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Geekpedia » C# Code » Set Image Opacity Using C#

Set Image Opacity Using C#

A C# function for changing the opacity on an image to the specified value. It uses the System.Drawing, System.Drawing.Imaging and System.Drawing.Drawing2D namespaces.

On Wednesday, April 16th 2008 at 12:28 AM

By Andrew Pociu (View Profile)

(Rated 4.8 with 4 votes)

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public static Image SetImgOpacity(Image imgPic, float imgOpac)
{
      Bitmap bmpPic = new Bitmap(imgPic.Width, imgPic.Height);
      Graphics gfxPic = Graphics.FromImage(bmpPic);
      ColorMatrix cmxPic = new ColorMatrix();
      cmxPic.Matrix33 = imgOpac;
 
      ImageAttributes iaPic = new ImageAttributes();
      iaPic.SetColorMatrix(cmxPic, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
      gfxPic.DrawImage(imgPic, new Rectangle(0, 0, bmpPic.Width, bmpPic.Height), 0, 0, imgPic.Width, imgPic.Height, GraphicsUnit.Pixel, iaPic);
      gfxPic.Dispose();
 
      return bmpPic;
}

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Current Comments

by http://codelog.blogial.com on Friday, October 17th 2008 at 04:42 AM

Nice post. Was really helpful.

by Ankit Rajpoot on Sunday, November 9th 2008 at 10:41 AM

Very nice post. Saved my time. Thanks

by Dharmin on Sunday, December 27th 2009 at 01:21 PM

Very very helpful! Thanks a lot!

by shayan on Sunday, February 14th 2010 at 03:50 PM

Very Nice Thank you

by darki699 on Monday, March 1st 2010 at 08:58 AM

Add:
iaPic.Dispose();

to prevent memory leaks.

^^

by Hirushan on Friday, May 14th 2010 at 10:53 PM

Thanks Man!! Great job!!

by Alexandre on Tuesday, July 6th 2010 at 05:33 AM

Ce code est tout simplement génial.
Maintenant je peut créer une image PNG avec une couche alpha transparente.

BRAVO !!!

by Eladio Meza on Monday, July 26th 2010 at 09:48 PM

Justo lo que andaba buscando...muchas gracias

Buen aporte..

Es increible que se pueda hacer tan facil y hay gente que quiere vender un programa pagando licencia por este tipo de ejemplos...

Gracias