Drop shadow on text in C# winform

Question

How to drop shadow on text in winform. Especially, draw text on a bitmap object. I know we can draw that text with a dark color and bring to the right position to make it like a shadow. But this shadow seems so slim and solid. I want it wider and blurred. I found some functions that can blur and image. But when I apply to my situation, it turns the transparent area to black. Please give me a guide.

Answer 1

As an alternative to rendering a blurred shadow, a more performance-friendly option might be to render the shadow slightly offset down and to the right (as you initially suggested), but with an alpha-transparency so that the shadow does not appear to be so "solid":

protected void RenderDropshadowText(
    Graphics graphics, string text, Font font, Color foreground, Color shadow, 
    int shadowAlpha, PointF location)
{
    const int DISTANCE = 2;
    for (int offset = 1; 0 <= offset; offset--)
    {
        Color color = ((offset < 1) ? 
            foreground : Color.FromArgb(shadowAlpha, shadow));
        using (var brush = new SolidBrush(color))
        {
            var point = new PointF()
            {
                X = location.X + (offset * DISTANCE),
                Y = location.Y + (offset * DISTANCE)
            };
            graphics.DrawString(text, font, brush, point);
        }
    }
}

To give an example of how this would be called from code, such as in an OnPaint method:

RenderDropshadowText(e.Graphics, "Dropshadow Text", 
    this.Font, Color.MidnightBlue, Color.DimGray, 64, new PointF(10, 10));

To spruce things up a bit, and get a more convincing shadow effect, we might be able to modify the above function to simulate a blur effect by drawing the text with further alpha transparency slightly, once to the left, and once slightly to the right of the drop shadow:

if (offset > 0)
{
    using (var blurBrush = new SolidBrush(Color.FromArgb((shadowAlpha / 2), color)))
    {
        graphics.DrawString(text, font, blurBrush, (point.X + 1), point.Y);
        graphics.DrawString(text, font, blurBrush, (point.X - 1), point.Y);
    }
}

Here is a screenshot of the resultant output: