FLTK 1.3.4
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:
Fl_Group Fl_Widget

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 X, int Y, int W, int H)
 Resizes the Fl_Scroll widget and moves its children if necessary. 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_Groupas_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_Widgetchild (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_Widgetresizable () 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. 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_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...
 
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...
 

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_Groupcurrent ()
 Returns the currently active group. More...
 
static void current (Fl_Group *g)
 Sets the current group. More...
 
- 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

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:

Fl_Scroll.png

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_not_clipped(int x,int y,int w,int h) to find out if a particular area of the widget must be drawn.

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]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_Group.

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

Resizes the Fl_Scroll widget and moves its children if necessary.

The Fl_Scroll widget first resizes itself, and then it moves all its children if (and only if) the Fl_Scroll widget has been moved. The children are moved by the same amount as the Fl_Scroll widget has been moved, hence all children keep their relative positions.

Note
Fl_Scroll::resize() does not call Fl_Group::resize(), and child widgets are not resized.

Since children of an Fl_Scroll are not resized, the resizable() widget is ignored (if it is set).

The scrollbars are moved to their proper positions, as given by Fl_Scroll::scrollbar.align(), and switched on or off as necessary.

Note
Due to current (FLTK 1.3.x) implementation constraints some of this may effectively be postponed until the Fl_Scroll is drawn the next time. This may change in a future release.
See Also
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.

This is like moving the scrollbars of the Fl_Scroll around. For instance:

Fl_Scroll scroll (10,10,200,200);
Fl_Box b1 ( 10, 10,50,50,"b1"); // relative (x,y) = (0,0)
Fl_Box b2 ( 60, 60,50,50,"b2"); // relative (x,y) = (50,50)
Fl_Box b3 ( 60,110,50,50,"b3"); // relative (x,y) = (50,100)
// populate scroll with more children ...
scroll.end();
scroll.scroll_to(50,100);

will move the logical origin of the internal scroll area to (-50,-100) relative to the origin of the Fl_Scroll (10,10), i.e. Fl_Box b3 will be visible in the top left corner of the scroll area.

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::scrollbar_size() 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]newSizeSets 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: