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using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.ComponentModel;
using System.Xml;

namespace Dalssoft.DiagramNet
{
    /// <summary>
    /// This is the base for all element the will be draw on the
    /// document.
    /// </summary>
    [Serializable]
    public abstract class BaseElement
    {
        protected Point location;
        protected Size size;
        protected bool visible = true;
        protected Color borderColor = Color.Black;
        protected int borderWidth = 1;
        protected int opacity = 100;
        internal protected Rectangle invalidateRec = Rectangle.Empty;
        internal protected bool IsInvalidated = true;

        protected BaseElement()
        {
        }

        protected BaseElement(int top, int left, int width, int height)
        {
            location  = new Point(top, left);
            size = new Size(width, height);
        }

        public virtual Point Location
        {
            get
            {
                return location;
            }
            set
            {
                location = value;
                OnAppearanceChanged(new EventArgs());
            }
        }

        public virtual Size Size
        {
            get
            {
                return size;
            }
            set
            {
                size = value;
                OnAppearanceChanged(new EventArgs());
            }
        }

        public virtual bool Visible
        {
            get
            {
                return visible;
            }
            set
            {
                visible = value;
                OnAppearanceChanged(new EventArgs());
            }
        }

        public virtual Color BorderColor
        {
            get
            {
                return borderColor;
            }
            set
            {
                borderColor = value;
                OnAppearanceChanged(new EventArgs());
            }
        }

        public virtual int BorderWidth
        {
            get
            {
                return borderWidth;
            }
            set
            {
                borderWidth = value;
                OnAppearanceChanged(new EventArgs());
            }
        }
        
        public virtual int Opacity
        {
            get
            {
                return opacity;
            }
            set
            {
                if ((value >= 0) || (value <=100))
                    opacity = value;
                else
                    throw new Exception("'" + value + "' is not a valid value for 'Opacity'. 'Opacity' should be between 0 and 100.");

                OnAppearanceChanged(new EventArgs());
            }
        }
        internal virtual void Draw(Graphics g)
        {
            IsInvalidated = false;
        }


        public virtual void Invalidate()
        {
            if (IsInvalidated)
                invalidateRec = Rectangle.Union(invalidateRec, GetUnsignedRectangle());
            else
                invalidateRec = GetUnsignedRectangle();

            IsInvalidated = true;
        }

        public virtual Rectangle GetRectangle()
        {
            return new Rectangle(this.Location, this.Size);
        }

        public virtual Rectangle GetUnsignedRectangle()
        {
            
            return GetUnsignedRectangle(GetRectangle());
        }

        internal static Rectangle GetUnsignedRectangle(Rectangle rec)
        {
            Rectangle retRectangle = rec;
            if (rec.Width < 0)
            {
                retRectangle.X = rec.X + rec.Width;
                retRectangle.Width = - rec.Width;
            }
            
            if (rec.Height < 0)
            {
                retRectangle.Y = rec.Y + rec.Height;
                retRectangle.Height = - rec.Height;
            }

            return retRectangle;
        }

        #region Events
        [field: NonSerialized]
        public event EventHandler AppearanceChanged;

        protected virtual void OnAppearanceChanged(EventArgs e)
        {
            if (AppearanceChanged != null)
                AppearanceChanged(this, e);
        }
        #endregion

    }
}