基于C#实现一个流程图工具的代码示例

// 节点类型枚举
publicenum NodeType
{
    Rectangle,  // 矩形节点
    Ellipse,    // 椭圆节点  
    Diamond     // 菱形节点
}

// 连接方向枚举
publicenum ConnectionDirection
{
    Forward,    // 正向箭头 (起始->结束)
    Backward,   // 反向箭头 (结束->起始)
    Both,       // 双向箭头
    None        // 无箭头
}

public class Connection
{
    public FlowChartNode StartNode { get; set; }
    public FlowChartNode EndNode { get; set; }
    public ConnectionDirection Direction { get; set; }

    public Connection(FlowChartNode startNode, FlowChartNode endNode)
        : this(startNode, endNode, ConnectionDirection.Forward)
    {
    }

    public Connection(FlowChartNode startNode, FlowChartNode endNode, ConnectionDirection direction)
    {
        StartNode = startNode;
        EndNode = endNode;
        Direction = direction;
    }
}

// 计算节点边缘的连接点
private Point GetNodeEdgePoint(FlowChartNode fromNode, FlowChartNode toNode)
{
    Rectangle fromBounds = fromNode.Bounds;
    Rectangle toBounds = toNode.Bounds;

    // 计算两个节点中心点
    Point fromCenter = new Point(
        fromBounds.X + fromBounds.Width / 2,
        fromBounds.Y + fromBounds.Height / 2);

    Point toCenter = new Point(
        toBounds.X + toBounds.Width / 2,
        toBounds.Y + toBounds.Height / 2);

    // 计算方向向量
    double dx = toCenter.X - fromCenter.X;
    double dy = toCenter.Y - fromCenter.Y;
    double distance = Math.Sqrt(dx * dx + dy * dy);

    if (distance == 0) return fromCenter;

    // 单位方向向量
    double unitX = dx / distance;
    double unitY = dy / distance;

    return GetNodeBoundaryPoint(fromNode, unitX, unitY);
}

// 矩形边界点计算
private Point GetRectangleBoundaryPoint(Rectangle bounds, Point center, double dirX, double dirY)
{
    double halfWidth = bounds.Width / 2.0;
    double halfHeight = bounds.Height / 2.0;

    double t = Math.Min(halfWidth / Math.Abs(dirX), halfHeight / Math.Abs(dirY));

    returnnew Point(
        (int)(center.X + dirX * t),
        (int)(center.Y + dirY * t)
    );
}

// 椭圆边界点计算
private Point GetEllipseBoundaryPoint(Rectangle bounds, Point center, double dirX, double dirY)
{
    double theta = Math.Atan2(dirY, dirX);
    double a = bounds.Width / 2.0;
    double b = bounds.Height / 2.0;
    double x = center.X + a * Math.Cos(theta);
    double y = center.Y + b * Math.Sin(theta);
    returnnew Point((int)x, (int)y);
}

public class CustomPanel : Panel
{
    public CustomPanel()
    {
        // 启用双缓冲和自定义绘制
        this.SetStyle(ControlStyles.AllPaintingInWmPaint |
                     ControlStyles.UserPaint |
                     ControlStyles.DoubleBuffer |
                     ControlStyles.ResizeRedraw, true);

        this.UpdateStyles();
    }
}

private void pnlMain_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button == MouseButtons.Left)
    {
        FlowChartNode clickedNode = GetNodeAt(e.Location);

        if (isConnecting)
        {
            // 连接模式下的处理逻辑
            if (clickedNode != null && clickedNode != connectStartNode)
            {
                connections.Add(new Connection(connectStartNode, clickedNode, currentConnectionDirection));
                isConnecting = false;
                connectStartNode = null;
                pnlMain.Invalidate();
            }
        }
        else
        {
            // 选择和拖拽模式
            selectedNode = clickedNode;
            if (selectedNode != null)
            {
                isDragging = true;
                dragNode = selectedNode;
                dragStartPoint = e.Location;
            }
        }
    }
}

// 计算椭圆边界点
private Point GetEllipseBoundaryPoint(Rectangle bounds, Point center, double dirX, double dirY)
{
    // 获取目标点方向的极角
    double theta = Math.Atan2(dirY, dirX);
    double a = bounds.Width / 2.0;
    double b = bounds.Height / 2.0;
    double x = center.X + a * Math.Cos(theta);
    double y = center.Y + b * Math.Sin(theta);
    returnnew Point((int)x, (int)y);
}

// 计算菱形边界点
private Point GetDiamondBoundaryPoint(Rectangle bounds, Point center, double dirX, double dirY)
{
    double halfWidth = bounds.Width / 2.0;
    double halfHeight = bounds.Height / 2.0;

    // 根据方向角度计算交点
    double absX = Math.Abs(dirX);
    double absY = Math.Abs(dirY);

    // 菱形边界条件：|x/a| + |y/b| = 1
    double scale = 1.0 / (absX / halfWidth + absY / halfHeight);

    returnnew Point(
        (int)(center.X + dirX * scale),
        (int)(center.Y + dirY * scale)
    );
}