cursor-guardrail-utility/source/Windows/Forms/ScreensLayout.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using CursorGuardRail.Dtos;
using RyzStudio.Drawing;

namespace CursorGuardRail.Windows.Forms
{
    public class ScreensLayout : RyzStudio.Windows.ThemedForms.T3UserControl
    {
        private readonly Pen screenBorderColour = new Pen(Color.Black, 2f);
        private readonly Brush screenBackColour = new SolidBrush(Color.FromArgb(218, 218, 218));
        private readonly Brush selectedScreenBackColour = new SolidBrush(Color.FromArgb(0, 120, 215));
        private readonly Pen selectedAreaBorderColour = new Pen(Color.FromArgb(254, 135, 0), 2f)
        {
            DashStyle = System.Drawing.Drawing2D.DashStyle.Dot
        };


        public ScreensLayout()
        {
            this.Font = new Font(this.Font.FontFamily, 20f, FontStyle.Regular);
        }


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

            var g = e.Graphics;

            for (var i=0; i<this.Screens.Count; i++)
            {
                var screen = this.Screens[i];
                var backColour = screen.IsSelected ? selectedScreenBackColour : screenBackColour;
                var foreColour = screen.IsSelected ? Color.White : this.ForeColor;
                var font = screen.IsPrimary ? new Font(this.Font, FontStyle.Bold) : this.Font;
                var label = (i + 1).ToString();

                var rect = screen.Bound.ToRectangle();
                rect = new Rectangle(rect.X, rect.Y, rect.Width, rect.Height - 5);

                g.FillRectangle(backColour, screen.Bound);
                g.DrawRectangle(screenBorderColour, screen.Bound);

                TextRenderer.DrawText(g, label, font, rect, foreColour, TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter | TextFormatFlags.NoPadding| TextFormatFlags.EndEllipsis);
            }

            if (this.Screens.Any(x => x.IsSelected))
            {
                var area = CalcMaxBound(this.Screens.Where(x => x.IsSelected).Select(x => x.Bound).ToList());

                g.DrawRectangle(selectedAreaBorderColour, area);
            }

            g.Flush();
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);

            if (e.Button == MouseButtons.Left)
            {
                for (var i = 0; i < this.Screens.Count; i++)
                {
                    if (this.Screens[i].Bound.Contains(e.Location))
                    {
                        this.Screens[i].IsSelected = !this.Screens[i].IsSelected;
                        break;
                    }
                }
            }
        }

        protected override void OnResize(EventArgs e)
        {
            base.OnResize(e);

            this.InvalidateScreens();
        }


        protected override void UpdateBackground()
        {
            if (base.ClientRectangle.Width <= 0 || base.ClientRectangle.Height <= 0)
            {
                return;
            }

            var backColour = Color.FromArgb(242, 242, 242);
            var backgroundImage = new Rectangoid(base.ClientRectangle, CurrentStyle.Border.Radius, CurrentStyle.Border.Width).ToBitmap(new Pen(new SolidBrush(CurrentStyle.Border.Colour), CurrentStyle.Border.Width), new SolidBrush(backColour));

            this.BackgroundImage = backgroundImage;
        }

        public void InvalidateScreens()
        {
            var virtualDesktop = SystemInformation.VirtualScreen;
            var offsetX = (virtualDesktop.X <= 0 ? -virtualDesktop.X : 0);

            this.Screens.Clear();

            foreach (var screen in Screen.AllScreens)
            {
                var bound = screen.Bounds;
                bound.Offset(offsetX, 0);

                var newBound = new RectangleF(bound.X, bound.Y, bound.Width, bound.Height);
                newBound = newBound.ScaleDown(ScaleRatio);

                this.Screens.Add(new ScreenItem()
                {
                    Bound = newBound,
                    IsPrimary = screen.Primary,
                    IsSelected = false
                });
            }

            CenterRectangles(this.Screens);

            this.Invalidate();
        }


        private int ActualWidth
        {
            get => this.ClientSize.Width - this.Padding.Horizontal;
        }

        private int ActualHeight
        {
            get => this.ClientSize.Height - this.Padding.Vertical;
        }

        public List<ScreenItem> Screens
        {
            get
            {
                if (field == null) field = new List<ScreenItem>();

                return field;
            }
            private set
            {
                field = value;

                //this.Invalidate();
            }
        }

        private decimal ScaleRatio
        {
            get
            {
                var virtualScreen = SystemInformation.VirtualScreen;

                var widthRatio = decimal.Divide(virtualScreen.Width, ActualWidth);
                var heightRatio = decimal.Divide(virtualScreen.Height, ActualHeight);

                return Math.Max(widthRatio, heightRatio);
            }
        }

        private PointF CalcCentreOffset(List<RectangleF> rectangles)
        {
            if (rectangles.Count <= 0)
            {
                return PointF.Empty;
            }

            // Find the bounds
            var left = rectangles.Min(r => r.Left);
            var top = rectangles.Min(r => r.Top);
            var right = rectangles.Max(r => r.Right);
            var bottom = rectangles.Max(r => r.Bottom);

            var bounds = RectangleF.FromLTRB(left, top, right, bottom);

            // Calculate offset
            var offsetX = this.Padding.Left + (ActualWidth - bounds.Width) / 2 - bounds.Left;
            var offsetY = this.Padding.Top + (ActualHeight - bounds.Height) / 2 - bounds.Top;

            return new PointF(offsetX, offsetY);
        }

        private void CenterRectangles(List<ScreenItem> screen)
        {
            var offset = CalcCentreOffset(screen.Select(x => x.Bound).ToList());

            for (var i=0; i<screen.Count; i++)
            {
                screen[i].Bound = new RectangleF(screen[i].Bound.X + offset.X, screen[i].Bound.Y + offset.Y, screen[i].Bound.Width, screen[i].Bound.Height);
            }
        }

        private RectangleF CalcMaxBound(List<RectangleF> bounds)
        {
            RectangleF? rect = null;

            for (var i = 0; i < bounds.Count; i++)
            {
                if (rect == null)
                {
                    rect = bounds[i];
                }
                else
                {
                rect = RectangleF.Union(bounds[i], rect.Value);
                }
            }

            return rect ?? Rectangle.Empty;
        }

    }
}