#include <ttauri/widgets/widget.hpp>

Inheritance diagram for tt::widget:

Public Member Functions
	widget (gui_window &window, widget *parent) noexcept

	widget (const widget &)=delete

widget &	operator= (const widget &)=delete

	widget (widget &&)=delete

widget &	operator= (widget &&)=delete

virtual void	init () noexcept
	Should be called right after allocating and constructing a widget.

virtual void	deinit () noexcept
	Should be called right after allocating and constructing a widget.

virtual float	margin () const noexcept
	Get the margin around the Widget.

extent2	minimum_size () const noexcept
	Minimum size.

extent2	preferred_size () const noexcept
	Preferred size.

extent2	maximum_size () const noexcept
	Maximum size.

void	set_layout_parameters (geo::transformer auto const &local_to_parent, extent2 size, aarectangle const &clipping_rectangle) noexcept
	Set the location and size of the widget inside the window.

void	set_layout_parameters_from_parent (aarectangle child_rectangle, aarectangle parent_clipping_rectangle, float draw_layer_delta) noexcept

void	set_layout_parameters_from_parent (aarectangle child_rectangle) noexcept

matrix3	parent_to_local () const noexcept

matrix3	local_to_parent () const noexcept

matrix3	window_to_local () const noexcept

matrix3	local_to_window () const noexcept

extent2	size () const noexcept

float	width () const noexcept

float	height () const noexcept

aarectangle	rectangle () const noexcept
	Get the rectangle in local coordinates.

virtual float	base_line () const noexcept
	Return the base-line where the text should be located.

aarectangle	clipping_rectangle () const noexcept

virtual hitbox	hitbox_test (point2 position) const noexcept
	Find the widget that is under the mouse cursor.

virtual bool	accepts_keyboard_focus (keyboard_focus_group group) const noexcept
	Check if the widget will accept keyboard focus.

virtual bool	constrain (hires_utc_clock::time_point display_time_point, bool need_reconstrain) noexcept
	Update the constraints of the widget.

virtual void	layout (hires_utc_clock::time_point display_time_point, bool need_layout) noexcept
	Update the internal layout of the widget.

virtual color	background_color () const noexcept

virtual color	foreground_color () const noexcept

virtual color	focus_color () const noexcept

virtual color	accent_color () const noexcept

virtual color	label_color () const noexcept

virtual void	draw (draw_context context, hires_utc_clock::time_point display_time_point) noexcept
	Draw the widget.

virtual void	request_redraw () const noexcept

virtual bool	handle_event (command command) noexcept
	Handle command.

virtual bool	handle_event (std::vector< command > const &commands) noexcept

virtual bool	handle_command_recursive (command command, std::vector< widget const * > const &reject_list) noexcept
	Handle command recursive.

virtual bool	handle_event (mouse_event const &event) noexcept

virtual bool	handle_event (keyboard_event const &event) noexcept
	Handle keyboard event.

virtual widget const *	find_next_widget (widget const *current_keyboard_widget, keyboard_focus_group group, keyboard_focus_direction direction) const noexcept
	Find the next widget that handles keyboard focus.

widget const *	find_first_widget (keyboard_focus_group group) const noexcept

widget const *	find_last_widget (keyboard_focus_group group) const noexcept

bool	is_first (keyboard_focus_group group) const noexcept
	Is this widget the first widget in the parent container.

bool	is_last (keyboard_focus_group group) const noexcept
	Is this widget the last widget in the parent container.

virtual void	scroll_to_show (tt::rectangle rectangle) noexcept
	Scroll to show the given rectangle on the window.

std::vector< widget const * >	parent_chain () const noexcept
	Get a list of parents of a given widget.

void	clear () noexcept
	Remove and deallocate all child widgets.

widget &	add_widget (std::unique_ptr< widget > widget) noexcept
	Add a widget directly to this widget.

Data Fields
gui_window &	window
	Convenient reference to the Window.

widget *const	parent
	Pointer to the parent widget.

std::string	id
	A name of widget, should be unique between siblings.

observable< bool >	enabled = true
	The widget is enabled.

observable< bool >	visible = true
	The widget is visible.

float	draw_layer
	The draw layer of the widget.

int	semantic_layer
	The draw layer of the widget.

int	logical_layer
	The logical layer of the widget.

Detailed Description

An interactive graphical object as part of the user-interface.

Rendering is done in four distinct phases:

Updating Constraints: widget::constrain()
Update layout parameters widget::set_layout_parameters()
Updating Layout: widget::layout()
Drawing: widget::draw()

Constructor & Destructor Documentation

◆ widget()

tt::widget::widget	(	gui_window &	window,
		widget *	parent )

noexcept

Constructor for creating sub views.

Member Function Documentation

◆ accepts_keyboard_focus()

virtual bool tt::widget::accepts_keyboard_focus ( keyboard_focus_group group ) const

inlinevirtualnoexcept

Check if the widget will accept keyboard focus.

Precondition: mutex must be locked by current thread.

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ add_widget()

widget & tt::widget::add_widget ( std::unique_ptr< widget > widget )

noexcept

Add a widget directly to this widget.

Thread safety: locks.

◆ base_line()

virtual float tt::widget::base_line ( ) const

virtualnoexcept

Return the base-line where the text should be located.

Returns: Number of pixels from the bottom of the widget where the base-line is located.

◆ clear()

void tt::widget::clear ( )

noexcept

Remove and deallocate all child widgets.

◆ constrain()

virtual bool tt::widget::constrain	(	hires_utc_clock::time_point	display_time_point,
		bool	need_reconstrain )

virtualnoexcept

Update the constraints of the widget.

This function is called on each vertical sync, even if no drawing is to be done.

This function may be used for expensive calculations, such as text-shaping, which should only be done when the data changes. Because this function is called on every vertical sync it should cache these calculations.

Subclasses should call constrain() on its base-class to check if its or any of its children's constraints where changed, before doing specific constraining

If the container, due to a change in constraints, wants the window to resize to the minimum size it should set window::request_resize to true.

Postcondition: This function will change what is returned by widget::minimum_size(), widget::preferred_size() and widget::maximum_size().

Parameters

display_time_point	The time point when the widget will be shown on the screen.
need_reconstrain	Force the widget to re-constrain.

Returns: True if its or any children's constraints has changed.

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ deinit()

virtual void tt::widget::deinit ( )

virtualnoexcept

Should be called right after allocating and constructing a widget.

◆ draw()

virtual void tt::widget::draw	(	draw_context	context,
		hires_utc_clock::time_point	display_time_point )

virtualnoexcept

Draw the widget.

This function is called by the window (optionally) on every frame. It should recursively call this function on every visible child. This function is only called when updateLayout() has returned true.

The overriding function should call the base class's draw(), the place where the call this function will determine the order of the vertices into each buffer. This is important when needing to do the painters algorithm for alpha-compositing. However the pipelines are always drawn in the same order.

Precondition: mutex must be locked by current thread.

Parameters

context	The context to where the widget will draw.
display_time_point	The time point when the widget will be shown on the screen.

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ find_next_widget()

virtual widget const * tt::widget::find_next_widget	(	widget const *	current_keyboard_widget,
		keyboard_focus_group	group,
		keyboard_focus_direction	direction ) const

virtualnoexcept

Find the next widget that handles keyboard focus.

This recursively looks for the current keyboard widget, then returns the next (or previous) widget that returns true from accepts_keyboard_focus().

Parameters

current_keyboard_widget	The widget that currently has focus; or empty to get the first widget that accepts focus.
group	The group to which the widget must belong.
direction	The direction in which to walk the widget tree.

Returns: A pointer to the next widget.

Return values

currentKeyboardWidget	when currentKeyboardWidget was found but no next widget was found.
empty	when currentKeyboardWidget is not found in this Widget.

◆ handle_command_recursive()

virtual bool tt::widget::handle_command_recursive	(	command	command,
		std::vector< widget const * > const &	reject_list )

virtualnoexcept

Handle command recursive.

Handle a command and pass it to each child.

Parameters

command	The command to handle by this widget.
reject_list	The widgets that should ignore this command

Returns: True when the command was handled by this widget or recursed child.

◆ handle_event() [1/3]

virtual bool tt::widget::handle_event ( command command )

virtualnoexcept

Handle command.

If a widget does not fully handle a command it should pass the command to the super class' handle_event().

◆ handle_event() [2/3]

virtual bool tt::widget::handle_event ( keyboard_event const & event )

virtualnoexcept

Handle keyboard event.

Called by the operating system when editing text, or entering special keys

Parameters

event The keyboard event.

Returns: If this widget has handled the keyboard event.

◆ handle_event() [3/3]

virtual bool tt::widget::handle_event ( mouse_event const & event )

virtualnoexcept

Handle mouse event. Called by the operating system to show the position and button state of the mouse. This is called very often so it must be made efficient. This function is also used to determine the mouse cursor.

In most cased overriding methods should call the super's handle_event() at the start of the function, to detect hover.

When this method does not handle the event the window will call handle_event() on the widget's parent.

Parameters

event The mouse event, positions are in window coordinates.

Returns: If this widget has handled the mouse event.

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ hitbox_test()

virtual hitbox tt::widget::hitbox_test ( point2 position ) const

virtualnoexcept

Find the widget that is under the mouse cursor.

This function will recursively test with visual child widgets, when widgets overlap on the screen the hitbox object with the highest elevation is returned.

Parameters

position The coordinate of the mouse local to the widget.

Returns: A hit_box object with the cursor-type and a reference to the widget.

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ init()

virtual void tt::widget::init ( )

virtualnoexcept

Should be called right after allocating and constructing a widget.

◆ is_first()

bool tt::widget::is_first ( keyboard_focus_group group ) const

noexcept

Is this widget the first widget in the parent container.

◆ is_last()

bool tt::widget::is_last ( keyboard_focus_group group ) const

noexcept

Is this widget the last widget in the parent container.

◆ layout()

virtual void tt::widget::layout	(	hires_utc_clock::time_point	display_time_point,
		bool	need_layout )

virtualnoexcept

Update the internal layout of the widget.

This function is called on each vertical sync, even if no drawing is to be done.

This function may be used for expensive calculations, such as geometry calculations, which should only be done when the data or sizes change. Because this function is called on every vertical sync it should cache these calculations.

Subclasses should call widget::set_layout_parameters() to position and size each child relative to this widget. At the end of the function the subclass should call layout() on its base-class to recursively update the layout of the children.

Precondition: widget::set_layout_parameters() should be called.

Postcondition: This function will change what is returned by widget::size() and the transformation matrices.

Parameters

display_time_point	The time point when the widget will be shown on the screen.
need_layout	Force the widget to layout

Reimplemented in tt::scroll_bar_widget< Axis >.

◆ margin()

virtual float tt::widget::margin ( ) const

virtualnoexcept

Get the margin around the Widget.

A container widget should layout the children in such a way that the maximum margin of neighboring widgets is maintained.

Precondition: mutex must be locked by current thread.

Returns: The margin for this widget.

◆ maximum_size()

extent2 tt::widget::maximum_size ( ) const

noexcept

Maximum size.

The maximum size of a widget. Containers will try to not grow a widget beyond the maximum size, but it may do so to satisfy the minimum constraint on a neighboring widget. For windows the maximum size becomes a hard limit for the window size.

◆ minimum_size()

extent2 tt::widget::minimum_size ( ) const

noexcept

Minimum size.

The absolute minimum size of the widget. A container will never reserve less space for the widget. For windows this size becomes a hard limit for the minimum window size.

◆ parent_chain()

std::vector< widget const * > tt::widget::parent_chain ( ) const

noexcept

Get a list of parents of a given widget.

The chain includes the given widget.

◆ preferred_size()

extent2 tt::widget::preferred_size ( ) const

noexcept

Preferred size.

The preferred size of a widget. Containers will initialize their layout algorithm at this size before growing or shrinking. For scroll-views this size will be used in the scroll-direction. For tab-views this is propagated. For windows this size is used to set the initial window size.

◆ rectangle()

aarectangle tt::widget::rectangle ( ) const

noexcept

Get the rectangle in local coordinates.

Precondition: mutex must be locked by current thread.

◆ scroll_to_show()

virtual void tt::widget::scroll_to_show ( tt::rectangle rectangle )

virtualnoexcept

Scroll to show the given rectangle on the window.

This will call parents, until all parents have scrolled the rectangle to be shown on the window.

◆ set_layout_parameters()

void tt::widget::set_layout_parameters	(	geo::transformer auto const &	local_to_parent,
		extent2	size,
		aarectangle const &	clipping_rectangle )

noexcept

Set the location and size of the widget inside the window.

The parent should call this set_layout_paramters() before this updateLayout().

If the parent's layout did not change, it does not need to call this set_layout_parameters(). This way the parent does not need to keep a cache, recalculate or query the client for these layout parameters for each frame.

Precondition: mutex must be locked by current thread.

Field Documentation

◆ draw_layer

float tt::widget::draw_layer

The draw layer of the widget.

Drawing layers start at 0.0 and go up to 100.0.

Each child widget that has drawing to do increases the layer by 1.0.

The widget should draw within 0.0 and 1.0 of its drawing layer. The toWindowTransfer and the DrawingContext will already include the draw_layer.

An overlay widget such as pop-ups will increase the layer by 25.0, to make sure the overlay will draw above other widgets in the window. *

◆ enabled

observable<bool> tt::widget::enabled = true

The widget is enabled.

When a widget is disabled it is drawn in gray and will not react to user input.

◆ id

std::string tt::widget::id

A name of widget, should be unique between siblings.

◆ logical_layer

int tt::widget::logical_layer

The logical layer of the widget.

The logical layer can be used to determine how far away from the window-widget (root) the current widget is.

Logical layers start at 0 for the window-widget. Each child widget increases the logical layer by 1.

◆ parent

widget* const tt::widget::parent

Pointer to the parent widget.

May be a nullptr only when this is the top level widget.

◆ semantic_layer

int tt::widget::semantic_layer

The draw layer of the widget.

The semantic layer is used mostly by the draw() function for selecting colors from the theme, to denote nesting widgets inside other widgets.

Semantic layers start at 0 for the window-widget and for any pop-up widgets.

The semantic layer is increased by one, whenever a user of the user-interface would understand the next layer to begin.

In most cases it would mean that a container widget that does not draw itself will not increase the semantic_layer number.

◆ visible

observable<bool> tt::widget::visible = true

The widget is visible.

When a widget is invisible it will not be layout or drawn.

◆ window

gui_window& tt::widget::window

Convenient reference to the Window.

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

hikogui/src/ttauri/widgets/widget.hpp

Public Member Functions

Data Fields

Detailed Description

Constructor & Destructor Documentation

◆ widget()

Member Function Documentation

◆ accepts_keyboard_focus()

◆ add_widget()

◆ base_line()

◆ clear()

◆ constrain()

◆ deinit()

◆ draw()

◆ find_next_widget()

◆ handle_command_recursive()

◆ handle_event() [1/3]

◆ handle_event() [2/3]

◆ handle_event() [3/3]

◆ hitbox_test()

◆ init()

◆ is_first()

◆ is_last()

◆ layout()

◆ margin()

◆ maximum_size()

◆ minimum_size()

◆ parent_chain()

◆ preferred_size()

◆ rectangle()

◆ scroll_to_show()

◆ set_layout_parameters()

Field Documentation

◆ draw_layer

◆ enabled

◆ id

◆ logical_layer

◆ parent

◆ semantic_layer

◆ visible

◆ window