Event Handling

ui_event_t *ui_event(ui_t *ctx, ui_form_t *form);

This is the heart of SMGUI, this function queries the events and also adds an UI layer on top with the desired form [layout] to the window.

Parameter	Description
`ctx`	Pointer to UI context
`form`	Form [layout]

Returns NULL if the main loop should exit, an event otherwise.

If you change one of the variables that the passed form references, then you must call ui_refresh() before calling ui_event() to force a [redrawing].

The returned event should be parsed with a switch on evt->type, because most fields depend on the type.

No Event

Nothing happened.

Parameter	Description
`evt->type`	`UI_EVT_NONE` (0)

Mouse

This is generated whenever a mouse button is pressed or released.

Parameter	Description
`evt->type`	`UI_EVT_MOUSE`
`evt->btn`	Current button's state
`evt->x`	Current mouse X position
`evt->y`	Current mouse Y position

The btn field is a bitfield with the following values:

Define	Description
`UI_BTN_L`	Left mouse button
`UI_BTN_M`	Middle mouse button
`UI_BTN_R`	Right mouse button
`UI_BTN_U`	Wheel scrolled up
`UI_BTN_D`	Wheel scrolled down
`UI_BTN_A`	Wheel scrolled left
`UI_BTN_B`	Wheel scrolled right
`UI_BTN_RELEASE`	set if this is a release event

If you want to know the mouse's position without an event, then you can use

int ui_getmouse(ui_t *ctx, int *x, int *y);

Parameter	Description
`ctx`	Pointer to UI context
`x`	Pointer to store X position
`y`	Pointer to store Y position

Returns 0 on success, error code otherwise.

Gamepad

This is generated whenever the gamepad state changes.

Parameter	Description
`evt->type`	`UI_EVT_GAMEPAD`
`evt->btn`	Current button's state
`evt->x`	Left joystick X position
`evt->y`	Left joystick Y position
`evt->rx`	Right joystick X position
`evt->ry`	Right joystick Y position
`evt->key[0]`	Gamepad's index if there's more than one

Joystick coordinates are signed, and in the range -32768 .. +32768. The btn field is a bitfield with the following values:

Define	Description
`UI_BTN_A`	The 'A'/cross button state
`UI_BTN_B`	The 'B'/circle button state
`UI_BTN_X`	The 'X'/square button state
`UI_BTN_Y`	The 'Y'/triangle button state
`UI_BTN_L`	DPad left button state
`UI_BTN_R`	DPad right button state
`UI_BTN_U`	DPad up button state
`UI_BTN_D`	DPad down button state
`UI_BTN_BA`	Back button state
`UI_BTN_ST`	Start button state
`UI_BTN_GU`	Guide button state
`UI_BTN_LT`	Left thumb button state
`UI_BTN_RT`	Right thumb button state
`UI_BTN_LS`	Left shoulder button state
`UI_BTN_RS`	Right shoulder button state

Keyboard

This is generated whenever a key is pressed on the keyboard.

Parameter	Description
`evt->type`	`UI_EVT_KEY`
`evt->btn`	Modifier key's state
`evt->key`	Pressed key

The returned key is an UTF-8 character, or (in case of special keys) an invalid UTF-8 sequence with the key's name. To distinguish, check if key[1] is non-zero and the most significant bit in key[0] is set (valid UTF-8) or clear (a key name).

HINT: There's no mapping with magic defines, to figure out what code a certain key generates, just print evt->key.

The btn field is a bitfield with the following values:

Define	Description
`UI_BTN_SHIFT`	One of the Shift keys is pressed
`UI_BTN_CONTROL`	One of the Control keys is pressed
`UI_BTN_ALT`	One of the Alt keys is pressed (right key is often called AltGr)
`UI_BTN_GUI`	One of the GUI keys is pressed

For the modifier keys (LShift, RShift, LCtrl, RCtrl, LAlt, RAlt, LGui and RGui) you'll also receive a key release event, with UI_BTN_RELEASE being set. Other keys only generate a key press event.

Dropped File

This is generated whenever a file is dropped on the window.

Parameter	Description
`evt->type`	`UI_EVT_DROP`
`evt->x`	Current mouse X position
`evt->y`	Current mouse Y position
`evt->fn`	Path of the file

Window Resize

This is generated whenever the window is resized.

Parameter	Description
`evt->type`	`UI_EVT_RESIZE`
`evt->x`	New window width
`evt->y`	New window height

Clipboard

Paste

To query the clipboard (after you have received a [keyboard] event with Paste key), call

char *ui_getclipboard(ui_t *ctx);

Parameter	Description
`ctx`	Pointer to UI context

Returns NULL if the clipboard is empty, otherwise the content in a newly allocated buffer. It is the caller's duty to free this buffer after finished using it.

Copy

To set the clipboard (after you have received Cut or Copy key), call

char *ui_setclipboard(ui_t *ctx, char *str);

Parameter	Description
`ctx`	Pointer to UI context
`str`	String to copy to clipboard