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LoadAsync(Stream,LeadRect,object) Method

Summary

Loads the specified rectangle from the specified image stream using default options asynchronously.

Syntax

Java

WinRT C#

C++

public RasterImage LoadAsync( 
   Stream stream, 
   LeadRect tile, 
   object userState 
)

Public Overloads Function LoadAsync( _ 
   ByVal stream As Stream, _ 
   ByVal tile As Leadtools.LeadRect, _ 
   ByVal userState As Object _ 
) As Leadtools.RasterImage

public Leadtools.RasterImage LoadAsync(  
   Stream stream, 
   Leadtools.LeadRect tile, 
   object userState 
)

public Object loadAsync(ILeadStream stream, LeadRect tile, Object userState)

 function Leadtools.Codecs.RasterCodecs.LoadAsync(Stream,LeadRect,Object)(  
   stream , 
   tile , 
   userState  
)

public: 
Leadtools.RasterImage^ LoadAsync(  
   Stream^ stream, 
   Leadtools.LeadRect tile, 
   Object^ userState 
)

Parameters

stream
A Stream containing the image data to load.

tile
A LeadRect describing the tile/area of the image to load.

userState
A user-defined object that is passed to the method invoked when the asynchronous operation completes.

Return Value

The RasterImage object that this method loads. See remarks for the usage of this object.

Remarks

This method loads a section of an image stream (any format). The section begins is defined by tile rectangle.

LEADTOOLS will attempt to load corrupted files so you can see at least a portion of the image. For these images, the load methods succeed, but LoadStatus will return an error code.

Use the CodecsLoadOptions class to set up other load option parameters before calling this method.

Support for 12 and 16-bit grayscale images is only available in the Document/Medical Imaging editions.

For supported formats, refer to Summary of All Supported Image File Formats.

LEADTOOLS loads all PDF files as Raster PDF uncompressed RasterImageFormat.RasPdf, regardless of the compression and color space used when saving the file.

The RasterCodecs class supports loading image files asynchronously using the LoadAsync methods. When calling any of these methods, the caller thread will not be blocked and the method will return instantly with an instance of RasterImage that is in a loading status (RasterImage.IsLoading set to true). You should not use the other properties of this object while the object is in loading status.

When the RasterCodecs object finishes loading the image, the various properties of the RasterImage will be populated with the image information and data and the RasterImage.IsLoading property will be set to false.

Do not poll the RasterImage.IsLoading property to determine whether the image has finished loading. Instead, subscribe to the LoadAsyncCompleted event to get notification when the LoadAsync operation has completed and whether any errors occurred.

The LoadAsyncCompleted event data will also contain the same object returned from LoadAsync so you do not have to keep the original object in your application.

The CodecsLoadOptions.AllPages property controls whether RasterCodecs will try to load all pages or just the first page if the image data contains multiple pages.

Example

Requirements

Target Platforms