CAP_CUSTOMINTERFACEGUID

Description

Uniquely identifies an interface for a Data Source, so that an Application can properly interpret its custom content.

This is a read only capability.

Application

Use the value from this capability to interpret all of the numeric values referenced in the See Also section below.

Consider the following example, which results in three GUID’s, one for Vendor ABC and two for Vendor XYZ:

Vendor ABC’s Scanner models Fred and Wilma have a custom capability called CAP_MYFEATURE with a numeric value of x .

Vendor XYZ’s Scanner model Barney has a custom capability CAP_OURFEATURE with a numeric value of x , but their Scanner Model Betty has a different custom capability CAP_BETTERFEATURE with a numeric value of x .

The challenge for the Application is to know what x means. Historically, this has been determined from the Source’s TW_IDENTITY structure. But this is hard to maintain, and requires the Application to constantly update its recognition code, even in the case of Vendor ABC whose interface stays the same from one model to the next.

Using CAP_CUSTOMINTERFACEGUID the Application can immediately identity Vendor ABC’s unique interface, without having to check its TW_IDENTITY structure.

Source

Values

The Source writer is responsible for creating a GUID. This GUID guarantees that the custom numeric values have exactly the same meaning for any Source that reports that GUID.

If you need to create a GUID, but don’t know how, go to the TWAIN Working Group website and click on FAQ.

Type: TW_STR

Allowed Values: A string in GUID format

{XXXXXXXX XXXX XXXX XXXX XXXXXXXXXXXX}

Containers

MSG_GET TW_ONEVALUE MSG_GETCURRENT TW_ONEVALUE MSG_GETDEFAULT TW_ONEVALUE MSG_SET Not Allowed

MSG_RESET Not Allowed MSG_SETCONSTRAINT Not Allowed MSG_QUERYSUPPORT TW_ONEVALUE

Required By

Sources that support Custom Content.

TWAIN Version Introduced

Version 2.1

Related

CAP_CUSTOMBASE