From 49329abcdbecdcd1cefcac9d73e9a14df5c14798 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Thu, 17 Jan 2008 19:36:50 +0000 Subject: Update LV2 UI header. git-svn-id: http://svn.drobilla.net/lad/slv2@1066 a436a847-0d15-0410-975c-d299462d15a1 --- slv2/lv2_ui.h | 304 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 304 insertions(+) create mode 100644 slv2/lv2_ui.h (limited to 'slv2/lv2_ui.h') diff --git a/slv2/lv2_ui.h b/slv2/lv2_ui.h new file mode 100644 index 0000000..744a71c --- /dev/null +++ b/slv2/lv2_ui.h @@ -0,0 +1,304 @@ +/************************************************************************ + * + * In-process UI extension for LV2 + * + * Copyright (C) 2006-2007 Lars Luthman + * + * Based on lv2.h, which was + * + * Copyright (C) 2000-2002 Richard W.E. Furse, Paul Barton-Davis, + * Stefan Westerfeld + * Copyright (C) 2006 Steve Harris, Dave Robillard. + * + * This header is free software; you can redistribute it and/or modify it + * under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, + * or (at your option) any later version. + * + * This header is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 + * USA. + * + ***********************************************************************/ + +/** @file + This extension defines an interface that can be used in LV2 plugins and + hosts to create UIs for plugins. The UIs are plugins that reside in + shared object files in an LV2 bundle and are referenced in the RDF data + using the triples (Turtle shown) +
    
+    @@prefix uiext:  .
+        uiext:ui      .
+        a            uiext:GtkUI .
+      uiext:binary  .
+
+ where is the URI of the plugin, is + the URI of the plugin UI and is the relative URI to the shared + object file. 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. In this case the class is + uiext:GtkUI, which is the only class defined by this extension. + + (Note: the prefix above is used throughout this file for the same URI) + + It's entirely 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. + + 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 does not have to be the same. There are many + valid reasons for having the plugin and the UI in different processes, or + even on different machines. This means that you can _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 all you can expect to work. + + Since the LV2 specification itself allows for extensions that may add + new types of data and configuration parameters that plugin authors may + want to control with a UI, this extension allows for meta-extensions that + can extend the interface between the UI and the host. These extensions + mirror the extensions used for plugins - there are required and optional + "features" that you declare in the RDF data for the UI as +
    
+     uiext:requiredFeature  .
+     uiext:optionalFeature  .
+
+ These predicates have the same semantics as lv2:requiredFeature and + lv2:optionalFeature - if a UI is declaring a feature as required, the + host is NOT allowed to load it unless it supports that feature, and if it + does support a feature (required or optional) it MUST pass that feature's + URI and any additional data (specified by the meta-extension that defines + the feature) to the UI's instantiate() function. + + These features may be used to specify how to pass data between the UI + and the plugin port buffers - see LV2UI_Write_Function for details. + + UIs written to this specification do not need to be threadsafe - the + functions defined below may only be called in the same thread as the UI + main loop is running in. + + Note that this UI extension is NOT a lv2:Feature. There is no way for a + plugin to know whether the host that loads it supports UIs or not, and + the plugin must ALWAYS work without the UI (although it may be rather + useless unless it has been configured using the UI in a previous session). + + A UI does not have to be a graphical widget, it could just as well be a + server listening for OSC input or an interface to some sort of hardware + device, depending on the RDF class of the UI. +*/ + +#ifndef LV2_IPUI_H +#define LV2_IPUI_H + +#include "lv2.h" + + +#ifdef __cplusplus +extern "C" { +#endif + + +/** A pointer to some widget or other type of UI handle. + The actual type is defined by the type URI of the UI, e.g. if + " a uiext:GtkUI", this is a pointer + to a GtkWidget compatible with GTK+ 2.0 and the UI can expect the GTK+ + main loop to be running during the entire lifetime of all instances of that + UI. All the functionality provided by this extension is toolkit + independent, the host only needs to pass the necessary callbacks and + display the widget, if possible. Plugins may have several UIs, in various + toolkits, but uiext:GtkUI is the only type that is defined in this + extension. */ +typedef void* LV2UI_Widget; + + +/** A pointer to some host data required to instantiate a UI. + Like the type of the widget, the actual type of this pointer is defined by + the type URI of the UI. Hosts can use this to pass toolkit specific data + to a UI it needs to instantiate (type map, drawing context, etc). For the + uiext:GtkUI type this should be NULL. */ +typedef void* LV2UI_Host_Data; + + +/** This handle indicates a particular instance of a UI. + It is valid to compare this to NULL (0 for C++) but otherwise the + host MUST not attempt to interpret it. The UI plugin may use it to + reference internal instance data. */ +typedef void* LV2UI_Handle; + + +/** This handle indicates a particular plugin instance, provided by the host. + It is valid to compare this to NULL (0 for C++) but otherwise the + UI plugin MUST not attempt to interpret it. The host may use it to + reference internal plugin instance data. */ +typedef void* LV2UI_Controller; + + +/** This is the type of the host-provided function that the UI can use to + send data to a plugin's input ports. The @c buffer parameter must point + to a block of data, @c buffer_size bytes large. The contents of this buffer + will depend on the class of the port it's being sent to, and the transfer + mechanism specified for that port class. + + Transfer mechanisms are Features and may be defined in meta-extensions. + They specify how to translate the data buffers passed to this function + to input data for the plugin ports. If a UI wishes to write data to an + input port, it must list a transfer mechanism Feature for that port's + class as an optional or required feature (depending on whether the UI + will work without being able to write to that port or not). The only + exception is ports of the class lv2:ControlPort, for which @c buffer_size + should always be 4 and the buffer should always contain a single IEEE-754 + float. + + The UI MUST NOT try to write to a port for which there is no specified + transfer mechanism, or to an output port. The UI is responsible for + allocating the buffer and deallocating it after the call. A function + pointer of this type will be provided to the UI by the host in the + instantiate() function. */ +typedef void (*LV2UI_Write_Function)(LV2UI_Controller controller, + uint32_t port_index, + uint32_t buffer_size, + const void* buffer); + + +/** */ +typedef struct _LV2UI_Descriptor { + + /** The URI for this UI (not for the plugin it controls). */ + const char* URI; + + /** Create a new UI object and return a handle to it. This function works + similarly to the instantiate() member in LV2_Descriptor. + + @param descriptor The descriptor for the UI that you want to instantiate. + @param plugin_uri The URI of the plugin that this UI will control. + @param bundle_path The path to the bundle containing the RDF data file + that references this shared object file, including the + trailing '/'. + @param write_function A function provided by the host that the UI can + use to send data to the plugin's input ports. + @param controller A handle for the plugin instance that should be passed + as the first parameter of @c write_function. + @param host_data Data required from the host for instantiation. + The type of this depends on the RDF class of the UI. + If the UI type does not specify anything to be passed + here, the host should pass NULL. + @param widget A pointer to an LV2UI_Widget. The UI will write a + widget pointer to this location (what type of widget + depends on the RDF class of the UI) that will be the + main UI widget. + @param features An array of LV2_Feature pointers. The host must pass + all feature URIs that it and the plugin supports and any + additional data, just like in the LV2 plugin + instantiate() function. + */ + LV2UI_Handle (*instantiate)(const struct _LV2UI_Descriptor* descriptor, + const char* plugin_uri, + const char* bundle_path, + LV2UI_Write_Function write_function, + LV2UI_Controller controller, + LV2UI_Host_Data host_data, + LV2UI_Widget* widget, + const LV2_Feature* const* features); + + + /** Destroy the UI object and the associated widget. The host must not try + to access the widget after calling this function. + */ + void (*cleanup)(LV2UI_Handle ui); + + /** Tell the UI that something interesting has happened at a plugin port. + What is interesting and how it is written to the buffer passed to this + function is defined by the specified transfer mechanism for that port + class (see LV2UI_Write_Function). The only exception is ports of the + class lv2:ControlPort, for which this function should be called + when the port value changes (it must not be called for every single + change if the host's UI thread has problems keeping up with the thread + the plugin is running in), @c buffer_size should be 4 and the buffer + should contain a single IEEE-754 float. + + By default, the host should only call this function for input ports of + the lv2:ControlPort class. However, the default setting can be modified + by using the following URIs in the UI's RDF data: + 
+      uiext:portNotification
+      uiext:noPortNotification
+      uiext:plugin
+      uiext:portIndex
+
+ For example, if you want the UI with uri + for the plugin with URI + to get notified when the value of the + output control port with index 4 changes, you would use the following + in the RDF for your UI: + 
+       uiext:portNotification [ uiext:plugin  ;
+                                                      uiext:portIndex 4 ] .
+
+ and similarly with uiext:noPortNotification if you wanted + to prevent notifications for a port for which it would be on by default + otherwise. The UI is not allowed to request notifications for ports + for which no transfer mechanism is specified, if it does it should be + considered broken and the host should not load it. + + The @c buffer is only valid during the time of this function call, so if + the UI wants to keep it for later use it has to copy the contents to an + internal buffer. + + This member may be set to NULL if the UI is not interested in any + port events. + */ + void (*port_event)(LV2UI_Handle ui, + uint32_t port, + uint32_t buffer_size, + const void* buffer); + + /** Returns a data structure associated with an extension URI, for example + a struct containing additional function pointers. Avoid returning + function pointers directly since standard C++ has no valid way of + casting a void* to a function pointer. This member may be set to NULL + if the UI is not interested in supporting any extensions. This is similar + to the extension_data() member in LV2_Descriptor. + */ + const void* (*extension_data)(const char* uri); + +} LV2UI_Descriptor; + + + +/** A plugin UI programmer must include a function called "lv2ui_descriptor" + with the following function prototype within the shared object + file. This function will have C-style linkage (if you are using + C++ this is taken care of by the 'extern "C"' clause at the top of + the file). This function will be accessed by the UI host using the + @c dlsym() function and called to get a LV2UI_UIDescriptor for the + wanted plugin. + + Just like lv2_descriptor(), this function takes an index parameter. The + index should only be used for enumeration and not as any sort of ID number - + the host should just iterate from 0 and upwards until the function returns + NULL, or a descriptor with an URI matching the one the host is looking for + is returned. +*/ +const LV2UI_Descriptor* lv2ui_descriptor(uint32_t index); + + +/** This is the type of the lv2ui_descriptor() function. */ +typedef const LV2UI_Descriptor* (*LV2UI_DescriptorFunction)(uint32_t index); + + + +#ifdef __cplusplus +} +#endif + + +#endif -- cgit v1.2.1