Xmp VB.NET Reference Documentation

Xmp

Current Version: 10.1.2

Requires Chilkat Bundle License

Chilkat XMP is a software component (SDK, toolkit, library, etc) for accessing, manipulating, and adding XMP metadata to JPEG and TIFF files.

Object Creation

Dim obj As New Chilkat.Xmp()

Properties

DebugLogFilePath

DebugLogFilePath As String

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

A timeout property set to 0, indicating an infinite timeout.
A hang occurring within an event callback in the application code.
An internal bug in the Chilkat code causing the hang.

More Information and Examples

Example showing how to use DebugLogFilePath.

LastErrorHtml

LastErrorHtml As String (ReadOnly)

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastErrorText

LastErrorText As String (ReadOnly)

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

LastErrorXml As String (ReadOnly)

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

LastMethodSuccess

LastMethodSuccess As Boolean

Indicates the success or failure of the most recent method call: True means success, False means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.

NumEmbedded

NumEmbedded As Integer (ReadOnly)

The number of XMP metadata documents found within the JPG or TIFF file loaded by LoadAppFile.

StructInnerDescrip

StructInnerDescrip As Boolean

Determines whether structures are stored with rdf:parseType="Resource", or within an "rdf:Description" sub-node.

UncommonOptions

UncommonOptions As String

Introduced in version 9.5.0.80

A property to be used for future uncommon needs. The default value is the empty string.

VerboseLogging

VerboseLogging As Boolean

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version

Version As String (ReadOnly)

Version of the component/library, such as "10.1.0"

More Information and Examples

How to get the Chilkat version at runtime.

Methods

AddArray

Function AddArray(ByVal xml As Xml, ByVal arrType As String, ByVal propName As String, ByVal values As StringArray) As Boolean

Adds or replaces an XMP property array. The XMP metadata to be updated is contained in the XML object passed in the 1st argument. The 2nd argument specifies the array type, which can be "bag", "seq", or "alt". The property name should be prefixed with the namespace, such as "dc:subject".

More Information and Examples

XMP Array Property - Bag, Seq, or Alt

AddNsMapping

Sub AddNsMapping(ByVal ns As String, ByVal uri As String)

Adds a namespace to URI mapping. When a property is added via AddSimpleString or any of the other methods, the property name is namespace qualified. When adding the first property in a namespace, the rdf:Description is automatically added and the URI is obtained from the namespace-to-URI mappings. The standard (and commonly used) namespace mappings are defined by default. This is only used if the namespace is custom or not already handled.

AddSimpleInt

Function AddSimpleInt(ByVal iXml As Xml, ByVal propName As String, ByVal propVal As Integer) As Boolean

Adds or updates an XMP integer property. The XMP metadata to be updated is contained in the XML object passed in the 1st argument. The property name should be prefixed with the namespace, such as "tiff:XResolution".

AddSimpleStr

Function AddSimpleStr(ByVal iXml As Xml, ByVal propName As String, ByVal propVal As String) As Boolean

Adds or updates a simple XMP string property. The XMP metadata to be updated is contained in the XML object passed in the 1st argument. The property name should be prefixed with the namespace, such as "photoshop:Credit".

AddStructProp

Function AddStructProp(ByVal iChilkatXml As Xml, ByVal structName As String, ByVal propName As String, ByVal propValue As String) As Boolean

Adds or updates an XMP structured property value. The XMP metadata to be updated is contained in the XML object passed in the 1st argument. The structure name should be prefixed with the namespace, such as "Iptc4xmpCore:CreatorContactInfo". The property name within the structure should also be prefixed with the namespace, such as "Iptc4xmpCore:CiAdrCity".

Append

Function Append(ByVal iXml As Xml) As Boolean

Appends a new XMP metadata file to the XMP object. Any XMPs appended via this method will be present in the file when SaveAppFile is called. Files containing XMP metadata typically only include a single XMP document, so this method is usually only called when adding XMP metadata to a file for the first time.

GetArray

Function GetArray(ByVal iXml As Xml, ByVal propName As String) As StringArray

Finds and returns an XMP array property. The property name should be prefixed with the namespace, such as "dc:subject".

Returns Nothing on failure

GetEmbedded

Function GetEmbedded(ByVal index As Integer) As Xml

Returns the Nth embedded XMP document as a Chilkat XML object.

Returns Nothing on failure

More Information and Examples

Extract XMP MetaData as XML

GetProperty

Function GetProperty(ByVal iXml As Xml, ByVal propName As String) As Xml

To be documented soon...

Returns Nothing on failure

GetSimpleInt

Function GetSimpleInt(ByVal iXml As Xml, ByVal propName As String) As Integer

Finds and returns an XMP integer property. The property name should be prefixed with the namespace, such as "tiff:ResolutionUnit".

GetSimpleStr

Function GetSimpleStr(ByVal iXml As Xml, ByVal propName As String) As String

Finds and returns an XMP simple string property. The property name should be prefixed with the namespace, such as "photoshop:Source".

Returns Nothing on failure

More Information and Examples

Get a String Property Value from XMP

GetStructPropNames

Function GetStructPropNames(ByVal iXml As Xml, ByVal structName As String) As StringArray

Returns the property names used by an exsting structure within an XMP document. The contents of the structure can be retrieved by calling GetStructValue for each property name returned by GetStructPropNames.

Returns Nothing on failure

GetStructValue

Function GetStructValue(ByVal iXml As Xml, ByVal structName As String, ByVal propName As String) As String

Returns the value of a single item within an XMP structure property. Property names should always be prefixed with the namespace.

Returns Nothing on failure

More Information and Examples

Get a Structure Property Value from XMP

LoadAppFile

Function LoadAppFile(ByVal filename As String) As Boolean

Loads a TIFF or JPG file into the XMP object.

LoadFromBuffer

Function LoadFromBuffer(ByVal fileData As Byte(), ByVal ext As String) As Boolean

Loads a JPG or TIFF from an byte buffer containing the image file data.

NewXmp

Function NewXmp() As Xml

Creates and returns a new/empty XMP metadata document as a Chilkat XML object.

Returns Nothing on failure

More Information and Examples

Add XMP MetaData to JPG or TIFF

RemoveAllEmbedded

Function RemoveAllEmbedded() As Boolean

Removes all XMP metadata documents from an XMP object. After calling this method, call SaveAppFile to rewrite the JPG or TIFF file with the XMP metadata removed.

Returns True for success, False for failure.

RemoveArray

Function RemoveArray(ByVal iXml As Xml, ByVal propName As String) As Boolean

Removes an XMP array property from the XMP document.

RemoveEmbedded

Function RemoveEmbedded(ByVal index As Integer) As Boolean

Removes a single XMP metadata document from the JPG or TIFF file. Call SaveAppFile to persist the changes to disk.

Returns True for success, False for failure.

RemoveNsMapping

Sub RemoveNsMapping(ByVal ns As String)

Removes a namespace-to-URI mapping.

RemoveSimple

Function RemoveSimple(ByVal iXml As Xml, ByVal propName As String) As Boolean

Removes a simple XMP property from the XMP document.

RemoveStruct

Function RemoveStruct(ByVal iXml As Xml, ByVal structName As String) As Boolean

Removes an XMP structure property from the XMP document.

RemoveStructProp

Function RemoveStructProp(ByVal iXml As Xml, ByVal structName As String, ByVal propName As String) As Boolean

Removes a single member from an XMP structured property.

SaveAppFile

Function SaveAppFile(ByVal filename As String) As Boolean

Persists all changes made to the XMP document(s) by saving the XMP object to a file. Changes made by adding, updating, or removing properties are not persisted to the filesystem until this is called.

SaveToBuffer

Function SaveToBuffer() As Byte()

Saves a JPG or TIFF image with updated XMP to a byte buffer.

Returns an empty byte array on failure