Using LEADTOOLS Document Converters

The Document Converters allow conversion from any type of document to another with a minimal amount of code.

Both input and output document types can be any file format supported by LEADTOOLS, which includes but is not limited to:

• Adobe Acrobat PDF and PDF/A

• Microsoft Office DOCX/DOC, XLSX/XLS, and PPTX/PPT

• CAD formats such as DXF, DWG, and DWF

• TIFF, JPEG, PNG, EXIF, BMP, and one hundred more raster image formats

• AFP, MODCA and PTOCA

The DocumentConverter class will analyze the input and output documents types and then automatically use a combination of the LEADTOOLS Raster, SVG, and OCR engines to convert the data using the best possible combination of accuracy and speed. Each conversion operation is called a Document Converter Job in the framework.

Input Document

The DocumentConverter uses the LEADTOOLS Documents Library to obtain information about the input file. The Document class encapsulates the file format details and returns a uniform set of the functionality needed for reading the pages and parsing the data needed for the conversion job. This includes loading page data as RasterImage or SvgDocument objects, reading the table of contents and internal page links and any annotation objects embedded in file or stored in an associated file.

Output Document

There are two types of output document file formats, as follows:

• Document File Formats. The generated output file will have all the text, images, shapes, and any other objects found in the input document converted as-is. For example, searchable PDF and Microsoft Word DOCX files are created with these characteristics.

  In this mode, the converter engine will use SvgDocument or IOcrEngine to parse the text and objects from the input document regardless of its type. For example, SVG is used if the input file is also a document format (such as PDF) and OCR is used if the input file is a raster format (such as TIFF).

  The main object used for creating these types documents is DocumentWriter. Before running any conversion operations, you must set a new DocumentWriter instance in the converter using SetDocumentWriterInstance. You can get this value at any time using DocumentWriterInstance. Use this value to set up the extra document format options needed using DocumentWriter.SetOptions.

• Raster File Formats. The generated output file will only have the raster image representation of the text, images, shapes, and any other objects found in the input document. Example of these documents are TIFF, JPEG, PNG, or raster PDF files.

  In this mode, the converter engine will not use SVG nor OCR, and instead will rely on the extensive file format support provided by LEADTOOLS to load the pages of the input document as raster and save them directly into the output file.

  The main object used for creating these types documents is RasterCodecs.

Conversion Options

The document conversion is designed to run unattended. However, the DocumentConverter provides many options to monitor and modify the operation and to customize the output document as needed. This includes the following options:

• Built-in multi-threading support

• Diagnostics and logging through standard .NET tracing

• Extensive events to report job status and progress as well as to allow modification of the data on the fly

• Pre-processing to clean up the images loaded from the input documents

• Annotations support for both input and output documents

• Error recovery and quarantine

• Page numbering template

Starting Up: DocumentConverter class

The DocumentConverter class is the main entry to the framework. Initialize an instance of this class to be used for converting one or more documents and then set the following options:

Creating Jobs

Once the DocumentConverter class is initialized, use the DocumentConverterJobs class (accessed through the DocumentConverter.Jobs property) to create new conversion jobs.

The parameters for a job are set in a DocumentConverterJobData structure. This contains the following members:

The DocumentConverterJobs.CreateJobData overloaded methods can also be used to quickly create jobs from common input and output options.

When all the options are set, the DocumentConverterJobs.CreateJob method is used to create an instance of the DocumentConverterJob class that holds the job options as well as its status. This object will then be passed to DocumentConverterJobs.RunJob or DocumentConverterJobs.RunJobAsync to run the operation.

Running Jobs

The DocumentConverterJobs.RunJob or DocumentConverterJobs.RunJobAsync methods are used to run the job from the data created in the previous section. While the job is running, the DocumentConverterJobs.JobStarted (once), DocumentConverterJobs.JobOperation (more than once), and the DocumentConverterJobs.JobCompleted (once) events will fire to indicate the job progress.

The data for the DocumentConverterJobEventArgs type events contains all the necessary information about the current job and its status:

For more information about these members and how they can be used or modified, refer to DocumentConverterJobOperation.

The InputDocumentPageNumber property can be used to show a progress bar indicator of the current conversion operation.

Completing Jobs

The job is completed when the RunJob method returns. If RunJobAsync was used, then the JobCompleted should be used to indicate when the job is completed. In both cases, the DocumentConverterJob object passed will contain information about the status of this operation as follows:

Multi-Threading

The DocumentConverter is multi-threaded safe. The RunJobAsync method can be used to run multiple jobs at the same time and run them in separate threads. Internally, the converter uses the .NET Thread Pool exclusively for creating and managing threads.

The RunJobAsync will perform a sanity check about the options and then start the job and return control back to the user immediately. The JobOperation and JobCompleted events can be used to monitor the job's status and to make notifications when a job is completed. AbortAllJobs can be used at any time to abort all running and cancel any pending jobs.