winfrom-绘制十字线

今天药忘吃喽~ 2022-07-12 01:30 137阅读 0赞

using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Windows.Forms;
    
    namespace crossline
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
    
                ResizeRedraw = true; //改变大小重绘
                DoubleBuffered = true;
                SetStyle(ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
    
                this.Paint += new PaintEventHandler(Form1_Paint);
                this.MouseClick += new MouseEventHandler(Form1_MouseClick);
                this.MouseMove += new MouseEventHandler(Form1_MouseMove);
                this.Resize += new EventHandler(this.Form1_Resize);
            }
    
            private void Form1_Paint(object sender, PaintEventArgs e)
            {
                Pen pen = new Pen(Color.Black);
                e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
                e.Graphics.Clear(SystemColors.Control);
    
                foreach (var p in dicPoint)
                {
                    e.Graphics.DrawLine(pen, p[0], p[1]);
                    e.Graphics.DrawLine(pen, p[2], p[3]);
                }
    
                var lineP = GetPoint();
                e.Graphics.DrawLine(pen, lineP[0], lineP[1]);
                e.Graphics.DrawLine(pen, lineP[2], lineP[3]);
    
                if (clickTag)
                {
                    dicPoint.Add(lineP);
                    clickTag = false; //重置标记
                }
            }
    
            private Point[] GetPoint()
            {
                Point[] p = new Point[4];
    
                var w = this.Width;
                var h = this.Height;
    
                p[0] = new Point(0, clickTag ? clickPoint.Y : mousePoint.Y);
                p[1] = new Point(w, clickTag ? clickPoint.Y : mousePoint.Y);
                p[2] = new Point(clickTag ? clickPoint.X : mousePoint.X, 0);
                p[3] = new Point(clickTag ? clickPoint.X : mousePoint.X, h);
    
                return p;
            }
    
            bool clickTag = false;
            Point clickPoint, mousePoint;
            readonly List<Point[]> dicPoint = new List<Point[]>();
    
            private void Form1_MouseClick(object sender, MouseEventArgs e)
            {
                //if (e.Button == MouseButtons.Left)
                clickTag = true;
                clickPoint = new Point(e.X, e.Y);
            }
    
            private void Form1_Resize(object sender, EventArgs e)
            {
                this.label1.Text = string.Format("{0},{1}", Width, Height);
    
                foreach (var p in dicPoint)
                {
                    p[1].X = this.Width;
                    p[3].Y = this.Height;
                }
            }
    
            private void Form1_MouseMove(object sender, MouseEventArgs e)
            {
                mousePoint = e.Location;
                Invalidate();
            }
    
            //...
    
        }
    }

![SouthEast][]

[SouthEast]: /images/20220711/a843b60182244b86aeae751dd6b91a91.png