FLTK 1.4.0
Fl_Scrollbar Class Reference

The Fl_Scrollbar widget displays a slider with arrow buttons at the ends of the scrollbar. More...

#include <Fl_Scrollbar.H>

Inheritance diagram for Fl_Scrollbar:
Fl_Slider Fl_Valuator Fl_Widget

Public Member Functions

 Fl_Scrollbar (int X, int Y, int W, int H, const char *L=0)
 Creates a new Fl_Scrollbar widget with given position, size, and label. More...
 
int handle (int) FL_OVERRIDE
 Handles the specified event. More...
 
int linesize () const
 Get the size of step, in lines, that the arror keys move.
 
void linesize (int i)
 This number controls how big the steps are that the arrow keys do. More...
 
int value () const
 Gets the integer value (position) of the slider in the scrollbar. More...
 
int value (int p)
 Sets the value (position) of the slider in the scrollbar. More...
 
int value (int pos, int windowSize, int first_line, int total_lines)
 Sets the position, size and range of the slider in the scrollbar. More...
 
 ~Fl_Scrollbar ()
 Destroys the Scrollbar.
 
- Public Member Functions inherited from Fl_Slider
void bounds (double a, double b)
 Sets the minimum (a) and maximum (b) values for the valuator widget. More...
 
 Fl_Slider (int X, int Y, int W, int H, const char *L=0)
 Creates a new Fl_Slider widget using the given position, size, and label string. More...
 
 Fl_Slider (uchar t, int X, int Y, int W, int H, const char *L)
 Creates a new Fl_Slider widget using the given type, position, size, and label string.
 
int handle (int) FL_OVERRIDE
 Handles the specified event. More...
 
int scrollvalue (int pos, int size, int first, int total)
 Sets the size and position of the sliding knob in the box. More...
 
Fl_Boxtype slider () const
 Gets the slider box type.
 
void slider (Fl_Boxtype c)
 Sets the slider box type.
 
float slider_size () const
 Get the dimensions of the moving piece of slider.
 
void slider_size (double v)
 Set the dimensions of the moving piece of slider. More...
 
- Public Member Functions inherited from Fl_Valuator
void bounds (double a, double b)
 Sets the minimum (a) and maximum (b) values for the valuator widget.
 
double clamp (double)
 Clamps the passed value to the valuator range.
 
virtual int format (char *)
 Uses internal rules to format the fields numerical value into the character array pointed to by the passed parameter. More...
 
double increment (double, int)
 Adds n times the step value to the passed value. More...
 
double maximum () const
 Gets the maximum value for the valuator. More...
 
void maximum (double a)
 Sets the maximum value for the valuator. More...
 
double minimum () const
 Gets the minimum value for the valuator. More...
 
void minimum (double a)
 Sets the minimum value for the valuator. More...
 
void precision (int digits)
 Sets the step value to 1.0 / 10digits. More...
 
void range (double a, double b)
 Sets the minimum and maximum values for the valuator. More...
 
double round (double)
 Round the passed value to the nearest step increment. More...
 
double step () const
 Gets or sets the step value. More...
 
void step (double a, int b)
 See double Fl_Valuator::step() const

 
void step (double s)
 See double Fl_Valuator::step() const.
 
void step (int a)
 See double Fl_Valuator::step() const

 
double value () const
 Gets the floating point(double) value. More...
 
int value (double)
 Sets the current value. More...
 
- 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 class Fl_Gl_Window const * as_gl_window () const
 
virtual Fl_Groupas_group ()
 Returns an Fl_Group pointer if this widget is an Fl_Group. More...
 
virtual Fl_Group const * as_group () const
 
virtual Fl_Windowas_window ()
 Returns an Fl_Window pointer if this widget is an Fl_Window. More...
 
virtual Fl_Window const * as_window () const
 
void bind_deimage (Fl_Image *img)
 Sets the image to use as part of the widget label when in the inactive state. More...
 
void bind_deimage (int f)
 Bind the inactive image to the widget, so the widget will delete the image when it is no longer needed. More...
 
void bind_image (Fl_Image *img)
 Sets the image to use as part of the widget label when in the active state. More...
 
void bind_image (int f)
 Bind the image to the widget, so the widget will delete the image when it is no longer needed. 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)
 Sets the current callback function for the widget. More...
 
void callback (Fl_Callback *cb, Fl_Callback_User_Data *p, bool auto_free)
 Sets the current callback function and managed user data for the widget. More...
 
void callback (Fl_Callback *cb, void *p)
 Sets the current callback function and data 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.
 
void deactivate ()
 Deactivates the widget. More...
 
Fl_Imagedeimage ()
 Gets the image that is used as part of the widget label when in the inactive state. More...
 
const Fl_Imagedeimage () const
 Gets the image that is used as part of the widget label when in the inactive state. More...
 
void deimage (Fl_Image &img)
 Sets the image to use as part of the widget label when in the inactive state. More...
 
void deimage (Fl_Image *img)
 Sets the image to use as part of the widget label when in the inactive state. More...
 
int deimage_bound () const
 Returns whether the inactive image is managed by the widget. More...
 
void do_callback (Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
 Calls the widget callback function with default arguments. More...
 
void do_callback (Fl_Widget *widget, long arg, Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
 Calls the widget callback function with arbitrary arguments. More...
 
void do_callback (Fl_Widget *widget, void *arg=0, Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
 Calls the widget callback function with arbitrary arguments. More...
 
virtual void draw ()=0
 Draws the widget. 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 int handle (int event)
 Handles the specified event. More...
 
virtual void hide ()
 Makes a widget invisible. More...
 
Fl_Imageimage ()
 Gets the image that is used as part of the widget label when in the active state. More...
 
const Fl_Imageimage () const
 Gets the image that is used as part of the widget label when in the active state. More...
 
void image (Fl_Image &img)
 Sets the image to use as part of the widget label when in the active state. More...
 
void image (Fl_Image *img)
 Sets the image to use as part of the widget label when in the active state. More...
 
int image_bound () const
 Returns whether the image is managed by the widget. 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...
 
bool needs_keyboard () const
 Returns whether this widget needs a keyboard. More...
 
void needs_keyboard (bool needs)
 Sets whether this widget needs a keyboard. 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...
 
int shortcut_label () const
 Returns whether the widget's label uses '&' to indicate shortcuts. More...
 
void shortcut_label (int value)
 Sets whether the widget's label uses '&' to indicate shortcuts. 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 (Fl_Callback_User_Data *v, bool auto_free)
 Sets the user data for this widget.
 
void user_data (void *v)
 Sets the user data for this widget.
 
unsigned int visible () const
 Returns whether a widget is visible. More...
 
unsigned int visible_focus () const
 Checks whether this widget has a visible focus. More...
 
void visible_focus (int v)
 Modifies keyboard focus navigation. 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

void draw () FL_OVERRIDE
 Draws the widget. More...
 
- Protected Member Functions inherited from Fl_Slider
void draw () FL_OVERRIDE
 Draws the widget. More...
 
void draw (int, int, int, int)
 
int handle (int, int, int, int, int)
 
- Protected Member Functions inherited from Fl_Valuator
 Fl_Valuator (int X, int Y, int W, int H, const char *L)
 Creates a new Fl_Valuator widget using the given position, size, and label string. More...
 
void handle_drag (double newvalue)
 Called during a drag operation, after an FL_WHEN_CHANGED event is received and before the callback.
 
void handle_push ()
 Stores the current value in the previous value.
 
void handle_release ()
 Called after an FL_WHEN_RELEASE event is received and before the callback.
 
int horizontal () const
 Tells if the valuator is an FL_HORIZONTAL one.
 
double previous_value () const
 Gets the previous floating point value before an event changed it.
 
void set_value (double v)
 Sets the current floating point value.
 
double softclamp (double)
 Clamps the value, but accepts v if the previous value is not already out of range.
 
virtual void value_damage ()
 Asks for partial redraw. More...
 
- 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.
 
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.
 
void draw_focus () const
 Draws a focus rectangle around the widget. More...
 
void draw_focus (Fl_Boxtype t, int X, int Y, int W, int H) const
 Draws a focus rectangle around the widget. More...
 
void draw_focus (Fl_Boxtype t, int x, int y, int w, int h, Fl_Color bg) const
 Draws a focus box for the widget at the given position and size. More...
 
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...
 

Additional Inherited Members

- Static Public Member Functions inherited from Fl_Widget
static void default_callback (Fl_Widget *widget, void *data)
 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 ,
  NEEDS_KEYBOARD = 1<<20 , IMAGE_BOUND = 1<<21 , DEIMAGE_BOUND = 1<<22 , AUTO_DELETE_USER_DATA = 1<<23 ,
  MAXIMIZED = 1<<24 , POPUP = 1<<25 , USERFLAG3 = 1<<29 , USERFLAG2 = 1<<30 ,
  USERFLAG1 = 1<<31
}
 flags possible values enumeration. More...
 

Detailed Description

The Fl_Scrollbar widget displays a slider with arrow buttons at the ends of the scrollbar.

Clicking on the arrows move up/left and down/right by linesize(). Scrollbars also accept FL_SHORTCUT events: the arrows move by linesize(), and vertical scrollbars take Page Up/Down (they move by the page size minus linesize()) and Home/End (they jump to the top or bottom).

Scrollbars have step(1) preset (they always return integers). If desired you can set the step() to non-integer values. You will then have to use casts to get at the floating-point versions of value() from Fl_Slider.

Constructor & Destructor Documentation

◆ Fl_Scrollbar()

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

Creates a new Fl_Scrollbar widget with given position, size, and label.

You need to do type(FL_HORIZONTAL) if you want a horizontal scrollbar.

Member Function Documentation

◆ draw()

void Fl_Scrollbar::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 = &scrollbar; // scrollbar is an embedded Fl_Scrollbar
s->draw(); // calls Fl_Scrollbar::draw()
Fl_Widget is the base class for all widgets in FLTK.
Definition: Fl_Widget.H:104

Implements Fl_Widget.

◆ handle()

int Fl_Scrollbar::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.

One exception to the rule in the previous paragraph is if you really want to override the behavior of the base class. This requires knowledge of the details of the inherited class.

In rare cases you may want to return 1 from your handle() method although you don't really handle the event. The effect would be to filter event processing, for instance if you want to dismiss non-numeric characters (keypresses) in a numeric input widget. You may "ring the bell" or show another visual indication or drop the event silently. In such a case you must not call the handle() method of the base class and tell FLTK that you consumed the event by returning 1 even if you didn't do anything with it.

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.

◆ linesize()

void Fl_Scrollbar::linesize ( int  i)
inline

This number controls how big the steps are that the arrow keys do.

In addition page up/down move by the size last sent to value() minus one linesize(). The default is 16.

◆ value() [1/3]

int Fl_Scrollbar::value ( ) const
inline

Gets the integer value (position) of the slider in the scrollbar.

You can get the floating point value with Fl_Slider::value().

See also
Fl_Scrollbar::value(int p)
Fl_Scrollbar::value(int pos, int size, int first, int total)

◆ value() [2/3]

int Fl_Scrollbar::value ( int  p)
inline

Sets the value (position) of the slider in the scrollbar.

See also
Fl_Scrollbar::value()
Fl_Scrollbar::value(int pos, int size, int first, int total)

◆ value() [3/3]

int Fl_Scrollbar::value ( int  pos,
int  windowSize,
int  first_line,
int  total_lines 
)
inline

Sets the position, size and range of the slider in the scrollbar.

Parameters
[in]posposition, first line displayed
[in]windowSizenumber of lines displayed
[in]first_linenumber of first line
[in]total_linestotal number of lines

You should call this every time your window changes size, your data changes size, or your scroll position changes (even if in response to a callback from this scrollbar). All necessary calls to redraw() are done.

Calls Fl_Slider::scrollvalue(int pos, int size, int first, int total).


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