Added support for (Lars Luthman's) GTK GUI extension (SLV2 still does NOT depend on GTK!).

git-svn-id: http://svn.drobilla.net/lad/slv2@546 a436a847-0d15-0410-975c-d299462d15a1

5 files changed, 366 insertions, 0 deletions

diff --git a/slv2/Makefile.am b/slv2/Makefile.am
index 8e57eb1..e0a9c0e 100644
--- a/slv2/Makefile.am
+++ b/slv2/Makefile.am
@@ -2,9 +2,11 @@ slv2includedir = $(includedir)/slv2
 
 slv2include_HEADERS = \
 	lv2.h \
+	lv2-gtk2gui.h \
 	plugin.h \
 	pluginclass.h \
 	pluginclasses.h \
+	pluginguiinstance.h \
 	plugininstance.h \
 	plugins.h \
 	port.h \
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
diff --git a/slv2/plugin.h b/slv2/plugin.h
index 4d53bb3..9dc53e7 100644
--- a/slv2/plugin.h
+++ b/slv2/plugin.h
@@ -321,6 +321,32 @@ slv2_plugin_get_port_by_symbol(SLV2Plugin  plugin,
                                const char* symbol);
 
 
+/** Get a list of all GUIs available for this plugin.
+ *
+ * Note this returns the URI of the GUI, and not the path/URI to its shared
+ * library, use slv2_plugin_gui_get_library_uri with the values returned
+ * here for that.
+ *
+ * \param plugin The plugin to get the GUIs for. 
+ *
+ * Time = Query
+ */
+SLV2Values
+slv2_plugin_get_guis(SLV2Plugin plugin);
+
+
+/** Get the URI for a GUI library.
+ *
+ * \param plugin The plugin that the GUI is for.
+ * \param gui    A GUI identifier as returned by slv2_plugin_get_guis().
+ *
+ * Time = Query
+ */
+SLV2Value
+slv2_plugin_gui_get_library_uri(SLV2Plugin plugin, 
+                                SLV2Value  gui);
+
+
 /** @} */
 
 #ifdef __cplusplus
diff --git a/slv2/pluginguiinstance.h b/slv2/pluginguiinstance.h
new file mode 100644
index 0000000..82628a7
--- /dev/null
+++ b/slv2/pluginguiinstance.h
@@ -0,0 +1,125 @@
+/* SLV2
+ * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
+ *  
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This library 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 General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __SLV2_PLUGINGUIINSTANCE_H__
+#define __SLV2_PLUGINGUIINSTANCE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <assert.h>
+#include <slv2/lv2-gtk2gui.h>
+#include <slv2/plugin.h>
+
+/** \defgroup lib Plugin GUI library access
+ *
+ * An SLV2GUIInstance is an instantiated GUI for a SLV2Plugin. GUI instances
+ * are loaded from dynamically loaded libraries.  These functions interact 
+ * with the GUI code in the binary library only, they do not read data files
+ * in any way.
+ * 
+ * @{
+ */
+
+
+typedef struct _GUIInstanceImpl* SLV2GUIInstanceImpl;
+
+  
+struct _GtkWidget;
+
+
+/** Instance of a plugin GUI.
+ *
+ * All details are in hidden in the pimpl member to avoid making the
+ * implementation a part of the ABI.
+ */
+typedef struct _GUIInstance {
+	SLV2GUIInstanceImpl      pimpl; ///< Private implementation
+}* SLV2GUIInstance;
+
+
+
+/** Instantiate a plugin GUI.
+ *
+ * The returned object represents shared library objects loaded into memory,
+ * it must be cleaned up with slv2_gui_instance_free when no longer
+ * needed.
+ * 
+ * \a plugin is not modified or directly referenced by the returned object
+ * (instances store only a copy of the plugin's URI).
+ * 
+ * \a host_features NULL-terminated array of features the host supports.
+ * NULL may be passed if the host supports no additional features (unlike
+ * the LV2 specification - SLV2 takes care of it).
+ *
+ * \return NULL if instantiation failed.
+ */
+SLV2GUIInstance
+slv2_plugin_gui_instantiate(SLV2Plugin                 plugin,
+			    SLV2Value                  gui,
+			    LV2UI_Set_Control_Function control_function,
+			    LV2UI_Controller           controller,
+			    const LV2_Host_Feature**   host_features);
+
+
+/** Free a plugin GUI instance.
+ *
+ * \a instance is invalid after this call.
+ */
+void
+slv2_gui_instance_free(SLV2GUIInstance instance);
+
+
+/** Get the GTK+ 2.0 widget for the GUI instance.
+ */
+struct _GtkWidget*
+slv2_gui_instance_get_widget(SLV2GUIInstance instance);
+
+
+/** Get the LV2UI_Descriptor of the plugin GUI instance.
+ *
+ * Normally hosts should not need to access the LV2UI_Descriptor directly,
+ * use the slv2_gui_instance_* functions.
+ *
+ * The returned descriptor is shared and must not be deleted.
+ */
+const LV2UI_Descriptor*
+slv2_gui_instance_get_descriptor(SLV2GUIInstance instance);
+
+
+/** Get the LV2UI_Handle of the plugin GUI instance.
+ *
+ * Normally hosts should not need to access the LV2UI_Handle directly,
+ * use the slv2_gui_instance_* functions.
+ * 
+ * The returned handle is shared and must not be deleted.
+ */
+LV2_Handle
+slv2_gui_instance_get_handle(SLV2GUIInstance instance);
+
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* __SLV2_PLUGINGUIINSTANCE_H__ */
+
diff --git a/slv2/slv2.h b/slv2/slv2.h
index 9573e9c..e5c2b07 100644
--- a/slv2/slv2.h
+++ b/slv2/slv2.h
@@ -29,6 +29,7 @@ extern "C" {
 #include <slv2/plugin.h>
 #include <slv2/port.h>
 #include <slv2/plugins.h>
+#include <slv2/pluginguiinstance.h>
 #include <slv2/plugininstance.h>
 #include <slv2/value.h>
 #include <slv2/values.h>