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Diffstat (limited to 'slv2/lv2-gtk2gui.h')
| -rw-r--r-- | slv2/lv2-gtk2gui.h | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/slv2/lv2-gtk2gui.h b/slv2/lv2-gtk2gui.h new file mode 100644 index 0000000..fd57d28 --- /dev/null +++ b/slv2/lv2-gtk2gui.h @@ -0,0 +1,212 @@ +/************************************************************************ + * + * GTK2 in-process UI extension for LV2 + * + * Copyright (C) 2006 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 GTK2 GUIs for plugins. The GUIs will be plugins that + will reside in shared object files in a LV2 bundle and be referenced in + the RDF file using the triples +<pre> + <http://my.plugin> <http://ll-plugins.nongnu.org/lv2/ext/gtk2gui#gui> <http://my.plugingui> + <http://my.plugingui> <http://ll-plugins.nongnu.org/lv2/ext/gtk2gui#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. + + 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 GTK + main loop is running in. +*/ + +#ifndef LV2_GTK2GUI_H +#define LV2_GTK2GUI_H + +#include "lv2.h" + + +#ifdef __cplusplus +extern "C" { +#endif + +/* The original header includes <gtk/gtkwidget.h>, but we don't want + libslv2 to depend on GTK+ so we forward declare the _GtkWidget struct + instead. */ +struct _GtkWidget; + + + +/** 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 changes the value + of a control rate float input port in a plugin instance. A function + pointer of this type will be provided to the GUI bu the host in the + instantiate() function. */ +typedef void (*LV2UI_Set_Control_Function)(LV2UI_Controller controller, + uint32_t port, + float value); + + +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 change control port values in the plugin + (control_function and controller) and a pointer to a GtkWidget pointer + is passed, which the GUI plugin should set to point to a newly created + widget which will be the main GUI for the plugin. + + 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> <http://ll-plugins.nongnu.org/lv2/dev/gtk2gui#optionalFeature> <http://my.guifeature> + </pre> + or + <pre> + <http://my.plugingui> <http://ll-plugins.nongnu.org/lv2/dev/gtk2gui#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_Set_Control_Function control_function, + LV2UI_Controller controller, + struct _GtkWidget** widget, + const LV2_Host_Feature** features); + + + /** Destroy the GUI object and the associated widget. + */ + void (*cleanup)(LV2UI_Handle gui); + + /** Tell the GUI that a control port value has changed. This member may be + set to NULL if the GUI is not interested in control port changes. + */ + void (*set_control)(LV2UI_Handle gui, + uint32_t port, + float value); + + /** 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; + + + +/** Accessing a plugin GUI. + + 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 |