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LEADTOOLS Image File Support (Leadtools.Codecs assembly)
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LoadOptions(String) Method








Leadtools.Codecs Namespace > RasterCodecs Class > LoadOptions Method : LoadOptions(String) Method
A String that contains the name of a disk file containing the options to load
Loads the options into this RasterCodecs from a disk file.
Syntax
public void LoadOptions( 
   string fileName
)
'Declaration
 

Public Overloads Sub LoadOptions( _
   ByVal fileName As String _
) 
'Usage
 

Dim instance As RasterCodecs
Dim fileName As String
 
instance.LoadOptions(fileName)
public void LoadOptions( 
   string fileName
)
 function Leadtools.Codecs.RasterCodecs.LoadOptions(String)( 
   fileName 
)

public:
void LoadOptions( 
   String^ fileName
)

Parameters

fileName
A String that contains the name of a disk file containing the options to load
Remarks

The RasterCodecs options can be easily saved to a disk or stream using SaveOptions(string fileName) or SaveOptions(Stream stream) and then loaded back into the same or a different RasterCodecs object using LoadOptions(string fileName) or LoadOptions(Stream stream).

Saving and loading the options is handy for situations where a RasterCodecs with specialized options other than the default is used. For example, in a server application as demonstrated by the example.

The options are saved in a standard XML file (with UTF-8 encoding) in the following format:


            <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
            <leadtools_raster_codecs>
              <options>
                 <option FullPropertyName="value" />
              </options>
            </leadtools_raster_codecs>

FullPropertyName is the exact .NET property name of the options as accessed by the RasterCodecs object, for example, if you have a RasterCodecs object called rasterCodecsInstance, then you can access the CodecsRasterizeDocumentLoadOptions.XResolution using:


            rasterCodecsInstance.RasterizeDocument.Load.XResolution

And hence, the FullPropertyName if this option will be RasterizeDocument.Load.XResolution.

The LoadOptions(string fileName) and LoadOptions(Stream stream) methods will merge the content of the XML file with the current RasterCodecs options. Therefore, you can delete any option elements that do not override the default behavior from the file if desired.

Example

This example shows how to save the options and then load them in a server application.

Copy Code   
Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing
Imports Leadtools.ImageProcessing.Color
Imports Leadtools.Drawing
Imports Leadtools.Svg

' A bare-boned REST service that loads an image from a URL and returns it as PNG
<System.ServiceModel.ServiceContract()> _
Public Interface ISampleService
   <System.ServiceModel.OperationContract(Name:="Load", IsTerminating:=False, IsInitiating:=True, IsOneWay:=False, AsyncPattern:=False, Action:="Load")> _
   <System.ServiceModel.Web.WebGet(UriTemplate:="/load?url={url}&page={pageNumber}")> _
   Function Load(url As String, pageNumber As Integer) As System.IO.Stream
End Interface
' Implementation
Public Class SampleService
   Implements ISampleService

   ' This is the REST service call
   Public Function Load(url As String, pageNumber As Integer) As System.IO.Stream Implements ISampleService.Load
      ' Load the page
      Using rasterCodecs As New RasterCodecs()
         ' Get the name of the options file from the configuraion file
         Dim optionsFilePath As String = System.Configuration.ConfigurationManager.AppSettings("RasterCodecsOptionsFilePath")

         ' See if it is set and contains a valid file
         If Not IsNothing(optionsFilePath) AndAlso System.IO.File.Exists(optionsFilePath) Then
            ' Set it, this will use the options previously saved with SampleService.PrepareOptions
            rasterCodecs.LoadOptions(optionsFilePath)
         End If

         ' Now load the image
         Using rasterImage As RasterImage = rasterCodecs.Load(New Uri(url), pageNumber)
            ' Save it as PNG
            Dim ms As New System.IO.MemoryStream()
            rasterCodecs.Save(rasterImage, ms, RasterImageFormat.Png, 24)

            ' Set the content length and MIME type
            System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentType = "image/png"
            System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentLength = ms.Length

            ms.Position = 0
            Return ms
         End Using
      End Using
   End Function

   ' This is a helper method to create the RasterCodecs options file. This method
   ' is meant to be called from ourside the service by an administrator.
   '
   ' We can change any option we want off-line and then save the file
   ' Our service will pick up the new options from the file and use them
   Public Shared Sub PrepareOptions()
      ' Get the name of the options file from the configuraion file
      Dim optionsFilePath As String = System.Configuration.ConfigurationManager.AppSettings("RasterCodecsOptionsFilePath")

      ' See if it is set
      If Not IsNothing(optionsFilePath) Then
         ' Yes, create a new RasterCodecs object
         Using rasterCodecs As New RasterCodecs()
            ' Change any options, for example, set the default resolution for document files ...
            rasterCodecs.Options.RasterizeDocument.Load.XResolution = 300
            rasterCodecs.Options.RasterizeDocument.Load.YResolution = 300
            ' And enable loading text files as RasterImage support
            rasterCodecs.Options.Txt.Load.Enabled = True

            ' Save the options to the file specified by the config
            rasterCodecs.SaveOptions(optionsFilePath)
         End Using
      End If
   End Sub
End Class
using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Color;
using Leadtools.Svg;

// A bare-boned REST service that loads an image from a URL and returns it as PNG
[System.ServiceModel.ServiceContract()]
public interface ISampleService
{
   [System.ServiceModel.OperationContract(Name = "Load", IsTerminating = false, IsInitiating = true, IsOneWay = false, AsyncPattern = false, Action = "Load")]
   [System.ServiceModel.Web.WebGet(UriTemplate = "/load?url={url}&page={pageNumber}")]
   System.IO.Stream Load(string url, int pageNumber);
}
// Implementation
public class SampleService : ISampleService
{
   // This is the REST service call
   public System.IO.Stream Load(string url, int pageNumber)
   {
      // Load the page
      using (RasterCodecs rasterCodecs = new RasterCodecs())
      {
         // Get the name of the options file from the configuraion file
         string optionsFilePath = System.Configuration.ConfigurationManager.AppSettings["RasterCodecsOptionsFilePath"];

         // See if it is set and contains a valid file
         if (optionsFilePath != null && System.IO.File.Exists(optionsFilePath))
         {
            // Set it, this will use the options previously saved with SampleService.PrepareOptions
            rasterCodecs.LoadOptions(optionsFilePath);
         }

         // Now load the image
         using (RasterImage rasterImage = rasterCodecs.Load(new Uri(url), pageNumber))
         {
            // Save it as PNG
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            rasterCodecs.Save(rasterImage, ms, RasterImageFormat.Png, 24);

            // Set the content length and MIME type
            System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentType = "image/png";
            System.ServiceModel.Web.WebOperationContext.Current.OutgoingResponse.ContentLength = ms.Length;

            ms.Position = 0;
            return ms;
         }
      }
   }

   // This is a helper method to create the RasterCodecs options file. This method
   // is meant to be called from ourside the service by an administrator.
   //
   // We can change any option we want off-line and then save the file
   // Our service will pick up the new options from the file and use them
   public static void PrepareOptions()
   {
      // Get the name of the options file from the configuraion file
      string optionsFilePath = System.Configuration.ConfigurationManager.AppSettings["RasterCodecsOptionsFilePath"];

      // See if it is set
      if (optionsFilePath != null)
      {
         // Yes, create a new RasterCodecs object
         using (RasterCodecs rasterCodecs = new RasterCodecs())
         {
            // Change any options, for example, set the default resolution for document files ...
            rasterCodecs.Options.RasterizeDocument.Load.XResolution = 300;
            rasterCodecs.Options.RasterizeDocument.Load.YResolution = 300;
            // And enable loading text files as RasterImage support
            rasterCodecs.Options.Txt.Load.Enabled = true;

            // Save the options to the file specified by the config
            rasterCodecs.SaveOptions(optionsFilePath);
         }
      }
   }
}
Requirements

Target Platforms

See Also

Reference

RasterCodecs Class
RasterCodecs Members
Overload List

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