Event System (event)

The input event abstraction layer for the window subsystem, unifying keyboard, rotary encoder, mouse, touch, joystick, and system events, delivering events from input devices to windows via a FIFO queue.

Event Types

Type	Value	Description
`EVENT_TYPE_KEY_DOWN`	0x0100	Key pressed
`EVENT_TYPE_KEY_UP`	0x0101	Key released
`EVENT_TYPE_ROTARY_STEP`	0x0200	Rotary encoder step
`EVENT_TYPE_MOUSE_DOWN`	0x0300	Mouse button pressed
`EVENT_TYPE_MOUSE_MOVE`	0x0301	Mouse moved
`EVENT_TYPE_MOUSE_UP`	0x0302	Mouse button released
`EVENT_TYPE_MOUSE_WHEEL`	0x0303	Mouse wheel scrolled
`EVENT_TYPE_TOUCH_BEGIN`	0x0400	Touch started
`EVENT_TYPE_TOUCH_MOVE`	0x0401	Touch moved
`EVENT_TYPE_TOUCH_END`	0x0402	Touch ended
`EVENT_TYPE_JOYSTICK_LEFTSTICK`	0x0500	Joystick left stick
`EVENT_TYPE_JOYSTICK_RIGHTSTICK`	0x0501	Joystick right stick
`EVENT_TYPE_JOYSTICK_LEFTTRIGGER`	0x0502	Joystick left trigger
`EVENT_TYPE_JOYSTICK_RIGHTTRIGGER`	0x0503	Joystick right trigger
`EVENT_TYPE_JOYSTICK_BUTTONDOWN`	0x0504	Joystick button pressed
`EVENT_TYPE_JOYSTICK_BUTTONUP`	0x0505	Joystick button released
`EVENT_TYPE_SYSTEM_EXIT`	0x1000	System exit

Data Structure

struct event_t {
    void * device;              /* Source device */
    enum event_type_t type;     /* Event type */
    ktime_t timestamp;          /* Event timestamp */

    union {
        struct { uint32_t key; } key_down;          /* Key pressed */
        struct { uint32_t key; } key_up;             /* Key released */
        struct { int32_t delta; } rotary_step;       /* Rotary step */
        struct { int32_t x, y; uint32_t button; } mouse_down;   /* Mouse pressed */
        struct { int32_t x, y; } mouse_move;         /* Mouse moved */
        struct { int32_t x, y; uint32_t button; } mouse_up;     /* Mouse released */
        struct { int32_t dx, dy; } mouse_wheel;      /* Mouse wheel */
        struct { int32_t x, y; uint32_t id; } touch_begin;  /* Touch started */
        struct { int32_t x, y; uint32_t id; } touch_move;   /* Touch moved */
        struct { int32_t x, y; uint32_t id; } touch_end;    /* Touch ended */
        struct { int32_t x, y; } joystick_left_stick;   /* Left stick */
        struct { int32_t x, y; } joystick_right_stick;  /* Right stick */
        struct { int32_t v; } joystick_left_trigger;    /* Left trigger */
        struct { int32_t v; } joystick_right_trigger;   /* Right trigger */
        struct { uint32_t button; } joystick_button_down;  /* Joystick pressed */
        struct { uint32_t button; } joystick_button_up;    /* Joystick released */
    } e;
};

Key Definitions

Key codes are ASCII-compatible (32-127), with extensions for function keys (1-31) and Latin-1 supplement characters (160-255). Common function keys:

Key	Value	Description
`KB_KEY_POWER`	1	Power key
`KB_KEY_UP`	2	Direction up
`KB_KEY_DOWN`	3	Direction down
`KB_KEY_LEFT`	4	Direction left
`KB_KEY_RIGHT`	5	Direction right
`KB_KEY_ENTER`	13	Enter key
`KB_KEY_BACK`	11	Back key
`KB_KEY_HOME`	10	Home key
`KB_KEY_MENU`	12	Menu key
`KB_KEY_DELETE`	127	Delete key

Mouse Buttons

Constant	Bit	Description
`MOUSE_BUTTON_LEFT`	bit 0	Left button
`MOUSE_BUTTON_RIGHT`	bit 1	Right button
`MOUSE_BUTTON_MIDDLE`	bit 2	Middle button
`MOUSE_BUTTON_X1`	bit 3	Side button 1
`MOUSE_BUTTON_X2`	bit 4	Side button 2

Joystick Buttons

Joystick buttons use a bitmask, supporting D-pad, A/B/X/Y, Back/Start/Guide, bumpers, and stick presses:

Constant	Bit	Description
`JOYSTICK_BUTTON_A`	bit 4	A button
`JOYSTICK_BUTTON_B`	bit 5	B button
`JOYSTICK_BUTTON_X`	bit 6	X button
`JOYSTICK_BUTTON_Y`	bit 7	Y button
`JOYSTICK_BUTTON_START`	bit 9	Start button
`JOYSTICK_BUTTON_GUIDE`	bit 10	Guide button

Event Push API

Input device drivers push events to the window system via the following functions:

Function	Description
`push_event_key_down(device, key)`	Push key down event
`push_event_key_up(device, key)`	Push key up event
`push_event_rotary_step(device, delta)`	Push rotary encoder step event
`push_event_mouse_button_down(device, x, y, button)`	Push mouse down event
`push_event_mouse_button_up(device, x, y, button)`	Push mouse up event
`push_event_mouse_move(device, x, y)`	Push mouse move event
`push_event_mouse_wheel(device, dx, dy)`	Push mouse wheel event
`push_event_touch_begin(device, x, y, id)`	Push touch begin event
`push_event_touch_move(device, x, y, id)`	Push touch move event
`push_event_touch_end(device, x, y, id)`	Push touch end event
`push_event_joystick_left_stick(device, x, y)`	Push left stick event
`push_event_joystick_right_stick(device, x, y)`	Push right stick event
`push_event_joystick_left_trigger(device, v)`	Push left trigger event
`push_event_joystick_right_trigger(device, v)`	Push right trigger event
`push_event_joystick_button_down(device, button)`	Push joystick button down event
`push_event_joystick_button_up(device, button)`	Push joystick button up event

Event Consumption

Events are retrieved from the window's event FIFO queue via window_pump_event():

struct event_t e;
while(window_pump_event(w, &e))
{
    switch(e.type)
    {
    case EVENT_TYPE_KEY_DOWN:
        LOG("key down: %d\n", e.e.key_down.key);
        break;
    case EVENT_TYPE_TOUCH_BEGIN:
        LOG("touch: (%d, %d) id=%u\n", e.e.touch_begin.x, e.e.touch_begin.y, e.e.touch_begin.id);
        break;
    default:
        break;
    }
}

Notes

All push_event_* functions internally construct an event_t structure and call push_event() to inject it into the window event queue
The device field identifies the source device, useful for distinguishing multiple input devices of the same type
Event timestamps are automatically filled via ktime_get()
Mouse and joystick buttons use bitmasks, supporting simultaneous button presses
Touch events use id to distinguish different touch points in multi-touch scenarios
Joystick coordinates and trigger values are raw ADC values; calibration and normalization are required before use

Event Types​

Data Structure​

Key Definitions​

Mouse Buttons​

Joystick Buttons​

Event Push API​

Event Consumption​

Notes​