---
product: Chilkat
product_version: 11.7.0
language: ckruby
language_label: Ruby
class: Xmp
class_name: CkXmp
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/rubyCkXmpRef.html
---
# Chilkat Xmp — Ruby — v11.7.0

> Chilkat 11.7.0 · language=ckruby · class=Xmp (CkXmp)
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/Xmp.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/ckruby/guide.md`.

## Purpose

**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.

**Legacy class:** `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**

Load a `JPG` or `TIFF` file from disk or memory and inspect how many embedded XMP documents were found.

**Access XMP as XML**

Retrieve embedded XMP documents as `Chilkat.Xml` objects for inspection, editing, or direct XML-level processing.

**Add simple properties**

Add or update namespace-qualified string and integer properties such as `dc:subject`, `photoshop:Credit`, or `tiff:XResolution`.

**Arrays and structures**

Work with XMP arrays such as `bag`, `seq`, and `alt`, and manage structured property values.

**Namespaces**

Use built-in namespace mappings or add custom namespace-to-URI mappings for application-specific XMP properties.

**Remove and save**

Remove properties, arrays, structures, or embedded XMP documents, then persist changes to a file or return the updated image as a byte buffer.

**Common pattern:** Load a JPG or TIFF with `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.

**Persistence note:** Changes made to the XMP XML object are not written back to the image file until `SaveAppFile` is called. For memory workflows, use `SaveToBuffer` to obtain the updated JPG or TIFF bytes.

## Object creation, unlocking and error handling

**Object Creation**

```ruby
obj = Chilkat::CkXmp.new()
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Ruby.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `# strVal is a string # ckStr is a CkString xmp.get_DebugLogFilePath(ckStr); strVal = xmp.debugLogFilePath(); xmp.put_DebugLogFilePath(strVal);` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `# strVal is a string # ckStr is a CkString xmp.get_LastErrorHtml(ckStr); strVal = xmp.lastErrorHtml();` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `# strVal is a string # ckStr is a CkString xmp.get_LastErrorText(ckStr); strVal = xmp.lastErrorText();` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `# strVal is a string # ckStr is a CkString xmp.get_LastErrorXml(ckStr); strVal = xmp.lastErrorXml();` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `# boolVal is a boolean boolVal = xmp.get_LastMethodSuccess(); xmp.put_LastMethodSuccess(boolVal);` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `Utf8` | `# boolVal is a boolean boolVal = xmp.get_Utf8(); xmp.put_Utf8(boolVal);` | read/write | When set to `true`, all `string` arguments and return values are interpreted as UTF-8 strings. |
| `VerboseLogging` | `# boolVal is a boolean boolVal = xmp.get_VerboseLogging(); xmp.put_VerboseLogging(boolVal);` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `# strVal is a string # ckStr is a CkString xmp.get_Version(ckStr); strVal = xmp.version();` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `NumEmbedded` | property, read-only | `# intVal is an integer intVal = xmp.get_NumEmbedded();` |
| `StructInnerDescrip` | property, read/write | `# boolVal is a boolean boolVal = xmp.get_StructInnerDescrip(); xmp.put_StructInnerDescrip(boolVal);` |
| `UncommonOptions` | property, read/write | `# strVal is a string # ckStr is a CkString xmp.get_UncommonOptions(ckStr); strVal = xmp.uncommonOptions(); xmp.put_UncommonOptions(strVal);` |
| `AddArray` | method | `# xml is a CkXml # arrType is a string # propName is a string # values is a CkStringArray status = xmp.AddArray(xml, arrType, propName, values);` |
| `AddNsMapping` | method | `# ns is a string # uri is a string xmp.AddNsMapping(ns, uri);` |
| `AddSimpleInt` | method | `# iXml is a CkXml # propName is a string # propVal is an integer status = xmp.AddSimpleInt(iXml, propName, propVal);` |
| `AddSimpleStr` | method | `# iXml is a CkXml # propName is a string # propVal is a string status = xmp.AddSimpleStr(iXml, propName, propVal);` |
| `AddStructProp` | method | `# iChilkatXml is a CkXml # structName is a string # propName is a string # propValue is a string status = xmp.AddStructProp(iChilkatXml, structName, propName, propValue);` |
| `Append` | method | `# iXml is a CkXml status = xmp.Append(iXml);` |
| `GetArray` | method | `# returns a CkStringArray # iXml is a CkXml # propName is a string ret_stringArray = xmp.GetArray(iXml, propName);` |
| `GetEmbedded` | method | `# returns a CkXml # index is an integer ret_xml = xmp.GetEmbedded(index);` |
| `GetProperty` | method | `# returns a CkXml # iXml is a CkXml # propName is a string ret_xml = xmp.GetProperty(iXml, propName);` |
| `GetSimpleInt` | method | `# iXml is a CkXml # propName is a string retInt = xmp.GetSimpleInt(iXml, propName);` |
| `GetSimpleStr` | method | `# iXml is a CkXml # propName is a string # outStr is a CkString (output) status = xmp.GetSimpleStr(iXml, propName, outStr); retStr = xmp.getSimpleStr(iXml, propName);` |
| `GetStructPropNames` | method | `# returns a CkStringArray # iXml is a CkXml # structName is a string ret_stringArray = xmp.GetStructPropNames(iXml, structName);` |
| `GetStructValue` | method | `# iXml is a CkXml # structName is a string # propName is a string # outStr is a CkString (output) status = xmp.GetStructValue(iXml, structName, propName, outStr); retStr = xmp.getStructValue(iXml, structName, propName);` |
| `LoadAppFile` | method | `# filename is a string status = xmp.LoadAppFile(filename);` |
| `NewXmp` | method | `# returns a CkXml ret_xml = xmp.NewXmp();` |
| `RemoveAllEmbedded` | method | `status = xmp.RemoveAllEmbedded();` |
| `RemoveArray` | method | `# iXml is a CkXml # propName is a string status = xmp.RemoveArray(iXml, propName);` |
| `RemoveEmbedded` | method | `# index is an integer status = xmp.RemoveEmbedded(index);` |
| `RemoveNsMapping` | method | `# ns is a string xmp.RemoveNsMapping(ns);` |
| `RemoveSimple` | method | `# iXml is a CkXml # propName is a string status = xmp.RemoveSimple(iXml, propName);` |
| `RemoveStruct` | method | `# iXml is a CkXml # structName is a string status = xmp.RemoveStruct(iXml, structName);` |
| `RemoveStructProp` | method | `# iXml is a CkXml # structName is a string # propName is a string status = xmp.RemoveStructProp(iXml, structName, propName);` |
| `SaveAppFile` | method | `# filename is a string status = xmp.SaveAppFile(filename);` |

Deprecated members are listed at the end of this file with their replacements; do not use them in new code.

## Properties

### Xmp.NumEmbedded

`Chilkat 11.7.0 · ckruby · Xmp · NumEmbedded · property · read-only`

```ruby
# intVal is an integer

intVal = xmp.get_NumEmbedded();
```

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

### Xmp.StructInnerDescrip

`Chilkat 11.7.0 · ckruby · Xmp · StructInnerDescrip · property · read/write`

```ruby
# boolVal is a boolean

boolVal = xmp.get_StructInnerDescrip();

xmp.put_StructInnerDescrip(boolVal);
```

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

### Xmp.UncommonOptions

`Chilkat 11.7.0 · ckruby · Xmp · UncommonOptions · property · read/write · since 9.5.0.80`

```ruby
# strVal is a string

# ckStr is a CkString

xmp.get_UncommonOptions(ckStr);

strVal = xmp.uncommonOptions();

xmp.put_UncommonOptions(strVal);
```

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

## Methods

### Xmp.AddArray

`Chilkat 11.7.0 · ckruby · Xmp · AddArray · method`

```ruby
# xml is a CkXml

# arrType is a string

# propName is a string

# values is a CkStringArray

status = xmp.AddArray(xml, arrType, propName, values);
```

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 true for success, false for failure.

### Xmp.AddNsMapping

`Chilkat 11.7.0 · ckruby · Xmp · AddNsMapping · method`

```ruby
# ns is a string

# uri is a string

xmp.AddNsMapping(ns, uri);
```

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.

### Xmp.AddSimpleInt

`Chilkat 11.7.0 · ckruby · Xmp · AddSimpleInt · method`

```ruby
# iXml is a CkXml

# propName is a string

# propVal is an integer

status = xmp.AddSimpleInt(iXml, propName, propVal);
```

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 true for success, false for failure.

### Xmp.AddSimpleStr

`Chilkat 11.7.0 · ckruby · Xmp · AddSimpleStr · method`

```ruby
# iXml is a CkXml

# propName is a string

# propVal is a string

status = xmp.AddSimpleStr(iXml, propName, propVal);
```

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 true for success, false for failure.

### Xmp.AddStructProp

`Chilkat 11.7.0 · ckruby · Xmp · AddStructProp · method`

```ruby
# iChilkatXml is a CkXml

# structName is a string

# propName is a string

# propValue is a string

status = xmp.AddStructProp(iChilkatXml, structName, propName, propValue);
```

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 true for success, false for failure.

### Xmp.Append

`Chilkat 11.7.0 · ckruby · Xmp · Append · method`

```ruby
# iXml is a CkXml

status = xmp.Append(iXml);
```

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 true for success, false for failure.

### Xmp.GetArray

`Chilkat 11.7.0 · ckruby · Xmp · GetArray · method`

```ruby
# returns a CkStringArray

# iXml is a CkXml

# propName is a string

ret_stringArray = xmp.GetArray(iXml, propName);
```

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

Returns `nil` on failure

### Xmp.GetEmbedded

`Chilkat 11.7.0 · ckruby · Xmp · GetEmbedded · method`

```ruby
# returns a CkXml

# index is an integer

ret_xml = xmp.GetEmbedded(index);
```

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

Returns `nil` on failure

### Xmp.GetProperty

`Chilkat 11.7.0 · ckruby · Xmp · GetProperty · method`

```ruby
# returns a CkXml

# iXml is a CkXml

# propName is a string

ret_xml = xmp.GetProperty(iXml, propName);
```

To be documented soon...

Returns `nil` on failure

### Xmp.GetSimpleInt

`Chilkat 11.7.0 · ckruby · Xmp · GetSimpleInt · method`

```ruby
# iXml is a CkXml

# propName is a string

retInt = xmp.GetSimpleInt(iXml, propName);
```

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

### Xmp.GetSimpleStr

`Chilkat 11.7.0 · ckruby · Xmp · GetSimpleStr · method`

```ruby
# iXml is a CkXml

# propName is a string

# outStr is a CkString (output)

status = xmp.GetSimpleStr(iXml, propName, outStr);

retStr = xmp.getSimpleStr(iXml, propName);
```

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.

### Xmp.GetStructPropNames

`Chilkat 11.7.0 · ckruby · Xmp · GetStructPropNames · method`

```ruby
# returns a CkStringArray

# iXml is a CkXml

# structName is a string

ret_stringArray = xmp.GetStructPropNames(iXml, structName);
```

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

### Xmp.GetStructValue

`Chilkat 11.7.0 · ckruby · Xmp · GetStructValue · method`

```ruby
# iXml is a CkXml

# structName is a string

# propName is a string

# outStr is a CkString (output)

status = xmp.GetStructValue(iXml, structName, propName, outStr);

retStr = xmp.getStructValue(iXml, structName, propName);
```

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.

### Xmp.LoadAppFile

`Chilkat 11.7.0 · ckruby · Xmp · LoadAppFile · method`

```ruby
# filename is a string

status = xmp.LoadAppFile(filename);
```

Loads a TIFF or JPG file into the XMP object.

Returns true for success, false for failure.

### Xmp.NewXmp

`Chilkat 11.7.0 · ckruby · Xmp · NewXmp · method`

```ruby
# returns a CkXml

ret_xml = xmp.NewXmp();
```

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

Returns `nil` on failure

### Xmp.RemoveAllEmbedded

`Chilkat 11.7.0 · ckruby · Xmp · RemoveAllEmbedded · method`

```ruby
status = xmp.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.

### Xmp.RemoveArray

`Chilkat 11.7.0 · ckruby · Xmp · RemoveArray · method`

```ruby
# iXml is a CkXml

# propName is a string

status = xmp.RemoveArray(iXml, propName);
```

Removes an XMP array property from the XMP document.

Returns true for success, false for failure.

### Xmp.RemoveEmbedded

`Chilkat 11.7.0 · ckruby · Xmp · RemoveEmbedded · method`

```ruby
# index is an integer

status = xmp.RemoveEmbedded(index);
```

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.

### Xmp.RemoveNsMapping

`Chilkat 11.7.0 · ckruby · Xmp · RemoveNsMapping · method`

```ruby
# ns is a string

xmp.RemoveNsMapping(ns);
```

Removes a namespace-to-URI mapping.

### Xmp.RemoveSimple

`Chilkat 11.7.0 · ckruby · Xmp · RemoveSimple · method`

```ruby
# iXml is a CkXml

# propName is a string

status = xmp.RemoveSimple(iXml, propName);
```

Removes a simple XMP property from the XMP document.

Returns true for success, false for failure.

### Xmp.RemoveStruct

`Chilkat 11.7.0 · ckruby · Xmp · RemoveStruct · method`

```ruby
# iXml is a CkXml

# structName is a string

status = xmp.RemoveStruct(iXml, structName);
```

Removes an XMP structure property from the XMP document.

Returns true for success, false for failure.

### Xmp.RemoveStructProp

`Chilkat 11.7.0 · ckruby · Xmp · RemoveStructProp · method`

```ruby
# iXml is a CkXml

# structName is a string

# propName is a string

status = xmp.RemoveStructProp(iXml, structName, propName);
```

Removes a single member from an XMP structured property.

Returns true for success, false for failure.

### Xmp.SaveAppFile

`Chilkat 11.7.0 · ckruby · Xmp · SaveAppFile · method`

```ruby
# filename is a string

status = xmp.SaveAppFile(filename);
```

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 true for success, false for failure.

## Deprecated members — do not use in new code

| Member | Kind | Deprecated in | Use instead |
|---|---|---|---|
| `LoadFromBuffer` | method | before 11.6.1 | — |
| `SaveToBuffer` | method | before 11.6.1 | — |

## Related classes

[`StringArray`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/ckruby/classes/StringArray.md), [`Xml`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/ckruby/classes/Xml.md)