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Diffstat (limited to 'slv2/lv2_gui.h')
| -rw-r--r-- | slv2/lv2_gui.h | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/slv2/lv2_gui.h b/slv2/lv2_gui.h new file mode 100644 index 0000000..696f20b --- /dev/null +++ b/slv2/lv2_gui.h @@ -0,0 +1,346 @@ +/************************************************************************ + * + * In-process UI extension for LV2 + * + * Copyright (C) 2006-2007 Lars Luthman <lars.luthman@gmail.com> + * + * Based on lv2.h, which is: + * + * 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 GUIs for plugins. The GUIs are plugins that reside in + shared object files in an LV2 bundle and be referenced in the RDF file + using the triples (Turtle shown) +<pre> + @prefix guiext: <http://ll-plugins.nongnu.org/lv2/ext/ipgui/1#> . + <http://my.plugin> guiext:gui <http://my.plugingui> . + <http://my.plugingui> guiext:binary <mygui.so> . +</pre> + where <http://my.plugin> is the URI of the plugin, <http://my.plugingui> is + the URI of the plugin GUI and <mygui.so> is the relative URI to the shared + object file. While it is possible to have the plugin GUI 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 GUIs don't have to load the GUI code. + + (Note: the prefix above is used throughout this file for the same URI) + + It's entirely possible to have multiple GUIs for the same plugin, or to have + the GUI for a plugin in a different bundle from the actual plugin - this + way people other than the plugin author can write plugin GUIs independently + without editing the original plugin bundle. If a GUI is in a separate bundle + the first triple above should be in that bundle's manifest.ttl file so that + hosts can find the GUI when scanning the manifests. + + Note that the process that loads the shared object file containing the GUI + 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 GUI 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 + GUI 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 GUI, this extension allows for meta-extensions that + can extend the interface between the GUI and the host. See the + instantiate() and extension_data() callback pointers for more details. + + Note that this extension is NOT a Host Feature. There is no way for a plugin + to know whether the host that loads it supports GUIs or not, and the plugin + must ALWAYS work without the GUI (although it may be rather useless unless + it has been configured using the GUI in a previous session). + + GUIs 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. +*/ + +#ifndef LV2_GUI_H +#define LV2_GUI_H + +#include "lv2.h" + + +#ifdef __cplusplus +extern "C" { +#endif + + +/** A pointer to some widget. + * The actual type of the widget is defined by the type URI of the GUI. + * e.g. if "<http://example.org/somegui> a guiext:GtkGUI", this is a pointer + * to a GtkWidget. 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 GUIs, + * in various toolkits. + */ +typedef void* LV2UI_Widget; + + +/** This handle indicates a particular instance of a GUI. + It is valid to compare this to NULL (0 for C++) but otherwise the + host MUST not attempt to interpret it. The GUI 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 + GUI plugin MUST not attempt to interpret it. The host may use it to + reference internal instance data. */ +typedef void* LV2UI_Controller; + + +/** This is the type of the host-provided function that the GUI 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. For ports of the + class lv2:ControlPort, buffer_size should be sizeof(float) and the buffer + contents should be a float value. For ports of the class llext:MidiPort the + buffer should contain the data bytes of a single MIDI event, and buffer_size + should be the number of bytes in the event. No other port classes are + allowed, unless the format and the meaning of the buffer passed to this + function is defined in the extension that specifies that class or in a + separate GUI host feature extension that is required by this GUI. + + The GUI is responsible for allocating the buffer and deallocating it after + the call. There are no timing guarantees at all for this function, although + the faster the host can get the data to the plugin port the better. A + function pointer of this type will be provided to the GUI 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); + +/** This is the type of the host-provided function that the GUI can use to + send arbitrary commands to the plugin. The parameters after the first one + should be const char* variables, terminated by a NULL pointer, and will be + interpreted as a command with arguments. A function of this type will be + provided to the GUI by the host in the instantiate() function. */ +typedef void (*LV2UI_Command_Function)(LV2UI_Controller controller, + uint32_t argc, + const char* const* argv); + +/** This is the type of the host-provided function that the GUI can use to + request a program change in the host. A function of this type will be + provided to the GUI by the host in the instantiate() function. Calling + this function does not guarantee that the program will change, it is just + a request. If the program does change, the GUI's current_program_changed() + callback will be called, either before or after this function returns + depending on whether the GUI host <-> plugin instance communication is + synchronous or asynchronous. */ +typedef void (*LV2UI_Program_Change_Function)(LV2UI_Controller controller, + unsigned char program); + +/** This is the type of the host-provided function that the GUI can use to + request that the current state of the plugin is saved to a program. + A function of this type will be provided to the GUI by the host in the + instantiate function. Calling this function does not guarantee that the + state will be saved, it is just a request. If the state is saved, the + GUI's program_added() callback will be called, either before or after + this function returns depending on whether the GUI host <-> plugin + instance communication is synchronous or asynchronous. */ +typedef void (*LV2UI_Program_Save_Function)(LV2UI_Controller controller, + unsigned char program, + const char* name); + + +/** */ +typedef struct _LV2UI_Descriptor { + + /** The URI for this GUI (not for the plugin it controls). */ + const char* URI; + + /** Create a new GUI object and return a handle to it. This function works + similarly to the instantiate() member in LV2_Descriptor, with the + additions that the URI for the plugin that this GUI is for is passed + as a parameter, a function pointer and a controller handle are passed to + allow the plugin to write to input ports in the plugin (write_function + and controller) and a pointer to a LV2_Widget is passed, which the GUI + plugin should set to point to a newly created widget which will be the + GUI for the plugin. This widget may only be destroyed by cleanup(). + + The features array works like the one in the instantiate() member + in LV2_Descriptor, except that the URIs should be denoted with the triples + <pre> + <http://my.plugingui> guiext:optionalFeature <http://my.guifeature> + </pre> + or + <pre> + <http://my.plugingui> guiext:requiredFeature <http://my.guifeature> + </pre> + in the RDF file, instead of the lv2:optionalFeature or lv2:requiredFeature + that is used by host features. These features are associated with the GUI, + not with the plugin - they are not actually LV2 Host Features, they just + use the same data structure. + + The same rules apply for these features as for normal host features - + if a feature is listed as required in the RDF file and the host does not + support it, it must not load the GUI. + */ + LV2UI_Handle (*instantiate)(const struct _LV2UI_Descriptor* descriptor, + const char* plugin_uri, + const char* bundle_path, + LV2UI_Write_Function write_function, + LV2UI_Command_Function command_function, + LV2UI_Program_Change_Function program_function, + LV2UI_Program_Save_Function save_function, + LV2UI_Controller controller, + LV2UI_Widget* widget, + const LV2_Host_Feature* const* host_features); + + + /** Destroy the GUI object and the associated widget. + */ + void (*cleanup)(LV2UI_Handle gui); + + /** Tell the GUI that something interesting has happened at a plugin port. + For control ports this would be when the value in the buffer has changed, + for message-based port classes like MIDI or OSC it would be when a + message has arrived in the buffer. For other port classes it is not + defined when this function is called, unless it is specified in the + definition of that port class extension. For control ports the default + setting is to call this function whenever an input control port value + has changed but not when any output control port value has changed, for + all other port classes the default setting is to never call this function. + + However, the default setting can be modified by using the following + URIs: + <pre> + guiext:portNotification + guiext:noPortNotification + guiext:plugin + guiext:portIndex + </pre> + For example, if you want the GUI with uri + <code><http://my.plugingui></code> for the plugin with URI + <code><http://my.plugin></code> 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 GUI: + <pre> + <http://my.plugingui> guiext:portNotification [ guiext:plugin <http://my.plugin> ; + guiext:portIndex 4 ] . + </pre> + and similarly with <code>guiext:noPortNotification</code> if you wanted to + prevent notifications for a port for which it would be on by default + otherwise. + + The @c buffer is only valid during the time of this function call, so if + the GUI wants to keep it for later use it has to copy the contents to an + internal buffer. + + The buffer is subject to the same rules as the ones for the + LV2_Write_Function type. This means that a plugin GUI may not request a + portNotification for a port that has a class other than lv2:ControlPort + or llext:MidiPort unless the buffer format and meaning is specified in + the extension that defines that port class, or in a separate GUI host + feature extension that is required by the GUI. Any GUI that does that + should be considered broken and the host should not use it. + + This member may be set to NULL if the GUI is not interested in any + port events. + */ + void (*port_event)(LV2UI_Handle gui, + uint32_t port, + uint32_t buffer_size, + const void* buffer); + + /** This function is called when the plugin instance wants to send feedback + to the GUI. It may be called in response to a command function call, + either before or after the command function has returned (depending on + whether the GUI host <-> plugin instance communication is synchronous or + asynchronous). */ + void (*feedback)(LV2UI_Handle gui, + uint32_t argc, + const char* const* argv); + + /** This function is called when the host adds a new program to its program + list, or changes the name of an old one. It may be set to NULL if the + GUI isn't interested in displaying program information. */ + void (*program_added)(LV2UI_Handle gui, + unsigned char number, + const char* name); + + /** This function is called when the host removes a program from its program + list. It may be set to NULL if the GUI isn't interested in displaying + program information. */ + void (*program_removed)(LV2UI_Handle gui, + unsigned char number); + + /** This function is called when the host clears its program list. It may be + set to NULL if the GUI isn't interested in displaying program + information. */ + void (*programs_cleared)(LV2UI_Handle gui); + + /** This function is called when the host changes the current program. It may + be set to NULL if the GUI isn't interested in displaying program + information. */ + void (*current_program_changed)(LV2UI_Handle gui, + unsigned char number); + + /** 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 GUI is not interested in supporting any extensions. This is similar + to the extension_data() member in LV2_Descriptor. + */ + void* (*extension_data)(LV2UI_Handle gui, + const char* uri); + +} LV2UI_Descriptor; + + + +/** A plugin 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 GUI 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 /* LV2_GUI_H */ + |