创建图形对象

Question

Im trying to create a billiard table with the ball made of colored pixels. My problem is I'm trying to make a Graphics Object for the pool table but I don't know how to initialize it I know supposed to use

PaintEventArgs pe

I have tried

        base.OnPaint(pe);
        // Declare and instantiate a new pen.
        System.Drawing.Pen myPen = new System.Drawing.Pen(Color.Aqua);

        // Draw an aqua rectangle in the rectangle represented by the control.
        pe.Graphics.DrawRectangle(myPen, new Rectangle(this.Location,
           this.Size));`

but it only creates half a rectangle and it requires a panel. Is this the correct way of doing this, since I am supposed to create a colored ball of pixels?

Answer 1

I would recommend creating a control for the billiard table something like this

public class Billiard:Control
{
    public List<Point> Balls { get; private set; } 

    public Billiard()
    {
        Balls=new List<Point>();
    }

    protected override void OnBackColorChanged(EventArgs e)
    {

    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        using (var imageBuffer = new Bitmap(Width, Height))
        {
            using (var graphicsObject=Graphics.FromImage(imageBuffer))
            {
                graphicsObject.Clear(Color.Green);

                using (var boundryPen=new Pen(Brushes.SaddleBrown,10))
                {
                    graphicsObject.DrawRectangle(boundryPen,0,0,Width,Height);
                }

                using (var ballPen = new Pen(Brushes.Red, 5))
                {
                    foreach (var ball in Balls)
                    {
                        graphicsObject.DrawEllipse(ballPen,new Rectangle(ball,new Size(5,5)));
                    }
                }

                e.Graphics.DrawImage((Image)imageBuffer.Clone(),0,0);
            }
        }
    }
}

Obviously you have to validate the location of the balls and other stuff. Create methods for doing stuff.

Answer 2

Have you tried obj.CreateGraphics() method. for example if you are drawing on the windows form then graphics object will be created like this.

Graphics g = this.CreateGraphics();

but if you are drawing on any panel or any control then you can use like this.

Graphics g = pnlYourPanel.CreateGraphics();