From 8cd3f1729a417d933744cf64e2adf78dc07e265c Mon Sep 17 00:00:00 2001 From: Bent Bisballe Nyeng Date: Mon, 23 Jan 2012 20:37:57 +0100 Subject: Make plugin store its state. Connect state and GUI (and use GUI) --- lv2/lv2_ui.h | 372 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 372 insertions(+) create mode 100644 lv2/lv2_ui.h (limited to 'lv2/lv2_ui.h') diff --git a/lv2/lv2_ui.h b/lv2/lv2_ui.h new file mode 100644 index 0000000..4be2c24 --- /dev/null +++ b/lv2/lv2_ui.h @@ -0,0 +1,372 @@ +/************************************************************************ + * + * In-process UI extension for LV2 + * + * Copyright (C) 2006-2008 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 uiext:GtkUI. The + class defines what type the UI is, e.g. what graphics toolkit it uses. + There are no UI classes defined in this extension, those are specified + separately (and anyone can define their own). + + (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) in a LV2_Feature struct (as defined in lv2.h) 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. + + There are four features defined in this extension that hosts may want to + implement: + +
+    uiext:makeResident
+
+ If this feature is required by a UI the host MUST NEVER unload the shared + library containing the UI implementation during the lifetime of the host + process (e.g. never calling dlclose() on Linux). This feature may be + needed by e.g. a Gtk UI that registers its own Glib types using + g_type_register_static() - if it gets unloaded and then loaded again the + type registration will break, since there is no way to unregister the + types when the library is unloaded. The data pointer in the LV2_Feature + for this feature should always be set to NULL. + +
+    uiext:makeSONameResident
+
+ This feature is ELF specific - it should only be used by UIs that + use the ELF file format for the UI shared object files (e.g. on Linux). + If it is required by an UI the UI should also list a number of SO names + (shared object names) for libraries that the UI shared object + depends on and that may not be unloaded during the lifetime of the host + process, using the predicate @c uiext:residentSONames, like this: +
+     uiext:residentSONames "libgtkmm-2.4.so.1", "libfoo.so.0"
+
+ The host MUST then make sure that the shared libraries with the given ELF + SO names are not unloaded when the plugin UI is, but stay loaded during + the entire lifetime of the host process. On Linux this can be accomplished + by calling dlopen() on the shared library file with that SO name and never + calling a matching dlclose(). However, if a plugin UI requires the + @c uiext:makeSONameResident feature, it MUST ALWAYS be safe for the host to + just never unload the shared object containing the UI implementation, i.e. + act as if the UI required the @c uiext:makeResident feature instead. Thus + the host only needs to find the shared library files corresponding to the + given SO names if it wants to save RAM by unloading the UI shared object + file when it is no longer needed. The data pointer for the LV2_Feature for + this feature should always be set to NULL. + +
+    uiext:noUserResize
+
+ If an 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. + +
+    uiext:fixedSize
+
+ If an UI requires this feature it indicates the same thing as + uiext: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. + + + 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_UI_H +#define LV2_UI_H + +#include + +#define LV2_UI_URI "http://lv2plug.in/ns/extensions/ui" + + +#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. + 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. */ +typedef void* LV2UI_Widget; + + +/** 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 + and what the host should do with it depends on the value of the @c format + parameter. + + The @c format parameter should either be 0 or a numeric ID for a "Transfer + mechanism". 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 when the UI wants to write single float values to + input ports of the class lv2:ControlPort, in which case @c buffer_size + should always be 4, the buffer should always contain a single IEEE-754 + float, and @c format should be 0. + + The numeric IDs for the transfer mechanisms are provided by a + URI-to-integer mapping function provided by the host, using the URI Map + feature with the map URI + "http://lv2plug.in/ns/extensions/ui". Thus a UI that requires transfer + mechanism features also requires the URI Map feature, but this is + implicit - the UI does not have to list the URI map feature as a required + or optional feature in it's RDF data. + + An UI MUST NOT pass a @c format parameter value (except 0) that has not + been returned by the host-provided URI mapping function for a + host-supported transfer mechanism feature URI. + + 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. +*/ +typedef void (*LV2UI_Write_Function)(LV2UI_Controller controller, + uint32_t port_index, + uint32_t buffer_size, + uint32_t format, + const void* buffer); + + +/** This struct contains the implementation of an UI. A pointer to an + object of this type is returned by the lv2ui_descriptor() function. +*/ +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 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 UI supports and any + additional data, just like in the LV2 plugin + instantiate() function. Note that UI features and plugin + features are NOT necessarily the same, they just share + the same data structure - this will probably not be the + same array as the one the plugin host passes to a + plugin. + */ + 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_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 @c format parameter, which has the same + meaning as in 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 does not have to 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. In this case the @c format + parameter should be 0. + + 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 of + types 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_index, + uint32_t buffer_size, + uint32_t format, + 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. +*/ +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 v1.2.3