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LoadAsync(ILeadStream,Int32,CodecsLoadByteOrder,Int32,Int32) Method

Summary

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

Syntax

WinRT C#

C++

public IAsyncOperation<RasterImage> LoadAsync(  
   ILeadStream stream, 
   int bitsPerPixel, 
   Leadtools.Codecs.CodecsLoadByteOrder order, 
   int firstPage, 
   int lastPage 
)

Public Overloads Function LoadAsync( _ 
   ByVal stream As ILeadStream, _ 
   ByVal bitsPerPixel As Integer, _ 
   ByVal order As Leadtools.Codecs.CodecsLoadByteOrder, _ 
   ByVal firstPage As Integer, _ 
   ByVal lastPage As Integer _ 
) As IAsyncOperation(Of RasterImage)

public IAsyncOperation<RasterImage> LoadAsync(  
   ILeadStream stream, 
   int bitsPerPixel, 
   Leadtools.Codecs.CodecsLoadByteOrder order, 
   int firstPage, 
   int lastPage 
)

 function Leadtools.Codecs.RasterCodecs.LoadAsync(ILeadStream,Int32,CodecsLoadByteOrder,Int32,Int32)(  
   stream , 
   bitsPerPixel , 
   order , 
   firstPage , 
   lastPage  
)

public: 
IAsyncOperation<RasterImage^>^ LoadAsync(  
   ILeadStream^ stream, 
   int bitsPerPixel, 
   Leadtools.Codecs.CodecsLoadByteOrder order, 
   int firstPage, 
   int lastPage 
)

Parameters

stream
A ILeadStream containing the image data to load.

bitsPerPixel
Resulting image pixel depth.

order
Color order for 16-bit, 24-bit, 32-bit, 48-bit, and 64-bit images. If the resulting image is less than 16 bits per pixel, this will have no effect since palletized images have no order.

firstPage
1-based index of the first page to load.

lastPage
The 1-based index of the last page to load. Must be greater than or equal to firstPage. You can pass -1 to load from firstPage to the last page in the file.

Return Value

When this method completes, it returns the image as a RasterImage.

Remarks

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

Valid values for the bitsPerPixel parameter are:

Value	Meaning
0	Keep the original file's pixel depth (Do not convert).
1 to 8	The specified bits per pixel in the resulting image.
12	12 bits per pixel in the resulting image.
16	16 bits per pixel in the resulting image.
24	24 bits per pixel in the resulting image.
32	32 bits per pixel in the resulting image.
48	48 bits per pixel in the resulting image.
64	64 bits per pixel in the resulting image.

Valid values are for the order parameter are:

Value	Meaning
CodecsLoadByteOrder.Rgb	Red, green, and blue color order in memory
CodecsLoadByteOrder.Bgr	Blue, green, and red color order in memory
CodecsLoadByteOrder.Gray	12 or 16-bit grayscale image. 12 and 16-bit grayscale images are only supported in the Document/Medical Imaging editions.
CodecsLoadByteOrder.RgbOrGray	Load the image as red, green, blue OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions
CodecsLoadByteOrder.BgrOrGray	Load the image as blue, green, red OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions
CodecsLoadByteOrder.Romm	ROMM order. ROMM only supports 24 and 48-bit images
CodecsLoadByteOrder.BgrOrGrayOrRomm	Load the image as red, green, blue OR as a 12 or 16-bit grayscale image OR as ROMM. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions only. ROMM only supports 24 and 48-bit color images.

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

Support for 12-bit 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 IAsyncOperation.Completed event to get notification when the LoadAsync operation has completed and whether any errors occurred.

When this method completes, it returns the image as a RasterImage.

Requirements

Target Platforms

Reference

RasterCodecs Class

RasterCodecs Members

Overload List

Loading and Saving Images

Loading and Saving Large TIFF / BigTIFF Files

Speeding Up 1-Bit Documents

Fast File Info

Help Version 19.0.2017.10.27