Question

IDE：visual studio，c＃，Windows from application

我想在面板上画一条线。我可以通过点击它在panel1上画线。

//Code  

public partial class Form1 : Form
{
    static int px=5, py=5;
    public Form1()
    {
        InitializeComponent();
    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.DrawLine(Pens.Red, 5, 5, px, py);
    }

    private void panel1_MouseDown(object sender, MouseEventArgs e)
    {
        initilizeXY(e.X, e.Y);

    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void panel1_MouseMove(object sender, MouseEventArgs e)
    {

    }
    private void initilizeXY( int pxx, int pyy)
    {
        px = pxx;
        py = pyy;           

    }

    private void panel1_MouseUp(object sender, MouseEventArgs e)
    {
       panel1.Refresh();
    }

    private void panel2_MouseDown(object sender, MouseEventArgs e)
    {
        initilizeXY(e.X, e.Y);
    }
}

//通过此代码，我可以在面板1上向下绘制一条线。

但是由于一些需求变化，还有另一个面板（panel2），它与panel1部分重叠。

现在我想在panel1上绘制相同的行，如果用户单击panel1或panel2。

请建议如何完成这项工作？

Answer 1

编辑：修复了正常运行的代码。在panel2与panel1右侧的panel1重叠的情况下测试，从panel1的顶部开始略低。

写这段代码我假设panel2的X和Y坐标大于panel1。如果是相反的话，也许你应该反转偏移量计算。

public partial class Form1 : Form
{
    static int px = 5, py = 5;
    static int p2x = 0, p2y = 0;
    int offsetX;
    int offsetY;

    public Form1()
    {
        InitializeComponent();
        offsetX = panel2.Location.X - panel1.Location.X;
        offsetY = panel2.Location.Y - panel1.Location.Y;
    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.DrawLine(Pens.Red, 5, 5, px, py);
    }

    private void panel1_MouseDown(object sender, MouseEventArgs e)
    {
        initilizeXY(e.X, e.Y);
    }

    private void Form1_Load(object sender, EventArgs e)
    {
    }

    private void initilizeXY(int pxx, int pyy)
    {
        px = pxx;
        py = pyy;
    }

    private void initilizeXY2(int pxx, int pyy)
    {
        p2x = pxx;
        p2y = pyy;
    }

    private void panel1_MouseUp(object sender, MouseEventArgs e)
    {
        panel1.Refresh();
        panel2.Refresh();
    }

    private void panel2_MouseDown(object sender, MouseEventArgs e)
    {
        initilizeXY(e.X+offsetX, e.Y+offsetY);
        initilizeXY2(e.X, e.Y);
    }

    private void panel2_Paint(object sender, PaintEventArgs e)
    {
        if (px > offsetX && py > offsetY)
        {
            int p2start = findIntersectFromLineEquation(new Point(5, 5), new Point(px, py));

            e.Graphics.DrawLine(Pens.Red, 0, p2start - offsetY, p2x, p2y);
        }
    }

    private int findIntersectFromLineEquation(Point start, Point end)
    {
        if (start.X == end.X || start.Y == end.Y)
            return 0;

        double a = (double)(end.Y - start.Y) / (double)(end.X - start.X);
        double b = (double)(start.Y) - (double)(a * start.X);

        return (int)(a * offsetX + b);
    }
}

请记住相应地订阅事件。

Answer 2

此代码有效：

Point bgn1 = new Point(5, 5);
Point end1 = new Point(5, 5);
Point bgn2 = new Point(0, 0);
Point end2 = new Point(0, 0);

private void Form1_Load(object sender, EventArgs e)
{
    Point pnt, pntscr;

    pnt.X = 5;
    pnt.Y = 5;

    pntscr = Panel1.PointToScreen(pnt);

    bgn2 = Panel2.PointToClient(pntscr);
    end2 = bgn2;
}

private void panel1_MouseDown(object sender, MouseEventArgs e)
{
    end1.X = e.X;
    end1.Y = e.Y;

    Point pntscr;

    pntscr = Panel1.PointToScreen(end1);

    end2 = Panel2.PointToClient(pntscr);
}

private void panel1_MouseUp(object sender, MouseEventArgs e)
{
    panel1.Refresh();
    panel2.Refresh();
}

private void panel2_MouseDown(object sender, MouseEventArgs e)
{
    end2.X = e.X;
    end2.Y = e.Y;

    Point pntscr;

    pntscr = Panel2.PointToScreen(end2);

    end1 = Panel1.PointToClient(pntscr);
}

private void panel2_MouseUp(object sender, MouseEventArgs e)
{
    panel1.Refresh();
    panel2.Refresh();
}

private void panel1_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawLine(Pens.Red, bgn1, end1);
}

private void panel2_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawLine(Pens.Red, bgn2, end2);
}

瓦尔特

如何在面板上绘制一条与其他面板重叠的线？

2 个答案: