c# - 如何使用随机在 pictureBox1 中心 + 10 中绘制点？

Question

每次我单击按钮时，我都会有这个简单的代码，它会在 pictureBox1 的位置 100,100 处绘制一个点

但我想首先计算(我需要学习如何做)pictureBox1 的中心。

然后我想使用随机，所以每次我单击按钮时，它都会从 pictureBox1 中心位置 + 10 随机绘制一个点

private void button5_MouseClick(object sender, MouseEventArgs e)
        {
            Random rnd = new Random();
            drawPoint(100, 100);
        }

        public void drawPoint(int x, int y)
        {
         Graphics g = Graphics.FromHwnd(pictureBox1.Handle);
         SolidBrush brush = new SolidBrush(Color.LimeGreen);
         Point dPoint = new Point(x, (pictureBox1.Height - y));
         dPoint.X = dPoint.X - 2;
         dPoint.Y = dPoint.Y - 2;
         Rectangle rect = new Rectangle(dPoint, new Size(4, 4));
         g.FillRectangle(brush, rect);
         g.Dispose();
        }

Answer 1

试试这个。它将计算距中心 +10 -10 的随机偏移

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var halfX = pictureBox1.ClientRectangle.Width / 2;
            var halfY = pictureBox1.ClientRectangle.Height / 2;

            Random rnd = new Random();
            var offsetX = rnd.Next(-10, 10);
            var offsetY = rnd.Next(-10, 10);

            drawPoint(halfX + offsetX, halfY + offsetY);
        }

        public void drawPoint(int x, int y)
        {
            Graphics g = Graphics.FromHwnd(pictureBox1.Handle);
            SolidBrush brush = new SolidBrush(Color.LimeGreen);
            Point dPoint = new Point(x, (pictureBox1.Height - y));
            dPoint.X = dPoint.X - 2;
            dPoint.Y = dPoint.Y - 2;
            Rectangle rect = new Rectangle(dPoint, new Size(4, 4));
            g.FillRectangle(brush, rect);
            g.Dispose();
        }
     }