Xmp Lazarus Pascal Reference Documentation
Xmp
Current Version: 11.6.0
Chilkat.Xmp
Load a
Retrieve embedded XMP documents as
Add or update namespace-qualified string and integer properties such as
Work with XMP arrays such as
Use built-in namespace mappings or add custom namespace-to-URI mappings
for application-specific XMP properties.
Remove properties, arrays, structures, or embedded XMP documents, then
persist changes to a file or return the updated image as a byte buffer.
Read, modify, add, remove, and save XMP metadata in JPG and TIFF files.
Chilkat.Xmp is a legacy class for working with embedded XMP
metadata in JPG and TIFF image files. It can load
image files or image data from memory, locate embedded XMP documents, return
XMP metadata as Chilkat.Xml, create new XMP documents, add or
update simple string and integer properties, manage arrays and structured
properties, add namespace mappings, remove selected XMP properties or entire
embedded XMP documents, and save the updated image back to a file or byte
buffer.
Chilkat.Xmp is maintained for existing JPG/TIFF XMP workflows,
but it is not planned to be extended to support additional file types.
Load JPG or TIFF metadata
JPG or TIFF file from disk or memory and
inspect how many embedded XMP documents were found.
Access XMP as XML
Chilkat.Xml objects for
inspection, editing, or direct XML-level processing.
Add simple properties
dc:subject, photoshop:Credit, or
tiff:XResolution.
Arrays and structures
bag, seq, and
alt, and manage structured property values.
Namespaces
Remove and save
LoadAppFile or
LoadFromBuffer, retrieve an embedded XMP document with
GetEmbedded or create one with NewXmp, modify it
using the add/remove property methods, then call SaveAppFile or
SaveToBuffer to persist the updated image metadata.
SaveAppFile is called. For memory workflows, use
SaveToBuffer to obtain the updated JPG or TIFF bytes.
Create / Free
uses
Chilkat.Xmp;
var
obj: TXmp;
begin
obj := TXmp.Create;
try
if not obj.IsValid then
raise Exception.Create('Failed to create a TXmp instance.');
// ... use obj ...
finally
obj.Free;
end;
end;
Allocates the underlying CkXmp object and returns a new TXmp instance. Simply adding Chilkat.Xmp to the unit's uses clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check obj.IsValid after calling Create; it is False if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed).
Every TXmp created by calling Create should eventually be released by calling .Free (inherited from TObject). The destructor automatically disposes the underlying CkXmp handle. A native (unmanaged) memory leak occurs if the object is never freed.
Properties
DebugLogFilePath
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.
LastErrorHtml
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.
topLastErrorText
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.
LastErrorXml
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.
topLastMethodSuccess
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. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
NumEmbedded
The number of XMP metadata documents found within the JPG or TIFF file loaded by LoadAppFile.
topStructInnerDescrip
Determines whether structures are stored with rdf:parseType=Resource, or within an rdf:Description sub-node.
UncommonOptions
A property to be used for future uncommon needs. The default value is the empty string.
topVerboseLogging
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
Methods
AddArray
// values is a TStringArray object.
function AddArray(xml: TChilkatBase;
const arrType: string;
const propName: string;
values: TChilkatBase): 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.
AddNsMapping
const uri: 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.
topAddSimpleInt
function AddSimpleInt(iXml: TChilkatBase;
const propName: string;
propVal: Integer): 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(iXml: TChilkatBase;
const propName: string;
const propVal: string): 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(iChilkatXml: TChilkatBase;
const structName: string;
const propName: string;
const propValue: string): 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(iXml: TChilkatBase): 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.
topGetArray
// Return value is a TStringArray object.
function GetArray(iXml: TChilkatBase;
const propName: string): TChilkatBase;
Finds and returns an XMP array property. The property name should be prefixed with the namespace, such as dc:subject.
Returns nil on failure
GetEmbedded
function GetEmbedded(index: Integer): TChilkatBase;
Returns the Nth embedded XMP document as a Chilkat XML object.
Returns nil on failure
GetProperty
// Return value is a TXml object.
function GetProperty(iXml: TChilkatBase;
const propName: string): TChilkatBase;
GetSimpleInt
function GetSimpleInt(iXml: TChilkatBase;
const propName: string): Integer;
Finds and returns an XMP integer property. The property name should be prefixed with the namespace, such as tiff:ResolutionUnit.
GetSimpleStr
function GetSimpleStr(iXml: TChilkatBase;
const propName: string): string;
Finds and returns an XMP simple string property. The property name should be prefixed with the namespace, such as photoshop:Source.
Returns True for success, False for failure.
GetStructPropNames
// Return value is a TStringArray object.
function GetStructPropNames(iXml: TChilkatBase;
const structName: string): TChilkatBase;
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
GetStructValue
function GetStructValue(iXml: TChilkatBase;
const structName: string;
const propName: string): string;
Returns the value of a single item within an XMP structure property. Property names should always be prefixed with the namespace.
Returns True for success, False for failure.
LoadAppFile
Loads a TIFF or JPG file into the XMP object.
topNewXmp
function NewXmp: TChilkatBase;
Creates and returns a new/empty XMP metadata document as a Chilkat XML object.
Returns nil on failure
RemoveAllEmbedded
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.
topRemoveArray
function RemoveArray(iXml: TChilkatBase;
const propName: string): Boolean;
Removes an XMP array property from the XMP document.
topRemoveEmbedded
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.
topRemoveNsMapping
Removes a namespace-to-URI mapping.
topRemoveSimple
function RemoveSimple(iXml: TChilkatBase;
const propName: string): Boolean;
Removes a simple XMP property from the XMP document.
topRemoveStruct
function RemoveStruct(iXml: TChilkatBase;
const structName: string): Boolean;
Removes an XMP structure property from the XMP document.
topRemoveStructProp
function RemoveStructProp(iXml: TChilkatBase;
const structName: string;
const propName: string): Boolean;
Removes a single member from an XMP structured property.
topSaveAppFile
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.
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