如何在WinForms中的两个图像之间绘制箭头？

Question

我必须这样做：在画布上的两个图像之间绘制一个箭头，因此当我单击带有箭头的按钮时，我单击一个图像以将箭头粘贴到其上，然后绘制箭头只要我需要并将其粘贴到第二张图片中。

Answer 1

要用两点绘制圆弧，您需要一个预定义的角度。我想你已经弄清楚了那部分。

为此，您需要绘制两条弧线，每个图像中各一条。弧线将比每个图像都大，但在第一个图像中，您可以将其剪裁在弧线退出图像并朝向第二个点的位置。

在第二个图像中，您需要将圆弧偏移两个图像原点之间的 x 和 y 距离。然后在第二张图像中从第一个点到第二个点绘制圆弧，并剪掉图像外部的部分。

如果您需要橡皮筋弧，则必须在鼠标移动时擦除并重新绘制它。如果您想在图像之间的表单上的空间上绘图，可以使用适当的偏移量来实现。

Answer 2

你有两个点，所以你可以画一条线。试试这个：

public class Shape
{
    public float X { get; set; }
    public float Y { get; set; }
    public Image Image { get; set; }
}

public class Line
{
    public Shape A { get; set; }
    public Shape B { get; set; }
}

和代码：

private string _currentTool;
private readonly List<Shape> _shapes;
private readonly List<Line> _lines;
private Line _currentLine;

private void Button1Click(object sender, EventArgs e)
{
    _currentTool = "img";
}

private void Button2Click(object sender, EventArgs e)
{
    _currentTool = "line";
}

private void PictureBox1MouseDown(object sender, MouseEventArgs e)
{
    switch (_currentTool)
    {
        case "img":
            _shapes.Add(new Shape { Image = button1.Image, X = e.X, Y = e.Y });
            pictureBox1.Invalidate();
            break;
        case "line":
                var selectedShapes = _shapes.Where(shape => (shape.X - 10 < e.X) && (e.X < shape.X + 10) &&
                                                           (shape.Y - 10 < e.Y) && (e.Y < shape.Y + 10));
                if (selectedShapes.Count() > 0)
                {
                    var selectedShape = selectedShapes.First();
                    _currentLine = new Line {A = selectedShape};
                    pictureBox1.Invalidate();
                }
            break;
    }
}

private void PictureBox1MouseUp(object sender, MouseEventArgs e)
{
    switch (_currentTool)
    {
        case "line":
                var selectedShapes = _shapes.Where(shape => (shape.X - 10 < e.X) && (e.X < shape.X + 10) &&
                                                           (shape.Y - 10 < e.Y) && (e.Y < shape.Y + 10));
                if (selectedShapes.Count() > 0)
                {
                    var selectedShape = selectedShapes.First();
                    _currentLine.B = selectedShape;
                    _lines.Add(_currentTool);
                    pictureBox1.Invalidate();
                }
            break;
    }
}

private void PictureBox1Paint(object sender, PaintEventArgs e)
{
    foreach (var shape in _shapes)
    {
        e.Graphics.DrawImage(shape.Image, shape.X, shape.Y);
    }
    foreach (var line in _lines)
    {
        e.Graphics.DrawLine(new Pen(Color.Black), line.A.X, line.A.Y, line.B.X, line.B.Y);
    }
}

Answer 3

public class Shape
{
public float X { get; set; }
public float Y { get; set; }
public Image Image { get; set; }

public bool Test_int(int x, int y)
    {
        if (((x <= this.x + (float)image.Width) && (x >= this.x)) && ((y <= this.y + (float)image.Height) && (y >= this.y)))
            return true;
        else
            return false;
    }
}



public class Line
{
    public Shape A { get; set; }
    public Shape B { get; set; }
}

和代码

private string currentTool;
private readonly List<Shape> shapes;
private readonly List<Line> lines;
private Line currentLine;

private void Button1Click(object sender, EventArgs e)
{
    currentTool = "img";
}

private void Button2Click(object sender, EventArgs e)
{
    currentTool = "line";
}


private void PictureBox1MouseDown(object sender, MouseEventArgs e)
{

    switch (currentTool)
    {
        case "img":
            shapes.Add(new Shape { Image = button1.Image, X = e.X, Y = e.Y });
            pictureBox1.Invalidate();
            break;
        case "line":
            foreach (Shape shape1 in shapes)
                {

                    if (shape1.Test_int(e.X, e.Y))
                    {

                        currentLine = new Line { A = shape1 };

                    }

                }
                drawArea1.Invalidate();
        break;
    }
}

private void PictureBox1MouseUp(object sender, MouseEventArgs e)
{

    switch (currentTool)
    {
        case "line":
            foreach (Shape shape1 in shapes)
            {

                if (shape1.Test_int(e.X, e.Y))
                {


                    currentLine.B = shape1;

                    }

                }
                lines.Add(currentLine);
                drawArea1.Invalidate();

            break;
    }
}

private void PictureBox1Paint(object sender, PaintEventArgs e)
{

    foreach (var shape in shapes)
    {
        e.Graphics.DrawImage(shape.Image, shape.X, shape.Y);
    }
    foreach (var line in lines)
    {
        Pen p = new Pen(Color.Gray, 1);
        Pen p2 = new Pen(Color.Black, 5);

        e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

        p2.StartCap = System.Drawing.Drawing2D.LineCap.Round;
        p2.EndCap = System.Drawing.Drawing2D.LineCap.ArrowAnchor;

        float x1 = line.A.X+line.A.Image.Width ;
        float y1 = line.A.Y+line.A.Image.Height/2;
        float x2 = line.B.X;
        float y2 = line.B.Y+line.B.Image.Height/2;
        double angle = Math.Atan2(y2 - y1, x2 - x1);

        e.Graphics.DrawLine(p, x1, y1, x2, y2);
        e.Graphics.DrawLine(p2, x2, y2, x2 + (float)(Math.Cos(angle)), y2 + (float)(Math.Sin(angle)));

    }
}