Xmp Xojo Plugin Reference Documentation

Xmp

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 xmp As New Chilkat.Xmp

Properties

DebugLogFilePath As String

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

LastErrorHtml As String (read-only)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastErrorText As String (read-only)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

LastErrorXml As String (read-only)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastMethodSuccess As Boolean

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

NumEmbedded As Int32 (read-only)

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

StructInnerDescrip As Boolean

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

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 As String (read-only)

Version of the component/library, such as "9.4.1.42"

Methods

Function AddArray(xml As Chilkat.Xml, arrType As String, propName As String, values As Chilkat.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".

XMP Array Property - Bag, Seq, or Alt

Sub AddNsMapping(ns As String, 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.

Function AddSimpleInt(iXml As Chilkat.Xml, propName As String, propVal As Int32) 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".

Function AddSimpleStr(iXml As Chilkat.Xml, propName As String, 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".

Function AddStructProp(iChilkatXml As Chilkat.Xml, structName As String, propName As String, 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".

Function Append(iXml As Chilkat.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.

Function GetArray(iXml As Chilkat.Xml, propName As String) As Chilkat.StringArray

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

Returns Nil on failure

Function GetEmbedded(index As Int32) As Chilkat.Xml

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

Returns Nil on failure

Function GetProperty(iXml As Chilkat.Xml, propName As String) As Chilkat.Xml

To be documented soon...

Returns Nil on failure

Function GetSimpleInt(iXml As Chilkat.Xml, propName As String) As Int32

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

Function GetSimpleStr(iXml As Chilkat.Xml, 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 Nil on failure

Get a String Property Value from XMP

Function GetStructPropNames(iXml As Chilkat.Xml, structName As String) As Chilkat.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 Nil on failure

Function GetStructValue(iXml As Chilkat.Xml, structName As String, 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 Nil on failure

Get a Structure Property Value from XMP

Function LoadAppFile(filename As String) As Boolean

Loads a TIFF or JPG file into the XMP object.

Function LoadFromBuffer(fileData As MemoryBlock, ext As String) As Boolean

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

Function NewXmp() As Chilkat.Xml

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

Returns Nil on failure

Add XMP MetaData to JPG or TIFF

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.

Function RemoveArray(iXml As Chilkat.Xml, propName As String) As Boolean

Removes an XMP array property from the XMP document.

Sub RemoveNsMapping(ns As String)

Removes a namespace-to-URI mapping.

Function RemoveSimple(iXml As Chilkat.Xml, propName As String) As Boolean

Removes a simple XMP property from the XMP document.

Function RemoveStruct(iXml As Chilkat.Xml, structName As String) As Boolean

Removes an XMP structure property from the XMP document.

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

Removes a single member from an XMP structured property.

Function SaveAppFile(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.

Function SaveLastError(path As String) As Boolean

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns True for success, False for failure.

Function SaveToBuffer() As MemoryBlock

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

Returns Nil on failure

Function UnlockComponent(unlockCode As String) As Boolean

Unlocks the XMP component at runtime. This must be called once at the beginning of your application. Passing an arbitrary value initiates a fully-functional 30-day trial. A purchased unlock code is required to use the component beyond 30 days.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Permanent Unlock Code

LastErrorText Standard Information