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SaveAsync(RasterCodecs,RasterImage,ILeadStream,RasterImageFormat,int,int,int,int,CodecsSavePageMode) Method


Asynchronously saves one or more pages of a RasterImage to a LEAD stream in any of the supported compressed or uncompressed formats.




RasterCodecs object to perform the operation.


The RasterImage object that holds the image data.


The stream where the image data will be saved.


The output file format. For valid values, refer to

Summary of All Supported File Formats.


Resulting file's pixel depth. Note that not all bits per pixel are available to all file formats. For valid values, refer to Summary of All Supported File Formats. If bitsPerPixel is 0, the image will be stored using the closest bits per pixel value supported by that format. For example, if a file format supports 1-, 4-, and 24-bits per pixel, and RasterImage.BitsPerPixel is 5, the file will be stored as 24-bit. Likewise, if RasterImage.BitsPerPixel is 2, the file will be stored as 4-bit.


1-based index of the first page in image to save.


1-based index of the last page in image to save. Pass -1 to save from

firstPage to the last page in image.


1-based index of the first output page. If the output file already exists, then this

parameter lets you control which pages to overwrite and/or where to append the new pages.


Determines how to handle the page when saving to multipage formats. The following values are possible:

Value Meaning
Append the new page(s) to the end of the file. If the file does not exist, this option will create the file and add the pages to it. firstSavePageNumber is not used.
Insert the new page(s) at the index specified by firstSavePageNumber.
Replace the page(s) starting at the index specified by firstSavePageNumber.
Overwrite the page(s) starting at the index specified by firstSavePageNumber.

Return Value

A Task that represents the asynchronous operation.


This topic is part of RasterCodecs support for .NET async/await support. Refer to RasterCodecs Async Operations for more information.

For general information on saving images using RasterCodecs, refer to Save.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
public async Task<MemoryStream> LoadAsPng(Uri uri, int pageNumber) 
	// For .NET Framework: Add a reference to Leadtools.Async to get the async support as extension methods 
	// For .NET Standard: async support is included. 
	MemoryStream memoryStream = new MemoryStream(); 
	using (RasterCodecs codecs = new RasterCodecs()) 
		// Create an ILeadStream for the output file 
		using (ILeadStream inputLeadStream = await LeadStream.Factory.FromUri(uri)) 
		// ILeadStream for the output stream 
		using (ILeadStream outputLeadStream = LeadStream.Factory.FromStream(memoryStream)) 
			// Load the image 
			using (RasterImage image = await codecs.LoadAsync(inputLeadStream, pageNumber)) 
				// Save it to the output stream 
				await codecs.SaveAsync(image, outputLeadStream, RasterImageFormat.Png, 0); 
	return memoryStream; 

For .NET Framework: A reference to the Leadtools.Async.dll assembly is required to use this functionality.

For .NET Standard: This functionality is included in the Leadtools.Codecs.dll assembly.

Target Platforms
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