C# .net窗体考试题目——绘图程序

题目：

界面：

代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _2017_2绘图程序
{
    public partial class Form1 : Form
    {
        Bitmap myBitmap;
        Graphics myBMPGraphics, myPicGraphics;
        Pen myPen, myClearTrackPen,mytransPen,mydongtaiPen, myClearTrackPen1;
        bool startDrawMark = false;
        Point startPt, prePt, preTrackPt;

        List<Point> myLinePts = new List<Point>();

        GraphicsPath myPath;
        Matrix myMatrix;

        public Form1()
        {
            InitializeComponent();
            myBitmap = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            myBMPGraphics = Graphics.FromImage(myBitmap); //内存的位图画板
            myPicGraphics = this.pictureBox1.CreateGraphics(); //窗体PictureBox的画板

            myPen = new Pen(Color.Blue, 3);
            myClearTrackPen = new Pen(pictureBox1.BackColor, 3);  //清除动态橡皮线的笔
            myClearTrackPen1 = new Pen(pictureBox1.BackColor, 3);
            myClearTrackPen1.DashStyle = DashStyle.Dot;
            mytransPen = new Pen(Color.Red, 3);//平移的笔
            mydongtaiPen = new Pen(Color.Blue, 3);
            mydongtaiPen.DashStyle = DashStyle.Dot;

            myMatrix = new Matrix();
            myPath = new GraphicsPath(); //路径
        }


        private void toolStripButton1_Click(object sender, EventArgs e)
        {

            //if (myLinePts.Count > 1)
            //{
            //    myBMPGraphics.TranslateTransform(10, 10, MatrixOrder.Prepend);
            //    myBMPGraphics.DrawLines(mytransPen, myLinePts.ToArray());

            //    myPicGraphics.DrawImage(myBitmap, 0, 0);
            //}

            if (myLinePts.Count > 1)
            {
                myMatrix.Reset();
                myMatrix.Translate(10, 10);
                myPath.Transform(myMatrix);
                // myPath.Transform是会保留，比如第一次点击平移，后面它的矩阵就变为平移一次的矩阵
                //之后在平移也是在原来平移一次矩阵的基础上进行平移
                //因此关键在于点要在结束的时候获取，并且重新绘制的时候重置矩阵
                myBMPGraphics.DrawPath(mytransPen, myPath);
                myPicGraphics.DrawImage(myBitmap, 0, 0);
            }
        }

        private void pictureBox1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawImage(myBitmap, 0, 0);
        }

        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                if (e.Clicks == 1)
                {
                    if (startDrawMark == false)
                    {
                        //myBMPGraphics.ResetTransform();
                        startDrawMark = true;
                        startPt = e.Location;
                        prePt = startPt;
                        preTrackPt = startPt;

                        myPath.Reset();
                        myLinePts.Clear();
                        myLinePts.Add(e.Location);
                    }
                    else
                    {
                        //myPicGraphics.DrawLine(myClearTrackPen, prePt, e.Location);
                        myBMPGraphics.DrawLine(myPen, prePt, e.Location);
                        prePt = e.Location;
                        preTrackPt = e.Location;

                        myLinePts.Add(e.Location);
                        
                    }
                
                }
                if(e.Clicks==2)
                {
                    myBMPGraphics.DrawLine(myPen, e.Location, startPt);
                    //if(myLinePts.Count>1)
                    //{
                    //    myBMPGraphics.DrawLines(myPen, myLinePts.ToArray());
                    //}
                    startDrawMark = false;
                    myPath.AddLines(myLinePts.ToArray());

                }
                myPicGraphics.DrawImage(myBitmap, 0, 0);

            }
        }


        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            if(startDrawMark)
            {
                myPicGraphics.DrawLine(myClearTrackPen1, prePt, preTrackPt);
                myPicGraphics.DrawLine(mydongtaiPen, prePt, e.Location);
                preTrackPt = e.Location;

                myPicGraphics.DrawImage(myBitmap, 0, 0);
            }
        }

}

2017某油的绘图程序题目，2024年考了一道类似的。