Images can be attached and placed in a drawing file, but they are not actually part of the file. The image is linked to the drawing file through a path name or a data management document ID. Linked image paths can be changed or removed at any time. To attach an image, you first create a RasterImageDef object which contains the definition information about the image file stored on disk being referenced and then you create a RasterImage object.
Once you have created a RasterImageDef object, you assign it to a RasterImage object. The RasterImage object represents the object you interact with in the drawing window and allows you to control the insertion point, scale, orientation, and appearance of the image among other properties. A single RasterImageDef object can be used to attach an image multiple times. Each attachment has its own clip boundary and its own settings for brightness, contrast, fade, and transparency.
You can set the scale factor for a raster image with the Scale property after you create a RasterImage object so that the image's geometry scale matches the scale of the geometry created in the AutoCAD drawing. When you attach an image, the image is inserted at a scale factor of 1 image unit of measurement to 1 AutoCAD unit of measurement. To set the image scale factor, you need to know the scale of the geometry on the image, and you need to know what unit of measurement (inches, feet, and so forth) you want to use to define 1 AutoCAD unit. The image file must contain resolution information defining the DPI, or dots per inch, and number of pixels in the image.
If an image has resolution information, AutoCAD combines it with the scale factor and the AutoCAD unit of measurement you supply to scale the image in your drawing. For example, if your raster image is a scanned blueprint on which the scale is 1 inch equals 50 feet, or 1:600, and your AutoCAD drawing is set up so that 1 unit represents 1 inch, then to set the scale factor of the image to 600. AutoCAD scales the image so the geometry in the image is brought into alignment with the vector geometry in the drawing.
This example adds a raster image in model space. This example uses the WorldMap.tif file found in the VBA sample directory. If you do not have this image, or if it is located in a different directory, revise the code to use a valid path and file name.
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
<CommandMethod("AttachRasterImage")> _
Public Sub AttachRasterImage()
' Get the current database and start a transaction
Dim acCurDb As Autodesk.AutoCAD.DatabaseServices.Database
acCurDb = Application.DocumentManager.MdiActiveDocument.Database
Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
' Define the name and image to use
Dim strImgName As String = "WorldMap"
Dim strFileName As String = "C:\AutoCAD\Sample\VBA\WorldMap.TIF"
Dim acRasterDef As RasterImageDef
Dim bRasterDefCreated As Boolean = False
Dim acImgDefId As ObjectId
' Get the image dictionary
Dim acImgDctID As ObjectId = RasterImageDef.GetImageDictionary(acCurDb)
' Check to see if the dictionary does not exist, it not then create it
If acImgDctID.IsNull Then
acImgDctID = RasterImageDef.CreateImageDictionary(acCurDb)
End If
' Open the image dictionary
Dim acImgDict As DBDictionary = acTrans.GetObject(acImgDctID, OpenMode.ForRead)
' Check to see if the image definition already exists
If acImgDict.Contains(strImgName) Then
acImgDefId = acImgDict.GetAt(strImgName)
acRasterDef = acTrans.GetObject(acImgDefId, OpenMode.ForWrite)
Else
' Create a raster image definition
Dim acRasterDefNew As New RasterImageDef
' Set the source for the image file
acRasterDefNew.SourceFileName = strFileName
' Load the image into memory
acRasterDefNew.Load()
' Add the image definition to the dictionary
acImgDict.UpgradeOpen()
acImgDefId = acImgDict.SetAt(strImgName, acRasterDefNew)
acTrans.AddNewlyCreatedDBObject(acRasterDefNew, True)
acRasterDef = acRasterDefNew
bRasterDefCreated = True
End If
' Open the Block table for read
Dim acBlkTbl As BlockTable
acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead)
' Open the Block table record Model space for write
Dim acBlkTblRec As BlockTableRecord
acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
OpenMode.ForWrite)
' Create the new image and assign it the image definition
Using acRaster As New RasterImage
acRaster.ImageDefId = acImgDefId
' Use ImageWidth and ImageHeight to get the size of the image in pixels (1024 x 768).
' Use ResolutionMMPerPixel to determine the number of millimeters in a pixel so you
' can convert the size of the drawing into other units or millimeters based on the
' drawing units used in the current drawing.
' Define the width and height of the image
Dim width As Vector3d
Dim height As Vector3d
' Check to see if the measurement is set to English (Imperial) or Metric units
If acCurDb.Measurement = MeasurementValue.English Then
width = New Vector3d((acRasterDef.ResolutionMMPerPixel.X * acRaster.ImageWidth) / 25.4, 0, 0)
height = New Vector3d(0, (acRasterDef.ResolutionMMPerPixel.Y * acRaster.ImageHeight) / 25.4, 0)
Else
width = New Vector3d(acRasterDef.ResolutionMMPerPixel.X * acRaster.ImageWidth, 0, 0)
height = New Vector3d(0, acRasterDef.ResolutionMMPerPixel.Y * acRaster.ImageHeight, 0)
End If
' Define the position for the image
Dim insPt As New Point3d(5.0, 5.0, 0.0)
' Define and assign a coordinate system for the image's orientation
Dim coordinateSystem As New CoordinateSystem3d(insPt, width * 2, height * 2)
acRaster.Orientation = coordinateSystem
' Set the rotation angle for the image
acRaster.Rotation = 0
' Add the new object to the block table record and the transaction
acBlkTblRec.AppendEntity(acRaster)
acTrans.AddNewlyCreatedDBObject(acRaster, True)
' Connect the raster definition and image together so the definition
' does not appear as "unreferenced" in the External References palette.
RasterImage.EnableReactors(True)
acRaster.AssociateRasterDef(acRasterDef)
If bRasterDefCreated Then
acRasterDef.Dispose()
End If
End Using
' Save the new object to the database
acTrans.Commit()
' Dispose of the transaction
End Using
End Sub
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
[CommandMethod("AttachRasterImage")]
public void AttachRasterImage()
{
// Get the current database and start a transaction
Database acCurDb;
acCurDb = Application.DocumentManager.MdiActiveDocument.Database;
using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
{
// Define the name and image to use
string strImgName = "WorldMap";
string strFileName = "C:\\AutoCAD\\Sample\\VBA\\WorldMap.TIF";
RasterImageDef acRasterDef;
bool bRasterDefCreated = false;
ObjectId acImgDefId;
// Get the image dictionary
ObjectId acImgDctID = RasterImageDef.GetImageDictionary(acCurDb);
// Check to see if the dictionary does not exist, it not then create it
if (acImgDctID.IsNull)
{
acImgDctID = RasterImageDef.CreateImageDictionary(acCurDb);
}
// Open the image dictionary
DBDictionary acImgDict = acTrans.GetObject(acImgDctID, OpenMode.ForRead) as DBDictionary;
// Check to see if the image definition already exists
if (acImgDict.Contains(strImgName))
{
acImgDefId = acImgDict.GetAt(strImgName);
acRasterDef = acTrans.GetObject(acImgDefId, OpenMode.ForWrite) as RasterImageDef;
}
else
{
// Create a raster image definition
RasterImageDef acRasterDefNew = new RasterImageDef();
// Set the source for the image file
acRasterDefNew.SourceFileName = strFileName;
// Load the image into memory
acRasterDefNew.Load();
// Add the image definition to the dictionary
acImgDict.UpgradeOpen();
acImgDefId = acImgDict.SetAt(strImgName, acRasterDefNew);
acTrans.AddNewlyCreatedDBObject(acRasterDefNew, true);
acRasterDef = acRasterDefNew;
bRasterDefCreated = true;
}
// Open the Block table for read
BlockTable acBlkTbl;
acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, OpenMode.ForRead) as BlockTable;
// Open the Block table record Model space for write
BlockTableRecord acBlkTblRec;
acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
OpenMode.ForWrite) as BlockTableRecord;
// Create the new image and assign it the image definition
using (RasterImage acRaster = new RasterImage())
{
acRaster.ImageDefId = acImgDefId;
// Use ImageWidth and ImageHeight to get the size of the image in pixels (1024 x 768).
// Use ResolutionMMPerPixel to determine the number of millimeters in a pixel so you
// can convert the size of the drawing into other units or millimeters based on the
// drawing units used in the current drawing.
// Define the width and height of the image
Vector3d width;
Vector3d height;
// Check to see if the measurement is set to English (Imperial) or Metric units
if (acCurDb.Measurement == MeasurementValue.English)
{
width = new Vector3d((acRasterDef.ResolutionMMPerPixel.X * acRaster.ImageWidth) / 25.4, 0, 0);
height = new Vector3d(0, (acRasterDef.ResolutionMMPerPixel.Y * acRaster.ImageHeight) / 25.4, 0);
}
else
{
width = new Vector3d(acRasterDef.ResolutionMMPerPixel.X * acRaster.ImageWidth, 0, 0);
height = new Vector3d(0, acRasterDef.ResolutionMMPerPixel.Y * acRaster.ImageHeight, 0);
}
// Define the position for the image
Point3d insPt = new Point3d(5.0, 5.0, 0.0);
// Define and assign a coordinate system for the image's orientation
CoordinateSystem3d coordinateSystem = new CoordinateSystem3d(insPt, width * 2, height * 2);
acRaster.Orientation = coordinateSystem;
// Set the rotation angle for the image
acRaster.Rotation = 0;
// Add the new object to the block table record and the transaction
acBlkTblRec.AppendEntity(acRaster);
acTrans.AddNewlyCreatedDBObject(acRaster, true);
// Connect the raster definition and image together so the definition
// does not appear as "unreferenced" in the External References palette.
RasterImage.EnableReactors(true);
acRaster.AssociateRasterDef(acRasterDef);
if (bRasterDefCreated)
{
acRasterDef.Dispose();
}
}
// Save the new object to the database
acTrans.Commit();
// Dispose of the transaction
}
}
Sub AttachRasterImage()
Dim insertionPoint(0 To 2) As Double
Dim scalefactor As Double
Dim rotationAngle As Double
Dim imageName As String
Dim rasterObj As AcadRasterImage
imageName = "C:/AutoCAD/sample/VBA/WorldMap.TIF"
insertionPoint(0) = 5
insertionPoint(1) = 5
insertionPoint(2) = 0
scalefactor = 2
rotationAngle = 0
On Error GoTo ERRORHANDLER
' Attach the raster image in model space
Set rasterObj = ThisDrawing.ModelSpace.AddRaster(imageName, insertionPoint, _
scalefactor, rotationAngle)
ZoomAll
Exit Sub
ERRORHANDLER:
MsgBox Err.Description
End Sub