How to create image with rounded corners in C#?

Question

I'd like to create image (from another one) with rounded corners with GDI+. What's the best way to do this?

PS: it's not for web, so I cannot make use of client CSS

Answer 1

The most straightforward way would be to use a scalable mask with rounded corners. Apply the mask to the image and export the new image.

Here is a CodeProject article dealing with precisely that.

Answer 2

This function seems to do what you want. It can also easily be modified to return a Bitmap if needed. You'll also need to clean up any images you no longer want, etc.. Adapted from: http://www.jigar.net/howdoi/viewhtmlcontent98.aspx

using System.Drawing;
using System.Drawing.Drawing2D;

public Image RoundCorners(Image StartImage, int CornerRadius, Color BackgroundColor)
{
    CornerRadius *= 2;
    Bitmap RoundedImage = new Bitmap(StartImage.Width, StartImage.Height);
    Graphics g = Graphics.FromImage(RoundedImage);
    g.Clear(BackgroundColor);
    g.SmoothingMode = SmoothingMode.AntiAlias;
    Brush brush = new TextureBrush(StartImage);
    GraphicsPath gp = new GraphicsPath();
    gp.AddArc(0, 0, CornerRadius, CornerRadius, 180, 90);
    gp.AddArc(0 + RoundedImage.Width - CornerRadius, 0, CornerRadius, CornerRadius, 270, 90);
    gp.AddArc(0 + RoundedImage.Width - CornerRadius, 0 + RoundedImage.Height - CornerRadius, CornerRadius, CornerRadius, 0, 90);
    gp.AddArc(0, 0 + RoundedImage.Height - CornerRadius, CornerRadius, CornerRadius, 90, 90);
    g.FillPath(brush, gp);
    return RoundedImage;
}

Image StartImage = Image.FromFile("YourImageFile.jpg");
Image RoundedImage = this.RoundCorners(StartImage, 25, Color.White);
//Use RoundedImage...

Answer 3

Using the Graphics.SetClip() method is the best way. For example:

    public static Image OvalImage(Image img) {
        Bitmap bmp = new Bitmap(img.Width, img.Height);
        using (GraphicsPath gp = new GraphicsPath()) {
            gp.AddEllipse(0, 0, img.Width, img.Height);
            using (Graphics gr = Graphics.FromImage(bmp)) {
                gr.SetClip(gp);
                gr.DrawImage(img, Point.Empty);
            }
        }
        return bmp;
    }