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Definitions

• TWAIN-compliant data source
  An acquisition source that complies with the TWAIN protocol.

• Source Manager
  Middle-ware that communicates between applications and TWAIN-compliant data sources.

• TWAIN session
  A state where a TWAIN variable has established a connection with the source manager. This process is also called "Opening a TWAIN session."

• Acquiring
  The act of transmitting an image from the data source to the application.

Requirements

TWAIN support was added to Paradox in version 9, Service Pack 1. ObjectPAL support for TWAIN came later in version 10.

• You must be running Paradox 10 (or later).
• The file pxtwn32.dll must be located in the same directory as pdxwin32.exe
• The file twain_32.dll must be present in your operating system directory (c:\winnt, c:\windows)
• At least one TWAIN-complaint data source installed on the machine.

Introduction

There are many advantages of putting TWAIN support into your application. This introduction discusses some of the common questions regarding TWAIN, and its uses.

What is TWAIN and TWAIN support?

TWAIN is an interface that enables applications to transmit images from imaging hardware devices. These devices primarily include digital cameras and page scanners. Images when acquired are scanned directly into the application for direct manipulation.

TWAIN support is a term for the client application. Applications which conform to the TWAIN interface and acquire images into their application are said to have TWAIN support. A data source which complies with the TWAIN interface is said to be TWAIN-compliant.

TWAIN is not an acronym. The word TWAIN is from Kipling's, "The Ballad of East and West" - "… and never the twain shall meet." However, many people believe that it is indeed an acronym. Perhaps the best entry for an acronym was "Technology Without An Interesting Name."

What are the benefits of TWAIN support?

Nearly every application that supports some form of photo-identification will benefit by including TWAIN support with their application. A health club that has photo-ID for its members or a hospital and employee identification tags. Even things as simple as a plant collection, fish database, and coin collections can benefit by having the ability to scan images into a table.

Next Part: Part 2: TWAIN Support Overview

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