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Diffstat (limited to 'ns/extensions/ui/ui.h')
| -rw-r--r-- | ns/extensions/ui/ui.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/ns/extensions/ui/ui.h b/ns/extensions/ui/ui.h new file mode 100644 index 0000000..6d64a0d --- /dev/null +++ b/ns/extensions/ui/ui.h @@ -0,0 +1,247 @@ +/* + LV2 UI Extension + Copyright 2009-2011 David Robillard <d@drobilla.net> + Copyright 2006-2008 Lars Luthman <lars.luthman@gmail.com> + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +/** + * @file + * C header for the LV2 UI extension <http://lv2plug.in/ns/extensions/ui>. + */ + +#ifndef LV2_UI_H +#define LV2_UI_H + +#include "lv2/lv2plug.in/ns/lv2core/lv2.h" + +#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; + +/** + A pointer to 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; + +/** + A pointer to a particular plugin controller, 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 + instance data. +*/ +typedef void* LV2UI_Controller; + +/** + 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 + <http://lv2plug.in/ns/ext/uri-map> 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); + +/** + The implementation of a 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, the buffer should contain a + single IEEE-754 float, and @c format 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: + <pre> + uiext:portNotification + uiext:noPortNotification + uiext:plugin + uiext:portIndex + </pre> + For example, if you want the UI with uri + <code><http://my.pluginui></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 UI: + <pre> + <http://my.pluginui> uiext:portNotification [ uiext:plugin <http://my.plugin> ; + uiext:portIndex 4 ] . + </pre> + and similarly with <code>uiext:noPortNotification</code> 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); + + /** + Return a data structure associated with an extension URI, for example + a struct containing additional function pointers. + + Avoid returning function pointers directly since standard C/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); + +/** + The type of the lv2ui_descriptor() function. +*/ +typedef const LV2UI_Descriptor* (*LV2UI_DescriptorFunction)(uint32_t index); + +#ifdef __cplusplus +} +#endif + +#endif /* LV2_UI_H */ |