sfizz/lv2/lv2/ui/ui.ttl

@prefix lv2:  <http://lv2plug.in/ns/lv2core#> .
@prefix owl:  <http://www.w3.org/2002/07/owl#> .
@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix ui:   <http://lv2plug.in/ns/extensions/ui#> .
@prefix xsd:  <http://www.w3.org/2001/XMLSchema#> .

<http://lv2plug.in/ns/extensions/ui>
	a owl:Ontology ;
	owl:imports <http://lv2plug.in/ns/lv2core> ;
	rdfs:seeAlso <ui.h> ,
		<lv2-ui.doap.ttl> ;
	lv2:documentation """
<p>This extension is used to create User Interfaces (UIs) for LV2 plugins.</p>

<p>UIs are implemented as an LV2UI_Descriptor loaded via lv2ui_descriptor() in
a shared library, and are distributed in bundles just like plugins.</p>

<p>UIs are associated with plugins in data:</p>

<pre class="turtle-code">
@prefix ui: &lt;http://lv2plug.in/ns/extensions/ui#&gt; .

&lt;http://my.plugin&gt;   ui:ui     &lt;http://my.pluginui&gt; .
&lt;http://my.pluginui&gt; a         ui:GtkUI ;
                     ui:binary &lt;myui.so&gt; .
</pre>

<p>where &lt;http://my.plugin&gt; is the URI of the plugin,
&lt;http://my.pluginui&gt; is the URI of the plugin UI and &lt;myui.so&gt; is
the relative URI to the shared object file.</p>

<p>While it is possible to have the plugin UI and the plugin in the same shared
object file it is probably a good idea to keep them separate so that hosts that
don't want UIs don't have to load the UI code.  A UI MUST specify its class in
the RDF data (ui:GtkUI in the above example). The class defines what type the
UI is, e.g. what graphics toolkit it uses.  Any type of UI class can be defined
separately from this extension.</p>

<p>It is possible to have multiple UIs for the same plugin, or to have the UI
for a plugin in a different bundle from the actual plugin - this way people
other than the plugin author can write plugin UIs independently without editing
the original plugin bundle.</p>

<p>Note that the process that loads the shared object file containing the UI
code and the process that loads the shared object file containing the actual
plugin implementation are not necessarily the same process (and not even
necessarily on the same machine).  This means that plugin and UI code MUST NOT
use singletons and global variables and expect them to refer to the same
objects in the UI and the actual plugin. The function callback interface
defined in this header is the only method of communication between UIs and
plugin instances (extensions may define more, though this is discouraged unless
absolutely necessary since the significant benefits of network transparency and
serialisability are lost).</p>

<p>UI functionality may be extended via features, much like plugins:</p>

<pre class="turtle-code">
&lt;http://my.pluginui&gt; lv2:requiredFeature &lt;http://my.feature&gt; .
&lt;http://my.pluginui&gt; lv2:optionalFeature &lt;http://my.feature&gt; .
</pre>

<p>The rules for a UI with a required or optional feature are identical to
those of lv2:Plugin instances: if a UI declares a feature as required, the host
is NOT allowed to load it unless it supports that feature; and if it does
support a feature, it MUST pass an appropriate LV2_Feature struct to the UI's
instantiate() method.  This extension defines several standard features for
common functionality.</p>

<p>UIs written to this specification do not need to be thread-safe.  All
functions may only be called in the <q>UI thread</q>.  There is only one UI
thread (for toolkits, the one the UI main loop runs in).  There is no
requirement that a <q>UI</q> actually be a graphical widget.</p>

<p>Note that UIs are completely separate from plugins.  From the plugin's
perspective, control from a UI is indistinguishable from any other control, as
it all occcurs via ports.</p>
""" .

ui:UI
	a rdfs:Class ,
		owl:Class ;
	rdfs:label "User Interface" ;
	rdfs:comment "A UI for an LV2 plugin" .

ui:GtkUI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "GTK2 UI" ;
	rdfs:comment """A UI where the LV2_Widget is a pointer to a Gtk+ 2.0 compatible GtkWidget, and the host guarantees that the Gtk+ library has been initialised and the Glib main loop is running before a UI of this type is instantiated.""" .

ui:Gtk3UI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "GTK3 UI" ;
	rdfs:comment """A UI where the LV2_Widget is a pointer to a Gtk+ 3.0 compatible GtkWidget, and the host guarantees that the Gtk+ library has been initialised and the Glib main loop is running before a UI of this type is instantiated.""" .

ui:Qt4UI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "Qt4 UI" ;
	rdfs:comment """A UI where the LV2_Widget is a pointer to a Qt4 compatible QWidget, and the host guarantees that the Qt4 library has been initialised and the Qt4 main loop is running before a UI of this type is instantiated.""" .

ui:Qt5UI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "Qt5 UI" ;
	rdfs:comment """A UI where the LV2_Widget is a pointer to a Qt5 compatible QWidget, and the host guarantees that the Qt5 library has been initialised and the Qt5 main loop is running before a UI of this type is instantiated.""" .

ui:X11UI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "X11 UI" ;
	rdfs:comment """A UI where the LV2_Widget is an X11 window ID.  Note this is actually an integer, i.e. the LV2_Widget is not a pointer to an X11 window ID, but should be itself taken as an integer value.  This is the native UI type on most POSIX systems.""" .

ui:WindowsUI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "Windows UI" ;
	rdfs:comment """A UI where the LV2_Widget is a Windows HWND window ID.  Note this is actually an unsigned 32-bit integer, i.e. the LV2_Widget is not a pointer to a HWND but should be interpreted as an HWND itself.  This is the native UI type on Microsoft Windows.""" .

ui:CocoaUI
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf ui:UI ;
	rdfs:label "Cocoa UI" ;
	rdfs:comment """A UI where the LV2_Widget is a pointer to a NSView, the basic view type for the Cocoa API (formerly OpenStep).  This is the native UI type on Mac OS X.""" .

ui:ui
	a rdf:Property ;
	rdfs:domain lv2:Plugin ;
	rdfs:range ui:UI ;
	rdfs:label "user interface" ;
	rdfs:comment """Relates a plugin to a UI that applies to it.""" .

ui:binary
	a rdf:Property ;
	owl:sameAs lv2:binary ;
	owl:deprecated "true"^^xsd:boolean ;
	rdfs:label "binary" ;
	rdfs:comment """The shared library a UI resides in.  This property is redundant, new UIs SHOULD use lv2:binary, however hosts MUST still support ui:binary at this time.""" .

ui:makeSONameResident
	a lv2:Feature ;
	owl:deprecated "true"^^xsd:boolean ;
	lv2:documentation """
<p>DEPRECATED</p>

<p>This feature was intended to support UIs that link against toolkit
libraries which may not be unloaded during the lifetime of the host.
This is better achieved by using the appropriate flags when linking the
UI, e.g. <code>gcc -Wl,-z,nodelete</code>.</p>
""" .

ui:noUserResize
	a lv2:Feature ;
	lv2:documentation """
<p>If a UI requires this feature it indicates that it does not make sense
to let the user resize the main widget, and the host should prevent that.
This feature may not make sense for all UI types. The data pointer for the
LV2_Feature for this feature should always be set to NULL.</p>
""" .

ui:fixedSize
	a lv2:Feature ;
	lv2:documentation """
<p>If a UI requires this feature it indicates the same thing as
ui:noUserResize, and additionally it means that the UI will not resize
the main widget on its own - it will always remain the same size (e.g. a
pixmap based GUI). This feature may not make sense for all UI types.
The data pointer for the LV2_Feature for this feature should always be set
to NULL.</p>
""" .

ui:parent
	a lv2:Feature ;
	lv2:documentation """
<p>The parent for the UI.</p>

<p>This feature can be used to pass a parent (e.g. a widget, container, canvas,
etc.) the UI should be a child of.  The format of data pointer of this feature
is determined by the UI type, and is generally the same type as the LV2_Widget
the UI would return (e.g. for a GtkUI the data would be a pointer to a
GtkWidget which is a GtkContainer).  This is particularly useful for
cross-toolkit embedding, where the parent often must be known at construction
time for embedding to work correctly.  UIs should not require this feature
unless it is absolutely necessary for them to work at all.</p>
""" .

ui:PortNotification
	a rdfs:Class ,
		owl:Class ;
	rdfs:subClassOf [
		a owl:Restriction ;
		owl:onProperty ui:plugin ;
		owl:cardinality 1 ;
		rdfs:comment "A PortNotification MUST have exactly one ui:plugin." ;
	] ;
	lv2:documentation """
<p>A port notification.  This describes which ports the host must send
notifications to the UI about.  The port can be specific by index, using the
ui:portIndex property, or symbol, using the lv2:symbol property.  Since port
indices are not guaranteed to be stable between different revisions (or even
instantiations) of a plugin, symbol is recommended, and index may only be used
by UIs shipped in the same bundle as the plugin.</p>

<p>A ui:PortNotification MUST have either a ui:portIndex or a lv2:symbol to
indicate which port it refers to.</p>
""" .

ui:portNotification
	a rdf:Property ,
		owl:ObjectProperty ;
	rdfs:domain ui:UI ;
	rdfs:range ui:PortNotification ;
	rdfs:label "port notification" ;
	lv2:documentation """
<p>Indicates that a UI should receive notification (via
LV2UI_Descriptor::port_event()) when a particular port's value changes.</p>

<p>For example:</p>
<pre class="turtle-code">
eg:ui
    a ui:GtkUI ;
    ui:portNotification [
        ui:plugin eg:plugin ;
        lv2:symbol "gain" ;
        ui:protocol ui:floatProtocol
    ] .
</pre>
""" .

ui:plugin
	a rdf:Property ,
		owl:ObjectProperty ;
	rdfs:domain ui:PortNotification ;
	rdfs:range lv2:Plugin ;
	rdfs:label "plugin" ;
	rdfs:comment "The plugin a portNotification applies to." .

ui:portIndex
	a rdf:Property ,
		owl:DatatypeProperty ;
	rdfs:domain ui:PortNotification ;
	rdfs:range xsd:decimal ;
	rdfs:label "port index" ;
	rdfs:comment "The index of the port a portNotification applies to." .

ui:notifyType
	a rdf:Property ;
	rdfs:domain ui:PortNotification ;
	rdfs:label "notify type" ;
	lv2:documentation """
<p>Indicates a particular type that the UI should be notified of.  In the case
of ports where several types of data can be present (e.g. event ports), this
can be used to indicate that only a particular type of data should cause
notification.  This is useful where port traffic is very dense, but only a
certain small number of events are actually of interest to the UI.</p>
""" .

ui:resize
	a lv2:Feature ,
		lv2:ExtensionData ;
	lv2:documentation """
<p>A feature that allows the UI to notify the host about its current size, or
request a size change.  This feature corresponds to the LV2UI_Resize struct,
which should be passed with the URI LV2_UI__resize.  This struct may also be
provided by the UI as extension data using the same URI, in which case it is
used by the host to request that the UI change its size.</p>
""" .

ui:portMap
	a lv2:Feature ;
	lv2:documentation """
<p>A feature for accessing the index of a port by symbol.  This makes it
possible to implement and distribute UIs separately from the plugin binaries
they control.  This feature corresponds to the LV2UI_Port_Index struct, which
should be passed with the URI LV2_UI__portIndex.</p>
""" .

ui:portSubscribe
	a lv2:Feature ;
	lv2:documentation """
<p>A feature for dynamically subscribing to updates from a port.  This makes it
possible for a UI to explicitly request a particular style of update from a
port at run-time, in a more flexible and powerful way than listing
subscriptions statically allows.  This feature corresponds to the
LV2UI_Port_Subscribe struct, which should be passed with the URI
LV2_UI__portSubscribe.</p>
""" .

ui:touch
	a lv2:Feature ;
	lv2:documentation """
<p>A feature to notify the host that the user has grabbed a particular port
control.  This is useful for automation, so the host can allow the user to take
control of a port, even if that port would otherwise be automated (much like
grabbing a physical morotised fader).  It can also be used for MIDI learn or in
any other situation where the host needs to do something with a particular
control and it would be convenient for the user to select it directly from the
plugin UI.  This feature corresponds to the LV2UI_Touch struct, which
should be passed with the URI LV2_UI__touch.</p>
""" .

ui:idleInterface
	a lv2:Feature ,
		lv2:ExtensionData ;
	lv2:documentation """
<p>A feature that provides a callback for the host to call rapidly to drive the
UI.  To support this feature, the UI should list it as a lv2:optionalFeature or
lv2:requiredFeature in its data, and also as lv2:extensionData.  When the UI's
extension_data() is called with this URI (LV2_UI__idleInterface), it should
return a pointer to an LV2UI_Idle_Interface.</p>

<p>To indicate support, the host should pass a feature to instantiate() with
this URI, with NULL for data.</p>
""" .

ui:showInterface
	a lv2:ExtensionData ;
	lv2:documentation """
<p>An interface for showing and hiding a window for a UI.  This allows UIs to
gracefully degrade to separate windows when the host is unable to embed the UI
widget for whatever reason.  When the UI's extension_data() is called with this
URI (LV2_UI__showInterface), it should return a pointer to an
LV2UI_Show_Interface.</p>
""" .

ui:windowTitle
	a rdf:Property ;
	rdfs:range xsd:string ;
	rdfs:label "window title" ;
	rdfs:comment "The title for the window shown by LV2UI_Show_Interface." .

ui:updateRate
	a rdf:Property ;
	rdfs:range xsd:float ;
	rdfs:label "update rate" ;
	rdfs:comment "The target rate, in Hz, to send updates to the UI." .

ui:protocol
	a rdf:Property ;
	rdfs:domain ui:PortNotification ;
	rdfs:range ui:PortProtocol ;
	rdfs:label "protocol" ;
	rdfs:comment "The protocol to be used for this notification." .

ui:PortProtocol
	a rdfs:Class ;
	rdfs:subClassOf lv2:Feature ;
	rdfs:label "Port Protocol" ;
	lv2:documentation """
<p>A PortProtocol defines a method to communicate port data between a UI and
plugin.</p>

<p>Any PortProtocol MUST define:</p>
<table>
<tr><th>Port Type</th>
    <td>Which plugin port types the buffer type is valid for.</td></tr>
<tr><th>Feature Data</th>
    <td>What data (if any) should be passed in the LV2_Feature.</td></tr>
</table>

<p>Any PortProtocol for an output port MUST define:</p>
<table>
<tr><th>Update Frequency</th>
    <td>When the host should call port_event().</td></tr>
<tr><th>Update Format</th>
    <td>The format of the data in the buffer passed to port_event().</td></tr>
<tr><th>Options</th>
    <td>The format of the options passed to subscribe() and unsubscribe().</td>
</tr></table>

<p>Any PortProtocol for an input port MUST define:</p>
<table>
<tr><th>Write Format</th>
    <td>The format of the data in the buffer passed to write_port().</td></tr>
<tr><th>Write Effect</th>
    <td>What happens when the UI calls write_port().</td></tr>
</table>

<p>For an example, see ui:floatProtocol or ui:peakProtocol.
</p>

<p>PortProtocol is a subclass of lv2:Feature, so UIs use lv2:optionalFeature and
lv2:requiredFeature to specify which PortProtocols they want to use.
</p>
""" .

ui:floatProtocol
	a ui:PortProtocol ;
	rdfs:label "floating point value" ;
	lv2:documentation """

<p>A protocol for transferring single floating point values.  The rules for
this protocol are:</p>
<table>
<tr><th>Port Type</th>
    <td>lv2:ControlPort</td></tr>
<tr><th>Feature Data</th>
    <td>None.</td></tr>
<tr><th>Update Frequency</th>
    <td>The host SHOULD call port_event() as soon as possible when the port
    value has changed, but there are no timing guarantees.</td></tr>
<tr><th>Update Format</th>
    <td>A single <code>float</code>.</td></tr>
<tr><th>Options</th>
    <td>None.</td></tr>
<tr><th>Write Format</th>
    <td>A single <code>float</code>.</td></tr>
<tr><th>Write Effect</th>
    <td>The host SHOULD set the port to the received value as soon as possible,
    but there is no guarantee that run() actually sees this value.</td></tr>
</table>
""" .

ui:peakProtocol
	a ui:PortProtocol ;
	rdfs:label "peak measurement for a period of audio" ;
	lv2:documentation """
<p>This port protocol defines a way for the host to send continuous peak
measurements of the audio signal at a certain port to the UI.  The
intended use is visualisation, e.g. an animated meter widget that shows
the level of the audio input or output.</p>

<p>A contiguous sequence of audio samples for which a peak value has been
computed is called a <em>measurement period</em>.</p>

<p>The rules for this protocol are:</p>
<table>
<tr><th>Port Type</th>
    <td>lv2:AudioPort</td></tr>
<tr><th>Feature Data</th>
    <td>None.</td></tr>
<tr><th>Update Frequency</th>
    <td>The host SHOULD call port_event() at regular intervals.  The
    measurement periods used for calls to port_event() for the same port SHOULD
    be contiguous (i.e. the measurement period for one call should begin right
    after the end of the measurement period for the previous call ends) unless
    the UI has removed and re-added the port subscription between those calls.
    However, UIs MUST NOT depend on either the regularity of the calls or the
    contiguity of the measurement periods; hosts may change the call rate or
    skip calls for performance or other reasons.  Measurement periods for
    different calls to port_event() for the same port MUST NOT
    overlap.</td></tr>
<tr><th>Update Format</th>
    <td>A single LV2UI_Peak_Data object.</td></tr>
<tr><th>Options</th>
    <td>None.</td></tr>
<tr><th>Write Format</th>
    <td>None.</td></tr>
<tr><th>Write Effect</th>
    <td>None.</td></tr>
</table>
""" .