Agar 1.7 Manual



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


ScreenshotThe 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.


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


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_INVERTInvert the logical interpretation of "state".
AG_CHECKBOX_SETSet default "state" to 1 (default = 0).
AG_CHECKBOX_EXCLAdvise that this checkbox is the only widget accessing "state" (so periodic updates are not needed).
AG_CHECKBOX_HFILLExpand horizontally in parent container.
AG_CHECKBOX_VFILLExpand vertically in parent container.

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.


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


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.


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.


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);

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);

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_Button(3), AG_Event(3), AG_Intro(3), AG_Radio(3), AG_Widget(3), AG_Window(3)


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

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