CAD

开发平台：
C#

ToolPolygon.cs：源码内容
							using System;
using System.Windows.Forms;
using System.Drawing;
namespace DrawTools
{
	/// <summary>
	/// Polygon tool
	/// </summary>
	class ToolPolygon : DrawTools.ToolObject
	{
		public ToolPolygon()
		{
            Cursor = new Cursor(GetType(), "Pencil.cur");
        }
        private int lastX;
        private int lastY;
        private DrawPolygon newPolygon;
        private const int minDistance = 15*15;
        /// <summary>
        /// Left nouse button is pressed
        /// </summary>
        /// <param name="drawArea"></param>
        /// <param name="e"></param>
        public override void OnMouseDown(DrawArea drawArea, MouseEventArgs e)
        {
            // Create new polygon, add it to the list
            // and keep reference to it
            newPolygon = new DrawPolygon(e.X, e.Y, e.X + 1, e.Y + 1);
            AddNewObject(drawArea, newPolygon);
            lastX = e.X;
            lastY = e.Y;
        }
        /// <summary>
        /// Mouse move - resize new polygon
        /// </summary>
        /// <param name="drawArea"></param>
        /// <param name="e"></param>
        public override void OnMouseMove(DrawArea drawArea, MouseEventArgs e)
        {
            drawArea.Cursor = Cursor;
            if ( e.Button != MouseButtons.Left )
                return;
            if ( newPolygon == null )
                return;                 // precaution
            Point point = new Point(e.X, e.Y);
            int distance = (e.X - lastX)*(e.X - lastX) + (e.Y - lastY)*(e.Y - lastY);
            if ( distance < minDistance )
            {
                // Distance between last two points is less than minimum -
                // move last point
                newPolygon.MoveHandleTo(point, newPolygon.HandleCount);
            }
            else
            {
                // Add new point
                newPolygon.AddPoint(point);
                lastX = e.X;
                lastY = e.Y;
            }
            drawArea.Refresh();
        }
        public override void OnMouseUp(DrawArea drawArea, MouseEventArgs e)
        {
            newPolygon = null;
            base.OnMouseUp (drawArea, e);
        }
	}
}

						