让表格对角线上的表格变色

----------1、点到直线的距离   方法（突然发现还有点小问题，如果需急用的话，用下面的第二个吧）

C#

找到响应的点（这里的点是表格的顶点，我默认的是表格中四个角的左下角为顶点）

 public class Test
    {



        /// <summary>
        /// 画制定矩形的对角线，
         /// </summary>
        /// <param name="width">指定矩形的长</param>
        /// <param name="hight">指定矩形的高（宽）</param>
        public List<ZuoBiao> PrintDiagonal1(int width1, int high1)
        {
            DateTime startDate = DateTime.Now;
            int width = width1;
            int high = high1;
            //对角线直线方程式：  这里 X×high+width×Y-width×high=0
            //点到直线的距离：P(x0,y0)点到直线Ax+By+C=0的距离公式为：
            //d=[Ax0+By0+C的绝对值]/[(A^2+B^2)的算术平方根]。
            List<ZuoBiao> list = new List<ZuoBiao>();
            for (int y = 0; y <= high; y++)
            {
                for (int x = 0; x <= width; x++)
                {
                    double juli = Convert.ToDouble(Math.Abs(high * x + width * y - width * high)) / Math.Sqrt(high * high + width * width); // 点到直线的距离

                    if (juli <= Math.Sqrt(2) / 2 )
                    {
                        ZuoBiao zb = new ZuoBiao();
                        zb.x = x;
                        zb.y = y;
                        if ((high * x + width * y) > high * width)
                        {
                            zb.x = x-1;
                            zb.y = y-1;
                        }
                        if ((high * x + width * y) == high * width)
                        {
                            zb.x = x;
                            zb.y = y;
                            if (width > high)
                            {
                                zb.x = x;
                                zb.y = y - 1;
                            }
                            if (width < high)
                            {
                                zb.x = x - 1;
                                zb.y = y;
                            }
                        }
                        list.Add(zb);
                    }
                }
            }
            DateTime endDate = DateTime.Now;
            TimeSpan times = endDate - startDate;
            
            return list;
        }
    }

    public class ZuoBiao  //用于存放坐标
    {
        public double x { get; set; }
        public double y { get; set; }
    }

画表格变色

我是放在了一个按钮的事件中，没有写注释，下次补上

 protected void btnPrint_Click(object sender, EventArgs e)
    {
        int width = txtWidth.Text.Trim() != null && txtWidth.Text.Trim() != "" ? Convert.ToInt32(txtWidth.Text.Trim()) : 0;
        int high = txtHigh.Text.Trim() != null && txtHigh.Text.Trim() != "" ? Convert.ToInt32(txtHigh.Text.Trim()) : 0;

        List<ZuoBiao> listZ = new Test().PrintDiagonal1(width,high);//这里式因为我把PrintDiagonal1方法放在了类库中了
        string str = "<table width='"+width*20+"' height='"+high*20+"'  border='1' cellpadding='0' cellspacing='0'>";
        for (int tr =0; tr <high; tr++)
        {
            str += "<tr>";
            for (int td = 0; td <width; td++)
            {
                string idStr = td.ToString() + tr.ToString();
                string emp="<td id='"+idStr+"'></td>";

                foreach (ZuoBiao zb in listZ)
                { 
                    string zbStr=zb.x.ToString()+zb.y.ToString();
                    if (zbStr == idStr)
                    {
                        emp = "<td id='" + idStr + "'  bgcolor='#FF0000'></td>";
                    }
                }
                str += emp;
            }
            str += "</tr>";
        }
        str += "</table>";
        ShowTable.InnerHtml = str;
    }

效果

-------------2、比例方法（是我一个朋友写，效果比我的更直观些）

先来看看效果

代码：

 public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }
        public int height = 0;
        public int width = 0;
        /// <summary>
        /// 绘制按钮事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
             height = int.Parse(this.textBox2.Text);
            width = int.Parse(this.textBox1.Text);
            Form1 f = new Form1(this);
            
            f.Show();
        }

    

    }

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        int height = 0;
        int width = 0;
        int scale = 20;
        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            Pen p = new Pen(Color.White);

            PointF Topleft = new PointF(10, 10);
            PointF Topright = new PointF(10 + width, 10);
            PointF Botleft = new PointF(10, 10 + height);
            PointF Botright = new PointF(10 + width, 10 + height);
            for (int i = 0; i <= height; i = i + scale)
            {
                g.DrawLine(p, new PointF(Topleft.X, Topleft.Y + i), new PointF(Topright.X, Topright.Y + i));
            }
            for (int j = 0; j <= width; j = j + scale)
            {
                g.DrawLine(p, new PointF(Topleft.X + j, Topleft.Y), new PointF(Botleft.X + j, Botleft.Y));
            }
            g.DrawLine(p, Topleft, Botright);

            float widthscaleheight = (float)width / (float)height;

            float heightscalewidth = (float)height / (float)width;


            PointF Topleftsmall = new PointF();

            #region 这是重点

            if (widthscaleheight > 1)
            {
                int[] fillPlace = new int[width / scale];

                int t = 1;
                float minNo = widthscaleheight;
                for (int i = 1; i < width / scale + 1; i++)
                {
                    if (minNo - 1 >= 0 || (minNo > 0.5 && minNo < 1))
                    {
                        fillPlace[i - 1] = t;
                        minNo -= 1;
                    }
                    else
                    {
                        minNo += widthscaleheight;
                        t++;
                        fillPlace[i - 1] = t;
                        minNo -= 1;
                    }
                }

                for (int i = 0; i < width / scale; i++)
                {
                    Topleftsmall = new PointF(Topleft.X + i * scale, Topleft.Y + (fillPlace[i] - 1) * scale);
                    g.FillRectangle(Brushes.Red, Topleftsmall.X, Topleftsmall.Y, scale, scale);
                }
            }
            else
            {
                int[] fillPlace = new int[height / scale];

                int t = 1;
                float minNo = heightscalewidth;
                for (int i = 1; i < height / scale + 1; i++)
                {
                    if (minNo - 1 >= 0 || (minNo > 0.5 && minNo < 1))
                    {
                        fillPlace[i - 1] = t;
                        minNo -= 1;
                    }
                    else
                    {
                        minNo += heightscalewidth;
                        t++;
                        fillPlace[i - 1] = t;
                        minNo -= 1;
                    }
                }
                for (int i = 0; i < height / scale; i++)
                {
                    Topleftsmall = new PointF(Topleft.X + (fillPlace[i] - 1) * scale, Topleft.Y + i * scale);
                    g.FillRectangle(Brushes.Red, Topleftsmall.X, Topleftsmall.Y, scale, scale);
                }
            }
            #endregion

        }
        public Form1(Form2 f)
        {
            InitializeComponent();
            this.height = f.height * scale;
            this.width = f.width * scale;
        }
    }