Question

作为一个背景，我已经使用C＃很长一段时间，而不是在这种用例中。我的导师作为一个小挑战让我“旋转一个矩形”。我通过使用Graphics和Matrix.RotateAt方法实现了这一点。单个矩形一切正常。然而，我想扩展它并创建一个名为“Square”的类，它具有位置和大小以及旋转它的功能。目前我已经修改了这个想法，现在我遇到了Square似乎剧烈旋转的问题。

我创建了一段非常短的视频并将其上传到YouTube：

https://www.youtube.com/watch?v=KwQjDKfExtg&feature=youtu.be

在这里你可以看到我试图注释掉所有不必要的代码。

//Import this namespace which it auto-generated for my Square class.
using CSharpIntro.Classes.Shapes_Rotation;

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace CSharpIntro
{
public partial class Form1 : Form
{
    //int rotateDegrees = 0;
    int numOfSquares = 1;
    List<Square> squares = new List<Square>();

    //Instantiate a new Matrix class.
    Matrix myMatrix = new Matrix();

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        for (int i = 0; i < numOfSquares; i++)
        {
            Square square = new Square();
            //Random rand = new Random();
            //square.boxX = rand.Next(0, ActiveForm.Size.Width);
            //square.boxY = rand.Next(0, ActiveForm.Size.Height);
            squares.Add(square);
            //MessageBox.Show("A square has been created");
        }
    }

    //private void DrawLineOnScreen()
    //{
    //  Random rand = new Random();

    //  Color randomColour = new Color();
    //  randomColour = Color.FromArgb(rand.Next(0, 255), rand.Next(0, 255), rand.Next(0, 255));

    //  Pen myPen = new Pen(randomColour);
    //  Graphics graphics = CreateGraphics();

    //  graphics.DrawLine(myPen, rand.Next(0, ActiveForm.Size.Width), rand.Next(0, ActiveForm.Size.Height), rand.Next(0, ActiveForm.Size.Width), rand.Next(0, ActiveForm.Size.Height));

    //  myPen.Dispose();
    //  graphics.Dispose();
    //}

    private void RectRotateTimer_Tick(object sender, EventArgs e)
    {
    //  Pen myPen = new Pen(Color.Red, 5);
    //  Graphics graphics = CreateGraphics();
    //  graphics.Clear(Color.White);

    //  int boxX = 100;
    //  int boxY = 100;

    //  int boxWidth = 100;
    //  int boxHeight = 100;

    //  //Get the rotation point
    //  //get the X position of the rectangle and add half of thw width to get the X.
    //  //get the Y position of the rectangle and add half of the height to get the Y.
    //  PointF rotatePoint = new PointF((boxX + (boxWidth / 2)), (boxY + (boxHeight / 2)));
    //  myMatrix.RotateAt(rotateDegrees, rotatePoint, MatrixOrder.Append);

    //  graphics.Transform = myMatrix;
    //  graphics.DrawRectangle(myPen, boxX, boxY, boxWidth, boxHeight);

    //  //Increment the rotation by 1 each tick.
    //  rotateDegrees += 1;

    //  //If rotateDegress is greater than 360, set it to 0.
    //  //360 is a full spin.
    //  if (rotateDegrees > 360)
    //      rotateDegrees = 0;

    //  //Debug information.
    //  //Console.WriteLine(rotateDegrees);

    //  //Dispose of the graphics and pen so we dont cause a memory leak.
    //  myPen.Dispose();
    //  graphics.Dispose();
    }

    private void RotateAllSquares_Tick(object sender, EventArgs e)
    {
        DrawAllRectangles();
    }

    public void DrawAllRectangles()
    {
        for (int i = 0; i < squares.Count; i++)
        {
            Pen myPen = new Pen(Color.Red, 3);
            Graphics graphics = CreateGraphics();
            graphics.Clear(Color.White);

            PointF rotatePoint = new PointF((squares[i].boxX + (squares[i].boxWidth / 2)), (squares[i].boxY + (squares[i].boxHeight / 2)));
            myMatrix.RotateAt(squares[i].rotateDegrees, rotatePoint, MatrixOrder.Append);
            graphics.Transform = myMatrix;

            graphics.DrawRectangle(myPen, squares[i].boxX, squares[i].boxY, squares[i].boxWidth, squares[i].boxHeight);

            squares[i].rotateDegrees ++;

            myPen.Dispose();
            graphics.Dispose();

            Console.WriteLine(string.Format("A square has been rotated at {0}, {1}", squares[i].boxX, squares[i].boxY));
            Console.WriteLine(squares[i].rotateDegrees);
        }
    }
}
}

这是简单的Square类，正如你所看到的那样，现在也大部分被注释掉了。

using System;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace CSharpIntro.Classes.Shapes_Rotation
{
public class Square
{
    //Create the variables with some basic numbers
    //Just in case they dont get set for some reason.
    public int boxX = 100;
    public int boxY = 100;
    public int boxWidth = 100;
    public int boxHeight = 100;

    public int rotateDegrees = 0;

    //Create a new Matrix class
    Matrix myMatrix = new Matrix();

    public void IncrementRotationDegrees()
    {
        rotateDegrees += 1;
        if (rotateDegrees > 360)
            rotateDegrees = 1;
    }

    //public void RotateSquare()
    //{
    //  Pen myPen = new Pen(Color.Red, 5);

    //  //Instantiate a new Form1 just so I can access CreateGraphics().
    //  Form1 form = new Form1();
    //  Graphics graphics = form.CreateGraphics();

    //  graphics.Clear(Color.White);

    //  //Get the rotation point
    //  //get the X position of the rectangle and add half of thw width to get the X.
    //  //get the Y position of the rectangle and add half of the height to get the Y.
    //  PointF rotatePoint = new PointF((boxX + (boxWidth / 2)), (boxY + (boxHeight / 2)));
    //  myMatrix.RotateAt(rotateDegrees, rotatePoint, MatrixOrder.Append);

    //  graphics.Transform = myMatrix;
    //  graphics.DrawRectangle(myPen, boxX, boxY, boxWidth, boxHeight);

    //  //Increment the rotation by 1 each tick.
    //  rotateDegrees += 1;

    //  //If rotateDegress is greater than 360, set it to 0.
    //  //360 is a full spin.
    //  if (rotateDegrees > 360)
    //      rotateDegrees = 0;

    //  //Debug information.
    //  //Console.WriteLine(rotateDegrees);

    //  //Dispose of the graphics and pen so we dont cause a memory leak.
    //  myPen.Dispose();
    //  graphics.Dispose();
    //}
}
}

由于大部分代码已被注释掉，我仍然不知道是什么原因导致它剧烈旋转。

感谢。

Answer 1

为了回复此帖子，您必须使用以下方法重置Matrix：

myMatrix.Reset（）;

或者你的矩阵叫什么。

感谢评论中的帮助。

C＃Graphics矩形剧烈旋转

1 个答案: