Remastered-Collection/CnCTDRAMapEditor/Controls/MenuButton.cs

//
// Copyright 2020 Electronic Arts Inc.
//
// The Command & Conquer Map Editor and corresponding source code is free 
// software: you can redistribute it and/or modify it under the terms of 
// the GNU General Public License as published by the Free Software Foundation, 
// either version 3 of the License, or (at your option) any later version.

// The Command & Conquer Map Editor and corresponding source code is distributed 
// in the hope that it will be useful, but with permitted additional restrictions 
// under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT 
// distributed with this program. You should have received a copy of the 
// GNU General Public License along with permitted additional restrictions 
// with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace MobiusEditor.Controls
{
    public partial class MenuButton : Button
    {
        public const int DefaultSplitWidth = 20;

        [DefaultValue(null), Browsable(true), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
        public ContextMenuStrip Menu { get; set; }

        [DefaultValue(DefaultSplitWidth), Browsable(true), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
        public int SplitWidth { get; set; } = DefaultSplitWidth;

        public MenuButton()
        {
            InitializeComponent();
        }

        protected override void OnMouseDown(MouseEventArgs mevent)
        {
            var splitRect = new Rectangle(Width - SplitWidth, 0, SplitWidth, Height);

            if ((Menu != null) && (mevent.Button == MouseButtons.Left) && splitRect.Contains(mevent.Location))
            {
                Menu.Show(this, 0, Height);
            }
            else
            {
                base.OnMouseDown(mevent);
            }
        }

        protected override void OnPaint(PaintEventArgs pevent)
        {
            base.OnPaint(pevent);

            if ((Menu != null) && (SplitWidth > 0))
            {
                int arrowX = ClientRectangle.Width - 14;
                int arrowY = ClientRectangle.Height / 2 - 1;

                var arrowBrush = Enabled ? SystemBrushes.ControlText : SystemBrushes.ButtonShadow;
                var arrows = new[] { new Point(arrowX, arrowY), new Point(arrowX + 7, arrowY), new Point(arrowX + 3, arrowY + 4) };
                pevent.Graphics.FillPolygon(arrowBrush, arrows);

                int lineX = ClientRectangle.Width - SplitWidth;
                int lineYFrom = arrowY - 4;
                int lineYTo = arrowY + 8;
                using (var separatorPen = new Pen(Brushes.DarkGray) { DashStyle = DashStyle.Dot })
                {
                    pevent.Graphics.DrawLine(separatorPen, lineX, lineYFrom, lineX, lineYTo);
                }
            }
        }
    }
}