Weird behavior of LinearGradientBrush

Question

I want to fill a Rectangle with a LinearGradientBrush. With some Rectangles I get some strange behavior. Example:

Rectangle rect = new Rectangle( 20, 20, 20, 34 );
LinearGradientMode mode = LinearGradientMode.Vertical;
Brush brush = new LinearGradientBrush( rect, Color.White, Color.Blue, mode );
e.Graphics.FillRectangle( brush, rect );

Most Rectangles work OK, but some (like the one above) fill the first pixel row with the second color (blue in this case). See attached image:

Any ideas?

Answer 1

Make the brush one pixel taller:

LinearGradientMode mode = LinearGradientMode.Vertical;
Rectangle BrushRect = rect;
BrushRect.Inflate(0, 1);
Brush brush = new LinearGradientBrush(BrushRect, Color.White, Color.Blue, mode);