Fl_Widget | +----Fl_Button | +----Fl_Check_Button, Fl_Light_Button, Fl_Repeat_Button, Fl_Return_Button, Fl_Round_Button
#include <FL/Fl_Button.H>
Buttons generate callbacks when they are clicked by the user. You control exactly when and how by changing the values for type() and when().
Buttons can also generate callbacks in response to FL_SHORTCUT events. The button can either have an explicit shortcut() value or a letter shortcut can be indicated in the label() with an '&' character before it. For the label shortcut it does not matter if Alt is held down, but if you have an input field in the same window, the user will have to hold down the Alt key so that the input field does not eat the event first as an FL_KEYBOARD event.
The second form sets the down box type. The default value of 0
causes FLTK to figure out the correct matching down version of
box().
int Fl_Button::set()
Same as value(1).
void Fl_Button::setonly()
Turns on this button and turns off all other radio buttons in the
group (calling value(1) or set() does not do this).
ulong Fl_Button::shortcut() const
The first form returns the current shortcut key for the button.
void Fl_Button::shortcut(ulong key)
The second form sets the shortcut key to key. Setting this
overrides the use of '&' in the label(). The value is a
bitwise OR of a key and a set of shift flags, for example FL_ALT
| 'a'
, FL_ALT | (FL_F + 10)
, or just
'a'
. A value of 0 disables the shortcut.
The key can be any value returned by Fl::event_key(), but will usually be an ASCII letter. Use a lower-case letter unless you require the shift key to be held down.
The shift flags can be any set of values accepted by Fl::event_state(). If the
bit is on that shift key must be pushed. Meta, Alt, Ctrl, and Shift
must be off if they are not in the shift flags (zero for the other
bits indicates a "don't care" setting).
uchar Fl_Button::type() const
The first form of type() returns the current button type,
which can be one of:
void Fl_Button::type(uchar t)
0
: The value is unchanged. FL_TOGGLE_BUTTON
: The value is inverted. FL_RADIO_BUTTON
: The value is set to 1, and all other
buttons in the current group with type() == FL_RADIO_BUTTON
are set to zero. FL_WHEN_RELEASE
:
0
: The callback is not done, instead changed() is
turned on. FL_WHEN_RELEASE
: The callback is done after the user
successfully clicks the button, or when a shortcut is typed. FL_WHEN_CHANGED
: The callback is done each time the
value() changes (when the user pushes and releases the button, and as
the mouse is dragged around in and out of the button).