===== The Element ===== ==== Definition and Usage ==== The [[regionbase|]] element groups a set of [[region|]] elements, each of which may contain another set of nested [[region|]] elements, and so on, recursively. Each [[regionbase|]] element is associated with a class of devices where presentation will take place. To identify the association, the [[regionbase|]] element defines the //device// attribute. When the attribute is not specified, the presentation takes place in the same device that runs the NCL player. There are two different types of device classes: active and passive. In an active class, a device is able to run some media players for [[media|]] element presentations. In a passive class, a device is not required to run media players, only to exhibit a bit map or a sequence of audio samples received from another device. The "deviceClass" property of a [[media|]] element is initialized with the //device// value, if the [[media|]] element indirectly refers to a [[region|]] element inside a [[regionbase|]], by using a [[descriptor|]] element. The chosen class also defines the global environment variables (properties of the settings object ---[[media|]] element of "application/x-ncl-settings" type): "system.screenSize(i)", "system.screenGraphicSize(i)", and "system.audioType(i)". The "systemScreen(1)" and "systemAudio(1)" are reserved to passive classes, and "systemScreen(2)" and "systemAudio(2)" are reserved to active classes. The [[regionbase|]] element that defines a passive class may also have a region attribute. This attribute is used to identify a [[region|]] element in another [[regionbase|]] associated with the parent device that creates the bit map sent to the passive class; in the specified region the bit map must also be exhibited. The "system.parentDeviceRegion(i)" property of the settings object ([[media|]] element of "application/x-ncl-settings" type) is initialized with the //region// attribute value. ==== Syntax ==== ^ Element ^ Attributes ^ Content ^ Parent ^ | [[regionbase|]] | //id//, //device//, //region// | ([[importbase|]] | [[region|]])+ | [[head|]] | ==== Attributes ==== ^ Name ^ Value ^ Description ^ | //id// | It may receive any string value that begins with a letter or an underscore and that only contains letters, digits, <".">, and <"_">. | The //id// attribute uniquely identifies the element within a document. | | //device// | "systemScreen(i)" or "systemAudio(i)". Where the attribute is not specified, the presentation shall take place in the same device class that runs the NCL player. | The //device// attribute identifies the class of devices where presentation will take place. | | //region// | IDREF. | The //region// attribute identify a [[region|]] element in another [[regionbase|]] associated with the parent device that creates the bit map sent to the passive class; in the specified region the bitmap must also be exhibited. |