Question

我有一个带有图片作为背景的图片框（实际上是地图），在它上面我产生了矩形。这些矩形应该按给定点移动。矩形以指定的速度移动，在到达（或接近）其中一个点后，它开始移动到下一个点。我的问题是，矩形不直接移动到给定点，它只是接近只有一个坐标，所以有些情况下矩形的Y坐标和点的Y坐标是相同，但矩形像60像素，不会移动。下面我将添加一张图片作为运动的一个例子。蓝色是预期路线，红色是实际路线。我已经检查了一百次坐标，它们是正确的，矩形只是移动到其他地方。注意：这只发生在某些点上。

enter image description here

这是我用来计算矩形相对于X轴和Y轴的移动的代码。

public void Move_calculate(Graphics g)
    {
        if (points[passed].X == 0 || points[passed].Y == 0) // this happens when the rectangle reaches it final point - it stays where it is (working fine)
        {
            Redraw(g);
            return;
        }
        speed = randomNumbers.Next(7, 13);
        if (points[passed].X > x_coordinate && points[passed].Y > y_coordinate)
        {
            Bx = points[passed].X;
            By = points[passed].Y;
            distanceForAlfaX = Bx - x_coordinate; // x_coordinate is the x coordinate of the rectangle
            distanceForAlfaY = By - y_coordinate;
            if (distanceForAlfaX <= 20 || distanceForAlfaY <= 20) speed = 5; // slowing down when approaching the point
            if (distanceForAlfaX + distanceForAlfaY <= 15) passed += 1;
            alpha = (distanceForAlfaY / distanceForAlfaX); // tangent alpha
            x_change = (int)(speed * (Math.Cos(alpha))); // get distance moved relative to axis X
            y_change = (int)Math.Sqrt(((speed * speed) + (x_change * x_change))); // again distance for axis Y, using Pythagoras theorem
            x_coordinate += x_change;
            y_coordinate += y_change;
        }
        else if (points[passed].X > x_coordinate && points[passed].Y < y_coordinate)
        {
            Bx = points[passed].X;
            By = points[passed].Y;
            distanceForAlfaX = Bx - x_coordinate;
            distanceForAlfaY = y_coordinate - By;
            if (distanceForAlfaX <= 20 || distanceForAlfaY <= 20) speed = 5;
            if (distanceForAlfaX + distanceForAlfaY <= 15) passed += 1;
            alpha = (distanceForAlfaY / distanceForAlfaX);
            x_change = (int)(speed * (Math.Cos(alpha)));
            y_change = (int)Math.Sqrt(((speed * speed) + (x_change * x_change)));
            x_coordinate += x_change;
            y_coordinate -= y_change;
        }
        else if (points[passed].X < x_coordinate && points[passed].Y > y_coordinate)
        {
            Bx = points[passed].X;
            By = points[passed].Y;
            distanceForAlfaX = x_coordinate - Bx;
            distanceForAlfaY = By - y_coordinate;
            if (distanceForAlfaX <= 20 || distanceForAlfaY <= 20) speed = 5;
            if (distanceForAlfaX+distanceForAlfaY <= 15) passed += 1;
            alpha = (distanceForAlfaY / distanceForAlfaX);
            x_change = (int)(speed * (Math.Cos(alpha)));
            y_change = (int)Math.Sqrt(((speed * speed) + (x_change * x_change)));
            x_coordinate -= x_change;
            y_coordinate += y_change;
        }
        else if (points[passed].X < x_coordinate && points[passed].Y < y_coordinate)
        {
            Bx = points[passed].X;
            By = points[passed].Y;
            distanceForAlfaX = x_coordinate - Bx;
            distanceForAlfaY = y_coordinate - By;
            if (distanceForAlfaX <= 20 || distanceForAlfaY <= 20) speed = 5;
            if (distanceForAlfaX + distanceForAlfaY <= 15) passed += 1;
            alpha = (distanceForAlfaY / distanceForAlfaX);
            x_change = (int)(speed * (Math.Cos(alpha)));
            y_change = (int)Math.Sqrt(((speed * speed) + (x_change * x_change)));
            x_coordinate -= x_change;
            y_coordinate -= y_change;
        }
        else
        {
            MessageBox.Show("Something went wrong"); // just notify me that it isnt working again..
        }
        Pen p = new Pen(Color.Turquoise, 2);
        r = new Rectangle(x_coordinate, y_coordinate, 5, 5); // redraw the rectangle
        g.DrawRectangle(p, r);
        p.Dispose();
    }

我不知道为什么会这样，有人可以帮忙吗？附：绝对不需要移动平滑，矩形的位置将使用定时器每两秒更新一次。现在它暂时设置为一个按钮。

编辑：这是foreach代码。标签只是PictureBox旁边显示的坐标

                     foreach (aircraft acft in aircrafts) // aircraft is an array aircrafts[]
                {
                        label2.Text = "xp" + acft.points[acft.passed].X;
                        label3.Text = "yp" + acft.points[acft.passed].Y;
                        label4.Text = acft.passed.ToString();
                        label5.Text = "y" + acft.y_coordinate.ToString();
                        //MessageBox.Show(acft.points[0].X.ToString());
                        acft.Move_calculate(e.Graphics);
                        spawn = string.Empty;
                    }

EDIT2：aircraft类

中的所有变量

        public string callsign;
    public int speed;
    public double heading;
    public bool moving = false;
    public Point[] points;
    public double alpha;
    public int x_change;
    public int y_change;
    public int x_coordinate;
    public int y_coordinate;
    public int Bx;
    public int By;
    public double distanceForAlfaX;
    public double distanceForAlfaY;
    public int passed = 0;
    public Rectangle r;

Answer 1

你检查过你的坐标系吗？（http://www.bobpowell.net/coordinatesystems.htm）

抱歉，您的问题链接错误。尝试使用Control.PointToClient进行调试，以确保所有坐标都在客户端空间中表示。（http://msdn.microsoft.com/en-us/library/system.windows.forms.control.pointtoclient.aspx）

你可以尝试：

    Point cPoint = this.PointToClient(new Point(x_coordinate, y_coordinate));
    Size cSize = new Size(5,5);
    r = new Rectangle(cPoint, cSize); // redraw the rectangle
    g.DrawRectangle(p, r);

您是否可以发布变量的数据类型以澄清您的代码？你可能会在某处丢失精度，特别是如果你使用整数除法。

（关于DJ KRAZE，a - = b;在C＃中也可以表示a = a - b;上下文很重要。）

Answer 2

我猜，

中存在数学错误

y_change = (int)Math.Sqrt(((speed * speed) + (x_change * x_change)));

...而且

// again distance for axis Y, using Pythagoras theorem

让Mr.Pythagoras成为，我宁愿使用与X轴相同的

y_change = (int)(speed * (Math.Sin(alpha)));

移动矩形不会根据给定的坐标移动

2 个答案: