AG_BUTTON(3)

NAME
AG_Button - agar button widget

SYNOPSIS

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

DESCRIPTION
AG_Button is a push-button displaying a text label or an image. It can trigger events and/or control a boolean value.

INHERITANCE HIERARCHY
AG_Object(3) -> AG_Widget(3) -> AG_Button.

INTERFACE
AG_Button * AG_ButtonNew(AG_Widget *parent, Uint flags, const char *format, ...)

AG_Button * AG_ButtonNewS(AG_Widget *parent, Uint flags, const char *label)

AG_Button * AG_ButtonNewFn(AG_Widget *parent, Uint flags, const char *label, void (*fn)(AG_Event *), const char *fnArgs, ...)

AG_Button * AG_ButtonNewInt(AG_Widget *parent, Uint flags, const char *label, int *p)

AG_Button * AG_ButtonNewUint(AG_Widget *parent, Uint flags, const char *label, Uint *p)

AG_Button * AG_ButtonNewFlag(AG_Widget *parent, Uint flags, const char *label, Uint *p, Uint bitmask)

void AG_ButtonSetInverted(AG_Button *button, int enable)

void AG_ButtonSetFocusable(AG_Button *button, int enable)

void AG_ButtonSetSticky(AG_Button *button, int enable)

void AG_ButtonJustify(AG_Button *button, enum ag_text_justify justify)

void AG_ButtonValign(AG_Button *button, enum ag_text_valign valign)

void AG_ButtonSetRepeatMode(AG_Button *button, int enable)

void AG_ButtonSurface(AG_Button *button, const AG_Surface *su)

void AG_ButtonSurfaceNODUP(AG_Button *button, AG_Surface *su)

void AG_ButtonText(AG_Button *button, const char *format, ...)

void AG_ButtonTextS(AG_Button *button, const char *label)

int AG_ButtonGetState(AG_Button *button)

int AG_ButtonSetState(AG_Button *button, int stateNew)

int AG_ButtonToggle(AG_Button *button)

The AG_ButtonNew() function allocates, initializes, and attaches an AG_Button. If label is non-NULL, it sets the initial text label. For a list of acceptable option flags refer to BUTTON FLAGS below.

The AG_ButtonNewFn() variant creates a button and also specifies a callback routine to run whenever it is pressed. Contrary to AG_ButtonNew(), it implies AG_BUTTON_EXCL (unless AG_BUTTON_NOEXCL is passed).

The AG_ButtonNewInt() shorthand creates a button and also sets its ‘state’ binding to the natural integer at memory location p.

The AG_ButtonNewFlag() shorthand creates a button and also sets its ‘state’ binding to the value of the bit(s) indicated by bitmask contained within the natural integer at memory location p.

AG_ButtonSetInverted() inverts the interpretation of the "state" binding (sets the AG_BUTTON_INVERTED flag).

AG_ButtonSetFocusable() sets whether the button is allowed to receive focus (0 = No, 1 = Yes). Default is Yes (see AG_WidgetFocus(3)).

AG_ButtonSetSticky() sets the behavior of the button when pressed (0 = Momentary, 1 = Sticky). In Momentary mode, the button springs back to its former state when released. Default is Sticky.

AG_ButtonJustify() sets the justification mode for the text label. The justify argument can be AG_TEXT_LEFT, AG_TEXT_CENTER or AG_TEXT_RIGHT.

AG_ButtonValign() sets the vertical alignment for the text label. The valign argument can be AG_TEXT_TOP, AG_TEXT_MIDDLE or AG_TEXT_BOTTOM.

AG_ButtonSetRepeatMode() enables or disables Repeat mode. Repeat mode causes multiple ‘button-pushed’ events to be posted periodically for as long as the button is triggered (with an interval of agMouseSpinIval ms).

AG_ButtonSurface() sets the button label to a copy of the given surface. AG_ButtonSurfaceNODUP() uses the given surface as source without copying (potentially unsafely). If a label is currently set, it is replaced.

AG_ButtonText() sets the label of the button from the specified text string. If a surface is currently set, it is removed.

AG_ButtonGetState() returns the current boolean state of the button (1 = pressed, 0 = released). AG_ButtonSetState() sets the state to stateNew and returns the previous state. AG_ButtonToggle() atomically toggles the state of the button and returns the new state.

BUTTON FLAGS
The following flags are provided:

AG_BUTTON_STICKY
    Prevent the button from springing back to its previous state following a click. Set on initialization or by AG_ButtonSetSticky().

AG_BUTTON_MOUSEOVER
    The cursor is over the button area (read-only).

AG_BUTTON_REPEAT
    Repeat mode is enabled (read-only, see AG_ButtonSetRepeatMode()).

AG_BUTTON_PRESSING
    The button is being activated (read-only).

AG_BUTTON_SET
    Set "state" to 1 when the button becomes visible.

AG_BUTTON_INVERTED
    Invert the interpretation of the "state" binding (Default: 0=Released, 1=Pressed).

AG_BUTTON_EXCL
    Disable the test for redrawing the button upon external changes to the "state" binding.

AG_BUTTON_NO_FOCUS
    Cannot gain focus (see AG_WidgetSetFocusable(3)).

AG_BUTTON_HFILL
    Expand horizontally in parent container.

AG_BUTTON_VFILL
    Expand vertically in parent container.

AG_BUTTON_EXPAND
    Shorthand for AG_BUTTON_HFILL | AG_BUTTON_VFILL.

EVENTS
The AG_Button widget generates the following events:

button-pushed(int new_state)
    The button was pressed. If using AG_BUTTON_STICKY, the new_state argument indicates the new state of the button.

BINDINGS
The AG_Button widget provides the following bindings. In all cases, a value of 1 is considered boolean TRUE, and a value of 0 is considered boolean FALSE.

BOOL *state
    Value (1/0) of natural integer
INT *state
    Value (1/0) of natural integer
UINT *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

EXAMPLES
The following code fragment creates a button and sets a handler function for the ‘button-pushed’ event:

    void
    MyHandlerFn(AG_Event *event)
    {
    	AG_TextMsg(AG_MSG_INFO, "Hello, %s!", AG_STRING(1));
    }
    ...
    AG_ButtonNewFn(parent, 0, "Hello", MyHandlerFn, "%s", "world");

The following code fragment uses buttons to control specific bits in a 32-bit word:

    Uint32 MyFlags = 0;
    AG_ButtonNewFlag32(parent, 0, "Bit 1", &MyFlags, 0x01);
    AG_ButtonNewFlag32(parent, 0, "Bit 2", &MyFlags, 0x02);

The following code fragment uses a button to control an int protected by a mutex device:

    int MyInt = 0;
    AG_Mutex MyMutex;
    AG_Button *btn;
    AG_MutexInit(&MyMutex);
    btn = AG_ButtonNew(parent, 0, "Mutex-protected flag");
    AG_BindIntMp(btn, "state", &MyInt, &MyMutex);

SEE ALSO
AG_Event(3), AG_Intro(3), AG_Surface(3), AG_Toolbar(3), AG_Widget(3), AG_Window(3)

HISTORY
The AG_Button widget first appeared in Agar 1.0. As of Agar 1.6.0 the AG_ButtonSetPadding() call is now deprecated (replaced by AG_SetStyle(3) with "padding" attribute). Agar 1.6.0 also introduced AG_BUTTON_SET.