生成带有白色边框的缩略图

Question

I need to generate thumbnails from a set of jpg's that need to have a small white border so that they appear to be "photos" when displayed on a map. Getting the thumbnails themselves is easy but I can't figure out how to get the border.

Answer 1

Here's a quick hack:

public Image AppendBorder(Image original, int borderWidth)
{
    var borderColor = Color.White;

    var newSize = new Size(
        original.Width + borderWidth * 2,
        original.Height + borderWidth * 2);

    var img = new Bitmap(newSize.Width, newSize.Height);
    var g = Graphics.FromImage(img);

    g.Clear(borderColor);
    g.DrawImage(original, new Point(borderWidth, borderWidth));
    g.Dispose();

    return img;
}

It creates a new Bitmap object which has the size of the original plus 2 times border width and then paint the original image in the middle and then return the finished image.

You can do a lot of drawing/painting with the Graphics object above too.