3rdpartylibs/fastreports.wpf/FastReport/QueryBuilder/Workspace.cs

using FastReport.Utils;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace FastReport.FastQueryBuilder
{
    internal class Workspace : UserControl
    {
        private PosCounter posC = new PosCounter(10, 10);
        private List<TableView> tableViews = new List<TableView>();
        private LinkMenu linkMenu;
        private Link highlightLink;

        public Workspace()
        {
            AllowDrop = true;
            BackColor = SystemColors.AppWorkspace;

            linkMenu = new LinkMenu(this);
            linkMenu.DeleteLink += LinkMenu_DeleteLink;

            SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.ResizeRedraw, true);
        }

        public List<Link> Links { get; set; }

        public event AddTableEventHandler OnAddTable;

        public void Clear()
        {
            foreach (TableView c in tableViews)
            {
                c.Dispose();
            }
            tableViews.Clear();
            Refresh();
        }

        public void AddTable(Table table) => AddTable(table, posC.Next);
        public void AddTable(Table table, Point pos) => OnAddTable?.Invoke(this, new AddTableEventArgs(table, pos));

        public ITableView DoAddTable(Table table, Point position)
        {
            TableView tbl = new TableView();
            tbl.OnDeleteTable += OnDeleteTable;
            table.TableView = tbl;
            tbl.Table = table;

            tbl.Location = new Point(-1000, -1000);
            tbl.Parent = this;
            tbl.Scale(new SizeF(this.DpiMultiplier(), this.DpiMultiplier()));
            tbl.UpdateDpiDependencies();
            tbl.Location = position.IsEmpty ? posC.Next : position;
            tbl.BringToFront();

            tableViews.Add(tbl);
            Refresh();
            return tbl;
        }

        private void OnDeleteTable(object sender, AddTableEventArgs e)
        {
            for (int i = Links.Count - 1; i >= 0; i--)
            {
                if ((Links[i].From.Table == e.table) || (Links[i].To.Table == e.table))
                    Links.RemoveAt(i);
            }
            tableViews.Remove((TableView)e.table.TableView);
            Refresh();
        }

        private void LinkMenu_DeleteLink(object sender, EventArgs e)
        {
            Links.Remove(linkMenu.CurrentLink);
            Refresh();
        }

        private GraphicsPath GetLinkPath(Link link)
        {
            LinkPosition lp1, lp2;

            int cp1 = link.From.Left + link.From.Width / 2;
            int cp2 = link.To.Left + link.To.Width / 2;

            if (cp1 > cp2)
            {
                if ((link.From.Left) < link.To.Left + link.To.Width)
                {
                    lp1 = LinkPosition.Right;
                    lp2 = LinkPosition.Right;
                }
                else
                {
                    lp1 = LinkPosition.Left;
                    lp2 = LinkPosition.Right;
                }
            }
            else
            {
                if ((link.From.Left + link.From.Width) > link.To.Left)
                {
                    lp2 = LinkPosition.Left;
                    lp1 = LinkPosition.Left;
                }
                else
                {
                    lp2 = LinkPosition.Left;
                    lp1 = LinkPosition.Right;
                }
            }

            Point pnt1 = link.From.GetPosition(lp1);
            Point pnt2 = link.To.GetPosition(lp2);
            int _2 = this.LogicalToDevice(2);
            int _4 = this.LogicalToDevice(4);
            int _8 = this.LogicalToDevice(8);

            var path = new GraphicsPath();

            int dx = (lp1 == LinkPosition.Left) ? _8 : -_8;
            Point pnt3 = new Point(pnt1.X + dx, pnt1.Y);
            path.AddLine(pnt1, pnt3);

            path.AddLine(pnt1, pnt2);

            dx = (lp2 == LinkPosition.Left) ? _4 : -_4;
            pnt3 = new Point(pnt2.X + dx, pnt2.Y);
            path.AddLine(pnt2, pnt3);

            path.AddRectangle(new Rectangle(pnt3.X + dx - _4, pnt3.Y - _2, _4, _4));

            return path;
        }

        private bool HitTestLink(Link link, Point point)
        {
            using (var path = GetLinkPath(link))
            using (var pen = new Pen(Color.Black, this.LogicalToDevice(5f)))
            {
                path.Widen(pen);
                return path.IsVisible(point);
            }
        }

        private void DrawLink(Link link, Graphics g, bool highlight)
        {
            using (var path = GetLinkPath(link))
            using (Pen pen = new Pen(highlight ? SystemColors.Highlight : Color.Black, this.LogicalToDevice(highlight ? 2 : 1)))
            {
                g.DrawPath(pen, path);
            }
        }

        protected override void OnDragOver(DragEventArgs e)
        {
            base.OnDragOver(e);
            if (e.Data.GetDataPresent(typeof(Table)))
                e.Effect = DragDropEffects.Copy;
            else
                e.Effect = DragDropEffects.None;
        }

        protected override void OnDragDrop(DragEventArgs e)
        {
            base.OnDragDrop(e);
            Table _table = (Table)e.Data.GetData(typeof(Table));
            if (_table != null)
            {
                AddTable(_table, PointToClient(new Point(e.X, e.Y)));
            }
        }

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

            if (tableViews.Count == 0)
            {
                TextRenderer.DrawText(e.Graphics, Res.Get("Forms,QueryBuilder,Hint"), Font, DisplayRectangle, Color.Black, TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter);
                return;
            }

            e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
            foreach (var link in Links)
            {
                DrawLink(link, e.Graphics, link == highlightLink);
            }
        }

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

            Link hl = null;
            foreach (var link in Links)
            {
                if (HitTestLink(link, e.Location))
                {
                    hl = link;
                    break;
                }
            }

            if (highlightLink != hl)
            {
                highlightLink = hl;
                Cursor = hl == null ? Cursors.Default : Cursors.Hand;
                Refresh();
            }
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            if (highlightLink != null)
            {
                linkMenu.Show(this, e.Location, highlightLink);
            }
        }

        protected override void OnSizeChanged(EventArgs e)
        {
            base.OnSizeChanged(e);
            posC.maxX = Width;
            posC.maxY = Height;
        }

        public void UpdateDpiDependencies()
        {
            posC.stepX = posC.stepY = this.LogicalToDevice(200);
            linkMenu.UpdateDpiDependencies();
            foreach (var tv in tableViews)
            {
                tv.UpdateDpiDependencies();
            }
        }
    }
}