# LV2 Morph

http://lv2plug.in/ns/ext/morph
Ports that can dynamically change type.

Version | 1.0
Date | 2018-03-16
Discuss | devel@lists.lv2plug.in (subscribe)
Developer | David Robillard

- Index
- Reference
- History
- API

This extension defines two port types: morph:MorphPort, which has a host-configurable type, and morph:AutoMorphPort, which may automatically change type when a MorphPort's type is changed. These ports always have a default type and work normally work in hosts that are unaware of this extension. Thus, this extension provides a backwards compatibility mechanism which allows plugins to use new port types but gracefully fall back to a default type in hosts that do not support them.

This extension only defines port types and properties for describing morph ports. The actual run-time switching is done via the opts:interface API.

## Index

Classes | Properties | Files
--- | --- | ---
AutoMorphPort MorphPort | currentType supportsType | lv2-morph.doap.ttl morph.h morph.ttl

## Reference

### Class morph:AutoMorphPort

Auto Morph Port

Ports of this type MUST have another type which defines the default buffer format (e.g. lv2:ControlPort) but may dynamically change types based on the configured types of any morph:MorphPort ports on the same plugin instance.

The type of a port may only change in response to a host call to LV2_Options_Interface::set(). Whenever any port type on the instance changes, the host MUST check the type of all morph:AutoMorphPort ports with LV2_Options_Interface::get() before calling run() again, since they may have changed. If the type of any port is zero, it means the current configuration is invalid and the plugin may not be run (unless that port is lv2:connectionOptional and connected to NULL).

This is mainly useful for outputs whose type depends on the type of corresponding inputs.

Sub-class of | lv2:Port

### Class morph:MorphPort

Morph Port

Ports of this type MUST have another type which defines the default buffer format (e.g. lv2:ControlPort) but can be dynamically changed to a different type in hosts that support opts:interface.

The host may change the type of a MorphPort by setting its morph:currentType with LV2_Options_Interface::set(). If the plugin has any morph:AutoMorphPort ports, the host MUST check their types after changing any port type since they may have changed.

Sub-class of | lv2:Port
In domain of | morph:supportsType
| morph:currentType

### Property morph:currentType

current type

The currently active type of the port. This is for dynamic use as an option and SHOULD NOT be listed in the static plugin data.

OWL Type | Object Property
Domain | morph:MorphPort

### Property morph:supportsType

supports type

Indicates that a port supports being switched to a certain type. A MorphPort MUST list each type it supports being switched to in the plugin data using this property.

OWL Type | Object Property
Domain | morph:MorphPort

## History

Version 1.0 (2012-10-14)
  - Initial release.