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Metadata means "data about data." Metadata is defined as the data providing information about one or more aspects of the data; it is used to summarize basic information about data which can make tracking and working with specific data easier. In the context of digital ink, there are several relevant items of information that need to be shared:

  • Means of creation of the data
  • Purpose of the data
  • Time and date of creation
  • Creator or author of the data
  • Context where the data was created
  • The ink capturing environment where it has been created, such as operating system (OS), firmware of the Input Device
  • Data quality
  • Source of the data


The Property is simple key-value pair and a list of properties can be assign to several Universal Ink Model structures.

Remarks: A Property instance is serialized according to section 8.2 Protocol Buffers Serialization Scheme using the protobuf message Property.


The properties which can be used to describe the Environment where the ink is recorded:

  • - Name of the operating system
  • - Name of the version
  • os.version.release - Release build number
  • - Name of the Wacom Ink technology
  • - Version number of the SDK


The properties which can be used to describe the InkInputProvider:

  • pen.type - Type of the pen device


The properties which can be used to describe the InputDevice:

  • - ID of the input device
  • dev.manufacturer - Manufacturer of the input device
  • dev.model - Model of the input device
  • dev.codename - Code name


The properties which can be used to describe the InkObject:

  • model.created - Creation time of model
  • model.last_modified - Last time the model has been modified
  • model.content.type - Description of the type of content, such as 'notes', 'sketch'

Notice: There is no pre-defined schema for the property keys yet. The key values are only examples.