c# - 圆内的随机点

Question

所以我在 Windows 窗体应用程序中得到了一个圆圈，并且必须在这个圆圈中放置 20 个随机点。我的想法是将圆圈分成 4 个部分，使其更加平衡。我的问题是这些点都是围绕中间生成的，我不知道如何解决这个问题......

    Graphics g;
    Pen p;
    Random r = new Random();
    int[] KegelX = new int[20];
    int[] KegelY = new int[20];
    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        Kegelplatzierung();
        p = new Pen(Color.Black);
        g = this.CreateGraphics();
        g.DrawEllipse(p, new Rectangle(50, 50, 400, 400));
        for (int i = 0; i < 20; i++)
        {
            g.DrawEllipse(p, new Rectangle(KegelX[i], KegelY[i], 1, 1));
        }
        p.Dispose();
        g.Dispose();
    }

    private void Kegelplatzierung() {
        for (int i = 0; i < 5; i++)
        {
            bool Kriterium = false;
            while (!Kriterium)
            {
                KegelX[i] = r.Next(50, 250);
                KegelY[i] = r.Next(50, 250);
                if (Math.Sqrt((250 - KegelX[i]) ^ 2 + (KegelY[i] - 250) ^ 2) < 200)
                {
                    Kriterium = true;
                }
            }
        }
        for (int i = 5; i < 10; i++)
        {
            bool Kriterium = false;
            while (!Kriterium)
            {
                KegelX[i] = r.Next(250, 450);
                KegelY[i] = r.Next(50, 250);
                if (Math.Sqrt((KegelX[i] - 250) ^ 2 + (KegelY[i] - 250) ^ 2) < 200)
                {
                    Kriterium = true;
                }
            }
        }
        for (int i = 10; i < 15; i++)
        {
            bool Kriterium = false;
            while (!Kriterium)
            {
                KegelX[i] = r.Next(50, 250);
                KegelY[i] = r.Next(250, 450);
                if (Math.Sqrt((250 - KegelX[i]) ^ 2 + (250 - KegelY[i]) ^ 2) < 200)
                {
                    Kriterium = true;
                }
            }
        }
        for (int i = 15; i < 20; i++)
        {
            bool Kriterium = false;
            while (!Kriterium)
            {
                KegelX[i] = r.Next(250, 450);
                KegelY[i] = r.Next(250, 450);
                if (Math.Sqrt((KegelX[i] - 250) ^ 2 + (250 - KegelY[i]) ^ 2) < 200)
                {
                    Kriterium = true;
                }
            }
        }

    }

示例:http://puu.sh/gB6Dg/e81f8c3486.png http://puu.sh/gB6Ec/306f61424c.png

感谢您的帮助!

Answer 1

这将按照您的计划进行。但是请注意，只有当您确实需要它来平衡非常少数点时，四个象限之间的对称性才是必要的。对于更大的数字，这是没有必要的，您可以将代码减少到一半左右……!

private void panel2_Paint(object sender, PaintEventArgs e)
{
    int dotsPerQuadrant = 666;
    Random R = new Random();
    Size s1x1 = new System.Drawing.Size(2, 2);
    int radius = 200;
    int rad2 = radius / 2;
    int off = 20;
    Rectangle bounds = new Rectangle(off, off, radius, radius);
    GraphicsPath gp = new GraphicsPath();
    gp.AddEllipse(bounds);
    Rectangle rectQ1 = new Rectangle(off, off, rad2, rad2);
    Rectangle rectQ2 = new Rectangle(off + rad2, off, rad2, rad2);
    Rectangle rectQ3 = new Rectangle(off, off + rad2, rad2, rad2);
    Rectangle rectQ4 = new Rectangle(off + rad2, off + rad2, rad2, rad2);
    List<Rectangle> quadrants = new List<Rectangle> { rectQ1, rectQ2, rectQ3, rectQ4 };
    e.Graphics.Clear(Color.AntiqueWhite);
    e.Graphics.DrawEllipse(Pens.Black, bounds);

    foreach (Rectangle rect in quadrants)
    {
        int count = 0;
        do
        {
            Point p = new Point(rect.X + R.Next(rad2), rect.Y + R.Next(rad2));
            if (gp.IsVisible(p))
            {
                e.Graphics.FillEllipse(Brushes.Red, new Rectangle(p, s1x1));
                count++;
            }
        } while (count < dotsPerQuadrant);
    }

}

这是结果。圆点均匀分布在整个圆上，不在中间聚集:

直接代码，无象限；

private void panel2_Paint(object sender, PaintEventArgs e)
{
    int dotstoDraw = 666*4;
    Random R = new Random();
    Size s1x1 = new System.Drawing.Size(2, 2);
    int radius = 200;
    int off = 20;
    Rectangle bounds = new Rectangle(off, off, radius, radius);
    GraphicsPath gp = new GraphicsPath();
    gp.AddEllipse(bounds);

    e.Graphics.Clear(Color.AntiqueWhite);
    e.Graphics.DrawEllipse(Pens.Black, bounds);

    int count = 0;
    do
    {
        Point p = new Point(off + R.Next(radius), off + R.Next(radius));
        if (gp.IsVisible(p))
        {
            e.Graphics.FillEllipse(Brushes.Red, new Rectangle(p, s1x1));
            count++;
        }
    } while (count < dotstoDraw);
 }