WIA Properties

This section contains all of the WIA properties and their attributes.

The reference topics for these properties list the following attributes: property type, valid values, and access rights.

Property Types

The following types are used in WIA to indicate the data type of a property:

VT_BSTR

A string of Unicode characters (a wide character string).

VT_I4

A 4-byte integer.

VT_R4

A 4-byte real number (a C float).

VT_UI2

A 2-byte unsigned integer.

VT_VECTOR

An array of elements of a particular type. If another property type is combined with VT_VECTOR by using the OR operator, the resulting value is a counted array that consists of a DWORD count of elements, followed by a pointer to the first of the elements in the array. For example, VT_UI2 | VT_VECTOR has a DWORD element count, followed by a pointer to an array of 2-byte unsigned integer elements.

Valid Values

The following types indicate whether a property exists as a single value, a range of values, a list of values, or a flag:

WIA_PROP_NONE

The property contains a single value.

WIA_PROP_RANGE

The property contains a range of values, including a minimum value, a maximum value, a nominal value, and an increment.

WIA_PROP_LIST

The property contains a list of values.

WIA_PROP_FLAG

The property contains a flag.

Access Rights

The following list describes the possible access rights for a property:

Read-only

The driver has read-only access.

Read/write

The driver has both read and write access.

The preceding lists describe only those types that are used in the WIA properties that this section includes. For more information about these and other property types, see WIA_PROPERTY_INFO.

The Windows SDK contain information about the WIA_RAW_HEADER structure. It also contains information about the WIA_EVENT_XXX and WIA_CMD_XXX constants, discussed in the WIA Event Identifiers topic.

 

 

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