Fl_Scroll Class Reference

This container widget lets you maneuver around a set of widgets much larger than your window. More...

`#include <Fl_Scroll.H>`

Inheritance diagram for Fl_Scroll:

## Public Types

enum | { HORIZONTAL = 1, VERTICAL = 2, BOTH = 3, ALWAYS_ON = 4, HORIZONTAL_ALWAYS = 5, VERTICAL_ALWAYS = 6, BOTH_ALWAYS = 7 }

## Public Member Functions

void | clear ()
| Clear all but the scrollbars... More...
| Fl_Scroll (int X, int Y, int W, int H, const char *l=0)
| Creates a new Fl_Scroll widget using the given position, size, and label string. More...
int | handle (int)
| Handles the specified event. More...
void | resize (int, int, int, int)
| Resizes the Fl_Group widget and all of its children. More...
void | scroll_to (int, int)
| Moves the contents of the scroll group to a new position. More...
int | scrollbar_size () const
| Gets the current size of the scrollbars' troughs, in pixels. More...
void | scrollbar_size (int newSize)
| Sets the pixel size of the scrollbars' troughs to `newSize`, in pixels. More...
int | xposition () const
| Gets the current horizontal scrolling position. More...
int | yposition () const
| Gets the current vertical scrolling position. More...
Public Member Functions inherited from Fl_Group
Fl_Widget *& | _ddfdesign_kludge ()
| This is for forms compatibility only.
void | add (Fl_Widget &)
| The widget is removed from its current group (if any) and then added to the end of this group.
void | add (Fl_Widget *o)
| See void Fl_Group::add(Fl_Widget &w)
void | add_resizable (Fl_Widget &o)
| Adds a widget to the group and makes it the resizable widget.
Fl_Widget *const * | array () const
| Returns a pointer to the array of children. More...
virtual Fl_Group * | as_group ()
| Returns an Fl_Group pointer if this widget is an Fl_Group. More...
void | begin ()
| Sets the current group so you can build the widget tree by just constructing the widgets. More...
Fl_Widget * | child (int n) const
| Returns array()[n]. More...
int | children () const
| Returns how many child widgets the group has.
void | clear ()
| Deletes all child widgets from memory recursively. More...
void | clip_children (int c)
| Controls whether the group widget clips the drawing of child widgets to its bounding box. More...
unsigned int | clip_children ()
| Returns the current clipping mode. More...
void | end ()
| Exactly the same as current(this->parent()). More...
int | find (const Fl_Widget *) const
| Searches the child array for the widget and returns the index. More...
int | find (const Fl_Widget &o) const
| See int Fl_Group::find(const Fl_Widget *w) const.
| Fl_Group (int, int, int, int, const char *=0)
| Creates a new Fl_Group widget using the given position, size, and label string. More...
void | focus (Fl_Widget *W)
void | forms_end ()
| This is for forms compatibility only.
void | init_sizes ()
| Resets the internal array of widget sizes and positions. More...
void | insert (Fl_Widget &, int i)
| The widget is removed from its current group (if any) and then inserted into this group. More...
void | insert (Fl_Widget &o, Fl_Widget *before)
| This does insert(w, find(before)). More...
void | remove (int index)
| Removes the widget at `index` from the group but does not delete it. More...
void | remove (Fl_Widget &)
| Removes a widget from the group but does not delete it. More...
void | remove (Fl_Widget *o)
| Removes the widget `o` from the group. More...
void | resizable (Fl_Widget &o)
| See void Fl_Group::resizable(Fl_Widget *box)
void | resizable (Fl_Widget *o)
| The resizable widget defines the resizing box for the group. More...
Fl_Widget * | resizable () const
| See void Fl_Group::resizable(Fl_Widget *box)
virtual | ~Fl_Group ()
| The destructor also deletes all the children. 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.
void | argument (long v)
| Sets the current user data (long) argument that is passed to the callback function. More...
virtual class Fl_Gl_Window * | as_gl_window ()
| Returns an Fl_Gl_Window pointer if this widget is an Fl_Gl_Window. More...
virtual Fl_Window * | as_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_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_Image * | deimage ()
| Gets the image that is used as part of the widget label. More...
const Fl_Image * | deimage () 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_Image * | image ()
| Gets the image that is used as part of the widget label. More...
const Fl_Image * | image () 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...
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_Group * | parent () 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...
Fl_Color | selection_color () const
| Gets the selection color. More...
void | selection_color (Fl_Color a)
| Sets the selection color. 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...
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_Window * | window () const
| Returns a pointer to the primary Fl_Window widget. 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...

## Public Attributes

Fl_Scrollbar | hscrollbar
Fl_Scrollbar | scrollbar

## Protected Member Functions

void | bbox (int &, int &, int &, int &)
| Returns the bounding box for the interior of the scrolling area, inside the scrollbars. More...
void | draw ()
| Draws the widget. More...
Protected Member Functions inherited from Fl_Group
void | draw_child (Fl_Widget &widget) const
| Forces a child to redraw. More...
void | draw_children ()
| Draws all children of the group. More...
void | draw_outside_label (const Fl_Widget &widget) const
| Parents normally call this to draw outside labels of child widgets. More...
int * | sizes ()
| Returns the internal array of widget sizes and positions. More...
void | update_child (Fl_Widget &widget) const
| Draws a child only if it needs it. 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. 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...

## Additional Inherited Members

Static Public Member Functions inherited from Fl_Group
static Fl_Group * | current ()
| Returns the currently active group. More...
static void | current (Fl_Group *g)
| Sets the current group. 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

This container widget lets you maneuver around a set of widgets much larger than your window.

If the child widgets are larger than the size of this object then scrollbars will appear so that you can scroll over to them:

If all of the child widgets are packed together into a solid rectangle then you want to set box() to FL_NO_BOX or one of the _FRAME types. This will result in the best output. However, if the child widgets are a sparse arrangement you must set box() to a real _BOX type. This can result in some blinking during redrawing, but that can be solved by using a Fl_Double_Window.

By default you can scroll in both directions, and the scrollbars disappear if the data will fit in the area of the scroll.

Use Fl_Scroll::type() to change this as follows :

- 0 - No scrollbars
- Fl_Scroll::HORIZONTAL - Only a horizontal scrollbar.
- Fl_Scroll::VERTICAL - Only a vertical scrollbar.
- Fl_Scroll::BOTH - The default is both scrollbars.
- Fl_Scroll::HORIZONTAL_ALWAYS - Horizontal scrollbar always on, vertical always off.
- Fl_Scroll::VERTICAL_ALWAYS - Vertical scrollbar always on, horizontal always off.
- Fl_Scroll::BOTH_ALWAYS - Both always on.

Use scrollbar.align(int) ( see void Fl_Widget::align(Fl_Align) ) : to change what side the scrollbars are drawn on.

If the FL_ALIGN_LEFT bit is on, the vertical scrollbar is on the left. If the FL_ALIGN_TOP bit is on, the horizontal scrollbar is on the top. Note that only the alignment flags in scrollbar are considered. The flags in hscrollbar however are ignored.

This widget can also be used to pan around a single child widget "canvas". This child widget should be of your own class, with a draw() method that draws the contents. The scrolling is done by changing the x() and y() of the widget, so this child must use the x() and y() to position its drawing. To speed up drawing it should test fl_push_clip().

Another very useful child is a single Fl_Pack, which is itself a group that packs its children together and changes size to surround them. Filling the Fl_Pack with Fl_Tabs groups (and then putting normal widgets inside those) gives you a very powerful scrolling list of individually-openable panels.

Fluid lets you create these, but you can only lay out objects that fit inside the Fl_Scroll without scrolling. Be sure to leave space for the scrollbars, as Fluid won't show these either.

You cannot use Fl_Window as a child of this since the clipping is not conveyed to it when drawn, and it will draw over the scrollbars and neighboring objects.

## Constructor & Destructor Documentation

Fl_Scroll::Fl_Scroll | ( | int | X,
|  | int | Y,
|  | int | W,
|  | int | H,
|  | const char * | L = `0`
| ) |  |

Creates a new Fl_Scroll widget using the given position, size, and label string.

The default boxtype is FL_NO_BOX.

The destructor also deletes all the children. This allows a whole tree to be deleted at once, without having to keep a pointer to all the children in the user code. A kludge has been done so the Fl_Scroll and all of its children can be automatic (local) variables, but you must declare the Fl_Scroll first, so that it is destroyed last.

## Member Function Documentation

void Fl_Scroll::bbox | ( | int & | X,
|  | int & | Y,
|  | int & | W,
|  | int & | H
| ) |  |

protected

Returns the bounding box for the interior of the scrolling area, inside the scrollbars.

Currently this is only reliable after draw(), and before any resizing of the Fl_Scroll or any child widgets occur.

Todo:
  The visibility of the scrollbars ought to be checked/calculated outside of the draw() method (STR #1895).

void Fl_Scroll::clear | ( |  | ) |

Clear all but the scrollbars...

void Fl_Scroll::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()

Reimplemented from Fl_Group.

int Fl_Scroll::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] | event | the kind of event received

Return values

  0 | if the event was not used or understood
  1 | if the event was used and can be deleted

See Also
  Fl_Event

Reimplemented from Fl_Group.

void Fl_Scroll::resize | ( | int | X,
|  | int | Y,
|  | int | W,
|  | int | H
| ) |  |

virtual

Resizes the Fl_Group widget and all of its children.

The Fl_Group widget first resizes itself, and then it moves and resizes all its children according to the rules documented for Fl_Group::resizable(Fl_Widget*)

See Also
  Fl_Group::resizable(Fl_Widget*)
  Fl_Group::resizable()
  Fl_Widget::resize(int,int,int,int)

Reimplemented from Fl_Group.

void Fl_Scroll::scroll_to | ( | int | X,
|  | int | Y
| ) |  |

Moves the contents of the scroll group to a new position.

int Fl_Scroll::scrollbar_size | ( |  | ) | const

inline

Gets the current size of the scrollbars' troughs, in pixels.

If this value is zero (default), this widget will use the Fl::scrollbar_size() value as the scrollbar's width.

Returns
  Scrollbar size in pixels, or 0 if the global Fl::scrollsize() is being used.

See Also
  Fl::scrollbar_size(int)

void Fl_Scroll::scrollbar_size | ( | int | newSize | ) |

inline

Sets the pixel size of the scrollbars' troughs to `newSize`, in pixels.

Normally you should not need this method, and should use Fl::scrollbar_size(int) instead to manage the size of ALL your widgets' scrollbars. This ensures your application has a consistent UI, is the default behavior, and is normally what you want.

Only use THIS method if you really need to override the global scrollbar size. The need for this should be rare.

Setting `newSize` to the special value of 0 causes the widget to track the global Fl::scrollbar_size(), which is the default.

Parameters

  [in] | newSize | Sets the scrollbar size in pixels. If 0 (default), scrollbar size tracks the global Fl::scrollbar_size()

See Also
  Fl::scrollbar_size()

int Fl_Scroll::xposition | ( |  | ) | const

inline

Gets the current horizontal scrolling position.

int Fl_Scroll::yposition | ( |  | ) | const

inline

Gets the current vertical scrolling position.

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

- Fl_Scroll.H
- Fl_Scroll.cxx

- © 1998-2012 by Bill Spitzak and others.