IImageService.ImageBuffer property

Applies To: IImageService

Image buffer is an array of bytes used for saving the requested image.

[Visual Basic 6.0]

object.ImageBuffer = [ value ]

Access

Read / Write

Type

Integer

Requirements

Platform	32 bit Windows OS (WinXP)
Environment	.NET Framework, COM, ANSI C / C++ Standard compliant
Dependency	ESRI.ImageServer.ISClient.dll (.NET Framework), ISClient.dll (COM/C++), ISClientC.dll (C/C++)
Include	isclientc.h (ANSI C)

Example

[Visual Basic 6.0]

‘ See the ISViewer sample code For more details

‘ The client has been instantiated And initialized successfully

‘ The service has been opened As Object theService

‘ theService.SetImageInfo has been called To Set the image dimensions

Dim myImageBuffer() As Byte ' Byte array to store returned image

Dim bufferSize As Long ‘ Size of the image buffer

Dim isImageCreated As Boolean

‘ determine the size of the buffer needed To store the requested image

bufferSize = theService.GetRecommendedBufferSize( )

' Resize the buffer to the recommended size

ReDim myImageBuffer (bufferSize)

' The address of myImageBuffer is stored in the service object

theService.ImageBuffer = VarPtr(myImageBuffer(0))

‘Extract the requested image, store In myImageBuffer

isImageCreated = theService.GetImageByExtent

‘At this point myImageBuffer contains the image values

[Visual C++ 2005]

// See the sample code C_ClientTest_Sample for more details

// ISClient_Export.h and ISClient_Export.c define access routines

// The client will have been instantiated and initialized successfully using

// IS_CO_Create() and IS_CO_Init()

// The image service will have been opened as theService using

// IS_CO_OpenImageService

// The image dimensions will have been set using

// IS_IService_SetImageInfo

// Buffer and buffer size for the image

unsigned char* myImageBuffer = 0;

long bufferSize = 0;

// determine the size of the buffer needed to store the requested image

bufferSize = IS_IService_BufferSize(theService);

// Allocate enough memory for the buffer

myImageBuffer = (unsigned char*)malloc(bufferSize);

// The address of buffer is stored in the service object, cast as an int

IS_IService_PutImageBuffer(theService, (int)(myImageBuffer));

// Extract the requested image, store in myImageBuffer

int result = IS_IService_ImageByExtent(theService);

// At this point myImageBuffer contains the image values, if result != 0

[C# .NET]

// Instantiate and initialize the client connection

ESRI.ImageServer.ISClient.IClientObject clientConn = new

ESRI.ImageServer.ISClient.CClientObjectClass();

if (!clientConn.Init(""))

{

Console.WriteLine("Error code: " + clientConn.Status);

clientConn.Close(); return;

}

// Use the connection object to open an Image Service

ESRI.ImageServer.ISClient.IImageService theService =

clientConn.OpenImageService("ImageService://isServer/someService", "");

if (theService == null)

{

Console.WriteLine("Error: " + clientConn.Status);

clientConn.Close(); return;

}

// Set image extents. First four are doubles, others are integers

// These values would have been previously determined

theService.SetImageInfo(xMin, yMin, xMax, yMax, cols, rows);

// Get the required buffer size, create a new image buffer

int bufferSize = theService.GetRecommendedBufferSize();

byte[] myImageBuffer = new byte[bufferSize];

// Provide a means for accessing a managed object as unmanaged memory.

// This is defined in System.Runtime.InteropServices

GCHandle gcH;

// Allocate a handle of the specified type for the specified object

// The pinned GC Handle prevents the garbage collector from moving the object.

// Use the free method to free the handle when it is no longer needed.

gcH = GCHandle.Alloc(myImageBuffer, GCHandleType.Pinned);

if (!gcH.IsAllocated) return; // error if allocation fails

// Convert the handle to integer, which is what theService is expecting

int bufAddress = gcH.AddrOfPinnedObject().ToInt32();

if (bufAddress == 0)

{

if (gcH.IsAllocated) gcH.Free(); return;

}

// Now the buffer address can be stored in theService

theService.ImageBuffer = bufAddress;

// A call to GetImageByExtent fills the buffer with imagery

if (!theService.GetImageByExtent())

{

// error condition. Free garbage collection handle and return

if (gcH.IsAllocated) gcH.Free(); return;

}

// myImageBuffer now has the imagery data. Do whatever is desired with it

// when finished, release the garbage collection handle

if (gcH.IsAllocated) gcH.Free();

[VB .NET]

‘assign configuration file and service name to appropriate strings

‘Establish client connection

Dim client as new ImageServerClient.CClientObject

if client.Init(ISCConfigConfigPath) = false Then

MsgBox(client.Status, vbCritical)

goto ErrHandler

End if

‘Open the image service by name

Dim theService as new ImageServerClient.CImageService

theService = client.OpenImageService(ImageServiceFileName, "")

if theService is Nothing Then

MsgBox(client.Status, vbCritical)

goto ErrHandler

End if

‘Define the image to be returned. Parameters set previously

‘ first four parameters are Doubles, last two are Integers

Dim setInfo as Boolean

setInfo = theService.SetImageInfo(Xmin, Ymin, Xmax, Ymax, Cols, Rows)

if setInfo = false Then

MsgBox(client.Status, vbInformation)

goto ErrHandler

End if

‘create a buffer of the appropriate size

Dim bufferSize as Integer

bufferSize = theService.GetRecommendedBufferSize()

Dim myImageBuffer() as byte

ReDim myImageBuffer(bufferSize)

‘set up handle to allow managed memory to be used as unmanaged memory

Dim gcHandle as System.Runtime.InteropServices.GCHandle

gcHandle = System.Runtime.InteropServices.GCHandle.Alloc(myImageBuffer, _

Runtime.InteropServices.GCHandleType.Pinned)

‘copy address to Int32 variable, which is what theService expects

Dim bufAddress as Int32

bufAddress = gcHandle.AddrOfPinnedObject.ToInt32

‘now the address of the image buffer can be stored in theService theService.ImageBuffer = bufAddress

‘fill the buffer with the GetImageByExtent method

if (Not theService.GetImageByExtent()) Then

MsgBox("Failed to get image")

goto ErrHandler

End if

‘use the image data.

‘When finished, free up the garbage collector handle

gcHandle.Free()

For a detailed example, please see the ISViewer Sample in VB 6.0 or the Client Application Sample in ANSI C in [ArcGIS Image Server installation folder]\Developer Kit\Client Applications\Samples\ folder.