Text Alignment Control for .NET

// 
// Designed and Developed by Norm Almond
// 15 September 2004
// Version 1.0.0
// www.software-kinetics.co.uk
//

using System;
using System.ComponentModel;
using System.Collections;
using System.Diagnostics;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Text;


namespace TextAlignCtrl
{
	/// <summary>
	/// Text Alignment Control
	/// </summary>
	[ToolboxBitmap(typeof(TextAlign), "images.TextAlign.bmp"),
	System.ComponentModel.DefaultPropertyAttribute("Angle")]
	public class TextAlign : System.Windows.Forms.UserControl
	{
		#region Events
		public delegate void OnAngleChangedHandler(object sender, int Angle);

		[Category("Action")]
		[Description("Fired when angle has changed")]
		public event OnAngleChangedHandler OnAngleChangedEvent;
		#endregion

		#region Variable Declarations
		private bool _trackMouse = false;
		private int _Angle   = 0;
		private const int PegSize = 3;
		private const int _Offset = 10;
		#endregion

		/// <summary>
		/// Required designer variable.
		/// </summary>
		private System.ComponentModel.Container components = null;

		public TextAlign(System.ComponentModel.IContainer container)
		{
			_Init();
			container.Add(this);
			InitializeComponent();
		}

		public TextAlign()
		{
			_Init();
			InitializeComponent();
		}

		/// <summary>
		/// Common Contructor Code
		/// </summary>
		private void _Init()
		{
			SetStyle(ControlStyles.AllPaintingInWmPaint, true);
			SetStyle(ControlStyles.DoubleBuffer, true);
			SetStyle(ControlStyles.ResizeRedraw, true);
			SetStyle(ControlStyles.UserPaint, true);
			UpdateStyles();
		}

		protected override bool ProcessDialogKey(Keys keyData)
		{
			if (!Enabled)
				return base.ProcessDialogKey (keyData);

			int delta = Angle;

			switch (keyData)
			{
				case Keys.Home:
					delta = 0;
					break;

				case (Keys.Down | Keys.Control):
					delta -= 15;
					delta = ((delta / 15) * 15);
					break;

				case Keys.Down:
					delta -= 1;
					break;

				case (Keys.Up | Keys.Control):
					delta += 15;
					delta = ((delta / 15) * 15);
					break;

				case Keys.Up:
					delta += 1;
					break;

				default:
					return base.ProcessDialogKey (keyData);

			}

			Angle = delta;
			return false;

		}


		/// <summary> 
		/// Clean up any resources being used.
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if(components != null)
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}


		#region Component Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			// 
			// TextAlign
			// 
			this.BackColor = System.Drawing.SystemColors.Window;
			this.Name = "TextAlign";
			this.Size = new System.Drawing.Size(120, 176);
			this.SizeChanged += new System.EventHandler(this.TextAlign_SizeChanged);
			this.Enter += new System.EventHandler(this.TextAlign_Enter);
			this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.TextAlign_MouseUp);
			this.Paint += new System.Windows.Forms.PaintEventHandler(this.TextAlign_Paint);
			this.Leave += new System.EventHandler(this.TextAlign_Leave);
			this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.TextAlign_MouseMove);
			this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.TextAlign_MouseDown);

		}
		#endregion

		#region Private Functions
		private void _Render(Graphics g, Rectangle rcClient)
		{
			// Render Background
			g.FillRectangle(Enabled ? new SolidBrush(this.BackColor) : SystemBrushes.Control, rcClient);

			// Render Frame
			g.DrawRectangle(Focused ? SystemPens.Highlight : SystemPens.ControlDark, rcClient.X, rcClient.Y, rcClient.Width-1, rcClient.Height-1);

			Point ptCenter = new Point(_Offset, rcClient.Height / 2);
  
			StringFormat format = new StringFormat(StringFormat.GenericDefault);
			format.HotkeyPrefix = HotkeyPrefix.None;
	
			SizeF sz = g.MeasureString("Text", Control.DefaultFont, Point.Empty,format);

			Rectangle rcText = rcClient;
			rcText.X += 2; // Indent from Left
			
			// Rotate text on given Angle
			g.TranslateTransform (ptCenter.X, ptCenter.Y);
			g.RotateTransform(-_Angle);
			g.DrawString("Text", Control.DefaultFont, SystemBrushes.WindowText, new Point(0,(int)-(sz.Height/2)), format);
			g.ResetTransform();	


			// Render Dial
			Rectangle rc;

			// Render tick @ 15 degree intervals
			for (int tick=-90; tick <= 90; tick+=15)
			{
				Point ptSelectStart = _AngleToPoint(ptCenter, (double)_Angle, ptCenter.X + sz.Width - 8);
				Point ptSelectEnd = _AngleToPoint(ptCenter	, (double)_Angle, rcClient.Width - 24);
		
				g.DrawLine(Pens.Black,ptSelectStart,ptSelectEnd);

				Point pt = _AngleToPoint(ptCenter, tick, rcClient.Width - 18);

				rc = new Rectangle(pt, Size.Empty);			
				rc.Inflate(1,1);

				g.FillRectangle(Brushes.Black, rc);

				if ((tick % 45) == 0)
				{
					using (GraphicsPath myPath = new GraphicsPath())
					{
						myPath.AddLine(pt.X, pt.Y - PegSize, pt.X + PegSize, pt.Y);
						myPath.AddLine(pt.X + PegSize, pt.Y, pt.X, pt.Y + PegSize);
						myPath.AddLine(pt.X, pt.Y + PegSize, pt.X - PegSize, pt.Y);
						myPath.CloseFigure();
						
						g.FillPath(tick == _Angle ? Brushes.Red : Brushes.Black, myPath);

						myPath.AddLine(pt.X, pt.Y - PegSize, pt.X + PegSize, pt.Y);
						myPath.AddLine(pt.X + PegSize, pt.Y, pt.X, pt.Y + PegSize);
						myPath.AddLine(pt.X, pt.Y + PegSize, pt.X - PegSize, pt.Y);
						myPath.CloseFigure();
						
						g.DrawPath(Pens.Black, myPath);
					}					
				}
			}
		}

		/// <summary>
		/// Convert Angle to point
		/// </summary>
		/// <param name="ptOffset"></param>
		/// <param name="angle"></param>
		/// <param name="radius"></param>
		/// <returns></returns>
		private Point _AngleToPoint(Point ptOffset, double angle, double radius) 
		{
			double radians = angle / (180.0 / Math.PI);
			int x = ptOffset.X + (int)((double)radius* Math.Cos(radians));
			int y = ptOffset.Y - (int)((double)radius * Math.Sin(radians));
			return new Point(x,y);
		}

		private double _ArcTangent(double ratio) 
		{
			double angle = Math.Atan(ratio);

			// convert radians to degrees 
			return angle * (180.0 / Math.PI);;
		}

		private double _ArcTangent(double x, double y) 
		{
			double angle = 0.0;

			// both x and y are 0
			if ((x == 0.0) && (y == 0.0))		 
			{	
				// Set tthe angle to Zero degrees 
				angle = 0.0;
			}
			else if (x == 0.0)
			{
				// If we're on the y axis line 
				angle = (y < 0.0) ? -90 : 90.0;
			}
			else
			{
				// else neither x or y is zero
				// Find the arc-tangent of y / x in degrees
				angle = _ArcTangent((y / x));   
				
				// if x is negative 
				if (x < 0.0)					
				{
					angle += (y > 0.0) ? 180.0 : -180.0;
				}

				if (angle < -90)
					angle = -90;

				if (angle > 90)
					angle = 90;

			}

			return angle;
		}

		/// <summary>
		/// Converts a point to angle
		/// </summary>
		/// <param name="point"></param>
		/// <param name="center"></param>
		/// <returns></returns>
		private double PointToAngle(Point point, Point center) 
		{
			// Calculate the position user click relative to the center
			int x = point.X - center.X;
			int y = center.Y - point.Y;

			//Convert xy position to an angle.
			double angle = _ArcTangent( (double) x, (double) y );

			return angle;
		}

		/// <summary>
		/// Render Control
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		private void TextAlign_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
		{
			_Render(e.Graphics, this.ClientRectangle);		
		}

		/// <summary>
		/// Update Angle in relation to mouse
		/// </summary>
		/// <param name="point"></param>
		private void _UpdateAngle(Point point)
		{
			Rectangle rcClient = this.ClientRectangle;
			Point ptCenter = new Point(_Offset, rcClient.Height / 2);

			if (_trackMouse)
			{
				//Convert xy position to an angle.
				Angle = (int)(PointToAngle(point, ptCenter));
			}

		}

		/// <summary>
		/// Track mouse as user moves mouse over control
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		private void TextAlign_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if (!Enabled)
				return;

			_UpdateAngle(new Point(e.X, e.Y));
			Invalidate();
		}

		/// <summary>
		/// End tracking mouse
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		private void TextAlign_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if (!Enabled)
				return;

			_UpdateAngle(new Point(e.X, e.Y));
			_trackMouse = false;
			Capture = false;
			Invalidate();

		}

		/// <summary>
		/// Begin Tracking mouse
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		private void TextAlign_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
		{
			if (!Enabled)
				return;

			_trackMouse = true;
			this.Capture = true;
			Focus();
			_UpdateAngle(new Point(e.X, e.Y));
			Invalidate();
		}

		/// <summary>
		/// Control size changed, refresh control
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		private void TextAlign_SizeChanged(object sender, System.EventArgs e)
		{
			Refresh();
		}

		#endregion

		private void TextAlign_Enter(object sender, System.EventArgs e)
		{
			Invalidate();
		}

		private void TextAlign_Leave(object sender, System.EventArgs e)
		{
			Invalidate();
		}


		#region Public Methods
		/// <summary>
		/// Get/Set Angle for control
		/// </summary>
		[Category("TextAlign")]
		[Description("Gets/Sets angle of text")]
		public int Angle
		{
			get
			{
				return _Angle;
			}

			set
			{
				if (!Enabled)
					return;

				if (value < -90 || value > 90)
					return;
			
				_Angle = value;
				Invalidate();

				if (OnAngleChangedEvent != null)
					OnAngleChangedEvent(this, _Angle);

			}
		}

		protected virtual void OnAngleChanged(object sender, int angle)
		{
			if (OnAngleChangedEvent != null)
				OnAngleChangedEvent(this, _Angle);		
		}
   
		#endregion
	}
}