Xmp React Native Reference Documentation
Xmp
Current Version: 11.6.1
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.
Object Creation
// npm install @chilkat/react-native react-native-nitro-modules
// (React Native 0.76+ with the New Architecture; then `pod install` for iOS. The Chilkat
// native library is downloaded and verified during the native build -- see the package README.)
import { Chilkat, Xmp } from '@chilkat/react-native'
// Once per app start, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial') // shorthand for new Global().unlockBundle(..)
const xmp = new Xmp()
// ... the native object is released when `xmp` is garbage collected, or now with xmp.dispose()Creates the underlying native Chilkat object. Xmp is a Nitro Module HybridObject: use it from the JavaScript thread only (it cannot be passed to a Worklet or another runtime). Every member is synchronous and blocks the JavaScript thread until Chilkat returns; a method that can take a while also exists as a ...Async twin returning a Promise, which runs the same call on a native worker thread so the UI keeps rendering. While such a call is pending, every other call on this object throws, except abort() and assigning onPercentDone / onProgressInfo.
Releases the native object immediately instead of waiting for garbage collection (useful for a large BinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws. An object with a pending ...Async call cannot be disposed until the promise settles.
Errors
A method that can fail throws a plain Error: a method whose only outcome is success or failure returns void and throws on failure; a method producing a string or an object returns it and throws where Chilkat would have returned null. The error's message is "Class.method(...): reason", where the reason is the last informative line of the object's lastErrorText, which holds the full Chilkat log of the failed call. A ...Async twin rejects its promise with the same Error instead of throwing. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain boolean.
try {
xmp.someMethod(...)
} catch (e) {
console.log((e as Error).message) // Xmp.someMethod(...): <reason>
console.log(xmp.lastErrorText) // the full Chilkat log of the failed call
}
// The same call without blocking the JavaScript thread:
try {
await xmp.someMethodAsync(...)
} catch (e) {
console.log((e as Error).message) // Xmp.someMethodAsync: <reason>
}Properties
DebugLogFilePath
debugLogFilePath: 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.
LastErrorHtml
readonly lastErrorHtml: string
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
readonly lastErrorText: string
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
readonly lastErrorXml: string
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
lastMethodSuccess: 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. 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
readonly numEmbedded: number
The number of XMP metadata documents found within the JPG or TIFF file loaded by LoadAppFile.
topStructInnerDescrip
structInnerDescrip: boolean
Determines whether structures are stored with rdf:parseType=Resource, or within an rdf:Description sub-node.
UncommonOptions
uncommonOptions: string
A property to be used for future uncommon needs. The default value is the empty string.
topVerboseLogging
verboseLogging: 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
readonly version: string
Methods
AddArray
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.
Returns normally on success; throws an Error on failure.
AddNsMapping
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
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.
Returns normally on success; throws an Error on failure.
AddSimpleStr
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.
Returns normally on success; throws an Error on failure.
AddStructProp
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.
Returns normally on success; throws an Error on failure.
Append
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.
Returns normally on success; throws an Error on failure.
GetArray
Finds and returns an XMP array property. The property name should be prefixed with the namespace, such as dc:subject.
Throws an Error on failure (where the description says null is returned, the method throws instead).
GetEmbedded
Returns the Nth embedded XMP document as a Chilkat XML object.
Throws an Error on failure (where the description says null is returned, the method throws instead).
GetProperty
To be documented soon...
Throws an Error on failure (where the description says null is returned, the method throws instead).
GetSimpleInt
Finds and returns an XMP integer property. The property name should be prefixed with the namespace, such as tiff:ResolutionUnit.
GetSimpleStr
Finds and returns an XMP simple string property. The property name should be prefixed with the namespace, such as photoshop:Source.
Throws an Error on failure (where the description says null is returned, the method throws instead).
GetStructPropNames
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.
Throws an Error on failure (where the description says null is returned, the method throws instead).
GetStructValue
Returns the value of a single item within an XMP structure property. Property names should always be prefixed with the namespace.
Throws an Error on failure (where the description says null is returned, the method throws instead).
LoadAppFile
Loads a TIFF or JPG file into the XMP object.
Returns normally on success; throws an Error on failure.
NewXmp
Creates and returns a new/empty XMP metadata document as a Chilkat XML object.
Throws an Error on failure (where the description says null is returned, the method throws instead).
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 normally on success; throws an Error on failure.
RemoveArray
Removes an XMP array property from the XMP document.
Returns normally on success; throws an Error on failure.
RemoveEmbedded
Removes a single XMP metadata document from the JPG or TIFF file. Call SaveAppFile to persist the changes to disk.
Returns normally on success; throws an Error on failure.
RemoveNsMapping
Removes a namespace-to-URI mapping.
topRemoveSimple
Removes a simple XMP property from the XMP document.
Returns normally on success; throws an Error on failure.
RemoveStruct
Removes an XMP structure property from the XMP document.
Returns normally on success; throws an Error on failure.
RemoveStructProp
Removes a single member from an XMP structured property.
Returns normally on success; throws an Error on failure.
SaveAppFile
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.
Returns normally on success; throws an Error on failure.