The Fl_Gl_Window widget sets things up so OpenGL works. More...

#include <Fl_Gl_Window.H>

Inheritance diagram for Fl_Gl_Window:

Public Member Functions
Fl_Gl_Window const *	as_gl_window () const FL_OVERRIDE

Fl_Gl_Window *	as_gl_window () FL_OVERRIDE
	Returns an Fl_Gl_Window pointer if this widget is an Fl_Gl_Window.

int	can_do ()
	Returns non-zero if the hardware supports the current OpenGL mode.

int	can_do_overlay ()
	Returns true if the hardware overlay is possible.

GLContext	context () const
	Returns a pointer to the window's OpenGL rendering context.

void	context (GLContext, int destroy_flag=0)
	Sets a pointer to the GLContext that this window is using.

char	context_valid () const
	Will only be set if the OpenGL context is created or recreated.

void	context_valid (char v)
	See char Fl_Gl_Window::context_valid() const.

	Fl_Gl_Window (int W, int H, const char *l=0)
	Creates a new Fl_Gl_Window widget using the given size, and label string.

	Fl_Gl_Window (int X, int Y, int W, int H, const char *l=0)
	Creates a new Fl_Gl_Window widget using the given position, size, and label string.

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

int	handle (int) FL_OVERRIDE
	Handle some FLTK events as needed.

void	hide () FL_OVERRIDE
	Hides the window and destroys the OpenGL context.

void	hide_overlay ()
	Hides the window if it is not this window, does nothing in Windows.

void	invalidate ()
	The invalidate() method turns off valid() and is equivalent to calling value(0).

void	make_current ()
	The make_current() method selects the OpenGL context for the widget.

void	make_overlay_current ()
	Selects the OpenGL context for the widget's overlay.

Fl_Mode	mode () const
	Returns the current OpenGL capabilities of the window.

int	mode (const int *a)
	Set the OpenGL capabilities of the window using platform-specific data.

int	mode (int a)
	Set or change the OpenGL capabilities of the window.

void	ortho ()
	Sets the projection so 0,0 is in the lower left of the window and each pixel is 1 unit wide/tall.

int	pixel_h ()
	Gives the window height in OpenGL pixels.

int	pixel_w ()
	Gives the window width in OpenGL pixels.

float	pixels_per_unit ()
	The number of pixels per FLTK unit of length for the window.

void	redraw_overlay ()
	Causes draw_overlay() to be called at a later time.

void	resize (int, int, int, int) FL_OVERRIDE
	Changes the size or position of the widget.

void	show () FL_OVERRIDE
	Makes a widget visible.

void	show (int a, char **b)
	Same as Fl_Window::show(int a, char **b)

void	swap_buffers ()
	The swap_buffers() method swaps the back and front buffers.

int	swap_interval () const
	Gets the rate at which the GL windows swaps buffers.

void	swap_interval (int)
	Sets the rate at which the GL windows swaps buffers.

char	valid () const
	Is turned off when FLTK creates a new context for this window or when the window resizes, and is turned on after draw() is called.

void	valid (char v)
	See char Fl_Gl_Window::valid() const.

	~Fl_Gl_Window ()
	The destructor removes the widget and destroys the OpenGL context associated with it.

Public Member Functions inherited from Fl_Window
virtual class Fl_Double_Window *	as_double_window ()
	Return non-null if this is an Fl_Double_Window object.

virtual class Fl_Overlay_Window *	as_overlay_window ()
	Return non-null if this is an Fl_Overlay_Window object.

Fl_Window const *	as_window () const FL_OVERRIDE

Fl_Window *	as_window () FL_OVERRIDE
	Returns an Fl_Window pointer if this widget is an Fl_Window.

unsigned int	border () const
	Returns whether the window possesses a border.

void	border (int b)
	Sets whether or not the window manager border is around the window.

void	clear_border ()
	Fast inline function to turn the window manager border off.

void	clear_modal_states ()
	Clears the "modal" flags and converts a "modal" or "non-modal" window back into a "normal" window.

void	copy_label (const char *a)
	Sets the window titlebar label to a copy of a character string.

void	cursor (const Fl_RGB_Image *, int, int)
	Changes the cursor for this window using the provided image as cursor's shape.

void	cursor (Fl_Cursor c, Fl_Color, Fl_Color=FL_WHITE)
	For back compatibility only.

void	cursor (Fl_Cursor)
	Changes the cursor for this window.

int	decorated_h () const
	Returns the window height including any window title bar and any frame added by the window manager.

int	decorated_w () const
	Returns the window width including any frame added by the window manager.

void	default_cursor (Fl_Cursor c, Fl_Color, Fl_Color=FL_WHITE)
	For back compatibility only.

void	default_cursor (Fl_Cursor)
	Sets the default window cursor.

void	draw_backdrop ()
	Draw the background image if one is set and is aligned inside.

	Fl_Window (int w, int h, const char *title=0)
	Creates a window from the given width `w`, height `h`, and `title`.

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

void	free_position ()
	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.

void	fullscreen ()
	Makes the window completely fill one or more screens, without any window manager border visible.

unsigned int	fullscreen_active () const
	Returns non zero if FULLSCREEN flag is set, 0 otherwise.

void	fullscreen_off ()
	Turns off any side effects of fullscreen()

void	fullscreen_off (int X, int Y, int W, int H)
	Turns off any side effects of fullscreen() and does resize(x,y,w,h).

void	fullscreen_screens (int top, int bottom, int left, int right)
	Sets which screens should be used when this window is in fullscreen mode.

int	handle (int) FL_OVERRIDE
	Handles the specified event.

void	hide () FL_OVERRIDE
	Removes the window from the screen.

void	hotspot (const Fl_Widget &p, 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 (int x, int y, int offscreen=0)
	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.

const void *	icon () const
	Gets the current icon window target dependent data.

void	icon (const Fl_RGB_Image *)
	Sets or resets a single window icon.

void	icon (const void *ic)
	Platform-specific method to set the window icon usable on Windows and X11 only.

void	iconize ()
	Iconifies the window.

const char *	iconlabel () const
	See void Fl_Window::iconlabel(const char*)

void	iconlabel (const char *)
	Sets the icon label.

void	icons (const Fl_RGB_Image *[], int)
	Sets the window icons.

void	icons (HICON big_icon, HICON small_icon)
	Sets the window icons using HICON handles (Windows platform only).

const char *	label () const
	See void Fl_Window::label(const char*)

void	label (const char *)
	Sets the window title bar label.

void	label (const char label, const char iconlabel)
	Sets the icon label.

void	make_current ()
	Sets things up so that the drawing functions in <FL/fl_draw.H> will go into this window.

void	maximize ()
	Maximizes a top-level window to its current screen.

unsigned int	maximize_active () const
	Returns whether the window is currently maximized.

unsigned int	menu_window () const
	Returns true if this window is a menu window.

unsigned int	modal () const
	Returns true if this window is modal.

unsigned int	non_modal () const
	Returns true if this window is modal or non-modal.

fl_uintptr_t	os_id ()
	Returns a platform-specific identification of a shown window, or 0 if not shown.

unsigned int	override () const
	Returns non zero if OVERRIDE flag is set, 0 otherwise.

void	resize (int X, int Y, int W, int H) FL_OVERRIDE
	Changes the size and position of the window.

int	screen_num ()
	The number of the screen containing the mapped window.

void	screen_num (int screen_num)
	Set the number of the screen where to map the window.

void	set_menu_window ()
	Marks the window as a menu window.

void	set_modal ()
	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).

void	set_non_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.

void	set_override ()
	Activates the flags NOBORDER\|OVERRIDE.

void	set_tooltip_window ()
	Marks the window as a tooltip window.

const Fl_Image *	shape ()
	Returns the image controlling the window shape or NULL.

void	shape (const Fl_Image &b)
	Set the window's shape with an Fl_Image.

void	shape (const Fl_Image *img)
	Assigns a non-rectangular shape to the window.

void	show () FL_OVERRIDE
	Puts the window on the screen.

void	show (int argc, char **argv)
	Puts the window on the screen with show() and parses command-line arguments.

int	shown ()
	Returns non-zero if show() has been called (but not hide() ).

void	size_range (int minw, int minh, int maxw=0, int maxh=0, int dw=0, int dh=0, int aspect=0)
	Sets the allowable range the user can resize this window to.

unsigned int	tooltip_window () const
	Returns true if this window is a tooltip window.

void	un_maximize ()
	Returns a previously maximized top-level window to its previous size.

void	wait_for_expose ()
	Waits for the window to be displayed after calling show().

int	x_root () const
	Gets the x position of the window on the screen.

const char *	xclass () const
	Returns the xclass for this window, or a default.

void	xclass (const char *c)
	Sets the xclass for this window.

int	y_root () const
	Gets the y position of the window on the screen.

virtual	~Fl_Window ()
	The destructor also deletes all the children.

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.

Fl_Group const *	as_group () const FL_OVERRIDE

Fl_Group *	as_group () FL_OVERRIDE
	Returns an Fl_Group pointer if this widget is an Fl_Group.

void	begin ()
	Sets the current group so you can build the widget tree by just constructing the widgets.

Fl_Widget *	child (int n) const
	Returns array()[n].

int	children () const
	Returns how many child widgets the group has.

void	clear ()
	Deletes all child widgets from memory recursively.

unsigned int	clip_children ()
	Returns the current clipping mode.

void	clip_children (int c)
	Controls whether the group widget clips the drawing of child widgets to its bounding box.

virtual int	delete_child (int n)
	Removes the widget at `index` from the group and deletes it.

void	end ()
	Exactly the same as current(this->parent()).

int	find (const Fl_Widget &o) const
	See int Fl_Group::find(const Fl_Widget *w) const.

int	find (const Fl_Widget *) const
	Searches the child array for the widget and returns the index.

	Fl_Group (int, int, int, int, const char *=0)
	Creates a new Fl_Group widget using the given position, size, and label string.

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.

void	insert (Fl_Widget &, int i)
	The widget is removed from its current group (if any) and then inserted into this group.

void	insert (Fl_Widget &o, Fl_Widget *before)
	This does insert(w, find(before)).

void	remove (Fl_Widget &)
	Removes a widget from the group but does not delete it.

void	remove (Fl_Widget *o)
	Removes the widget `o` from the group.

void	remove (int index)
	Removes the widget at `index` from the group but does not delete it.

Fl_Widget *	resizable () const
	Returns the group's resizable widget.

void	resizable (Fl_Widget &o)
	Sets the group's resizable widget.

void	resizable (Fl_Widget *o)
	The resizable widget defines both the resizing box and the resizing behavior of the group and its children.

virtual	~Fl_Group ()
	The destructor also deletes all the children.

Public Member Functions inherited from Fl_Widget
void	_clear_fullscreen ()

void	_set_fullscreen ()

void	activate ()
	Activates the widget.

unsigned int	active () const
	Returns whether the widget is active.

int	active_r () const
	Returns whether the widget and all of its parents are active.

Fl_Align	align () const
	Gets the label alignment.

void	align (Fl_Align alignment)
	Sets the label alignment.

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.

void	bind_deimage (Fl_Image *img)
	Sets the image to use as part of the widget label when in the inactive state.

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.

void	bind_image (Fl_Image *img)
	Sets the image to use as part of the widget label when in the active state.

void	bind_image (int f)
	Bind the image to the widget, so the widget will delete the image when it is no longer needed.

Fl_Boxtype	box () const
	Gets the box type of the widget.

void	box (Fl_Boxtype new_box)
	Sets the box type for the widget.

Fl_Callback_p	callback () const
	Gets the current callback function for the widget.

void	callback (Fl_Callback *cb)
	Sets the current callback function for the widget.

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.

void	callback (Fl_Callback cb, void p)
	Sets the current callback function and data for the widget.

void	callback (Fl_Callback0 *cb)
	Sets the current callback function for the widget.

void	callback (Fl_Callback1 *cb, long p=0)
	Sets the current callback function for the widget.

unsigned int	changed () const
	Checks if the widget value changed since the last callback.

void	clear_active ()
	Marks the widget as inactive without sending events or changing focus.

void	clear_changed ()
	Marks the value of the widget as unchanged.

void	clear_damage (uchar c=0)
	Clears or sets the damage flags.

void	clear_output ()
	Sets a widget to accept input.

void	clear_visible ()
	Hides the widget.

void	clear_visible_focus ()
	Disables keyboard focus navigation with this widget.

Fl_Color	color () const
	Gets the background color of the widget.

void	color (Fl_Color bg)
	Sets the background color of the widget.

void	color (Fl_Color bg, Fl_Color sel)
	Sets the background and selection color of the widget.

Fl_Color	color2 () const
	For back compatibility only.

void	color2 (unsigned a)
	For back compatibility only.

int	contains (const Fl_Widget *w) const
	Checks if w is a child of this widget.

void	copy_label (const char *new_label)
	Sets the current label.

void	copy_tooltip (const char *text)
	Sets the current tooltip text.

uchar	damage () const
	Returns non-zero if draw() needs to be called.

void	damage (uchar c)
	Sets the damage bits for the widget.

void	damage (uchar c, int x, int y, int w, int h)
	Sets the damage bits for an area inside the widget.

int	damage_resize (int, int, int, int)
	Internal use only.

void	deactivate ()
	Deactivates the widget.

Fl_Image *	deimage ()
	Gets the image that is used as part of the widget label when in the inactive state.

const Fl_Image *	deimage () const
	Gets the image that is used as part of the widget label when in the inactive state.

void	deimage (Fl_Image &img)
	Sets the image to use as part of the widget label when in the inactive state.

void	deimage (Fl_Image *img)
	Sets the image to use as part of the widget label when in the inactive state.

int	deimage_bound () const
	Returns whether the inactive image is managed by the widget.

void	do_callback (Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
	Calls the widget callback function with default arguments.

void	do_callback (Fl_Widget *widget, long arg, Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
	Calls the widget callback function with arbitrary arguments.

void	do_callback (Fl_Widget widget, void arg=0, Fl_Callback_Reason reason=FL_REASON_UNKNOWN)
	Calls the widget callback function with arbitrary arguments.

void	draw_label (int, int, int, int, Fl_Align) const
	Draws the label in an arbitrary bounding box with an arbitrary alignment.

int	h () const
	Gets the widget height.

Fl_Image *	image ()
	Gets the image that is used as part of the widget label when in the active state.

const Fl_Image *	image () const
	Gets the image that is used as part of the widget label when in the active state.

void	image (Fl_Image &img)
	Sets the image to use as part of the widget label when in the active state.

void	image (Fl_Image *img)
	Sets the image to use as part of the widget label when in the active state.

int	image_bound () const
	Returns whether the image is managed by the widget.

int	inside (const Fl_Widget *wgt) const
	Checks if this widget is a child of `wgt`.

int	is_label_copied () const
	Returns whether the current label was assigned with copy_label().

const char *	label () const
	Gets the current label text.

void	label (const char *text)
	Sets the current label pointer.

void	label (Fl_Labeltype a, const char *b)
	Shortcut to set the label text and type in one call.

Fl_Color	labelcolor () const
	Gets the label color.

void	labelcolor (Fl_Color c)
	Sets the label color.

Fl_Font	labelfont () const
	Gets the font to use.

void	labelfont (Fl_Font f)
	Sets the font to use.

Fl_Fontsize	labelsize () const
	Gets the font size in pixels.

void	labelsize (Fl_Fontsize pix)
	Sets the font size in pixels.

Fl_Labeltype	labeltype () const
	Gets the label type.

void	labeltype (Fl_Labeltype a)
	Sets the label type.

void	measure_label (int &ww, int &hh) const
	Sets width ww and height hh accordingly with the label size.

bool	needs_keyboard () const
	Returns whether this widget needs a keyboard.

void	needs_keyboard (bool needs)
	Sets whether this widget needs a keyboard.

unsigned int	output () const
	Returns if a widget is used for output only.

Fl_Group *	parent () const
	Returns a pointer to the parent widget.

void	parent (Fl_Group *p)
	Internal use only - "for hacks only".

void	position (int X, int Y)
	Repositions the window or widget.

void	redraw ()
	Schedules the drawing of the widget.

void	redraw_label ()
	Schedules the drawing of the label.

Fl_Color	selection_color () const
	Gets the selection color.

void	selection_color (Fl_Color a)
	Sets the selection color.

void	set_active ()
	Marks the widget as active without sending events or changing focus.

void	set_changed ()
	Marks the value of the widget as changed.

void	set_output ()
	Sets a widget to output only.

void	set_visible ()
	Makes the widget visible.

void	set_visible_focus ()
	Enables keyboard focus navigation with this widget.

int	shortcut_label () const
	Returns whether the widget's label uses '&' to indicate shortcuts.

void	shortcut_label (int value)
	Sets whether the widget's label uses '&' to indicate shortcuts.

void	size (int W, int H)
	Changes the size of the widget.

int	take_focus ()
	Gives the widget the keyboard focus.

unsigned int	takesevents () const
	Returns if the widget is able to take events.

int	test_shortcut ()
	Returns true if the widget's label contains the entered '&x' shortcut.

const char *	tooltip () const
	Gets the current tooltip text.

void	tooltip (const char *text)
	Sets the current tooltip text.

Fl_Window *	top_window () const
	Returns a pointer to the top-level window for the widget.

Fl_Window *	top_window_offset (int &xoff, int &yoff) const
	Finds the x/y offset of the current widget relative to the top-level window.

uchar	type () const
	Gets the widget type.

void	type (uchar t)
	Sets the widget type.

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.

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.

unsigned int	visible_focus () const
	Checks whether this widget has a visible focus.

void	visible_focus (int v)
	Modifies keyboard focus navigation.

int	visible_r () const
	Returns whether a widget and all its parents are visible.

int	w () const
	Gets the widget width.

Fl_When	when () const
	Returns the conditions under which the callback is called.

void	when (uchar i)
	Sets the flags used to decide when a callback is called.

Fl_Window *	window () const
	Returns a pointer to the nearest parent window up the widget hierarchy.

int	x () const
	Gets the widget position in its window.

int	y () const
	Gets the widget position in its window.

virtual	~Fl_Widget ()
	Destroys the widget.

Static Public Member Functions
static int	can_do (const int *m)
	Returns non-zero if the hardware supports the given OpenGL mode.

static int	can_do (int m)
	Returns non-zero if the hardware supports the given OpenGL mode.

Static Public Member Functions inherited from Fl_Window
static Fl_Window *	current ()
	Returns the last window that was made current.

static void	default_callback (Fl_Window , void v)
	Back compatibility: Sets the default callback v for win to call on close event.

static void	default_icon (const Fl_RGB_Image *)
	Sets a single default window icon.

static void	default_icons (const Fl_RGB_Image *[], int)
	Sets the default window icons.

static void	default_icons (HICON big_icon, HICON small_icon)
	Sets the default window icons (Windows platform only).

static const char *	default_xclass ()
	Returns the default xclass.

static void	default_xclass (const char *)
	Sets the default window xclass.

static bool	is_a_rescale ()
	Returns true when a window is being rescaled.

static char	show_next_window_iconic ()
	Returns the static flag whether the next window should be opened iconified.

static void	show_next_window_iconic (char stat)
	Sets a static flag whether the next window should be opened iconified.

Static Public Member Functions inherited from Fl_Group
static Fl_Group *	current ()
	Returns the currently active group.

static void	current (Fl_Group *g)
	Sets the current group.

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.

static unsigned int	label_shortcut (const char *t)
	Returns the Unicode value of the '&x' shortcut in a given text.

static int	test_shortcut (const char *, const bool require_alt=false)
	Returns true if the given text `t` contains the entered '&x' shortcut.

Protected Member Functions
void	draw () FL_OVERRIDE
	Draws the Fl_Gl_Window.

void	draw_begin ()
	Supports drawing to an Fl_Gl_Window with the FLTK 2D drawing API.

void	draw_end ()
	To be used as a match for a previous call to Fl_Gl_Window::draw_begin().

Protected Member Functions inherited from Fl_Window
void	default_size_range ()
	Protected method to calculate the default size range of a window.

void	draw () FL_OVERRIDE
	Draws the widget.

int	force_position () const
	Returns the internal state of the window's FORCE_POSITION flag.

void	force_position (int force)
	Sets an internal flag that tells FLTK and the window manager to honor position requests.

void	free_icons ()
	Deletes all icons previously attached to the window.

int	is_resizable ()
	Protected method to determine whether a window is resizable.

Protected Member Functions inherited from Fl_Group
Fl_Rect *	bounds ()
	Returns the internal array of widget sizes and positions.

void	draw_child (Fl_Widget &widget) const
	Forces a child to redraw.

void	draw_children ()
	Draws all children of the group.

void	draw_outside_label (const Fl_Widget &widget) const
	Parents normally call this to draw outside labels of child widgets.

virtual int	on_insert (Fl_Widget *, int)
	Allow derived groups to act when a widget is added as a child.

virtual int	on_move (int, int)
	Allow derived groups to act when a widget is moved within the group.

virtual void	on_remove (int)
	Allow derived groups to act when a child widget is removed from the group.

int *	sizes ()
	Returns the internal array of widget sizes and positions.

void	update_child (Fl_Widget &widget) const
	Draws a child only if it needs it.

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.

void	draw_focus (Fl_Boxtype t, int X, int Y, int W, int H) const
	Draws a focus rectangle around the widget.

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.

void	draw_label () const
	Draws the widget's label at the defined label position.

void	draw_label (int, int, int, int) const
	Draws the label in an arbitrary bounding box.

	Fl_Widget (int x, int y, int w, int h, const char *label=0L)
	Creates a widget at the given position and size.

unsigned int	flags () const
	Gets the widget flags mask.

void	h (int v)
	Internal use only.

void	set_flag (unsigned int c)
	Sets a flag in the flags mask.

void	w (int v)
	Internal use only.

void	x (int v)
	Internal use only.

void	y (int v)
	Internal use only.

Friends
class	Fl_Gl_Window_Driver

Additional Inherited Members
Public Types inherited from Fl_Window
typedef struct HICON__ *	HICON

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...

Static Protected Attributes inherited from Fl_Window
static Fl_Window *	current_
	Stores the last window that was made current.

Detailed Description

The Fl_Gl_Window widget sets things up so OpenGL works.

It also keeps an OpenGL "context" for that window, so that changes to the lighting and projection may be reused between redraws. Fl_Gl_Window also flushes the OpenGL streams and swaps buffers after draw() returns.

OpenGL hardware typically provides some overlay bit planes, which are very useful for drawing UI controls atop your 3D graphics. If the overlay hardware is not provided, FLTK tries to simulate the overlay. This works pretty well if your graphics are double buffered, but not very well for single-buffered.

Please note that the FLTK drawing and clipping functions will not work inside an Fl_Gl_Window. All drawing should be done using OpenGL calls exclusively.

See also: OpenGL and support of HighDPI displays

Note: FLTK 1.4 introduces a driver system for graphic calls. It is now possible to add a selection of widgets to an OpenGL window. The widgets will draw on top of any OpenGL rendering. The number of supported widgets will increase as the driver development improves. Program test/cube.cxx illustrates how to do that.; FLTK expects that when an Fl_Gl_Window is a child of a parent Fl_Window, the child window lies entirely inside its parent window. If that's not the case, what happens to the part of the GL subwindow which leaks outside its parent is undefined and susceptible to be platform-specific.

Constructor & Destructor Documentation

◆ Fl_Gl_Window() [1/2]

Fl_Gl_Window::Fl_Gl_Window	(	int	W,
		int	H,
		const char *	l = `0`
	)

inline

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

The default boxtype is FL_NO_BOX. The default mode is FL_RGB|FL_DOUBLE|FL_DEPTH.

◆ Fl_Gl_Window() [2/2]

Fl_Gl_Window::Fl_Gl_Window	(	int	X,
		int	Y,
		int	W,
		int	H,
		const char *	l = `0`
	)

inline

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

The default boxtype is FL_NO_BOX. The default mode is FL_RGB|FL_DOUBLE|FL_DEPTH.

Member Function Documentation

◆ as_gl_window() [1/2]

Fl_Gl_Window const * Fl_Gl_Window::as_gl_window ( ) const

inlinevirtual

Reimplemented from Fl_Widget.

◆ as_gl_window() [2/2]

Fl_Gl_Window * Fl_Gl_Window::as_gl_window ( )

inlinevirtual

Returns an Fl_Gl_Window pointer if this widget is an Fl_Gl_Window.

Use this method if you have a widget (pointer) and need to know whether this widget is derived from Fl_Gl_Window. If it returns non-NULL, then the widget in question is derived from Fl_Gl_Window.

Return values

NULL	if this widget is not derived from Fl_Gl_Window.

Note: This method is provided to avoid dynamic_cast.

See also: Fl_Widget::as_group(), Fl_Widget::as_window()

Reimplemented from Fl_Widget.

◆ can_do()

static int Fl_Gl_Window::can_do ( const int * m )

inlinestatic

Returns non-zero if the hardware supports the given OpenGL mode.

See also: Fl_Gl_Window::mode(const int *a)

◆ can_do_overlay()

int Fl_Gl_Window::can_do_overlay ( )

Returns true if the hardware overlay is possible.

If this is false, FLTK will try to simulate the overlay, with significant loss of update speed. Calling this will cause FLTK to open the display.

◆ context() [1/2]

GLContext Fl_Gl_Window::context ( ) const

inline

Returns a pointer to the window's OpenGL rendering context.

See also: void context(GLContext c, int destroy_flag)

◆ context() [2/2]

void Fl_Gl_Window::context	(	GLContext	v,
		int	destroy_flag = `0`
	)

Sets a pointer to the GLContext that this window is using.

This is a system-dependent structure, but it is portable to copy the context from one window to another. You can also set it to NULL, which will force FLTK to recreate the context the next time make_current() is called, this is useful for getting around bugs in OpenGL implementations.

If destroy_flag is true the context will be destroyed by fltk when the window is destroyed, or when the mode() is changed, or the next time context(x) is called.

◆ context_valid()

char Fl_Gl_Window::context_valid ( ) const

inline

Will only be set if the OpenGL context is created or recreated.

It differs from Fl_Gl_Window::valid() which is also set whenever the context changes size.

◆ draw()

void Fl_Gl_Window::draw ( void )

protectedvirtual

Draws the Fl_Gl_Window.

You must subclass Fl_Gl_Window and provide an implementation for draw(). You may also provide an implementation of draw_overlay() if you want to draw into the overlay planes. You can avoid reinitializing the viewport and lights and other things by checking valid() at the start of draw() and only doing the initialization if it is false.

The draw() method can only use OpenGL calls. Do not attempt to call X, any of the functions in <FL/fl_draw.H>, or glX directly. Do not call gl_start() or gl_finish().

If double-buffering is enabled in the window, the back and front buffers are swapped after this function is completed.

The following pseudo-code shows how to use "if (!valid())" to initialize the viewport:

void mywindow::draw() {
 if (!valid()) {
     glViewport(0,0,pixel_w(),pixel_h());
     glFrustum(...) or glOrtho(...)
     ...other initialization...
 }
 if (!context_valid()) {
     ...load textures, etc. ...
 }
 // clear screen
 glClearColor(...);
 glClear(...);
 ... draw your geometry here ...
}

Actual example code to clear screen to black and draw a 2D white "X":

void mywindow::draw() {
    if (!valid()) {
        glLoadIdentity();
        glViewport(0,0,pixel_w(),pixel_h());
        glOrtho(-w(),w(),-h(),h(),-1,1);
    }
    // Clear screen
    glClear(GL_COLOR_BUFFER_BIT);
    // Draw white 'X'
    glColor3f(1.0, 1.0, 1.0);
    glBegin(GL_LINE_STRIP); glVertex2f(w(), h()); glVertex2f(-w(),-h()); glEnd();
    glBegin(GL_LINE_STRIP); glVertex2f(w(),-h()); glVertex2f(-w(), h()); glEnd();
}

Regular FLTK widgets can be added as children to the Fl_Gl_Window. To correctly overlay the widgets, Fl_Gl_Window::draw() must be called after rendering the main scene.

void mywindow::draw() {
  // draw 3d graphics scene
  Fl_Gl_Window::draw();
  // -- or --
  draw_begin();
  Fl_Window::draw();
  // other 2d drawing calls, overlays, etc.
  draw_end();
}

Implements Fl_Widget.

Reimplemented in Fl_Glut_Window.

◆ draw_begin()

void Fl_Gl_Window::draw_begin ( )

protected

Supports drawing to an Fl_Gl_Window with the FLTK 2D drawing API.

See also: Using FLTK widgets in OpenGL Windows

◆ draw_end()

void Fl_Gl_Window::draw_end ( )

protected

To be used as a match for a previous call to Fl_Gl_Window::draw_begin().

See also: Using FLTK widgets in OpenGL Windows

◆ flush()

void Fl_Gl_Window::flush ( )

virtual

Forces the window to be drawn, this window is also made current and calls draw().

Reimplemented from Fl_Window.

◆ handle()

int Fl_Gl_Window::handle ( int event )

virtual

Handle some FLTK events as needed.

Reimplemented from Fl_Widget.

Reimplemented in Fl_Glut_Window.

◆ hide()

void Fl_Gl_Window::hide ( )

virtual

Hides the window and destroys the OpenGL context.

Reimplemented from Fl_Widget.

◆ make_current()

void Fl_Gl_Window::make_current ( )

The make_current() method selects the OpenGL context for the widget.

It is called automatically prior to the draw() method being called and can also be used to implement feedback and/or selection within the handle() method.

◆ make_overlay_current()

void Fl_Gl_Window::make_overlay_current ( )

Selects the OpenGL context for the widget's overlay.

This method is called automatically prior to the draw_overlay() method being called and can also be used to implement feedback and/or selection within the handle() method.

◆ mode() [1/3]

Fl_Mode Fl_Gl_Window::mode ( ) const

inline

Returns the current OpenGL capabilities of the window.

Don't use this if capabilities were set through Fl_Gl_Window::mode(const int *a).

◆ mode() [2/3]

int Fl_Gl_Window::mode ( const int * a )

inline

Set the OpenGL capabilities of the window using platform-specific data.

Parameters

a	zero-ending array of platform-specific attributes and attribute values

Unix/Linux platform: attributes are GLX attributes adequate for the 3rd argument of the glXChooseVisual() function (e.g., GLX_DOUBLEBUFFER, defined by including <GL/glx.h>).

Note: What attributes are adequate here is subject to change. The preferred, stable public API is Fl_Gl_Window::mode(int a).

Windows platform: this member function is of no use.

Mac OS X platform: attributes belong to the CGLPixelFormatAttribute enumeration (defined by including <OpenGL/OpenGL.h>, e.g., kCGLPFADoubleBuffer) and may be followed by adequate attribute values.

◆ mode() [3/3]

int Fl_Gl_Window::mode ( int a )

inline

Set or change the OpenGL capabilities of the window.

The value can be any of the following OR'd together:

FL_RGB - RGB color (not indexed)
FL_RGB8 - RGB color with at least 8 bits of each color
FL_INDEX - Indexed mode
FL_SINGLE - not double buffered
FL_DOUBLE - double buffered
FL_ACCUM - accumulation buffer
FL_ALPHA - alpha channel in color
FL_DEPTH - depth buffer
FL_STENCIL - stencil buffer
FL_MULTISAMPLE - multisample antialiasing
FL_OPENGL3 - use OpenGL version 3.0 or more.

FL_RGB and FL_SINGLE have a value of zero, so they are "on" unless you give FL_INDEX or FL_DOUBLE.

If the desired combination cannot be done, FLTK will try turning off FL_MULTISAMPLE. If this also fails the show() will call Fl::error() and not show the window.

You can change the mode while the window is displayed. This is most useful for turning double-buffering on and off. Under X this will cause the old X window to be destroyed and a new one to be created. If this is a top-level window this will unfortunately also cause the window to blink, raise to the top, and be de-iconized, and the xid() will change, possibly breaking other code. It is best to make the GL window a child of another window if you wish to do this!

mode() must not be called within draw() since it changes the current context.

The FL_OPENGL3 flag is required to access OpenGL version 3 or more under the X11 and MacOS platforms; it's optional under Windows and Wayland. See more details in Using OpenGL 3.0 (or higher versions).

Version: the FL_OPENGL3 flag appeared in version 1.3.4

◆ ortho()

void Fl_Gl_Window::ortho ( )

Sets the projection so 0,0 is in the lower left of the window and each pixel is 1 unit wide/tall.

If you are drawing 2D images, your draw() method may want to call this if valid() is false.

◆ pixel_h()

int Fl_Gl_Window::pixel_h ( )

inline

Gives the window height in OpenGL pixels.

When an Fl_Gl_Window is mapped to a HighDPI display, the value given by Fl_Gl_Window::h() which is expressed in FLTK units, may differ from the window height in pixels. Calls to OpenGL functions expecting pixel values (e.g., glViewport) should therefore use pixel_h() rather than h(). Method pixel_h() detects when the GUI is rescaled or when the window has been moved between low and high resolution displays and automatically adjusts the returned value.

Version: 1.3.4

◆ pixel_w()

int Fl_Gl_Window::pixel_w ( )

inline

Gives the window width in OpenGL pixels.

When an Fl_Gl_Window is mapped to a HighDPI display, the value given by Fl_Gl_Window::w() which is expressed in FLTK units, may differ from the window width in pixels. Calls to OpenGL functions expecting pixel values (e.g., glViewport) should therefore use pixel_w() rather than w(). Method pixel_w() detects when the GUI is rescaled or when the window has been moved between low and high resolution displays and automatically adjusts the returned value.

Version: 1.3.4

◆ pixels_per_unit()

float Fl_Gl_Window::pixels_per_unit ( )

The number of pixels per FLTK unit of length for the window.

This method dynamically adjusts its value when the GUI is rescaled or when the window is moved to/from displays of distinct resolutions. This method is useful, e.g., to convert, in a window's handle() method, the FLTK units returned by Fl::event_x() and Fl::event_y() to the pixel units used by the OpenGL source code.

Version: 1.3.4

◆ redraw_overlay()

void Fl_Gl_Window::redraw_overlay ( )

Causes draw_overlay() to be called at a later time.

Initially the overlay is clear. If you want the window to display something in the overlay when it first appears, you must call this immediately after you show() your window.

◆ resize()

void Fl_Gl_Window::resize	(	int	x,
		int	y,
		int	w,
		int	h
	)

virtual

Changes the size or position of the widget.

This is a virtual function so that the widget may implement its own handling of resizing. The default version does not call the redraw() method, but instead relies on the parent widget to do so because the parent may know a faster way to update the display, such as scrolling from the old position.

Some window managers under X11 call resize() a lot more often than needed. Please verify that the position or size of a widget did actually change before doing any extensive calculations.

position(X, Y) is a shortcut for resize(X, Y, w(), h()), and size(W, H) is a shortcut for resize(x(), y(), W, H).

Parameters

[in]	x,y	new position relative to the parent window
[in]	w,h	new size

See also: position(int,int), size(int,int)

Reimplemented from Fl_Widget.

◆ show()

void Fl_Gl_Window::show ( )

virtual

Makes a widget visible.

An invisible widget never gets redrawn and does not get keyboard or mouse events, but can receive a few other events like FL_SHOW.

The visible() method returns true if the widget is set to be visible. The visible_r() method returns true if the widget and all of its parents are visible. A widget is only visible if visible() is true on it and all of its parents.

Changing it will send FL_SHOW or FL_HIDE events to the widget. Do not change it if the parent is not visible, as this will send false FL_SHOW or FL_HIDE events to the widget. redraw() is called if necessary on this or the parent.

See also: hide(), visible(), visible_r()

Reimplemented from Fl_Widget.

◆ swap_buffers()

void Fl_Gl_Window::swap_buffers ( )

The swap_buffers() method swaps the back and front buffers.

It is called automatically after the draw() method is called.

◆ swap_interval() [1/2]

int Fl_Gl_Window::swap_interval ( ) const

Gets the rate at which the GL windows swaps buffers.

This method can be called after the OpenGL context was created, typically within the user overridden Fl_Gl_Window::draw() method that will be overridden by the user.

Note: This method depends highly on the underlying OpenGL contexts and driver implementation. Some drivers return no information, most drivers don't support intervals with multiple frames and return only 0 or 1.; Some drivers have the ability to set the swap interval but no way to query it, hence this method may return -1 even though the interval was set correctly. Conversely a return value greater zero does not guarantee that the driver actually honors the setting.

Returns: an integer greater zero if vertical blanking is taken into account when swapping OpenGL buffers; 0 if the vertical blanking is ignored; -1 if the information can not be retrieved

◆ swap_interval() [2/2]

void Fl_Gl_Window::swap_interval ( int frames )

Sets the rate at which the GL windows swaps buffers.

This method can be called after the OpenGL context was created, typically within the user overridden Fl_Gl_Window::draw() method that will be overridden by the user.

Note: This method depends highly on the underlying OpenGL contexts and driver implementation. Most driver seem to accept only 0 and 1 to swap buffer asynchronously or in sync with the vertical blank.

Parameters

[in] frames set the number of vertical frame blanks between OpenGL buffer swaps

◆ valid()

char Fl_Gl_Window::valid ( ) const

inline

Is turned off when FLTK creates a new context for this window or when the window resizes, and is turned on after draw() is called.

You can use this inside your draw() method to avoid unnecessarily initializing the OpenGL context. Just do this:

void mywindow::draw() {
 if (!valid()) {
   glViewport(0,0,pixel_w(),pixel_h());
   glFrustum(...);
   ...other initialization...
 }
 if (!context_valid()) {
   ...load textures, etc. ...
 }
 ... draw your geometry here ...
}

You can turn valid() on by calling valid(1). You should only do this after fixing the transformation inside a draw() or after make_current(). This is done automatically after draw() returns.

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

Fl_Gl_Window.H
Fl_Gl_Overlay.cxx
Fl_Gl_Window.cxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Fl_Gl_Window() [1/2]

◆ Fl_Gl_Window() [2/2]

Member Function Documentation

◆ as_gl_window() [1/2]

◆ as_gl_window() [2/2]

◆ can_do()

◆ can_do_overlay()

◆ context() [1/2]

◆ context() [2/2]

◆ context_valid()

◆ draw()

◆ draw_begin()

◆ draw_end()

◆ flush()

◆ handle()

◆ hide()

◆ make_current()

◆ make_overlay_current()

◆ mode() [1/3]

◆ mode() [2/3]

◆ mode() [3/3]

◆ ortho()

◆ pixel_h()

◆ pixel_w()

◆ pixels_per_unit()

◆ redraw_overlay()

◆ resize()

◆ show()

◆ swap_buffers()

◆ swap_interval() [1/2]

◆ swap_interval() [2/2]

◆ valid()