Imaging;

using GRBIF._CONST;

using System;

namespace IntelliPhoto

{

// Description: A simple GDI+ function for brightening

// Author: G. R. Roosta

// License: Free To Use (No Restriction)

public class BasicFilter

{

public static void Brighten(Bitmap bitmap, int brightness, string newFullFileName)

{

Brighten(bitmap, brightness);

bitmap.Save(newFullFileName);

return;

}

public static void Brighten(Bitmap bitmap, int brightness) // -255 <= brightness <= 255

{

if (brightness < -255 brightness > 255)

throw new Exception("Invalid 'brightness' value!");

BitmapData bmpData = bitmap.LockBits(

new Rectangle(0, 0, bitmap.Width, bitmap.Height),

ImageLockMode.ReadWrite,

PixelFormat.Format24bppRgb);

int stride = bmpData.Stride;

System.IntPtr Scan0 = bmpData.Scan0;

unsafe
{

byte* ptr = (byte*)(void*)Scan0;

int offset = stride - bitmap.Width * 3;

int netWidth = bitmap.Width * 3;

for (int y = 0; y <>

{

for (int x = 0; x <>

{

int c = ptr[0] + brightness;

if (c > 255)
c = 255;

else if (c <>

c = 0;

ptr[0] = (byte)c;

++ptr;

}

ptr += offset;

}

}

bitmap.UnlockBits(bmpData);

return;

}

}

}

Example:

Original Image (taken by Digital Camera: Sony DSC-S650)




Brightened with brightness=+40 using IntelliPhoto.BasicFilter.Brigten



Brightened with brightness=+80 using IntelliPhoto.BasicFilter.Brigten





Brightened with brightness=-40 using IntelliPhoto.BasicFilter.Brigten





Brightened with brightness=-80 using IntelliPhoto.BasicFilter.Brigten