Code sample: Polygon rubberband for WinControls.BitmapViewer

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Security.Permissions;
using Aurigma.GraphicsMill;
using Aurigma.GraphicsMill.Drawing;
using Aurigma.GraphicsMill.Transforms;

namespace Aurigma.GraphicsMill.WinControls.Samples
{
	public sealed class PolygonRubberband : Aurigma.GraphicsMill.WinControls.UserInputController, IRubberband
	{
		private enum ActionType
		{
			AddNew,
			MoveExisting
		};
		private System.Collections.ArrayList _points;
		private ActionType _actionType;
		private int _movingPoint;

		public PolygonRubberband()
		{
			_actionType = ActionType.AddNew;
			_points = new System.Collections.ArrayList();
			_movingPoint = -1;
		}

		protected override void OnBitmapViewerMouseMove(System.Windows.Forms.MouseEventArgs e)
		{
			if(_actionType == ActionType.MoveExisting)
				MoveExistingPoint(_movingPoint, new System.Drawing.Point(e.X, e.Y));
		}

		protected override void OnBitmapViewerMouseDown(System.Windows.Forms.MouseEventArgs e)
		{
			System.Drawing.Point point = new System.Drawing.Point(e.X, e.Y);
			if(!BitmapViewer.CanvasRenderingRectangle.Contains(point))
				return;

			int pointIndex = FindPointIndex(point);

			if(pointIndex < 0)
			{
				_actionType = ActionType.AddNew;
				AddNewPoint(point);
			}
			else
			{
				_actionType = ActionType.MoveExisting;
				_movingPoint = pointIndex;
			}
	    }

		protected override void OnBitmapViewerMouseUp(System.Windows.Forms.MouseEventArgs e)
		{
			_movingPoint = -1;
			_actionType = ActionType.AddNew;
		}

		protected override void OnBitmapViewerDoubleBufferPaint(System.Windows.Forms.PaintEventArgs e)
		{
			DrawPolygon(e.Graphics);
		}

		private void DrawPolygon(System.Drawing.Graphics graphics)
		{
			if(_points.Count < 4)
				return;

			System.Drawing.Pen pen = new System.Drawing.Pen(System.Drawing.Color.Red, 2);
			System.Drawing.Point point1;
			System.Drawing.Point point2;
			for(int i = 0; i < _points.Count - 1; i++)
			{
				point1 = BitmapViewer.BitmapToControlPoint((System.Drawing.Point)_points[i]);
				point2 = BitmapViewer.BitmapToControlPoint((System.Drawing.Point)_points[i + 1]);
				graphics.DrawLine(pen, point1, point2);
			}

			point1 = BitmapViewer.BitmapToControlPoint((System.Drawing.Point)_points[0]);
			point2 = BitmapViewer.BitmapToControlPoint((System.Drawing.Point)_points[_points.Count - 1]);
			graphics.DrawLine(pen, point1, point2);

			DrawGrips(graphics);
		}

		private void DrawGrips(System.Drawing.Graphics graphics)
		{
			System.Drawing.Brush brush = new System.Drawing.SolidBrush(System.Drawing.Color.Green);
			for(int i = 0; i < _points.Count; i++)
			{
				System.Drawing.Point point = BitmapViewer.BitmapToControlPoint((System.Drawing.Point)_points[i]);
				graphics.FillRectangle(brush, point.X - 5, point.Y - 5, 10, 10);
			}
		}

		private int FindPointIndex(System.Drawing.Point point)
		{
			int returnValue = -1;
			point = BitmapViewer.ControlToBitmapPoint(point);
			for(int i = 0; i < _points.Count; i++)
			{
				System.Drawing.Point tmpPoint = (System.Drawing.Point)_points[i];

				int distX = tmpPoint.X - point.X;
				distX *= distX;

				int distY = tmpPoint.Y - point.Y;
				distY *= distY;
				if(Math.Sqrt(distX + distY) < 10.0)
				{
					returnValue = i;
					break;
				}
			}
			return returnValue;
		}

		private void AddNewPoint(System.Drawing.Point point)
		{
			_points.Add(BitmapViewer.ControlToBitmapPoint(point));
			BitmapViewer.Invalidate();
		}

		private void MoveExistingPoint(int pointIndex, System.Drawing.Point newPosition)
		{
			System.Drawing.Rectangle renderingRectangle = BitmapViewer.CanvasRenderingRectangle;
			int difX = Math.Min(newPosition.X - renderingRectangle.Left, 0);
			if(difX == 0)
				difX = Math.Max(newPosition.X - renderingRectangle.Right, 0);

			int difY = Math.Min(newPosition.Y - renderingRectangle.Top, 0);
			if(difY == 0)
				difY = Math.Max(newPosition.Y - renderingRectangle.Bottom, 0);

			BitmapViewer.Scroll(difX, difY);

			newPosition.X = Math.Max(newPosition.X, renderingRectangle.Left);
			newPosition.X = Math.Min(newPosition.X, renderingRectangle.Right);
			newPosition.Y = Math.Max(newPosition.Y, renderingRectangle.Top);
			newPosition.Y = Math.Min(newPosition.Y, renderingRectangle.Bottom);

			_points[pointIndex] = BitmapViewer.ControlToBitmapPoint(newPosition);
			BitmapViewer.Invalidate();
		}
	};

} // namespace Aurigma.GraphicsMill.WinControls.Samples