The theory of moveable objects

using System;
using System .Collections .Generic;
using System .ComponentModel;
using System .Drawing;
using System .Windows .Forms;

using MoveGraphLibrary;

namespace TheoryOfMoveableObjects
{
    public partial class Form_Nodes : Form
    {
        Mover mover;
        PrimitiveCircle circle;
        PrimitiveRectangle rect;
        PrimitiveStrip strip;
        TextM info;
        bool bShowCovers = false;

        string infotext = "The cover for each object consists of one node.\r\n" +
                          "All objects are moveable; no resizing or rotation.";

        // -------------------------------------------------
        public Form_Nodes ()
        {
            InitializeComponent ();
            mover = new Mover (this);

            circle = new PrimitiveCircle (new Point (150, 120), 100, Color .Blue);
            rect = new PrimitiveRectangle (new Rectangle (240, 60, 250, 140), Color .Green);
            strip = new PrimitiveStrip (new Point (100, 340), new Point (320, 240), 30, Color .Red);
            info = new TextM (this, new Point (300, 300), infotext);
            info .BackColor = Color .Yellow;

            mover .Add (info);
            mover .Add (circle);
            mover .Add (rect);
            mover .Add (strip);
            mover .Insert (0, btnCovers);
        }
        // -------------------------------------------------        OnPaint
        private void OnPaint (object sender, PaintEventArgs e)
        {
            Graphics grfx = e .Graphics;

            strip .Draw (grfx);
            rect .Draw (grfx);
            circle .Draw (grfx);
            info .Draw (grfx);

            if (bShowCovers)
            {
                mover .DrawCovers (grfx);
            }
        }
        // -------------------------------------------------        OnMouseDown
        private void OnMouseDown (object sender, MouseEventArgs mea)
        {
            mover .Catch (mea .Location, mea .Button);
        }
        // -------------------------------------------------        OnMouseUp
        private void OnMouseUp (object sender, MouseEventArgs e)
        {
            mover .Release ();
        }
        // -------------------------------------------------        OnMouseMove
        private void OnMouseMove (object sender, MouseEventArgs mea)
        {
            if (mover .Move (mea .Location))
            {
                Invalidate ();
            }
        }
        // -------------------------------------------------        Click_btnCovers
        private void Click_btnCovers (object sender, EventArgs e)
        {
            bShowCovers = !bShowCovers;
            Invalidate ();
        }
    }
    // ******************************************
    public class PrimitiveCircle : GraphicalObject
    {
        Point center;
        int radius;
        Color clr;

        // -------------------------------------------------
        public PrimitiveCircle (Point pt, int rad, Color color)
        {
            center = pt;
            radius = rad;
            clr = color;
        }
        // -------------------------------------------------        Draw
        public void Draw (Graphics grfx)
        {
            Auxi_Drawing .FillEllipse (grfx, center, radius, clr);
        }
        // -------------------------------------------------        DefineCover
        public override void DefineCover ()
        {
            CoverNode node = new CoverNode (0, center, radius, Cursors .SizeAll);
            cover = new Cover (new CoverNode [] { node });
            // another variant
            //cover = new Cover (new PointF [] { center }, radius);
            //cover .SetCursor (Cursors .SizeAll);
        }
        // -------------------------------------------------
        public override void Move (int dx, int dy)
        {
            center += new Size (dx, dy);
        }
        // -------------------------------------------------        MoveNode
        public override bool MoveNode (int i, int dx, int dy, Point ptM, MouseButtons catcher)
        {
            bool bRet = false;

            if (catcher == MouseButtons .Left)
            {
                Move (dx, dy);
                bRet = true;
            }
            return (bRet);
        }
    }
    // ******************************************
    public class PrimitiveRectangle : GraphicalObject
    {
        Rectangle rc;
        Color clr;

        // -------------------------------------------------
        public PrimitiveRectangle (Rectangle rect, Color color)
        {
            rc = rect;
            clr = color;
        }
        // -------------------------------------------------        Draw
        public void Draw (Graphics grfx)
        {
            grfx .FillRectangle (new SolidBrush (clr), rc);
        }
        // -------------------------------------------------        DefineCover
        public override void DefineCover ()
        {
            CoverNode node = new CoverNode (0, Auxi_Geometry .CornersOfRectangle (rc));
            node .Clearance = true;
            cover = new Cover (new CoverNode [] { node });
        }
        // -------------------------------------------------
        public override void Move (int dx, int dy)
        {
            rc .Location += new Size (dx, dy);
        }
        // -------------------------------------------------        MoveNode
        public override bool MoveNode (int i, int dx, int dy, Point ptM, MouseButtons catcher)
        {
            bool bRet = false;

            if (catcher == MouseButtons .Left)
            {
                Move (dx, dy);
                bRet = true;
            }
            return (bRet);
        }
    }
    // ******************************************
    public class PrimitiveStrip : GraphicalObject
    {
        Point pt0, pt1;
        int radius;
        SolidBrush brush;

        // -------------------------------------------------
        public PrimitiveStrip (Point ptA, Point ptB, int rad, Color color)
        {
            pt0 = ptA;
            pt1 = ptB;
            radius = rad;
            brush = new SolidBrush (color);
        }
        // -------------------------------------------------        Draw
        public void Draw (Graphics grfx)
        {
            Auxi_Drawing .FillRoundedStrip (grfx, pt0, pt1, radius, brush);
        }
        // -------------------------------------------------        DefineCover
        public override void DefineCover ()
        {
            cover = new Cover (new CoverNode [] { new CoverNode (0, pt0, pt1, radius, Cursors .SizeAll) });
        }
        // -------------------------------------------------
        public override void Move (int dx, int dy)
        {
            Size size = new Size (dx, dy);
            pt0 += size;
            pt1 += size;
        }
        // -------------------------------------------------        MoveNode
        public override bool MoveNode (int i, int dx, int dy, Point ptM, MouseButtons catcher)
        {
            Move (dx, dy);
            return (true);
        }
    }
}