FLTK 1.3.4
Fl_Button Class Reference

Buttons generate callbacks when they are clicked by the user. More...

#include <Fl_Button.H>

Inheritance diagram for Fl_Button:
Fl_Widget Fl_Light_Button Fl_Radio_Button Fl_Repeat_Button Fl_Return_Button Fl_Toggle_Button Fl_Check_Button Fl_Radio_Light_Button Fl_Round_Button Fl_Radio_Round_Button

Public Member Functions

int clear ()
 Same as value(0). More...
 
Fl_Boxtype down_box () const
 Returns the current down box type, which is drawn when value() is non-zero. More...
 
void down_box (Fl_Boxtype b)
 Sets the down box type. More...
 
Fl_Color down_color () const
 (for backwards compatibility)
 
void down_color (unsigned c)
 (for backwards compatibility)
 
 Fl_Button (int X, int Y, int W, int H, const char *L=0)
 The constructor creates the button using the given position, size, and label. More...
 
virtual int handle (int)
 Handles the specified event. More...
 
int set ()
 Same as value(1). More...
 
void setonly ()
 Turns on this button and turns off all other radio buttons in the group (calling value(1) or set() does not do this).
 
int shortcut () const
 Returns the current shortcut key for the button. More...
 
void shortcut (int s)
 Sets the shortcut key to s. More...
 
void shortcut (const char *s)
 (for backwards compatibility)
 
int value (int v)
 Sets the current value of the button. More...
 
char value () const
 Returns the current value of the button (0 or 1).
 
- Public Member Functions inherited from Fl_Widget
void _clear_fullscreen ()
 
void _set_fullscreen ()
 
void activate ()
 Activates the widget. More...
 
unsigned int active () const
 Returns whether the widget is active. More...
 
int active_r () const
 Returns whether the widget and all of its parents are active. More...
 
Fl_Align align () const
 Gets the label alignment. More...
 
void align (Fl_Align alignment)
 Sets the label alignment. More...
 
long argument () const
 Gets the current user data (long) argument that is passed to the callback function. More...
 
void argument (long v)
 Sets the current user data (long) argument that is passed to the callback function. More...
 
virtual class Fl_Gl_Windowas_gl_window ()
 Returns an Fl_Gl_Window pointer if this widget is an Fl_Gl_Window. More...
 
virtual Fl_Groupas_group ()
 Returns an Fl_Group pointer if this widget is an Fl_Group. More...
 
virtual Fl_Windowas_window ()
 Returns an Fl_Window pointer if this widget is an Fl_Window. More...
 
Fl_Boxtype box () const
 Gets the box type of the widget. More...
 
void box (Fl_Boxtype new_box)
 Sets the box type for the widget. More...
 
Fl_Callback_p callback () const
 Gets the current callback function for the widget. More...
 
void callback (Fl_Callback *cb, void *p)
 Sets the current callback function for the widget. More...
 
void callback (Fl_Callback *cb)
 Sets the current callback function for the widget. More...
 
void callback (Fl_Callback0 *cb)
 Sets the current callback function for the widget. More...
 
void callback (Fl_Callback1 *cb, long p=0)
 Sets the current callback function for the widget. More...
 
unsigned int changed () const
 Checks if the widget value changed since the last callback. More...
 
void clear_active ()
 Marks the widget as inactive without sending events or changing focus. More...
 
void clear_changed ()
 Marks the value of the widget as unchanged. More...
 
void clear_damage (uchar c=0)
 Clears or sets the damage flags. More...
 
void clear_output ()
 Sets a widget to accept input. More...
 
void clear_visible ()
 Hides the widget. More...
 
void clear_visible_focus ()
 Disables keyboard focus navigation with this widget. More...
 
Fl_Color color () const
 Gets the background color of the widget. More...
 
void color (Fl_Color bg)
 Sets the background color of the widget. More...
 
void color (Fl_Color bg, Fl_Color sel)
 Sets the background and selection color of the widget. More...
 
Fl_Color color2 () const
 For back compatibility only. More...
 
void color2 (unsigned a)
 For back compatibility only. More...
 
int contains (const Fl_Widget *w) const
 Checks if w is a child of this widget. More...
 
void copy_label (const char *new_label)
 Sets the current label. More...
 
void copy_tooltip (const char *text)
 Sets the current tooltip text. More...
 
uchar damage () const
 Returns non-zero if draw() needs to be called. More...
 
void damage (uchar c)
 Sets the damage bits for the widget. More...
 
void damage (uchar c, int x, int y, int w, int h)
 Sets the damage bits for an area inside the widget. More...
 
int damage_resize (int, int, int, int)
 Internal use only. More...
 
void deactivate ()
 Deactivates the widget. More...
 
Fl_Imagedeimage ()
 Gets the image that is used as part of the widget label. More...
 
const Fl_Imagedeimage () const
 
void deimage (Fl_Image *img)
 Sets the image to use as part of the widget label. More...
 
void deimage (Fl_Image &img)
 Sets the image to use as part of the widget label. More...
 
void do_callback ()
 Calls the widget callback. More...
 
void do_callback (Fl_Widget *o, long arg)
 Calls the widget callback. More...
 
void do_callback (Fl_Widget *o, void *arg=0)
 Calls the widget callback. More...
 
void draw_label (int, int, int, int, Fl_Align) const
 Draws the label in an arbitrary bounding box with an arbitrary alignment. More...
 
int h () const
 Gets the widget height. More...
 
virtual void hide ()
 Makes a widget invisible. More...
 
Fl_Imageimage ()
 Gets the image that is used as part of the widget label. More...
 
const Fl_Imageimage () const
 
void image (Fl_Image *img)
 Sets the image to use as part of the widget label. More...
 
void image (Fl_Image &img)
 Sets the image to use as part of the widget label. More...
 
int inside (const Fl_Widget *wgt) const
 Checks if this widget is a child of wgt. More...
 
int is_label_copied () const
 Returns whether the current label was assigned with copy_label(). More...
 
const char * label () const
 Gets the current label text. More...
 
void label (const char *text)
 Sets the current label pointer. More...
 
void label (Fl_Labeltype a, const char *b)
 Shortcut to set the label text and type in one call. More...
 
Fl_Color labelcolor () const
 Gets the label color. More...
 
void labelcolor (Fl_Color c)
 Sets the label color. More...
 
Fl_Font labelfont () const
 Gets the font to use. More...
 
void labelfont (Fl_Font f)
 Sets the font to use. More...
 
Fl_Fontsize labelsize () const
 Gets the font size in pixels. More...
 
void labelsize (Fl_Fontsize pix)
 Sets the font size in pixels. More...
 
Fl_Labeltype labeltype () const
 Gets the label type. More...
 
void labeltype (Fl_Labeltype a)
 Sets the label type. More...
 
void measure_label (int &ww, int &hh) const
 Sets width ww and height hh accordingly with the label size. More...
 
unsigned int output () const
 Returns if a widget is used for output only. More...
 
Fl_Groupparent () const
 Returns a pointer to the parent widget. More...
 
void parent (Fl_Group *p)
 Internal use only - "for hacks only". More...
 
void position (int X, int Y)
 Repositions the window or widget. More...
 
void redraw ()
 Schedules the drawing of the widget. More...
 
void redraw_label ()
 Schedules the drawing of the label. More...
 
virtual void resize (int x, int y, int w, int h)
 Changes the size or position of the widget. More...
 
Fl_Color selection_color () const
 Gets the selection color. More...
 
void selection_color (Fl_Color a)
 Sets the selection color. More...
 
void set_active ()
 Marks the widget as active without sending events or changing focus. More...
 
void set_changed ()
 Marks the value of the widget as changed. More...
 
void set_output ()
 Sets a widget to output only. More...
 
void set_visible ()
 Makes the widget visible. More...
 
void set_visible_focus ()
 Enables keyboard focus navigation with this widget. More...
 
virtual void show ()
 Makes a widget visible. More...
 
void size (int W, int H)
 Changes the size of the widget. More...
 
int take_focus ()
 Gives the widget the keyboard focus. More...
 
unsigned int takesevents () const
 Returns if the widget is able to take events. More...
 
int test_shortcut ()
 Returns true if the widget's label contains the entered '&x' shortcut. More...
 
const char * tooltip () const
 Gets the current tooltip text. More...
 
void tooltip (const char *text)
 Sets the current tooltip text. More...
 
Fl_Windowtop_window () const
 Returns a pointer to the top-level window for the widget. More...
 
Fl_Windowtop_window_offset (int &xoff, int &yoff) const
 Finds the x/y offset of the current widget relative to the top-level window. More...
 
uchar type () const
 Gets the widget type. More...
 
void type (uchar t)
 Sets the widget type. More...
 
int use_accents_menu ()
 Returns non zero if MAC_USE_ACCENTS_MENU flag is set, 0 otherwise.
 
void * user_data () const
 Gets the user data for this widget. More...
 
void user_data (void *v)
 Sets the user data for this widget. More...
 
unsigned int visible () const
 Returns whether a widget is visible. More...
 
void visible_focus (int v)
 Modifies keyboard focus navigation. More...
 
unsigned int visible_focus ()
 Checks whether this widget has a visible focus. More...
 
int visible_r () const
 Returns whether a widget and all its parents are visible. More...
 
int w () const
 Gets the widget width. More...
 
Fl_When when () const
 Returns the conditions under which the callback is called. More...
 
void when (uchar i)
 Sets the flags used to decide when a callback is called. More...
 
Fl_Windowwindow () const
 Returns a pointer to the nearest parent window up the widget hierarchy. More...
 
int x () const
 Gets the widget position in its window. More...
 
int y () const
 Gets the widget position in its window. More...
 
virtual ~Fl_Widget ()
 Destroys the widget. More...
 

Protected Member Functions

virtual void draw ()
 Draws the widget. More...
 
void simulate_key_action ()
 
- Protected Member Functions inherited from Fl_Widget
void clear_flag (unsigned int c)
 Clears a flag in the flags mask.
 
void draw_backdrop () const
 If FL_ALIGN_IMAGE_BACKDROP is set, the image or deimage will be drawn.
 
void draw_box () const
 Draws the widget box according its box style.
 
void draw_box (Fl_Boxtype t, Fl_Color c) const
 Draws a box of type t, of color c at the widget's position and size. More...
 
void draw_box (Fl_Boxtype t, int x, int y, int w, int h, Fl_Color c) const
 Draws a box of type t, of color c at the position X,Y and size W,H. More...
 
void draw_focus ()
 draws a focus rectangle around the widget
 
void draw_focus (Fl_Boxtype t, int x, int y, int w, int h) const
 Draws a focus box for the widget at the given position and size.
 
void draw_label () const
 Draws the widget's label at the defined label position. More...
 
void draw_label (int, int, int, int) const
 Draws the label in an arbitrary bounding box. More...
 
 Fl_Widget (int x, int y, int w, int h, const char *label=0L)
 Creates a widget at the given position and size. More...
 
unsigned int flags () const
 Gets the widget flags mask.
 
void h (int v)
 Internal use only. More...
 
void set_flag (unsigned int c)
 Sets a flag in the flags mask.
 
void w (int v)
 Internal use only. More...
 
void x (int v)
 Internal use only. More...
 
void y (int v)
 Internal use only. More...
 

Static Protected Member Functions

static void key_release_timeout (void *)
 

Static Protected Attributes

static Fl_Widget_Trackerkey_release_tracker = 0
 

Additional Inherited Members

- Static Public Member Functions inherited from Fl_Widget
static void default_callback (Fl_Widget *cb, void *d)
 The default callback for all widgets that don't set a callback. More...
 
static unsigned int label_shortcut (const char *t)
 Returns the Unicode value of the '&x' shortcut in a given text. More...
 
static int test_shortcut (const char *, const bool require_alt=false)
 Returns true if the given text t contains the entered '&x' shortcut. More...
 
- Protected Types inherited from Fl_Widget
enum  {
  INACTIVE = 1<<0, INVISIBLE = 1<<1, OUTPUT = 1<<2, NOBORDER = 1<<3,
  FORCE_POSITION = 1<<4, NON_MODAL = 1<<5, SHORTCUT_LABEL = 1<<6, CHANGED = 1<<7,
  OVERRIDE = 1<<8, VISIBLE_FOCUS = 1<<9, COPIED_LABEL = 1<<10, CLIP_CHILDREN = 1<<11,
  MENU_WINDOW = 1<<12, TOOLTIP_WINDOW = 1<<13, MODAL = 1<<14, NO_OVERLAY = 1<<15,
  GROUP_RELATIVE = 1<<16, COPIED_TOOLTIP = 1<<17, FULLSCREEN = 1<<18, MAC_USE_ACCENTS_MENU = 1<<19,
  USERFLAG3 = 1<<29, USERFLAG2 = 1<<30, USERFLAG1 = 1<<31
}
 flags possible values enumeration. More...
 

Detailed Description

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(int s) 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.

Todo:
Refactor the doxygen comments for Fl_Button type() documentation.

For an Fl_Button object, the type() call returns one of:

  • FL_NORMAL_BUTTON (0): value() remains unchanged after button press.
  • FL_TOGGLE_BUTTON: value() is inverted after button press.
  • FL_RADIO_BUTTON: value() is set to 1 after button press, and all other buttons in the current group with type() == FL_RADIO_BUTTON are set to zero.
Todo:
Refactor the doxygen comments for Fl_Button when() documentation.

For an Fl_Button object, the following when() values are useful, the default being 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).

Constructor & Destructor Documentation

Fl_Button::Fl_Button ( int  X,
int  Y,
int  W,
int  H,
const char *  L = 0 
)

The constructor creates the button using the given position, size, and label.

The default box type is box(FL_UP_BOX).

You can control how the button is drawn when ON by setting down_box(). The default is FL_NO_BOX (0) which will select an appropriate box type using the normal (OFF) box type by using fl_down(box()).

Derived classes may handle this differently.

Parameters
[in]X,Y,W,Hposition and size of the widget
[in]Lwidget label, default is no label

Member Function Documentation

int Fl_Button::clear ( )
inline

Same as value(0).

See Also
value(int v)
Fl_Boxtype Fl_Button::down_box ( ) const
inline

Returns the current down box type, which is drawn when value() is non-zero.

Return values
Fl_Boxtype
void Fl_Button::down_box ( Fl_Boxtype  b)
inline

Sets the down box type.

The default value of 0 causes FLTK to figure out the correct matching down version of box().

Some derived classes (e.g. Fl_Round_Button and Fl_Light_Button use down_box() for special purposes. See docs of these classes.

Parameters
[in]bdown box type
void Fl_Button::draw ( )
protectedvirtual

Draws the widget.

Never call this function directly. FLTK will schedule redrawing whenever needed. If your widget must be redrawn as soon as possible, call redraw() instead.

Override this function to draw your own widgets.

If you ever need to call another widget's draw method from within your own draw() method, e.g. for an embedded scrollbar, you can do it (because draw() is virtual) like this:

Fl_Widget *s = &scroll; // scroll is an embedded Fl_Scrollbar
s->draw(); // calls Fl_Scrollbar::draw()

Implements Fl_Widget.

Reimplemented in Fl_Light_Button, and Fl_Return_Button.

int Fl_Button::handle ( int  event)
virtual

Handles the specified event.

You normally don't call this method directly, but instead let FLTK do it when the user interacts with the widget.

When implemented in a widget, this function must return 0 if the widget does not use the event or 1 otherwise.

Most of the time, you want to call the inherited handle() method in your overridden method so that you don't short-circuit events that you don't handle. In this last case you should return the callee retval.

Parameters
[in]eventthe kind of event received
Return values
0if the event was not used or understood
1if the event was used and can be deleted
See Also
Fl_Event

Reimplemented from Fl_Widget.

Reimplemented in Fl_Light_Button, Fl_Return_Button, and Fl_Repeat_Button.

int Fl_Button::set ( )
inline

Same as value(1).

See Also
value(int v)
int Fl_Button::shortcut ( ) const
inline

Returns the current shortcut key for the button.

Return values
int
void Fl_Button::shortcut ( int  s)
inline

Sets the shortcut key to s.

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', or 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).

Parameters
[in]sbitwise OR of key and shift flags
int Fl_Button::value ( int  v)

Sets the current value of the button.

A non-zero value sets the button to 1 (ON), and zero sets it to 0 (OFF).

Parameters
[in]vbutton value.
See Also
set(), clear()

The documentation for this class was generated from the following files: