Draw a Fill Rectangle with low opacity

c# winforms graphics drawing
Hossein Moradinia picture Hossein Moradinia · Sep 28, 2011 · Viewed 65k times · Source

I a have a PictureBox with a picture in a Windows Form application in C# language.I want draw a FillRectangle in some location of picturebox.but i also need to see picture of picture box.how can i draw this rectangle with low opacity to see image of picturebox?

Answer

Marco picture Marco · Sep 28, 2011

Do you mean:

using (Graphics g = Graphics.FromImage(pb.Image))
{
    using(Brush brush = new SolidBrush(your_color))
    {
        g.FillRectangle(brush , x, y, width, height);
    }
}

or you can use 

Brush brush = new SolidBrush(Color.FromArgb(alpha, red, green, blue))

where alpha goes from 0 to 255, so a value of 128 for your alpha will give you 50% opactity.

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