Manipulate the Current View

You access the current view of a viewport in Model or Paper space by using the GetCurrentView method of the Editor object. The GetCurrentView method returns a ViewTableRecord object. You use the ViewTableRecord object to manipulate the magnification, position, and orientation of the view in the active viewport. Once the ViewTableRecord object has been changed, you update the current view of the active viewport with the SetCurrentView method.

Some of the common properties that you will use to manipulate the current view are:

CenterPoint - Center point of a view in DCS coordinates.
Height - Height of a view in DCS coordinates. Increase the height to zoom out; decrease the height to zoom in.
Target - Target of a view in WCS coordinates.
ViewDirection - Vector from the target to the camera of a view in WCS coordinates.
ViewTwist - Twist angle in radians of a view.
Width - Width of a view in DCS coordinates. Increase the width to zoom out; decrease the width to zoom in.

VBA Code Cross Reference

Function used to manipulate the current view

This example code is a common procedure that is used by later examples. The Zoom procedure accepts four parameters to accomplish zooming to a boundary, panning or centering the view of a drawing, and scaling the view of a drawing by a given factor. The Zoom procedure expects all coordinate values to be provided in WCS coordinates.

The parameters of the Zoom procedure are:

Minimum point - 3D point used to define the lower-left corner of the area to display.
Maximum point - 3D point used to define the upper-right corner of the area to display.
Center point - 3D point used to define the center of a view.
Scale factor - Real number used to specify the scale to increase or decrease the size of a view.

VB.NET

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.Geometry

Public Sub Zoom(ByVal pMin As Point3d, ByVal pMax As Point3d, _

                ByVal pCenter As Point3d, ByVal dFactor As Double)

  '' Get the current document and database

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  Dim nCurVport As Integer = System.Convert.ToInt32(Application.GetSystemVariable("CVPORT"))

  '' Get the extents of the current space when no points

  '' or only a center point is provided

  '' Check to see if Model space is current

  If acCurDb.TileMode = True Then

      If pMin.Equals(New Point3d()) = True And _

          pMax.Equals(New Point3d()) = True Then

          pMin = acCurDb.Extmin

          pMax = acCurDb.Extmax

      End If

  Else

      '' Check to see if Paper space is current

      If nCurVport = 1 Then

          If pMin.Equals(New Point3d()) = True And _

             pMax.Equals(New Point3d()) = True Then

              pMin = acCurDb.Pextmin

              pMax = acCurDb.Pextmax

          End If

      Else

          '' Get the extents of Model space

          If pMin.Equals(New Point3d()) = True And _

             pMax.Equals(New Point3d()) = True Then

              pMin = acCurDb.Extmin

              pMax = acCurDb.Extmax

          End If

      End If

  End If

  '' Start a transaction

  Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

      '' Get the current view

      Using acView As ViewTableRecord = acDoc.Editor.GetCurrentView()

          Dim eExtents As Extents3d

          '' Translate WCS coordinates to DCS

          Dim matWCS2DCS As Matrix3d

          matWCS2DCS = Matrix3d.PlaneToWorld(acView.ViewDirection)

          matWCS2DCS = Matrix3d.Displacement(acView.Target - Point3d.Origin) * matWCS2DCS

          matWCS2DCS = Matrix3d.Rotation(-acView.ViewTwist, _

                                         acView.ViewDirection, _

                                         acView.Target) * matWCS2DCS

          '' If a center point is specified, define the

          '' min and max point of the extents

          '' for Center and Scale modes

          If pCenter.DistanceTo(Point3d.Origin) <> 0 Then

              pMin = New Point3d(pCenter.X - (acView.Width / 2), _

                                 pCenter.Y - (acView.Height / 2), 0)

              pMax = New Point3d((acView.Width / 2) + pCenter.X, _

                                 (acView.Height / 2) + pCenter.Y, 0)

          End If

          '' Create an extents object using a line

          Using acLine As Line = New Line(pMin, pMax)

              eExtents = New Extents3d(acLine.Bounds.Value.MinPoint, _

                                       acLine.Bounds.Value.MaxPoint)

          End Using

          '' Calculate the ratio between the width and height of the current view

          Dim dViewRatio As Double

          dViewRatio = (acView.Width / acView.Height)

          '' Tranform the extents of the view

          matWCS2DCS = matWCS2DCS.Inverse()

          eExtents.TransformBy(matWCS2DCS)

          Dim dWidth As Double

          Dim dHeight As Double

          Dim pNewCentPt As Point2d

          '' Check to see if a center point was provided (Center and Scale modes)

          If pCenter.DistanceTo(Point3d.Origin) <> 0 Then

              dWidth = acView.Width

              dHeight = acView.Height

              If dFactor = 0 Then

                  pCenter = pCenter.TransformBy(matWCS2DCS)

              End If

              pNewCentPt = New Point2d(pCenter.X, pCenter.Y)

          Else '' Working in Window, Extents and Limits mode

              '' Calculate the new width and height of the current view

              dWidth = eExtents.MaxPoint.X - eExtents.MinPoint.X

              dHeight = eExtents.MaxPoint.Y - eExtents.MinPoint.Y

              '' Get the center of the view

              pNewCentPt = New Point2d(((eExtents.MaxPoint.X + eExtents.MinPoint.X) * 0.5), _

                                       ((eExtents.MaxPoint.Y + eExtents.MinPoint.Y) * 0.5))

          End If

          '' Check to see if the new width fits in current window

          If dWidth > (dHeight * dViewRatio) Then dHeight = dWidth / dViewRatio

          '' Resize and scale the view

          If dFactor <> 0 Then

              acView.Height = dHeight * dFactor

              acView.Width = dWidth * dFactor

          End If

          '' Set the center of the view

          acView.CenterPoint = pNewCentPt

          '' Set the current view

          acDoc.Editor.SetCurrentView(acView)

      End Using

      '' Commit the changes

      acTrans.Commit()

  End Using

End Sub

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.Geometry;

static void Zoom(Point3d pMin, Point3d pMax, Point3d pCenter, double dFactor)

  // Get the current document and database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  int nCurVport = System.Convert.ToInt32(Application.GetSystemVariable("CVPORT"));

  // Get the extents of the current space no points

  // or only a center point is provided

  // Check to see if Model space is current

  if (acCurDb.TileMode == true)

      if (pMin.Equals(new Point3d()) == true &&

          pMax.Equals(new Point3d()) == true)

          pMin = acCurDb.Extmin;

          pMax = acCurDb.Extmax;

  else

      // Check to see if Paper space is current

      if (nCurVport == 1)

          // Get the extents of Paper space

          if (pMin.Equals(new Point3d()) == true &&

              pMax.Equals(new Point3d()) == true)

              pMin = acCurDb.Pextmin;

              pMax = acCurDb.Pextmax;

      else

          // Get the extents of Model space

          if (pMin.Equals(new Point3d()) == true &&

              pMax.Equals(new Point3d()) == true)

              pMin = acCurDb.Extmin;

              pMax = acCurDb.Extmax;

  // Start a transaction

  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())

      // Get the current view

      using (ViewTableRecord acView = acDoc.Editor.GetCurrentView())

          Extents3d eExtents;

          // Translate WCS coordinates to DCS

          Matrix3d matWCS2DCS;

          matWCS2DCS = Matrix3d.PlaneToWorld(acView.ViewDirection);

          matWCS2DCS = Matrix3d.Displacement(acView.Target - Point3d.Origin) * matWCS2DCS;

          matWCS2DCS = Matrix3d.Rotation(-acView.ViewTwist,

                                         acView.ViewDirection,

                                         acView.Target) * matWCS2DCS;

          // If a center point is specified, define the min and max

          // point of the extents

          // for Center and Scale modes

          if (pCenter.DistanceTo(Point3d.Origin) != 0)

              pMin = new Point3d(pCenter.X - (acView.Width / 2),

                                 pCenter.Y - (acView.Height / 2), 0);

              pMax = new Point3d((acView.Width / 2) + pCenter.X,

                                 (acView.Height / 2) + pCenter.Y, 0);

          // Create an extents object using a line

          using (Line acLine = new Line(pMin, pMax))

              eExtents = new Extents3d(acLine.Bounds.Value.MinPoint,

                                       acLine.Bounds.Value.MaxPoint);

          // Calculate the ratio between the width and height of the current view

          double dViewRatio;

          dViewRatio = (acView.Width / acView.Height);

          // Tranform the extents of the view

          matWCS2DCS = matWCS2DCS.Inverse();

          eExtents.TransformBy(matWCS2DCS);

          double dWidth;

          double dHeight;

          Point2d pNewCentPt;

          // Check to see if a center point was provided (Center and Scale modes)

          if (pCenter.DistanceTo(Point3d.Origin) != 0)

              dWidth = acView.Width;

              dHeight = acView.Height;

              if (dFactor == 0)

                  pCenter = pCenter.TransformBy(matWCS2DCS);

              pNewCentPt = new Point2d(pCenter.X, pCenter.Y);

          else // Working in Window, Extents and Limits mode

              // Calculate the new width and height of the current view

              dWidth = eExtents.MaxPoint.X - eExtents.MinPoint.X;

              dHeight = eExtents.MaxPoint.Y - eExtents.MinPoint.Y;

              // Get the center of the view

              pNewCentPt = new Point2d(((eExtents.MaxPoint.X + eExtents.MinPoint.X) * 0.5),

                                       ((eExtents.MaxPoint.Y + eExtents.MinPoint.Y) * 0.5));

          // Check to see if the new width fits in current window

          if (dWidth > (dHeight * dViewRatio)) dHeight = dWidth / dViewRatio;

          // Resize and scale the view

          if (dFactor != 0)

              acView.Height = dHeight * dFactor;

              acView.Width = dWidth * dFactor;

          // Set the center of the view

          acView.CenterPoint = pNewCentPt;

          // Set the current view

          acDoc.Editor.SetCurrentView(acView);

      // Commit the changes

      acTrans.Commit();