Implement Double Buffering into C# (with GDI+)?

Basq

Am working on an Air Hockey game in GDI+.

I'm drawing a puck and paddle (two circles ) over a pictureBox image of a table. My drawings were flickering, but not leaving much of a trail...

So i looked up on getting rid of that flicker and i found out about double buffering.

So i implemented that into my class, but now i'm getting a non-flickering image but it's leaving a trail now!

Any idea what could be wrong with the code below? What i require is for my paddle object to move without any flicker and leaving no trail.

Any help is much appreciated!

public frmTable()
{
InitializeComponent();

SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.DoubleBuffer, true);
}

private void frmTable_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
gameDraw();
}

private void gameDraw()
{
g = Graphics.FromImage(picTable.Image);

SolidBrush redBrush = new SolidBrush(Color.FromArgb(255,50,50));
Pen bluePen = new Pen( Color.Blue, 2 );
Pen blackPen = new Pen( Color.Black, 2 );

g.FillEllipse( redBrush, paddle_x, paddle_y, 32, 32 );
g.DrawEllipse( bluePen, paddle_x, paddle_y, 32, 32 );

g.FillEllipse( redBrush, puck_x, puck_y, 32, 32 );
g.DrawEllipse( blackPen, puck_x, puck_y, 32, 32 );

redBrush.Dispose();
bluePen.Dispose();
blackPen.Dispose();
}

private void picTable_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
paddle_x = e.X-25;
paddle_y = e.Y-25;
}

aidan_walsh

I assume you mean by "leaving a trail" that anything that was drawn before is still there?

Try using g.Clear(Color color) before the drawing methods.

Basq

doodle_sketch wrote:

I assume you mean by "leaving a trail" that anything that was drawn before is still there?

Try using g.Clear(Color color) before the drawing methods.

Cheers.... yeah, that's what i meant!

Tried a load of different methods.. including that Color.Clear method. The picture box just fills with that colour specified and doesn't change.

Below is the code with the code i changed in italics, is this what you had it mind?

public frmTable()
{
InitializeComponent();

SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.DoubleBuffer, true);
}

private void frmTable_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
g = Graphics.FromImage(picTable.Image);

gameDraw();
}

private void gameDraw()
{
g.Clear(Color.Gold);

SolidBrush redBrush = new SolidBrush(Color.FromArgb(255,50,50));
Pen bluePen = new Pen( Color.Blue, 2 );
Pen blackPen = new Pen( Color.Black, 2 );

g.FillEllipse( redBrush, paddle_x, paddle_y, 32, 32 );
g.DrawEllipse( bluePen, paddle_x, paddle_y, 32, 32 );

g.FillEllipse( redBrush, puck_x, puck_y, 32, 32 );
g.DrawEllipse( blackPen, puck_x, puck_y, 32, 32 );

redBrush.Dispose();
bluePen.Dispose();
blackPen.Dispose();
}

private void picTable_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
paddle_x = e.X-25;
paddle_y = e.Y-25;
}