fltk/FL/Fl_Window.H

//
// Window header file for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2023 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//

/** \file
   Fl_Window widget . */

#ifndef Fl_Window_H
#define Fl_Window_H

#include <FL/Fl.H>
#include <FL/Fl_Group.H>
#include <FL/Fl_Bitmap.H>

#define FL_WINDOW 0xF0          ///< window type id: all subclasses have type() >= this
#define FL_DOUBLE_WINDOW 0xF1   ///< double window type id

class Fl_X;
class Fl_Window_Driver;
class Fl_RGB_Image;
class Fl_Double_Window;

/**
  This widget produces an actual window.  This can either be a main
  window, with a border and title and all the window management controls,
  or a "subwindow" inside a window.  This is controlled by whether or not
  the window has a parent().

  Once you create a window, you usually add children Fl_Widget's to it
  by using window->add(child) for each new widget.
  See Fl_Group for more information on how to add and remove children.

  There are several subclasses of Fl_Window that provide
  double-buffering, overlay, menu, and OpenGL support.

  The window's callback is done if the user tries to close a window
  using the window manager and Fl::modal() is zero or equal to the
  window. Fl_Window has a default callback that calls Fl_Window::hide().
  Callback reasons can be \p FL_REASON_CANCELLED if the Escape key was pressed,
  or \p FL_REASON_CLOSED when the close button is clicked. \p FL_WHEN_...
  flags are ignored.
*/
class FL_EXPORT Fl_Window : public Fl_Group {
  friend class Fl_X;
  friend class Fl_Window_Driver;
private:
  static char *default_xclass_;
  static char show_next_window_iconic_; // 1 means create next window in iconic form

  int no_fullscreen_x;
  int no_fullscreen_y;
  int no_fullscreen_w;
  int no_fullscreen_h;
  int fullscreen_screen_top;
  int fullscreen_screen_bottom;
  int fullscreen_screen_left;
  int fullscreen_screen_right;

  // TODO: it would make sense to merge the use of Fl_X and Fl_Window_Driver, maybe simply by
  // TODO: deriving Fl_Window_Driver from Fl_X. However, there are a lot of historic kludges
  // TODO: for some platforms around Fl_X.
  Fl_X *flx_; // points at the system-specific stuff, but exists only after the window is mapped
  Fl_Window_Driver *pWindowDriver; // points at the system-specific stuff at window creation time

  const char* iconlabel_;
  char* xclass_;

  // private size_range stuff:
  int minw_, minh_, maxw_, maxh_;
  int dw_, dh_, aspect_;
  uchar size_range_set_;        // true (1) if size_range() has been set or calculated

  // cursor stuff
  Fl_Cursor cursor_default;

  void _Fl_Window(); // constructor innards

  // unimplemented copy ctor and assignment operator
  Fl_Window(const Fl_Window&);
  Fl_Window& operator=(const Fl_Window&);

  void is_maximized_(bool b);

protected:

  /** Stores the last window that was made current. See current() const */
  static Fl_Window *current_;
  void draw() FL_OVERRIDE;

public:

  /** Forces the window to be drawn, this window is also made current and calls draw(). */
  virtual void flush();

protected:

  /**
    Sets an internal flag that tells FLTK and the window manager to
    honor position requests.

    This is used internally and should not be needed by user code.

    \param[in] force 1 to set the FORCE_POSITION flag, 0 to clear it
  */
  void force_position(int force) {
    if (force) set_flag(FORCE_POSITION);
    else clear_flag(FORCE_POSITION);
  }
  /**
    Returns the internal state of the window's FORCE_POSITION flag.

    \retval 1 if flag is set
    \retval 0 otherwise

    \see force_position(int)
  */
  int force_position() const { return ((flags() & FORCE_POSITION)?1:0); }

  void free_icons();

  void default_size_range();  // calculate size_range() if not set explicitly
  int is_resizable();         // calculate size_range() and return whether this is resizable

public:

  /**
    Creates a window from the given width \p w, height \p h, and \p title.
    If Fl_Group::current() is not NULL, the window is created as a
    subwindow of the parent window.

    The (w, h) form of the constructor creates a top-level window
    and asks the window manager to position the window. The (x, y, w, h)
    form of the constructor either creates a subwindow or a
    top-level window at the specified location (x, y), subject to window
    manager configuration. If you do not specify the position of the
    window, the window manager will pick a place to show the window
    or allow the user to pick a location. Use position(x, y)
    or hotspot() before calling show() to request a
    position on the screen. See Fl_Window::resize()
    for some more details on positioning windows.

    Top-level windows initially have visible() set to 0
    and parent() set to NULL. Subwindows initially
    have visible() set to 1 and parent() set to
    the parent window pointer.

    Fl_Widget::box() defaults to FL_FLAT_BOX. If you plan to
    completely fill the window with children widgets you should
    change this to FL_NO_BOX. If you turn the window border off
    you may want to change this to FL_UP_BOX.

    \see Fl_Window(int x, int y, int w, int h, const char *title)
  */
    Fl_Window(int w, int h, const char *title = 0);
  /** Creates a window from the given position (x, y), size (w, h) and title.

   On a multi-screen system, the values computed by
   Fl::screen_xywh(int &X, int &Y, int &W, int &H, int n) can be used to
   discover the coordinates of the area of screen \#n.
   When these screens have various scale factor
   values, an \p (x, y) pair may not be enough to specify the targeted screen
   for the window, because the same \p (x,y) pair can belong to several screens.
   In that situation, a call to Fl_Window::screen_num(int) is to be used to identify
   unambiguously the targeted screen.

    \see Fl_Window(int w, int h, const char *title)
    \see Fl::screen_xywh(int &X, int &Y, int &W, int &H, int n)

   \note Under Wayland, it's generally not possible for the client app to control
   the position of a window in the system. It's possible to specify on what screen
   should the compositor place a fullscreen window. It's also possible to make an
   Fl_Window the child of another window or group and control with \p x and \p y
   its screen position relatively to the enclosing window. Apply member function
   Fl_Window::allow_expand_outside_parent() to the child window to allow it
   to expand partially or totally outside its parent.
  */
    Fl_Window(int x, int y, int w, int h, const char *title = 0);
  /**
    The destructor <I>also deletes all the children</I>. 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_Window and all of its children can be automatic (local)
    variables, but you must declare the Fl_Window <I>first</I> so
    that it is destroyed last.
  */
    virtual ~Fl_Window();

  int handle(int) FL_OVERRIDE;

  /**
    Changes the size and position of the window.  If shown() is true,
    these changes are communicated to the window server (which may
    refuse that size and cause a further resize).  If shown() is
    false, the size and position are used when show() is called.
    See Fl_Group for the effect of resizing on the child widgets.

    You can also call the Fl_Widget methods size(x,y) and position(w,h),
    which are inline wrappers for this virtual function.

    A top-level window can not force, but merely suggest a position and
    size to the operating system. The window manager may not be willing or
    able to display a window at the desired position or with the given
    dimensions. It is up to the application developer to verify window
    parameters after the resize request.
  */
  void resize(int X,int Y,int W,int H) FL_OVERRIDE;
  /** Sets whether or not the window manager border is around the window.
  The default value is true. <I>With some X window
  managers, this does not work after show() has been called.</I>
  */
  void border(int b);
  /**
    Fast inline function to turn the window manager border
    off. It only works before show() is called.
  */
  void clear_border()   {set_flag(NOBORDER);}
  /** Returns whether the window possesses a border */
  unsigned int border() const   {return !(flags() & NOBORDER);}
  /** Activates the flags NOBORDER|OVERRIDE */
  void set_override()   {set_flag(NOBORDER|OVERRIDE);}
  /** Returns non zero if OVERRIDE flag is set, 0 otherwise. */
  unsigned int override() const  { return flags()&OVERRIDE; }
  /**
    A "modal" window, when shown(), will prevent any events from
    being delivered to other windows in the same program, and will also
    remain on top of the other windows (if the X window manager supports
    the "transient for" property).  Several modal windows may be shown at
    once, in which case only the last one shown gets events.  You can see
    which window (if any) is modal by calling Fl::modal().
  */
  void set_modal()      {set_flag(MODAL);}
  /**  Returns true if this window is modal.  */
  unsigned int modal() const    {return flags() & MODAL;}
  /**
    A "non-modal" window (terminology borrowed from Microsoft Windows)
    acts like a modal() one in that it remains on top, but it has
    no effect on event delivery.  There are <I>three</I> states for a
    window: modal, non-modal, and normal.
  */
  void set_non_modal()  {set_flag(NON_MODAL);}
  /**  Returns true if this window is modal or non-modal. */
  unsigned int non_modal() const {return flags() & (NON_MODAL|MODAL);}

  /**
    Clears the "modal" flags and converts a "modal" or "non-modal"
    window back into a "normal" window.

    Note that there are <I>three</I> states for a window: modal,
    non-modal, and normal.

    You can not change the "modality" of a window whilst
    it is shown, so it is necessary to first hide() the window,
    change its "modality" as required, then re-show the window
    for the new state to take effect.

    This method can also be used to change a "modal" window into a
    "non-modal" one. On several supported platforms, the "modal" state
    over-rides the "non-modal" state, so the "modal" state must be
    cleared before the window can be set into the "non-modal"
    state.
    In general, the following sequence should work:

    \code
    win->hide();
    win->clear_modal_states();
    // Set win to new state as desired, or leave "normal", e.g...
    win->set_non_modal();
    win->show();
    \endcode

    \note Under some window managers, the sequence of hiding the
    window and changing its modality will often cause it to be
    re-displayed at a different position when it is subsequently
    shown. This is an irritating feature but appears to be
    unavoidable at present.
    As a result we would advise to use this method only when
    absolutely necessary.

    \see void set_modal(), void set_non_modal()
  */
  void clear_modal_states() {clear_flag(NON_MODAL | MODAL);}

  /**
    Marks the window as a menu window.

    This is intended for internal use, but it can also be used if you
    write your own menu handling. However, this is not recommended.

    This flag is used for correct "parenting" of windows in communication
    with the windowing system. Modern X window managers can use different
    flags to distinguish menu and tooltip windows from normal windows.

    This must be called before the window is shown and cannot be changed
    later.
  */
  void set_menu_window()        {set_flag(MENU_WINDOW);}

  /**  Returns true if this window is a menu window. */
  unsigned int menu_window() const {return flags() & MENU_WINDOW;}

  /**
    Marks the window as a tooltip window.

    This is intended for internal use, but it can also be used if you
    write your own tooltip handling. However, this is not recommended.

    This flag is used for correct "parenting" of windows in communication
    with the windowing system. Modern X window managers can use different
    flags to distinguish menu and tooltip windows from normal windows.

    This must be called before the window is shown and cannot be changed
    later.

    \note Since Fl_Tooltip_Window is derived from Fl_Menu_Window, this
    also \b clears the menu_window() state.
  */
  void set_tooltip_window()     { set_flag(TOOLTIP_WINDOW);
                                  clear_flag(MENU_WINDOW); }
  /**  Returns true if this window is a tooltip window. */
  unsigned int tooltip_window() const {return flags() & TOOLTIP_WINDOW;}

  /**
    Positions the window so that the mouse is pointing at the given
    position, or at the center of the given widget, which may be the
    window itself.  If the optional offscreen parameter is
    non-zero, then the window is allowed to extend off the screen (this
    does not work with some X window managers). \see position()
  */
  void hotspot(int x, int y, int offscreen = 0);
  /** See void Fl_Window::hotspot(int x, int y, int offscreen = 0) */
  void hotspot(const Fl_Widget*, int offscreen = 0);
  /** See void Fl_Window::hotspot(int x, int y, int offscreen = 0) */
  void hotspot(const Fl_Widget& p, int offscreen = 0) {hotspot(&p,offscreen);}

  /**
    Undoes the effect of a previous resize() or show() so that the next time
    show() is called the window manager is free to position the window.

    This is for Forms compatibility only.

    \deprecated please use force_position(0) instead
  */
  void free_position()  {clear_flag(FORCE_POSITION);}

  void size_range(int minw, int minh, int maxw=0, int maxh=0, int dw=0, int dh=0, int aspect=0);

  uchar get_size_range(int *minw, int *minh, int *maxw=NULL, int *maxh=NULL, int *dw=NULL, int *dh=NULL, int *aspect=NULL);

  /** See void Fl_Window::label(const char*)   */
  const char* label() const     {return Fl_Widget::label();}
  /**  See void Fl_Window::iconlabel(const char*)   */
  const char* iconlabel() const {return iconlabel_;}
  /** Sets the window title bar label. */
  void label(const char*);
  /** Sets the icon label. */
  void iconlabel(const char*);
  /** Sets the icon label. */
  void label(const char* label, const char* iconlabel); // platform dependent
  void copy_label(const char* a);

  static void default_xclass(const char*);
  static const char *default_xclass();
  const char* xclass() const;
  void xclass(const char* c);

  static void default_icon(const Fl_RGB_Image*);
  static void default_icons(const Fl_RGB_Image*[], int);
  void icon(const Fl_RGB_Image*);
  void icons(const Fl_RGB_Image*[], int);

#if defined(_WIN32) || defined(FL_DOXYGEN)
  typedef struct HICON__* HICON;
  // These 2 member functions break the driver model but are kept for back compatibility.
  // They are implemented in Fl_win32.cxx

  /** Sets the default window icons (Windows platform only).

   Convenience function to set the default icons using Windows'
   native HICON icon handles.

   The given icons are copied. You can free the icons immediately after
   this call.

   \param[in] big_icon default large icon for all windows
   subsequently created
   \param[in] small_icon default small icon for all windows
   subsequently created

   \see Fl_Window::default_icon(const Fl_RGB_Image *)
   \see Fl_Window::default_icons(const Fl_RGB_Image *[], int)
   \see Fl_Window::icon(const Fl_RGB_Image *)
   \see Fl_Window::icons(const Fl_RGB_Image *[], int)
   \see Fl_Window::icons(HICON, HICON)
   */
  static void default_icons(HICON big_icon, HICON small_icon);

  /** Sets the window icons using HICON handles (Windows platform only).

   The given icons are copied. You can free the icons immediately after
   this call.

   \param[in] big_icon large window icon
   \param[in] small_icon  small window icon
   */
  void icons(HICON big_icon, HICON small_icon);
#endif // defined(_WIN32) || defined(FL_DOXYGEN)

  /* for legacy compatibility */
  const void* icon() const;
  void icon(const void * ic);

  /**
    Returns non-zero if show() has been called (but not hide()
    ). You can tell if a window is iconified with (w->shown()
    && !w->visible()).
  */
  int shown() {return flx_ != 0;}
  /**
    Puts the window on the screen. This has the side
    effect of opening the display, if not done before.

    If the window is already shown then it is restored and raised to the
    top.  This is really convenient because your program can call show()
    at any time, even if the window is already up.  It also means that
    show() serves the purpose of raise() in other toolkits.

    Fl_Window::show(int argc, char **argv) is used for top-level
    windows and allows standard arguments to be parsed from the
    command-line.

    \note For some obscure reasons Fl_Window::show() resets the current
    group by calling Fl_Group::current(0). The comments in the code
    say "get rid of very common user bug: forgot end()". Although
    this is true it may have unwanted side effects if you show() an
    unrelated window (maybe for an error message or warning) while
    building a window or any other group widget.

    \todo Check if we can remove resetting the current group in a later
    FLTK version (after 1.3.x). This may break "already broken" programs
    though if they rely on this "feature".

    \see Fl_Window::show(int argc, char **argv)
  */
  void show() FL_OVERRIDE;
  /**
    Removes the window from the screen.  If the window is already hidden or
    has not been shown then this does nothing and is harmless.
  */
  void hide() FL_OVERRIDE;
  /**
    Puts the window on the screen with show() and parses command-line arguments.

    This call should be used for top-level windows, at least for the
    first (main) window. It allows standard arguments to be parsed, as done by Fl::args(int, char **),
    from the command-line. You can use \p argc and \p argv from
    main(int argc, char **argv) for this call.

    This call also sets up some system-specific internal variables, that is,
    it sets FL_SELECTION_COLOR and calls Fl::background(), Fl::background2(), Fl::foreground()
    with default or X resources-given values, and calls Fl::scheme(const char *) for the current scheme.
    On X11, it also calls Fl::dnd_text_ops(int), Fl_Tooltip::enable(int),
    Fl::visible_focus(int) with X resources-given values.

    \param argc command-line argument count, usually from main()
    \param argv command-line argument vector, usually from main()

    \see virtual void Fl_Window::show()
    \see Fl::args(int, char **)
  */
  void show(int argc, char **argv);

  // Enables synchronous show(), docs in Fl_Window.cxx
  void wait_for_expose();

  /**
    Makes the window completely fill one or more screens, without any
    window manager border visible.  You must use fullscreen_off() to
    undo this.

    \note On some platforms, this can result in the keyboard being
    grabbed. The window may also be recreated, meaning hide() and
    show() will be called.

    \see void Fl_Window::fullscreen_screens()
  */
  void fullscreen();
  /**
    Turns off any side effects of fullscreen()
  */
  void fullscreen_off();
  /**
    Turns off any side effects of fullscreen() and does
    resize(x,y,w,h).
  */
  void fullscreen_off(int X,int Y,int W,int H);
  /**
    Returns non zero if FULLSCREEN flag is set, 0 otherwise.
  */
  unsigned int fullscreen_active() const { return flags() & FULLSCREEN; }
  /**
    Sets which screens should be used when this window is in fullscreen
    mode. The window will be resized to the top of the screen with index
    \p top, the bottom of the screen with index \p bottom, etc.

    If this method is never called, or if any argument is < 0, then the
    window will be resized to fill the screen it is currently on.

    \see void Fl_Window::fullscreen()
    */
  void fullscreen_screens(int top, int bottom, int left, int right);

  void maximize();
  void un_maximize();
  /** Returns whether the window is currently maximized */
  unsigned int maximize_active() const { return flags() & MAXIMIZED; }
public:
  /**
    Iconifies the window.  If you call this when shown() is false
    it will show() it as an icon.  If the window is already
    iconified this does nothing.

    Call show() to restore the window.

    When a window is iconified/restored (either by these calls or by the
    user) the handle() method is called with FL_HIDE and
    FL_SHOW events and visible() is turned on and off.

    There is no way to control what is drawn in the icon except with the
    string passed to Fl_Window::xclass().  You should not rely on
    window managers displaying the icons.
  */
  void iconize();

  int x_root() const ;
  int y_root() const ;

 static Fl_Window *current();
  /**
    Sets things up so that the drawing functions in <FL/fl_draw.H> will go
    into this window. This is useful for incremental update of windows, such
    as in an idle callback, which will make your program behave much better
    if it draws a slow graphic. <B>Danger: incremental update is very hard to
    debug and maintain!</B>

    This method only works for the Fl_Window and Fl_Gl_Window derived classes.
  */
  void make_current();

  void cursor(Fl_Cursor);
  void cursor(const Fl_RGB_Image*, int, int);
  void default_cursor(Fl_Cursor);

  /* for legacy compatibility */
  void cursor(Fl_Cursor c, Fl_Color, Fl_Color=FL_WHITE);
  void default_cursor(Fl_Cursor c, Fl_Color, Fl_Color=FL_WHITE);

  static void default_callback(Fl_Window*, void* v);

  /** Returns the window width including any frame added by the window manager.

   Same as w() if applied to a subwindow, or if window is not yet mapped.
   \see decorated_h().
   */
  int decorated_w() const;

  /** Returns the window height including any window title bar and any frame
   added by the window manager.

   Same as h() if applied to a subwindow, or if window is not yet mapped.
   \note Under X11, FLTK is able to compute the size of window titlebars and borders
   only if these decoration elements are strictly X11-based. When that's not the case,
   decorated_h() returns the same value as h() and decorated_w() as w(), and FLTK
   cannot access window decorations.

   \note Under X11 again, the values returned by decorated_h() and decorated_w()
   may not be reliable <b> during a resize operation</b>. The size of decoration elements
   of a window is best computed when the window is first mapped.
   */
  int decorated_h() const;

  // Note: Doxygen docs in Fl_Widget.H to avoid redundancy.
  Fl_Window* as_window() FL_OVERRIDE { return this; }
  Fl_Window const* as_window() const FL_OVERRIDE { return this; }

  /**
   Return non-null if this is an Fl_Overlay_Window object.
   */
  virtual class Fl_Overlay_Window *as_overlay_window() {return 0L; }

  /**
   Return non-null if this is an Fl_Double_Window object.
   */
  virtual class Fl_Double_Window *as_double_window() {return 0L;}

  void shape(const Fl_Image* img);
  void shape(const Fl_Image& b);
  const Fl_Image *shape();
  void draw_backdrop();
  int screen_num();
  void screen_num(int screen_num);
  static bool is_a_rescale();
  fl_uintptr_t os_id();

  /**
    Sets a static flag whether the next window should be opened iconified.

    \note This is an <b>internal function</b>, you should not use this in user code.

    Please use Fl_Window::iconize() instead.
  */
  static void show_next_window_iconic(char stat) {
    show_next_window_iconic_ = stat ? 1 : 0;
  }

  /**
    Returns the static flag whether the next window should be opened iconified.

    \note This is an <b>internal function</b>, you should not use this in user code.

    Please use Fl_Window::iconize() to iconify a window.
  */
  static char show_next_window_iconic() {
    return show_next_window_iconic_;
  }

  void allow_expand_outside_parent();

};

#endif