Double buffering C#

LmSNe picture LmSNe · Jun 18, 2010 · Viewed 8k times · Source

I'm trying to implement the following method: void Ball::DrawOn(Graphics g);

The method should draw all previous locations(stored in a queue) of the ball and finally the current location. I don't know if that matters, but I print the previous locations using g.DrawEllipse(...) and the current location using g.FillEllipse(...).

The question is, that as you could imagine there is a lot of drawing to be done and thus the display starts to flicker much. I had searched for a way to double buffer, but all I could find is these 2 ways:

1) System.Windows.Forms.Control.DoubleBuffered = true;

2) SetStyle(ControlStyles.DoubleBuffer | ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);

while trying to use the first, I get the an error explaining that from in this method the Property DoubleBuffered is inaccessible due to its protection level. While I can't figure how to use the SetStyle method.

Is it possible at all to double buffer while all the access I have is to the Graphics Object I get as input in the method?

Thanks in Advance,

Edit: I had created the following class

namespace doubleBuffer
{
    class BufferedBall : System.Windows.Forms.Form{
        private Ball ball;
        public BufferedBall(Ball ball)
        {
            this.ball = ball;
        }

    public void DrawOn(Graphics g){
        this.DoubleBuffered = true;
        int num = 0;
        Rectangle drawArea1 = new Rectangle(5, 35, 30, 100);
        LinearGradientBrush linearBrush1 =
        new LinearGradientBrush(drawArea1, Color.Green, Color.Orange, LinearGradientMode.Horizontal);
        Rectangle drawArea2 = new Rectangle(5, 35, 30, 100);
        LinearGradientBrush linearBrush2 =
           new LinearGradientBrush(drawArea2, Color.Black, Color.Red, LinearGradientMode.Vertical);
        foreach (PointD point in ball.previousLocations)
        {
            Pen myPen1;
            if (num % 3 == 0)
                myPen1 = new Pen(Color.Yellow, 1F);
            else if (num % 3 == 1)
                myPen1 = new Pen(Color.Green, 2F);
            else
                myPen1 = new Pen(Color.Red, 3F);
            num++;
            myPen1.DashStyle = System.Drawing.Drawing2D.DashStyle.Solid;
            myPen1.StartCap = System.Drawing.Drawing2D.LineCap.RoundAnchor;
            myPen1.EndCap = System.Drawing.Drawing2D.LineCap.AnchorMask;
            g.DrawEllipse(myPen1, (float)(point.X - ball.radius), (float)(point.Y + ball.radius), (float)(2 * ball.radius), (float)(2 * ball.radius));
        }
        if ((ball.Host.ElapsedTime * ball.Host.FPS * 10) % 2 == 0){
            g.FillEllipse(linearBrush1, (float)(ball.Location.X - ball.radius), (float)(ball.Location.Y + ball.radius), (float)(2 * ball.radius), (float)(2 * ball.radius));
        }else{
            g.FillEllipse(linearBrush2, (float)(ball.Location.X - ball.radius), (float)(ball.Location.Y + ball.radius), (float)(2 * ball.radius), (float)(2 * ball.radius));
        }
    }
}

}

and the ball drawOn looks like this:

new BufferedBall(this).DrawOn(g);

Is that what you meant? because it is still flickering?

Answer

Andrey picture Andrey · Jun 18, 2010

Form class has DoubleBuffered property exposed as protected. http://msdn.microsoft.com/en-us/library/system.windows.forms.control.doublebuffered.aspx but since you derive your form from Form you can use it.