ZoomingMessageFilter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WF / Common / AuthoringOM / Design / MessageFilters / ZoomingMessageFilter.cs / 1305376 / ZoomingMessageFilter.cs
                        

                        
                            namespace System.Workflow.ComponentModel.Design 
{
 	using System;
	using System.Drawing;
	using System.Diagnostics; 
	using System.Windows.Forms;
 	using System.ComponentModel.Design; 
 
	#region Class ZoomingMessageFilter
 	///This MessageFilter needs coordinates in client coordinate system 
 	internal sealed class ZoomingMessageFilter : WorkflowDesignerMessageFilter
	{
 		#region Members and Constructor
        private static int ZoomIncrement = 20; 
        private static Cursor ZoomInCursor = new Cursor(typeof(WorkflowView), "Resources.zoomin.cur");
		private static Cursor ZoomOutCursor = new Cursor(typeof(WorkflowView), "Resources.zoomout.cur"); 
		private static Cursor ZoomDisabledCursor = new Cursor(typeof(WorkflowView), "Resources.zoomno.cur"); 

		private enum ZoomState { In, Out } 
 		private ZoomState initialState = ZoomState.In; //which tool to show by default
		private ZoomState currentState = ZoomState.In; //current tool
 		private DragRectangleMessageFilter fastZoomingMessageFilter = null;
 
 		private CommandID previousCommand;
		private Cursor previousCursor = Cursors.Default; 
 
 		internal ZoomingMessageFilter(bool initiateZoomIn)
		{ 
			this.currentState = this.initialState = (initiateZoomIn) ? ZoomState.In : ZoomState.Out;
		}
 		#endregion
 
		#region MessageFilter Overrides
 		protected override void Initialize(WorkflowView parentView) 
 		{ 
			base.Initialize(parentView);
 
 			StoreUIState();
			RefreshUIState();
		}
 
		protected override void Dispose(bool disposing)
 		{ 
			try 
 			{
 				if (this.fastZoomingMessageFilter != null) 
				{
 					this.fastZoomingMessageFilter.DragComplete -= new EventHandler(OnZoomRectComplete);
					ParentView.RemoveDesignerMessageFilter(this.fastZoomingMessageFilter);
					this.fastZoomingMessageFilter.Dispose(); 
					this.fastZoomingMessageFilter = null;
 				} 
				RestoreUIState(); 
 			}
 			finally 
			{
 				base.Dispose(disposing);
			}
		} 

		protected override bool OnShowContextMenu(Point menuPoint) 
 		{ 
			IMenuCommandService menuCommandService = (IMenuCommandService)GetService(typeof(IMenuCommandService));
 			if (menuCommandService != null) 
 			{
				menuCommandService.ShowContextMenu(WorkflowMenuCommands.ZoomMenu, menuPoint.X, menuPoint.Y);
 				RefreshUIState();
			} 
			return true;
		} 
 
 		protected override bool OnMouseEnter(MouseEventArgs eventArgs)
		{ 
 			RefreshUIState();
 			return true;
		}
 
 		protected override bool OnMouseDown(MouseEventArgs eventArgs)
		{ 
			if (eventArgs.Button == MouseButtons.Left) 
			{
                this.currentState = ((Control.ModifierKeys & Keys.Shift) != 0) ? ((this.initialState == ZoomState.In) ? ZoomState.Out : ZoomState.In) : this.initialState; 

 				bool forwardMessage = (this.fastZoomingMessageFilter == null);
				RefreshUIState();
 				if (forwardMessage && this.fastZoomingMessageFilter != null) 
 					((IWorkflowDesignerMessageSink)this.fastZoomingMessageFilter).OnMouseDown(eventArgs);
			} 
 			return true; 
		}
 
		protected override bool OnMouseMove(MouseEventArgs eventArgs)
		{
 			//We do not allow other behaviors to handle this message
			return true; 
 		}
 
 		protected override bool OnMouseDoubleClick(MouseEventArgs eventArgs) 
		{
 			return true; 
		}

        protected override bool OnMouseLeave()
        { 
            return true;
        } 
 
        protected override bool OnMouseCaptureChanged()
        { 
            return true;
        }

		protected override bool OnMouseUp(MouseEventArgs eventArgs) 
		{
 			if (eventArgs.Button == MouseButtons.Left && CanContinueZooming) 
			{ 
 				WorkflowView parentView = ParentView;
 				int zoom = parentView.Zoom + ((this.currentState == ZoomState.In) ? ZoomingMessageFilter.ZoomIncrement : (-1 * ZoomingMessageFilter.ZoomIncrement)); 
				Point center = new Point((this.currentState == ZoomState.In) ? eventArgs.X : parentView.ViewPortSize.Width / 2, (this.currentState == ZoomState.In) ? eventArgs.Y : parentView.ViewPortSize.Height / 2);
 				UpdateZoom(zoom, center);
			}
 
			return true;
		} 
 
 		protected override bool OnKeyDown(KeyEventArgs eventArgs)
		{ 
 			if (eventArgs.KeyValue == (int)Keys.Escape)
 			{
				ParentView.RemoveDesignerMessageFilter(this);
 			} 
			else
			{ 
				this.currentState = ((eventArgs.Modifiers & Keys.Shift) != 0) ? ((this.initialState == ZoomState.In) ? ZoomState.Out : ZoomState.In) : this.initialState; 
 				RefreshUIState();
			} 
 			return true;
 		}

		protected override bool OnKeyUp(KeyEventArgs eventArgs) 
 		{
			this.currentState = ((eventArgs.Modifiers & Keys.Shift) != 0) ? ((this.initialState == ZoomState.In) ? ZoomState.Out : ZoomState.In) : this.initialState; 
			RefreshUIState(); 
			return true;
 		} 

		protected override bool OnDragEnter(DragEventArgs eventArgs)
 		{
 			ParentView.RemoveDesignerMessageFilter(this); 
			return false;
 		} 
		#endregion 

		#region Helpers 
		internal bool ZoomingIn
 		{
			get
 			{ 
 				return (this.initialState == ZoomState.In);
			} 
 		} 

		private void OnZoomRectComplete(object sender, EventArgs e) 
		{
			Debug.Assert(this.currentState == ZoomState.In && CanContinueZooming && this.fastZoomingMessageFilter != null);
 			if (CanContinueZooming && this.currentState == ZoomState.In && this.fastZoomingMessageFilter != null && !this.fastZoomingMessageFilter.DragRectangle.IsEmpty)
			{ 
 				Rectangle dragRectangle = this.fastZoomingMessageFilter.DragRectangle;
 				WorkflowView parentView = ParentView; 
				Point center = parentView.LogicalPointToClient(new Point(dragRectangle.Location.X + dragRectangle.Width / 2, dragRectangle.Location.Y + dragRectangle.Height / 2)); 
 				int zoom = (int)(Math.Min((float)parentView.ViewPortSize.Width / (float)dragRectangle.Width, (float)parentView.ViewPortSize.Height / (float)dragRectangle.Height) * 100.0f);
				UpdateZoom(zoom, center); 
			}
		}

 		private void UpdateZoom(int zoomLevel, Point center) 
		{
 			PointF relativeCenterF = PointF.Empty; 
 			WorkflowView parentView = ParentView; 

			Point layoutOrigin = parentView.LogicalPointToClient(Point.Empty); 
 			center.X -= layoutOrigin.X; center.Y -= layoutOrigin.Y;
			relativeCenterF = new PointF((float)center.X / (float)parentView.HScrollBar.Maximum, (float)center.Y / (float)parentView.VScrollBar.Maximum);

			parentView.Zoom = Math.Min(Math.Max(zoomLevel, AmbientTheme.MinZoom), AmbientTheme.MaxZoom); 

			Point newCenter = new Point((int)((float)parentView.HScrollBar.Maximum * relativeCenterF.X), (int)((float)parentView.VScrollBar.Maximum * relativeCenterF.Y)); 
 			parentView.ScrollPosition = new Point(newCenter.X - parentView.HScrollBar.LargeChange / 2, newCenter.Y - parentView.VScrollBar.LargeChange / 2); 

			this.currentState = ((Control.ModifierKeys & Keys.Shift) != 0) ? ((this.initialState == ZoomState.In) ? ZoomState.Out : ZoomState.In) : this.initialState; 
 			RefreshUIState();
 		}

		private bool CanContinueZooming 
 		{
			get 
			{ 
				WorkflowView parentView = ParentView;
 				return ((this.currentState == ZoomState.Out && parentView.Zoom > AmbientTheme.MinZoom) || (this.currentState == ZoomState.In && parentView.Zoom < AmbientTheme.MaxZoom)); 
			}
 		}

 		private void StoreUIState() 
		{
 			IMenuCommandService menuCommandService = GetService(typeof(IMenuCommandService)) as IMenuCommandService; 
			if (menuCommandService != null) 
			{
				foreach (CommandID affectedCommand in CommandSet.NavigationToolCommandIds) 
 				{
					MenuCommand menuCommand = menuCommandService.FindCommand(affectedCommand);
 					if (menuCommand != null && menuCommand.Enabled && menuCommand.Checked)
 					{ 
						this.previousCommand = menuCommand.CommandID;
 						break; 
					} 
				}
			} 

 			this.previousCursor = ParentView.Cursor;
		}
 
 		private void RestoreUIState()
 		{ 
			IMenuCommandService menuCommandService = GetService(typeof(IMenuCommandService)) as IMenuCommandService; 
 			if (menuCommandService != null)
			{ 
                foreach (CommandID affectedCommand in CommandSet.NavigationToolCommandIds)
                {
					MenuCommand menuCommand = menuCommandService.FindCommand(affectedCommand);
					if (menuCommand != null && menuCommand.Enabled) 
 						menuCommand.Checked = (menuCommand.CommandID == this.previousCommand);
				} 
 			} 

 			ParentView.Cursor = this.previousCursor; 
		}

 		private void RefreshUIState()
		{ 
			//Update the cursor
			WorkflowView parentView = ParentView; 
 			if (!CanContinueZooming) 
				parentView.Cursor = ZoomingMessageFilter.ZoomDisabledCursor;
 			else if (this.currentState == ZoomState.In) 
 				parentView.Cursor = ZoomingMessageFilter.ZoomInCursor;
			else
 				parentView.Cursor = ZoomingMessageFilter.ZoomOutCursor;
 
			//Update the fast zoom
			if (this.fastZoomingMessageFilter == null && CanContinueZooming && this.currentState == ZoomState.In) 
			{ 
 				this.fastZoomingMessageFilter = new DragRectangleMessageFilter();
				this.fastZoomingMessageFilter.DragComplete += new EventHandler(OnZoomRectComplete); 
 				parentView.AddDesignerMessageFilter(this.fastZoomingMessageFilter);
 			}
			else if (this.fastZoomingMessageFilter != null && (!CanContinueZooming || this.currentState != ZoomState.In))
 			{ 
				this.fastZoomingMessageFilter.DragComplete -= new EventHandler(OnZoomRectComplete);
				parentView.RemoveDesignerMessageFilter(this.fastZoomingMessageFilter); 
				this.fastZoomingMessageFilter = null; 
 			}
 
			//Update the menu
 			IMenuCommandService menuCommandService = GetService(typeof(IMenuCommandService)) as IMenuCommandService;
 			if (menuCommandService != null)
			{ 
                foreach (CommandID affectedCommand in CommandSet.NavigationToolCommandIds)
                { 
 					MenuCommand menuCommand = menuCommandService.FindCommand(affectedCommand); 
					if (menuCommand != null && menuCommand.Enabled)
						menuCommand.Checked = (menuCommand.CommandID == ((this.initialState == ZoomState.In) ? WorkflowMenuCommands.ZoomIn : WorkflowMenuCommands.ZoomOut)); 
				}
 			}
		}
 		#endregion 
 	}
	#endregion 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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