标签：c mouseevent mouse-position drawellipse

我被困在这里我希望在“观察”光标的角度时画出眼睛.此外,它应该包含在更大的圆/象限内(就像一个眼球).可悲的是,它不会在正确的位置/角度和每次鼠标移动时吸引我.它唯一要做的就是在(0,0)画一个椭圆,但这不是我想要的.

我的想法是用毕达哥拉斯定理计算三角形的比率.然后在drawEllipse()中应用正确的坐标(使用正确的比率);方法.每次移动光标时都应重复此操作.

您可以检查我的图像以获得数学推理.

这是我的代码,请注意该面板是在设计器模式下制作的,该模式不包含在此代码中,但不应该是一个大问题：

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 oogjes2
{
    public partial class Form1 : Form
    {
        public int mousex;
        public int mousey;

        public Form1()
        {
            InitializeComponent();
            panel1.Paint += paintpanel;
            panel1.MouseMove += panel1_MouseMove;     
        }

        //panel1 cover the screen from (0.0) and onwards,
        void panel1_MouseMove(object sender, MouseEventArgs mea)
        {
            int mousex = mea.X;
            int mousey = mea.Y;
        } 

        void paintpanel(object obj, PaintEventArgs pea)
        {
            Pen blackpen = new Pen(Color.Black, 3);

            // the black outer circle which doesnt move
            pea.Graphics.DrawEllipse(blackpen, -125, -125, 250, 250);

            // e = 63. Diagonal distance from (0,0) to starting point drawEllipse
            // factor = multiplication from mea.x and mea.y to the respective ex and ey of the small circle.
            // ey = factor * mousex (mea.X). Same for ex.

            float e = (float)Math.Sqrt(45 * 45 + 45 * 45); //=63
            float factor = (e / (float)Math.Sqrt(mousex * mousex + mousey * mousey));
            int ex = mousex * (int)factor;
            int ey = mousey * (int)factor;

            //  the eye that should be redrawn at every mousemovement
            pea.Graphics.DrawEllipse(blackpen, ex, ey, 50, 50);
            this.Invalidate();
        }
    }
}

解决方法:

试试这个：

public partial class Form1 : Form
{

    private Timer tmr;
    private int PupilRadius = 20;
    private int EyeBallRadius = 50;
    private int DistanceBetweenEyes = 20;

    public Form1()
    {
        InitializeComponent();
        this.panel1.Paint += panel1_Paint;

        tmr = new Timer();
        tmr.Interval = 100;
        tmr.Tick += tmr_Tick;
        tmr.Start();
    }

    void tmr_Tick(object sender, EventArgs e)
    {
        panel1.Invalidate();
    }

    void panel1_Paint(object sender, PaintEventArgs e)
    {
        Point center = new Point(panel1.ClientSize.Width / 2, panel1.ClientSize.Height / 2);
        Point LeftEyeCenter = new Point(center.X - EyeBallRadius - (DistanceBetweenEyes / 2), center.Y);
        Point RightEyeCenter = new Point(center.X + EyeBallRadius + (DistanceBetweenEyes / 2), center.Y);

        Rectangle rc = new Rectangle(LeftEyeCenter, new Size(1, 1));
        rc.Inflate(EyeBallRadius, EyeBallRadius);
        e.Graphics.DrawEllipse(Pens.Black, rc);

        rc = new Rectangle(RightEyeCenter, new Size(1, 1));
        rc.Inflate(EyeBallRadius, EyeBallRadius);
        e.Graphics.DrawEllipse(Pens.Black, rc);

        Point curPos = panel1.PointToClient(Cursor.Position);
        Double DistanceFromLeftEyeToCursor = getDistance(LeftEyeCenter.X, LeftEyeCenter.Y, curPos.X, curPos.Y);
        Double DistanceFromRightEyeToCursor = getDistance(RightEyeCenter.X, RightEyeCenter.Y, curPos.X, curPos.Y);
        double angleLeft = getAngleInDegrees(LeftEyeCenter.X, LeftEyeCenter.Y, curPos.X, curPos.Y);
        double angleRight = getAngleInDegrees(RightEyeCenter.X, RightEyeCenter.Y, curPos.X, curPos.Y);

        rc = new Rectangle(new Point(Math.Min((int)DistanceFromLeftEyeToCursor, EyeBallRadius - PupilRadius), 0), new Size(1, 1));
        rc.Inflate(PupilRadius, PupilRadius);
        e.Graphics.TranslateTransform(LeftEyeCenter.X, LeftEyeCenter.Y);
        e.Graphics.RotateTransform((float)angleLeft);
        e.Graphics.FillEllipse(Brushes.Blue, rc);

        rc = new Rectangle(new Point(Math.Min((int)DistanceFromRightEyeToCursor, EyeBallRadius - PupilRadius), 0), new Size(1, 1));
        rc.Inflate(PupilRadius, PupilRadius);
        e.Graphics.ResetTransform();
        e.Graphics.TranslateTransform(RightEyeCenter.X, RightEyeCenter.Y);
        e.Graphics.RotateTransform((float)angleRight);
        e.Graphics.FillEllipse(Brushes.Blue, rc);
    }

    private Double getDistance(int Ax, int Ay, int Bx, int By)
    {
        return Math.Sqrt(Math.Pow((Double)Ax - Bx, 2) + Math.Pow((Double)Ay - By, 2));
    }

    private Double getAngleInDegrees(int cx, int cy, int X, int Y)
    {
        // draw a line from the center of the circle
        // to the where the cursor is...
        // If the line points:
        // up = 0 degrees
        // right = 90 degrees
        // down = 180 degrees
        // left = 270 degrees

        Double angle;
        int dy = Y - cy;
        int dx = X - cx;
        if (dx == 0) // Straight up and down | avoid divide by zero error!
        {
            if (dy <= 0)
            {
                angle = 0;
            }
            else
            {
                angle = 180;
            }
        }
        else
        {
            angle = Math.Atan((Double)dy / (Double)dx);
            angle = angle * ((Double)180 / Math.PI);

            if (X <= cx)
            {
                angle = 180 + angle;
            }
        }

        return angle;
    }

}

标签：c,mouseevent,mouse-position,drawellipse
来源： https://codeday.me/bug/20190528/1169748.html

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。