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:
The AutoCAD .NET API does not offer methods to directly manipulate the current view of a drawing like those found in the ActiveX Automation library. For example, if you want to zoom to the extents of the objects in a drawing or the limits of a drawing, you must manipulate the Width, Height and CenterPoint properties of the current view. To get the extents of limits of a drawing, you use the Extmin, Extmax, Limmin, and Limmax properties of the Database object.
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:
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 when 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();
}
}