lv2_progress.h File Reference

LV2 progress notification extension definition. More...

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Classes
struct	_LV2_Progress
	host feature structure More...

Macros
#define	LV2_PROGRESS_URI   "http://lv2plug.in/ns/dev/progress"

Typedefs
typedef struct _LV2_Progress	LV2_Progress
	host feature structure

Detailed Description

LV2 progress notification extension definition.

Purpose and scope

The purpose of this extension is to prevent thread (often the main one) freeze for plugins doing intensive computations during instantiation. Host may want to display progress bar of some sort and if it is using GUI toolkit event loop, to dispatch queued events.

Using this extension for reporting progress of other lengthy operations is possible and encouraged but not subject of this extension alone. It is probably not good idea to call progress callback from plugin created thread nor it is good idea to call it from a LV2 audio class function. Any extension that wants to work in conjunction with progress extension must define thread context semantics for calling the progress callback.

Plugin instantiation progress usage

Plugin calls the host provided callback on regular basis during instantiation. One second between calls is good target. Everything between half second and two seconds should provide enough motion so user does not get "the thing froze" impression.

Macro Definition Documentation

LV2_PROGRESS_URI

#define LV2_PROGRESS_URI   "http://lv2plug.in/ns/dev/progress"

URI for the plugin progress feature

Typedef Documentation

LV2_Progress

typedef struct _LV2_Progress LV2_Progress

host feature structure