gui-cs.Terminal.Gui/Terminal.Gui/Views/LineView.cs


namespace Terminal.Gui.Views;

/// <summary>A straight line control either horizontal or vertical</summary>
public class LineView : View
{
    /// <summary>Creates a horizontal line</summary>
    public LineView () : this (Orientation.Horizontal) { }

    /// <summary>Creates a horizontal or vertical line based on <paramref name="orientation"/></summary>
    public LineView (Orientation orientation)
    {
        CanFocus = false;

        switch (orientation)
        {
            case Orientation.Horizontal:
                Height = Dim.Auto (minimumContentDim: 1);
                Width = Dim.Fill ();
                LineRune = Glyphs.HLine;

                break;
            case Orientation.Vertical:
                Height = Dim.Fill ();
                Width = Dim.Auto (minimumContentDim: 1);
                LineRune = Glyphs.VLine;

                break;
            default:
                throw new ArgumentException ($"Unknown Orientation {orientation}");
        }

        Orientation = orientation;
    }

    /// <summary>
    ///     The rune to display at the end of the line (right end of horizontal line or bottom end of vertical). If not
    ///     specified then <see cref="LineRune"/> is used
    /// </summary>
    public Rune? EndingAnchor { get; set; }

    /// <summary>The symbol to use for drawing the line</summary>
    public Rune LineRune { get; set; }

    /// <summary>
    ///     The direction of the line.  If you change this you will need to manually update the Width/Height of the
    ///     control to cover a relevant area based on the new direction.
    /// </summary>
    public Orientation Orientation { get; set; }

    /// <summary>
    ///     The rune to display at the start of the line (left end of horizontal line or top end of vertical) If not
    ///     specified then <see cref="LineRune"/> is used
    /// </summary>
    public Rune? StartingAnchor { get; set; }

    /// <summary>Draws the line including any starting/ending anchors</summary>
    protected override bool OnDrawingContent ()
    {
        Move (0, 0);
        SetAttribute (GetAttributeForRole (VisualRole.Normal));

        int hLineWidth = Math.Max (1, Glyphs.HLine.GetColumns ());

        int dEnd = Orientation == Orientation.Horizontal ? Viewport.Width : Viewport.Height;

        for (var d = 0; d < dEnd; d += hLineWidth)
        {
            if (Orientation == Orientation.Horizontal)
            {
                Move (d, 0);
            }
            else
            {
                Move (0, d);
            }

            Rune rune = LineRune;

            if (d == 0)
            {
                rune = StartingAnchor ?? LineRune;
            }
            else if (d == dEnd - 1)
            {
                rune = EndingAnchor ?? LineRune;
            }

            Driver?.AddRune (rune);
        }
        return true;
    }
}