diff options
Diffstat (limited to 'lv2/lv2plug.in/ns/extensions/ui/ui.h')
| -rw-r--r-- | lv2/lv2plug.in/ns/extensions/ui/ui.h | 195 |
1 files changed, 93 insertions, 102 deletions
diff --git a/lv2/lv2plug.in/ns/extensions/ui/ui.h b/lv2/lv2plug.in/ns/extensions/ui/ui.h index e59e298..9eaa75c 100644 --- a/lv2/lv2plug.in/ns/extensions/ui/ui.h +++ b/lv2/lv2plug.in/ns/extensions/ui/ui.h @@ -1,6 +1,6 @@ /* LV2 UI Extension - Copyright 2009-2013 David Robillard <d@drobilla.net> + Copyright 2009-2014 David Robillard <d@drobilla.net> Copyright 2006-2011 Lars Luthman <lars.luthman@gmail.com> Permission to use, copy, modify, and/or distribute this software for any @@ -17,8 +17,9 @@ */ /** - @file ui.h - C header for the LV2 UI extension <http://lv2plug.in/ns/extensions/ui>. + @file ui.h User Interface API + + For high-level documentation, see <http://lv2plug.in/ns/extensions/ui>. */ #ifndef LV2_UI_H @@ -75,20 +76,16 @@ extern "C" { typedef void* LV2UI_Widget; /** - A pointer to an instance of a UI. + A pointer to UI instance internals. - 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. + The host may compare this to NULL, but otherwise MUST NOT interpret it. */ typedef void* LV2UI_Handle; /** A pointer to a 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. + The UI may compare this to NULL, but otherwise MUST NOT interpret it. */ typedef void* LV2UI_Controller; @@ -98,22 +95,20 @@ typedef void* LV2UI_Controller; typedef void* LV2UI_Feature_Handle; /** - The type of the host-provided function that the UI can use to - send data to a plugin's input ports. + A host-provided function that sends data to a plugin's input ports. - The @p buffer parameter must point to a block of data, @c buffer_size bytes + The @p buffer parameter must point to a block of data, @p buffer_size bytes large. The format of this data and how the host should use it is defined by the @p port_protocol. This buffer is owned by the UI and is only valid for the duration of this call. The @p port_protocol parameter should either be 0 or the URID for a ui:PortProtocol. If it is 0, the protocol is implicitly ui:floatProtocol, - the port must be an lv2:ControlPort input, @c buffer must point to a single - float value, and @c buffer_size must be sizeof(float). + the port MUST be an lv2:ControlPort input, @p buffer MUST point to a single + float value, and @p buffer_size MUST be sizeof(float). - The UI SHOULD NOT use a PortProtocol not supported by the host (i.e. one not - passed by the host as a feature), but the host MUST gracefully ignore any - port_protocol it does not understand. + The UI SHOULD NOT use a protocol not supported by the host, but the host + MUST gracefully ignore any protocol it does not understand. */ typedef void (*LV2UI_Write_Function)(LV2UI_Controller controller, uint32_t port_index, @@ -122,7 +117,7 @@ typedef void (*LV2UI_Write_Function)(LV2UI_Controller controller, const void* buffer); /** - The implementation of a UI. + A plugin UI. A pointer to an object of this type is returned by the lv2ui_descriptor() function. @@ -134,32 +129,29 @@ typedef struct _LV2UI_Descriptor { 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. + Create a new UI and return a handle to it. This function works + similarly to LV2_Descriptor::instantiate(). - @param descriptor The descriptor for the UI that you want to instantiate. + @param descriptor The descriptor for the UI 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 bundle_path The path to the bundle containing this UI, including + the trailing directory separator. - @param write_function A function provided by the host that the UI can use - to send data to the plugin's input ports. + @param write_function A function 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 @p write_function. + @param controller A handle for the plugin instance to be passed as the + first parameter of UI methods. - @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 widget (output) widget pointer. The UI points this at its main + widget, which has the type defined by the UI type in the data file. - @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. + @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, as + in LV2_Descriptor::instantiate(). Note that UI features and plugin + features are not necessarily the same. */ LV2UI_Handle (*instantiate)(const struct _LV2UI_Descriptor* descriptor, @@ -172,33 +164,29 @@ typedef struct _LV2UI_Descriptor { /** - Destroy the UI object and the associated widget. The host must not try - to access the widget after calling this function. + Destroy the UI. 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 @p 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), @p buffer_size should be 4, the buffer should - contain a single IEEE-754 float, and @p format should be 0. - - By default, the host should only call this function for input ports of - the lv2:ControlPort class. However, this can be modified by using - ui:portNotification in the UI data, or the ui:portSubscribe feature. - - The @p 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. + What is "interesting" and how it is written to @p buffer is defined by + @p format, which has the same meaning as in LV2UI_Write_Function(). + Format 0 is a special case for lv2:ControlPort, where this function + should be called when the port value changes (but not necessarily for + every change), @p buffer_size must be sizeof(float), and @p buffer + points to a single IEEE-754 float. + + By default, the host should only call this function for lv2:ControlPort + inputs. However, the UI can request updates for other ports statically + with ui:portNotification or dynamicaly with ui:portSubscribe. + + The UI MUST NOT retain any reference to @p buffer after this function + returns, it is only valid for the duration of the call. + + This member may be NULL if the UI is not interested in any port events. */ void (*port_event)(LV2UI_Handle ui, uint32_t port_index, @@ -207,22 +195,21 @@ typedef struct _LV2UI_Descriptor { const void* buffer); /** - Return a data structure associated with an extension URI, for example - a struct containing additional function pointers. + Return a data structure associated with an extension URI, typically an + interface struct with 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. + This member may be set to NULL if the UI is not interested in supporting + any extensions. This is similar to LV2_Descriptor::extension_data(). + */ const void* (*extension_data)(const char* uri); } LV2UI_Descriptor; /** - UI Resize Feature (LV2_UI__resize) + Feature/interface for resizable UIs (LV2_UI__resize). - This structure may be used in two ways: as a feature passed by the host via - LV2UI_Descriptor::instantiate(), or as extension data provided by a UI via + This structure is used in two ways: as a feature passed by the host via + LV2UI_Descriptor::instantiate(), or as an interface provided by a UI via LV2UI_Descriptor::extension_data()). */ typedef struct _LV2UI_Resize { @@ -232,13 +219,13 @@ typedef struct _LV2UI_Resize { LV2UI_Feature_Handle handle; /** - Request or advertise a size change. + Request/advertise a size change. - When this struct is provided by the host, the UI may call this - function to inform the host about the size of the UI. + When provided by the host, the UI may call this function to inform the + host about the size of the UI. - When this struct is provided by the UI, the host may call this - function to notify the UI that it should change its size accordingly. + When provided by the UI, the host may call this function to notify the + UI that it should change its size accordingly. @return 0 on success. */ @@ -246,16 +233,15 @@ typedef struct _LV2UI_Resize { } LV2UI_Resize; /** - Port Map Feature (LV2_UI__portMap). + Feature to map port symbols to UIs. - This feature can be used by the UI to get the index for a port with the - given symbol. This makes it possible to implement and distribute a UI - separately from the plugin (since symbol is a guaranteed stable port - identifier while index is not). + This can be used by the UI to get the index for a port with the given + symbol. This makes it possible to implement and distribute a UI separately + from the plugin (since symbol, unlike index, is a stable port identifier). */ typedef struct _LV2UI_Port_Map { /** - Pointer to opaque data which must be passed to ui_resize(). + Pointer to opaque data which must be passed to port_index(). */ LV2UI_Feature_Handle handle; @@ -269,11 +255,12 @@ typedef struct _LV2UI_Port_Map { } LV2UI_Port_Map; /** - Port subscription feature (LV2_UI__portSubscribe); + Feature to subscribe to port updates (LV2_UI__portSubscribe). */ typedef struct _LV2UI_Port_Subscribe { /** - Pointer to opaque data which must be passed to ui_resize(). + Pointer to opaque data which must be passed to subscribe() and + unsubscribe(). */ LV2UI_Feature_Handle handle; @@ -319,7 +306,7 @@ typedef struct _LV2UI_Port_Subscribe { } LV2UI_Port_Subscribe; /** - A feature to notify the host the user has grabbed a UI control. + A feature to notify the host that the user has grabbed a UI control. */ typedef struct _LV2UI_Touch { /** @@ -330,6 +317,9 @@ typedef struct _LV2UI_Touch { /** Notify the host that a control has been grabbed or released. + The host should cease automating the port or otherwise manipulating the + port value until the control has been ungrabbed. + @param handle The handle field of this struct. @param port_index The index of the port associated with the control. @param grabbed If true, the control has been grabbed, otherwise the @@ -341,19 +331,23 @@ typedef struct _LV2UI_Touch { } LV2UI_Touch; /** - UI Idle Feature (LV2_UI__idleInterface) + UI Idle Interface (LV2_UI__idleInterface) - This feature is an addition to the UI API that provides a callback for the - host to call rapidly, e.g. to drive the idle callback of a toolkit. + UIs can provide this interface to have an idle() callback called by the host + rapidly to update the UI. */ typedef struct _LV2UI_Idle_Interface { /** Run a single iteration of the UI's idle loop. - This will be called "frequently" in the UI thread at a rate appropriate - for a toolkit main loop. There are no precise timing guarantees. + This will be called rapidly in the UI thread at a rate appropriate + for a toolkit main loop. There are no precise timing guarantees, but + the host should attempt to call idle() at a high enough rate for smooth + animation, at least 30Hz. - @return 0 on success, or anything else to stop being called. + @return non-zero if the UI has been closed, in which case the host + should stop calling idle(), and can either completely destroy the UI, or + re-show it and resume calling idle(). */ int (*idle)(LV2UI_Handle ui); } LV2UI_Idle_Interface; @@ -361,11 +355,15 @@ typedef struct _LV2UI_Idle_Interface { /** UI Show Interface (LV2_UI__showInterface) - UIs can use this interface to provide show/hide methods to pop up a window, - which allows them to function in hosts unable to embed their widget type. + UIs can provide this interface to show and hide a window, which allows them + to function in hosts unable to embed their widget. This allows any UI to + provide a fallback for embedding that works in any host. - If used, LV2UI_Idle_Interface should also be used to drive the UI. The UI - should return non-zero from idle() when the window has been closed. + If used: + - The host MUST use LV2UI_Idle_Interface to drive the UI. + - The UI MUST return non-zero from LV2UI_Idle_Interface::idle() when it has been closed. + - If idle() returns non-zero, the host MUST call hide() and stop calling + idle(). It MAY later call show() then resume calling idle(). */ typedef struct _LV2UI_Show_Interface { /** @@ -407,17 +405,10 @@ typedef struct _LV2UI_Peak_Data { } LV2UI_Peak_Data; /** - 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 is - loaded from the library by the UI host and called to get a - LV2UI_Descriptor 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. + Prototype for UI accessor function. + + This is the entry point to a UI library, which works in the same way as + lv2_descriptor() but for UIs rather than plugins. */ LV2_SYMBOL_EXPORT const LV2UI_Descriptor* lv2ui_descriptor(uint32_t index); |