lv2_tinyUI.h

#define LV2_TinyUI_URI "http://example.org/lv2/tinyUI"
#define LV2_TinyUI_PREFIX LV2_INLINEDISPLAY_URI "#"
#define LV2_TinyUI__interface LV2_INLINEDISPLAY_PREFIX "Interface"
#define LV2_TinyUI__feature LV2_INLINEDISPLAY_PREFIX "Feature"

/** a LV2 Feature provided by the Host to the plugin */
typedef struct {
  /** Opaque host data */
	LV2UI_Controller controller;

	/** A host-provided function that sends data to a plugin's input ports.
	 *
	 * This mirrors the default UI callback function [1].
	 *
	 * While it is passed to the plugin's DSP instance, the plugin should
	 * only call it in response to a TinyUI Mouse Event (in the GUI thread).
	 *
	 * Note: the host may also pass the LV2_UI__touch [2] feature to the
	 * plugin in the same way.
	 *
	 * [1] https://lv2plug.in/doc/html/group__ui.html#ga62502987d06bc97ea88521aacc0990c9
	 * [2] http://lv2plug.in/ns/extensions/ui#touch
	 */
	LV2UI_Write_Function write_function;
} LV2_TinyUI;


/**
 * Extension-interface provided by Plugin.
 *
 * These function are called by the host to pass mouse-events to the plugin's TinyUI.
 * Rendering the tinyUI uses the inline-display extension.
 */
typedef struct {
	bool (*event_motion)(LV2_Handle instance, uint32_t x, uint32_t y);
	bool (*event_button)(LV2_Handle instance, uint32_t x, uint32_t y, uint32_t modifiers, uint32_t button, bool press);
	bool (*event_scroll)(LV2_Handle instance, uint32_t x, uint32_t y, uint32_t modifiers, double dx, double dy);

	/* Discuss:
	 *  - Preferably use an event-struct and single callback function (!)
	 *  - Define modifiers (key: ctrl, alt, shift;  button-state: single, double tipple click)
	 *  - scroll direction and distance
	 *  etc.
	 *
	 * .. just copy some existing standard :)
	 */
} LV2_TinyUI_Interface;