Question

美好的一天。

下面的代码用于在c＃中的齐次坐标中绘制正方形和变换。

缩放和旋转操作正常工作（代码体中注释的字符串），但翻译操作不起作用。看来，T矩阵的最后一行（坐标为[2,0]，[2,1]，[2,2]）不会影响操作。

有人能看到代码的错误吗？关心，谢谢。

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

namespace AFFINES02
{
    public partial class Form1 : Form
    {

        double[,] Sq = new double[4,3];
        double[,] T = new double [3,3];

        private double RadianToDegree(double angle)
        {
            return Math.PI * angle / 180.0;
        }

        public Form1()
        {
            InitializeComponent();
            ResizeRedraw = true;
            Load += Form1_Load;
            Paint += Form1_Paint;
        }

        private void Form1_Load(object sender, EventArgs e)
        {                       
            //Original matrix
            Sq[0, 0] = 0;
            Sq[0, 1] = 0;
            Sq[1, 0] = 50;
            Sq[1, 1] = 0;
            Sq[2, 0] = 50;
            Sq[2, 1] = 50;
            Sq[3, 0] = 0;
            Sq[3, 1] = 50;

            //Transformation matrix
            T[0, 0] = 1;
            T[0, 1] = 0;
            T[0, 2] = 0;
            T[1, 0] = 0;
            T[1, 1] = 1;
            T[1, 2] = 0;
            T[2, 0] = 2; //x-translation
            T[2, 1] = 2; //y-translation
            T[2, 2] = 1;

            //T[0, 0] = Math.Cos(RadianToDegree(90)); //0.707;                //T[0, 0] = 1;
            //T[0, 1] = Math.Sin(RadianToDegree(90));//0.707;                 //T[0, 1] = 0;
            //T[0, 2] = 0;                                    //T[0, 2] = 0;
            //T[1, 0] = -(Math.Sin(RadianToDegree(90)));//-0.707;             //T[1, 0] = 0;
            //T[1, 1] = Math.Cos(RadianToDegree(90));//0.707;                 //T[1, 1] = 1;
            //T[1, 2] = 0;                                    //T[1, 2] = 0;
            //T[2, 0] = 0;                                    //T[2, 0] = 0;
            //T[2, 1] = 0;                                    //T[2, 1] = 0;
            //T[2, 2] = 1;                                    //T[2, 2] = 1;




        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {

            double[] b = new double[3];//intermediate matrix
            for (int j = 0; j < 4; j++)//cicle for 4 point of square
            {

                for (int i = 0; i < 3; i++)
                {
                    b[i] = 0;
                    for (int k = 0; k < 3; k++)
                        b[i] = b[i] + Sq[j, k] * T[k, i];
                }
                for (int k = 0; k < 3; k++)
                    Sq[j, k] = b[k];

            }

            Graphics gfx = e.Graphics;
            Pen skyBluePen = new Pen(Brushes.DeepSkyBlue);
            int cx = ClientSize.Width / 2;
            int cy = ClientSize.Height / 2;
            gfx.DrawLine(skyBluePen, cx, 0, cx, ClientSize.Height);
            gfx.DrawLine(skyBluePen, 0, cy, ClientSize.Width, cy);
            Pen SqPen = new Pen(Brushes.BlueViolet);
            gfx.DrawLine(SqPen, (int)(cx + Sq[0, 0]), (int)(cy - Sq[0, 1]),
            (int)(cx + Sq[1, 0]), (int)(cy - Sq[1, 1]));
            gfx.DrawLine(SqPen, (int)(cx + Sq[1, 0]), (int)(cy - Sq[1, 1]),
            (int)(cx + Sq[2, 0]), (int)(cy - Sq[2, 1]));
            gfx.DrawLine(SqPen, (int)(cx + Sq[2, 0]), (int)(cy - Sq[2, 1]),
            (int)(cx + Sq[3, 0]), (int)(cy - Sq[3, 1]));
            gfx.DrawLine(SqPen, (int)(cx + Sq[3, 0]), (int)(cy - Sq[3, 1]),
            (int)(cx + Sq[0, 0]), (int)(cy - Sq[0, 1]));           
        }

    }
}

Answer 1

我不会自己编码，而是使用System.Drawing.Drawing2D.Matrix代替。你确定，你的矩阵乘法是正确的吗？首先尝试单独测试一个。为什么Sq需要大小为4x3？此外，您可能很容易对矩阵中的行和列感到困惑。您是否尝试过使用T [0,2]和T [1,2]？

同构坐标中的仿射变换：翻译不起作用，c＃

1 个答案: