NAME

AG_Checkbox — agar checkbox widget

SYNOPSIS

#include <agar/core.h>
#include <agar/gui.h>

DESCRIPTION

The AG_Checkbox widget controls a boolean variable (i.e., an int or a set of bits in an integer). If a text label is specified, it is displayed next to the control.

INHERITANCE HIERARCHY

AG_Object(3) -> AG_Widget(3) -> AG_Checkbox.

INITIALIZATION

AG_Checkbox *
AG_CheckboxNew(AG_Widget *parent, Uint flags, const char *format, ...);

AG_Checkbox *
AG_CheckboxNewS(AG_Widget *parent, Uint flags, const char *label);

AG_Checkbox *
AG_CheckboxNewFn(AG_Widget *parent, Uint flags, const char *label, AG_EventFn fn, const char *fmt, ...);

AG_Checkbox *
AG_CheckboxNewInt(AG_Widget *parent, Uint flags, const char *label, int *pBool);

AG_Checkbox *
AG_CheckboxNewUint(AG_Widget *parent, Uint flags, const char *label, Uint *pBool);

AG_Checkbox *
AG_CheckboxNewFlag(AG_Widget *parent, Uint flags, const char *label, Uint *pFlags, Uint bitmask);

void
AG_CheckboxSetFromFlags(AG_Widget *parent, Uint flags, Uint *pFlags, const AG_FlagDescr *flagsDescr);

void
AG_CheckboxSetFromFlagsFn(AG_Widget *parent, Uint flags, Uint *pFlags, const AG_FlagDescr *flagsDescr, AG_EventFn fn, const char *fmt, ...);

int
AG_CheckboxGetState(AG_Checkbox *checkbox);

void
AG_CheckboxSetState(AG_Checkbox *checkbox, int enable);

void
AG_CheckboxToggle(AG_Checkbox *checkbox);

The AG_CheckboxNew() function allocates, initializes, and attaches a AG_Checkbox widget. AG_CheckboxNew() accepts an optional text label argument. The AG_CheckboxNewFn() variant also assigns the specified callback function to the ‘checkbox-changed’ event.

Acceptable values for the flags argument include:

AG_CHECKBOX_INVERT: Invert the logical interpretation of "state".
AG_CHECKBOX_SET: Set default "state" to 1 (default = 0).
AG_CHECKBOX_EXCL: Advise that this checkbox is the only widget accessing "state" (so periodic updates are not needed).
AG_CHECKBOX_HFILL: Expand horizontally in parent container.
AG_CHECKBOX_VFILL: Expand vertically in parent container.
AG_CHECKBOX_EXPAND: Shorthand for AG_CHECKBOX_HFILL | AG_CHECKBOX_VFILL.

The AG_CheckboxNewInt() constructor binds "state" to a natural integer. AG_CheckboxNewFlag() binds "state" to one or more bits in the natural integer at pFlags, according to bitmask a.

AG_CheckboxSetFromFlags() creates a set of checkboxes for the given set of flags, described by an array of AG_FlagDescr structures:

typedef struct ag_flag_descr {
	Uint bitmask;			/* Bitmask */
	const char *descr;		/* Bit(s) description */
	int writeable;			/* User-editable */
} AG_FlagDescr;

The AG_CheckboxSetFromFlagsFn() variant sets the event handler for ‘checkbox-changed’ to the given function fn and optional arguments fmt.

AG_CheckboxGetState() returns the current state of the checkbox. AG_CheckboxSetState() sets the of the checkbox, where 0=inactive and 0=active. AG_CheckboxToggle() inverts the state atomically.

BINDINGS

The AG_Checkbox widget provides the following bindings:

BOOL *state: Value (1/0) of natural integer
INT *state: Value (1/0) of natural integer
UINT8 *state: Value (1/0) of 8-bit integer
UINT16 *state: Value (1/0) of 16-bit integer
UINT32 *state: Value (1/0) of 32-bit integer
FLAGS *state: Bits in an int
FLAGS8 *state: Bits in 8-bit word
FLAGS16 *state: Bits in 16-bit word
FLAGS32 *state: Bits in 32-bit word

EVENTS

The AG_Checkbox widget generates the following events:

checkbox-changed(int state): Checkbox state changed (1=enabled, 0=disabled). The ‘state’ binding remains locked during the event handler's execution.

STRUCTURE DATA

For the AG_Checkbox object:

int invert: Invert the logical interpretation of the ‘state’ binding.
AG_Label *lbl: Pointer to the AG_Label(3) displaying the caption text.

EXAMPLES

The following code fragment ties an AG_Checkbox to a boolean variable represented by an int:

int someOption = 0;

AG_Window *win = AG_WindowNew(0);
AG_CheckboxNewInt(win, 0, "Some option", &someOption);
AG_WindowShow(win);

The following code fragment uses an AG_Checkbox to trigger a callback function:

static void
MyCallback(AG_Event *event)
{
	AG_TextInfo(NULL, "Callback invoked");
}

AG_Window *win = AG_WindowNew(0);
AG_CheckboxNewFn(win, 0, "Execute callback", MyCallback, NULL);
AG_WindowShow(win);

The following code fragment creates an array of checkboxes, each tied to a specific bit in a word:

#define FLAG_FOO	0x01
#define FLAG_BAR	0x02
#define FLAG_BAZ	0x04

int myWord = 0;

AG_FlagDescr myFlagDescr[] = {
	{ FLAG_FOO,	"foo flag",		1 },
	{ FLAG_BAR,	"bar flag",		1 },
	{ FLAG_BAZ,	"baz flag (readonly)",	0 },
	{ 0,		NULL,			0 }
};

AG_Window *win = AG_WindowNew(0);
AG_CheckboxSetFromFlags(win, 0, &myWord, myFlagDescr);
AG_WindowShow(win);

HISTORY

The AG_Checkbox widget first appeared in Agar 1.0. AG_CheckboxToggle(), AG_CheckboxGetState() and AG_CheckboxSetState() appeared in Agar 1.6.0.