Suil 0.10.26 documentation

# Suil

Suil is a library for loading and wrapping LV2 plugin UIs.

With Suil, a host written in one supported toolkit can embed a plugin UI written in another. Suil insulates hosts from toolkit libraries used by plugin UIs. For example, a Gtk host can embed a Qt UI without linking against Qt at compile time.

Suil also handles the embedding of native platform UIs (which are recommended) in common toolkits, for example embedding an X11 UI in a Gtk host.

## Overview

The complete API is declared in `suil.h`:

    #include <suil/suil.h>

## Suil C API

### Callbacks

typedef void *SuilController

  UI controller.

  This is an opaque pointer passed by the user which is passed to the various UI control functions (e.g. `SuilPortWriteFunc`). It is typically used to pass a pointer to some controller object the host uses to communicate with plugins.

typedef uint32_t (*SuilPortIndexFunc)(SuilController controller, const char *port_symbol)

  Function to return the index for a port by symbol.

typedef uint32_t (*SuilPortSubscribeFunc)(SuilController controller, uint32_t port_index, uint32_t protocol, const LV2_Feature *const *features)

  Function to subscribe to notifications for a port.

typedef uint32_t (*SuilPortUnsubscribeFunc)(SuilController controller, uint32_t port_index, uint32_t protocol, const LV2_Feature *const *features)

  Function to unsubscribe from notifications for a port.

typedef void (*SuilPortWriteFunc)(SuilController controller, uint32_t port_index, uint32_t buffer_size, uint32_t protocol, void const *buffer)

  Function to write/send a value to a port.

typedef void (*SuilTouchFunc)(SuilController controller, uint32_t port_index, bool grabbed)

  Function called when a control is grabbed or released.

### Library

enum SuilArg

  Initialization argument.

void suil_init(int *argc, char ***argv, SuilArg key, ...)

  Initialize suil.

  This function should be called as early as possible, before any other GUI toolkit functions. The variable argument list is a sequence of `SuilArg` keys and corresponding value pairs for passing any necessary platform-specific information. It must be terminated with SUIL_ARG_NONE.

unsigned suil_ui_supported(const char *host_type_uri, const char *ui_type_uri)

  Check if suil can wrap a UI type.

  Parameters:

    - host_type_uri – The URI of the desired widget type of the host, corresponding to the `type_uri` parameter of `suil_instance_new()`.

    - ui_type_uri – The URI of the UI widget type.

  Returns:

    0 if wrapping is unsupported, otherwise the quality of the wrapping where 1 is the highest quality (direct native embedding with no wrapping) and increasing values are of a progressively lower quality and/or stability.

### Host

typedef struct SuilHostImpl SuilHost

  UI host descriptor.

  This contains the various functions that a plugin UI may use to communicate with the plugin. It is passed to `suil_instance_new()` to provide these functions to the UI.

void suil_host_free(SuilHost *host)

  Free `host`.

SuilHost *suil_host_new(SuilPortWriteFunc write_func, SuilPortIndexFunc index_func, SuilPortSubscribeFunc subscribe_func, SuilPortUnsubscribeFunc unsubscribe_func)

  Create a new UI host descriptor.

  Parameters:

    - write_func – Function to send a value to a plugin port.

    - index_func – Function to get the index for a port by symbol.

    - subscribe_func – Function to subscribe to port updates.

    - unsubscribe_func – Function to unsubscribe from port updates.

void suil_host_set_touch_func(SuilHost *host, SuilTouchFunc touch_func)

  Set a touch function for a host descriptor.

  Note this function will only be called if the UI supports it.

### Instance

typedef void *SuilHandle

  Opaque pointer to a UI handle.

typedef struct SuilInstanceImpl SuilInstance

  An instance of an LV2 plugin UI.

typedef void *SuilWidget

  Opaque pointer to a UI widget.

const void *suil_instance_extension_data(SuilInstance *instance, const char *uri)

  Return a data structure defined by some LV2 extension URI.

void suil_instance_free(SuilInstance *instance)

  Free a plugin UI instance.

  The caller must ensure all references to the UI have been dropped before calling this function (e.g. it has been removed from its parent).

SuilHandle suil_instance_get_handle(SuilInstance *instance)

  Get the handle for a UI instance.

  Returns the handle to the UI instance. The returned handle has opaque type to insulate the Suil API from LV2 extensions, but in pactice it is currently of type `LV2UI_Handle`. This should not normally be needed.

  The returned handle is shared and must not be deleted.

SuilWidget suil_instance_get_widget(SuilInstance *instance)

  Get the widget for a UI instance.

  Returns an opaque pointer to a widget, the type of which matches the `container_type_uri` parameter of `suil_instance_new()`. Note this may be a wrapper widget created by Suil, and not necessarily the widget directly implemented by the UI.

SuilInstance *suil_instance_new(SuilHost *host, SuilController controller, const char *container_type_uri, const char *plugin_uri, const char *ui_uri, const char *ui_type_uri, const char *ui_bundle_path, const char *ui_binary_path, const LV2_Feature *const *features)

  Instantiate a UI for an LV2 plugin.

  This function may load a suil module to adapt the UI to the desired toolkit. Suil is configured at compile time to load modules from the appropriate place, but this can be changed at run-time via the environment variable SUIL_MODULE_DIR. This makes it possible to bundle suil with an application.

  Note that some situations (Gtk in Qt, Windows in Gtk) require a parent container to be passed as a feature with URI LV2_UI__parent (http://lv2plug.in/ns/extensions/ui#ui) in order to work correctly. The data must point to a single child container of the host widget set.

  Parameters:

    - host – Host descriptor.

    - controller – Opaque host controller pointer.

    - container_type_uri – URI of the desired host container widget type.

    - plugin_uri – URI of the plugin to instantiate this UI for.

    - ui_uri – URI of the specifically desired UI.

    - ui_type_uri – URI of the actual UI widget type.

    - ui_bundle_path – Path of the UI bundle.

    - ui_binary_path – Path of the UI binary.

    - features – NULL-terminated array of supported features, or NULL.

  Returns:

    A new UI instance, or NULL if instantiation failed.

void suil_instance_port_event(SuilInstance *instance, uint32_t port_index, uint32_t buffer_size, uint32_t format, const void *buffer)

  Notify the UI about a change in a plugin port.

  This function can be used to notify the UI about any port change, but in the simplest case is used to set the value of lv2:ControlPort ports. For simplicity, this is a special case where `format` is 0, `buffer_size` is 4, and `buffer` should point to a single float.

  The `buffer` must be valid only for the duration of this call, the UI must not keep a reference to it.

  Parameters:

    - instance – UI instance.

    - port_index – Index of the port which has changed.

    - buffer_size – Size of `buffer` in bytes.

    - format – Format of `buffer` (mapped URI, or 0 for float).

    - buffer – Change data, e.g. the new port value.