CameraWindow Class Reference

A CameraWindow is a widget to capture image feed from the camera sensor and render it on screen using gstreamer media framework. More...

#include <camera.h>

Inheritance diagram for CameraWindow:

Public Member Functions
	CameraWindow (CameraWindow &&)=default
	CameraWindow (const CameraWindow &)=delete
	CameraWindow (const Rect &rect, const std::string &device="/dev/video0", PixelFormat format_hint=PixelFormat::yuyv, WindowHint hint=WindowHint::overlay)
	Create a camera window.
	CameraWindow (const std::string &device="/dev/video0", PixelFormat format_hint=PixelFormat::yuyv, WindowHint hint=WindowHint::overlay)
	Create a camera window.
	CameraWindow (Serializer::Properties &props)
	Construct a camera window.
	~CameraWindow () noexcept override
std::string	device () const
void	device (const std::string &device)
void	do_draw () override
	Perform the actual drawing.
void	draw (Painter &painter, const Rect &rect) override
	Draw the widget.
std::vector< std::string >	list_devices ()
CameraWindow &	operator= (CameraWindow &&)=default
CameraWindow &	operator= (const CameraWindow &)=delete
bool	play ()
	Set the camera pipeline to the play state.
EGT_NODISCARD bool	playing () const
	Check is the camera pipeline in play state.
void	scale (float hscale, float vscale) override
	Set the scale of the widget.
void	scale (float hscale, float vscale) override
	Set the scale of the widget.
void	serialize (Serializer &serializer) const override
	Serialize the widget to the specified serializer.
bool	start ()
	Initialize camera pipeline to capture image feed from the camera sensor and render to Window.
void	stop ()
	Stop camera.
Public Member Functions inherited from Window
	Window (const Rect &rect, PixelFormat format_hint=DEFAULT_FORMAT, WindowHint hint=WindowHint::automatic)
	Construct a window.
	Window (const Window &)=delete
	Window (Frame &parent, const Rect &rect, PixelFormat format_hint=DEFAULT_FORMAT, WindowHint hint=WindowHint::automatic)
	Construct a window.
	Window (PixelFormat format_hint=DEFAULT_FORMAT, WindowHint hint=WindowHint::automatic)
	Construct a window.
	Window (Serializer::Properties &props)
	Construct a window.
	Window (Window &&) noexcept
	~Window () noexcept override
void	begin_draw () override
	Cause the widget to draw itself and all of its children.
void	damage (const Rect &rect) override
	Mark the specified rect as a damaged area of the widget.
EGT_NODISCARD PixelFormat	format () const
	Get the pixel format of the window.
EGT_NODISCARD PixelFormat	format_hint () const
	Get the pixel format hint of the window.
void	format_hint (PixelFormat format_hint)
	Set the pixel format hint of the window.
EGT_NODISCARD bool	has_screen () const override
	Does this Widget have a screen?
void	hide () override
	Hide the Widget.
EGT_NODISCARD float	hscale () const
	Get horizontal scale value.
void	move (const Point &point) override
	Move the Widget to a new position.
Window &	operator= (const Window &)=delete
Window &	operator= (Window &&) noexcept
void	paint (Painter &painter) override
	Paint the Widget using a Painter.
void	resize (const Size &size) override
	Resize the widget.
void	scale (float hscale, float vscale) override
	Set the scale of the widget.
EGT_NODISCARD Screen *	screen () const override
	The buck stops on this call to Widget::screen() with a Window because the Window contains the screen.
void	serialize (Serializer &serializer) const override
	Serialize the widget to the specified serializer.
void	show () override
	Show the Widget.
EGT_NODISCARD float	vscale () const
	Get vertical scale value.
EGT_NODISCARD WindowHint	window_hint () const
	Get the window hint.
void	window_hint (WindowHint hint)
	Set the window hint.
Public Member Functions inherited from Frame
	Frame (const Frame &)=delete
	Frame (const Rect &rect={}, const Flags &flags={}) noexcept
	Frame (Frame &&) noexcept=default
	Frame (Frame &parent, const Rect &rect, const Flags &flags={}) noexcept
	Frame (Serializer::Properties &props) noexcept
	~Frame () noexcept override
template<class T >
void	add (const std::shared_ptr< T > &widget)
	Utility wrapper around add()
virtual void	add (const std::shared_ptr< Widget > &widget)
	Add a child widget.
void	add (Widget &widget)
	Add a child widget.
EGT_NODISCARD std::shared_ptr< Widget >	child_at (size_t index) const
	Get a child widget at a specific index.
EGT_NODISCARD detail::Range< SubordinatesArray > &	children ()
	Return the array of child widgets.
EGT_NODISCARD const detail::Range< SubordinatesArray > &	children () const
	Return the array of child widgets.
EGT_NODISCARD size_t	count_children () const
	Get the number of children widgets.
void	deserialize_children (const Deserializer &deserializer) override
	Deserialize the children of this widget.
template<class T >
std::shared_ptr< T >	find_child (const std::string &name)
	Find a child Widget in the entire tree by name.
Widget *	hit_test (const DisplayPoint &point)
	Get the widget under the given DisplayPoint.
bool	is_child (Widget *widget) const
	Returns true if the child exists.
void	on_screen_resized () override
	Overridden to be called recursively on all children.
Frame &	operator= (const Frame &)=delete
Frame &	operator= (Frame &&) noexcept=default
void	paint_children_to_file ()
	Paint individual children to file.
void	paint_to_file (const std::string &filename={}) override
	Save the entire frame surface to a file.
virtual void	remove (Widget *widget)
	Remove a child widget.
void	remove_all ()
	Remove all child widgets.
void	serialize_children (Serializer &serializer) const override
	Serialize the widget's children to the specified serializer.
template<typename T , typename... Args>
std::shared_ptr< T >	spawn (Args &&... args)
	Create a child widget of the specified type.
EGT_NODISCARD ChildDrawCallback	special_child_draw_callback () const
	Get the special child draw callback.
void	special_child_draw_callback (ChildDrawCallback func)
	Set the special child draw callback.
EGT_NODISCARD ChildDrawCallback	special_child_draw_callback (Widget *parent) const
	Get the child draw callback of the parent.
virtual EGT_NODISCARD Point	to_child (const Point &p) const
EGT_NODISCARD Rect	to_child (Rect rect) const
EGT_NODISCARD bool	top_level () const override
	Return true if this is a top level frame, with no parent.
void	walk (const WalkCallback &callback, int level=0) override
	Walk the Widget tree and call callback with each Widget.
virtual EGT_NODISCARD size_t	zorder () const
	Get the zorder of the widget.
size_t	zorder (const Widget *widget) const
	Get the zorder of the widget.
void	zorder (const Widget *widget, size_t rank)
	Set the zorder of the widget.
virtual void	zorder (size_t rank)
	Set the zorder of the widget.
virtual void	zorder_bottom ()
	Move the widget to the bottom.
void	zorder_bottom (const Widget *widget)
	Move the specified widget zorder to the bottom of the current list of widgets with the same parent.
virtual void	zorder_down ()
	Move this widgets zorder down relative to other widgets with the same parent.
void	zorder_down (const Widget *widget)
	Move the specified widget zorder down relative to other widgets with the same parent.
virtual void	zorder_top ()
	Move the widget to the top.
void	zorder_top (const Widget *widget)
	Move the specified widget zorder to the top of the current list of widgets with the same parent.
virtual void	zorder_up ()
	Move this widgets zorder up relative to other widgets with the same parent.
void	zorder_up (const Widget *widget)
	Move the specified widget zorder up relative to other widgets with the same parent.
Public Member Functions inherited from Widget
	Widget (const Rect &rect={}, const Widget::Flags &flags={}) noexcept
	Widget (const Widget &)=delete
	Widget (Frame &parent, const Rect &rect={}, const Widget::Flags &flags={}) noexcept
	Widget (Serializer::Properties &props) noexcept
	Widget (Widget &&) noexcept=default
	~Widget () noexcept override
EGT_NODISCARD bool	active () const
	Get the active state.
void	active (bool value)
	Set the active state.
AlignFlags &	align ()
	Get the alignment.
EGT_NODISCARD const AlignFlags &	align () const
	Get the alignment.
void	align (const AlignFlags &a)
	Align the widget.
EGT_NODISCARD float	alpha () const
	Get the alpha property.
void	alpha (float alpha)
	Set the alpha property.
EGT_NODISCARD bool	autoresize () const
	Return the autoresize state of the widget.
void	autoresize (bool value)
	Set the autoresize state.
EGT_NODISCARD Image *	background (bool allow_fallback=false) const
	Get the background image, if any, for the current group.
void	background (const Image &image, Palette::GroupId group=Palette::GroupId::normal)
	Add an image background to the widget's box.
EGT_NODISCARD Image *	background (Palette::GroupId group, bool allow_fallback=false) const
	Get the background image, if any, for the given group.
EGT_NODISCARD DefaultDim	border () const
	Get the border width.
void	border (DefaultDim border)
	Set the border width.
EGT_NODISCARD Theme::BorderFlags	border_flags () const
	Get the border flags.
void	border_flags (const Theme::BorderFlags &flags)
	Set the border flags.
EGT_NODISCARD float	border_radius () const
	Get the border radius.
void	border_radius (float radius)
	Set the border radius.
EGT_NODISCARD const Rect &	box () const
	Bounding box for the Widget.
void	box (const Rect &rect)
	Change the bounding box of the widget.
bool	can_handle_event () const
	Returns true if the widget is capable of handling an event.
EGT_NODISCARD Point	center () const
	Get the center point of the widget's box().
EGT_NODISCARD bool	checked () const
	Get the boolean checked state of the a widget.
virtual void	checked (bool value)
	Set the checked state of the widget.
EGT_NODISCARD bool	clip () const
	Return the clip state of the widget.
EGT_NODISCARD const Pattern &	color (Palette::ColorId id) const
	Get a Widget color.
void	color (Palette::ColorId id, const Pattern &color, Palette::GroupId group=Palette::GroupId::normal)
	Add a color to the widget's instance palette.
EGT_NODISCARD const Pattern &	color (Palette::ColorId id, Palette::GroupId group) const
	Get a Widget color.
virtual EGT_NODISCARD Rect	content_area () const
	Return the area that content is allowed to be positioned into.
void	continue_drag (Event &event)
	Handle 'pointer_drag' and 'pointer_drag_stop' events.
virtual void	damage ()
	Damage the box() of the widget and cause a redraw.
void	detach ()
	Detach this widget from its parent.
void	disable ()
	Set the disabled state to true.
void	disable_toggle ()
	Toggle the disabled state.
EGT_NODISCARD bool	disabled () const
	Return the disabled state of the widget.
void	disabled (bool value)
	Set the disabled state.
DisplayPoint	display_origin ()
	Get the display origin of the Widget.
virtual Point	display_to_local (const DisplayPoint &p) const
	Convert a display point to a local point.
void	draw_box (Painter &painter, Palette::ColorId bg, Palette::ColorId border) const
	Helper function to draw this widget's box using the appropriate theme.
void	draw_circle (Painter &painter, Palette::ColorId bg, Palette::ColorId border) const
	Helper function to draw this widget's circle using the appropriate theme.
void	enable ()
	Set the disabled state to false.
Theme::FillFlags &	fill_flags ()
	Get a modifiable fill flags reference.
EGT_NODISCARD const Theme::FillFlags &	fill_flags () const
	Get the fill flags.
void	fill_flags (const Theme::FillFlags &flags)
	Set the fill flags.
EGT_NODISCARD bool	focus () const
	Get the current focus state.
void	focus (bool value)
	Set the focus state.
EGT_NODISCARD const Font &	font () const
	Get the widget Font.
void	font (const Font &font)
	Set the widget Font.
EGT_NODISCARD bool	frame () const
	Return the frame state of the widget.
EGT_NODISCARD bool	grab_mouse () const
	Return the grab_mouse state of the widget.
void	grab_mouse (bool value)
	Set the grab_mouse state.
EGT_NODISCARD Palette::GroupId	group () const
	Get the current Palette::GroupId depending on the widget's state.
virtual void	handle (Event &event)
	Handle an event.
bool	has_font () const
	Check whether the widget has a custom Font.
EGT_NODISCARD bool	has_palette () const
	Check whether the widget has a custom palette.
EGT_NODISCARD DefaultDim	height () const
	Height of the widget's box().
void	height (DefaultDim h)
	Change the height.
EGT_NODISCARD bool	hit (const DisplayPoint &point) const
	Returns true if the DisplayPoint is within the widget box.
EGT_NODISCARD DefaultDim	horizontal_ratio () const
	Get the horizontal ratio relative to parent.
void	horizontal_ratio (DefaultDim horizontal)
	Set the horizontal ratio relative to parent.
EGT_NODISCARD bool	in_layout () const
	Indicate if the Widget is computing the layout or not.
virtual void	layout ()
	Perform layout of the Widget.
DisplayPoint	local_to_display (const Point &p) const
	Convert a local point to a display point.
EGT_NODISCARD DefaultDim	margin () const
	Get the margin width.
void	margin (DefaultDim margin)
	Set the margin width.
virtual EGT_NODISCARD Size	min_size_hint () const
	Get a minimum size hint for the Widget.
void	min_size_hint (const Size &size)
	Set the minimum size hint for the Widget.
EGT_NODISCARD size_t	moat () const
	Get the sum of the margin(), padding(), and border() around the content of the widget.
void	move_to_center ()
	Move the widget to the center of its parent.
void	move_to_center (const Point &point)
	Move the widget to the specified center point.
EGT_NODISCARD bool	no_layout () const
	Return the no_layout state of the widget.
void	no_layout (bool value)
	Set the no_layout state.
Widget &	operator= (const Widget &)=delete
Widget &	operator= (Widget &&) noexcept=default
EGT_NODISCARD DefaultDim	padding () const
	Return the padding width.
void	padding (DefaultDim padding)
	Set the padding width.
EGT_NODISCARD const Palette &	palette () const
	Get the widget palette.
void	palette (const Palette &palette)
	Set the widget instance Palette.
Widget *	parent ()
	Get a pointer to the parent Widget, or nullptr if none exists.
EGT_NODISCARD const Widget *	parent () const
	Get a pointer to the parent Widget, or nullptr if none exists.
EGT_NODISCARD bool	plane_window () const
	Return the plane_window state of the widget.
EGT_NODISCARD const Point &	point () const
	Get the origin of the widget's box().
virtual void	post_deserialize (Serializer::Properties &props)
	Resume deserializing of the widget after its children have been deserialized.
void	ratio (DefaultDim horizontal, DefaultDim vertical)
	Set the size ratio relative to parent.
void	ratio (DefaultDim ratio)
	Set the size ratio relative to parent.
EGT_NODISCARD bool	readonly () const
	Get the readonly state of the widget.
void	readonly (bool value)
	Set the readonly state of the widget.
void	readonly_toggle ()
	Toggle the readonly state.
void	reset_background (Palette::GroupId group=Palette::GroupId::normal)
	Remove an image background from the widget's box.
void	reset_font ()
	Reset the widget's Font.
void	reset_palette ()
	Clear the widget instance palette.
void	resize_by_ratio (DefaultDim hratio, DefaultDim vratio)
	Scale the current size of the Widget given the ratio.
void	resize_by_ratio (DefaultDim ratio)
	Scale the current size of the Widget given the ratio.
void	scale (float scale)
	Set the scale of the widget.
EGT_NODISCARD const Size &	size () const
	Get the size of the widget's box().
EGT_NODISCARD const Theme &	theme () const
	Get the Widget Theme.
EGT_NODISCARD Point	to_parent (const Point &r) const
	Convert a point with a local origin to a parent origin.
EGT_NODISCARD Rect	to_parent (const Rect &r) const
	Convert a point in a rect a local origin to a parent origin.
virtual EGT_NODISCARD std::string	type () const
	Returns a string representation of the type of this widget.
EGT_NODISCARD bool	user_drag () const
void	user_drag (bool value)
EGT_NODISCARD const Rect &	user_requested_box () const
	Get the box corresponding to the user requested one, not the actual one.
EGT_NODISCARD bool	user_track_drag () const
void	user_track_drag (bool value)
EGT_NODISCARD DefaultDim	vertical_ratio () const
	Get the vertical ratio relative to parent.
void	vertical_ratio (DefaultDim vertical)
	Set the vertical ratio relative to parent.
EGT_NODISCARD bool	visible () const
	Get the visible state of the widget.
void	visible (bool value)
	Set the visible state.
void	visible_toggle ()
	Toggle the visibility state.
EGT_NODISCARD WidgetId	widgetid () const
	Get the unique id of the widget.
EGT_NODISCARD DefaultDim	width () const
	Width of the widget's box().
void	width (DefaultDim w)
	Change the width.
EGT_NODISCARD DefaultDim	x () const
	X coordinate of the widget's box().
void	x (DefaultDim x)
	Set the X coordinate of the box.
EGT_NODISCARD DefaultDim	xratio () const
	Get the X position ratio relative to parent.
void	xratio (DefaultDim xratio)
	Set the X position ratio relative to parent.
EGT_NODISCARD DefaultDim	y () const
	Y coordinate of the widget's box().
void	y (DefaultDim y)
	Set the Y coordinate of the box.
EGT_NODISCARD DefaultDim	yratio () const
	Get the Y position ratio relative to parent.
void	yratio (DefaultDim yratio)
	Set the Y position ratio relative to parent.
Public Member Functions inherited from Object
	Object () noexcept=default
	Object (const Object &)=delete
	Object (Object &&)=default
virtual	~Object () noexcept=default
void	clear_handlers ()
	Clear all registered event handlers.
void	invoke_handlers (Event &event)
	Invoke all handlers with the specified event.
void	invoke_handlers (EventId event)
	Invoke all handlers with the specified EventId.
EGT_NODISCARD const std::string &	name () const
	Get the name of the Object.
void	name (const std::string &name)
	Set the name of the Object.
RegisterHandle	on_event (const EventCallback &handler, const FilterFlags &mask={})
	Add an event handler to be called when the widget generates an event.
Object &	operator= (const Object &)=delete
Object &	operator= (Object &&)=default
void	remove_handler (RegisterHandle handle)
	Remove an event handler.

Public Attributes
SignalW< const std::string & >	on_error
	Event signal.
SignalW< const std::string & >	on_connect
	Generated when an USB camera connected.
SignalW< const std::string & >	on_disconnect
	Generated when an USB camera disconnected.
Public Attributes inherited from Widget
Signal	on_checked_changed
	Event signal.
Signal	on_gain_focus
	Invoked when the widget gains focus.
Signal	on_lost_focus
	Invoked when the widget loses focus.
Signal	on_show
	Invoked when a widget is shown.
Signal	on_hide
	Invoked when a widget is hidden.

Protected Member Functions
	CameraWindow (Serializer::Properties &props, bool is_derived)
Protected Member Functions inherited from Window
	Window (Serializer::Properties &props, bool is_derived)
void	create_impl (const Rect &rect, PixelFormat format_hint, WindowHint hint)
	Select and allocate the backend implementation for the window.
void	main_window ()
	Set this window as the main window.
Protected Member Functions inherited from Frame
	Frame (Serializer::Properties &props, bool is_derived) noexcept
Protected Member Functions inherited from Widget
	Widget (Serializer::Properties &props, bool is_derived) noexcept
bool	accept_drag () const
	Tell the start_drag() method whether the widget accepts 'pointer_drag*' events.
void	add_component (Widget &widget)
	Add a component.
void	add_damage (const Rect &rect)
	Add damage to the damage array.
void	begin_draw (Widget *parent)
	Call the begin_draw() method of the parent.
EGT_NODISCARD detail::Range< SubordinatesArray > &	children ()
	Return the array of child widgets.
EGT_NODISCARD const detail::Range< SubordinatesArray > &	children () const
	Return the array of child widgets.
EGT_NODISCARD bool	component () const
	Get the component status.
void	component (bool value)
	Set the component flag.
EGT_NODISCARD detail::Range< SubordinatesArray > &	components ()
	Return the array of components widgets.
EGT_NODISCARD const detail::Range< SubordinatesArray > &	components () const
	Return the array of components widgets.
virtual void	damage_from_subordinate (const Rect &rect)
	Special variation of damage() that is to be called explicitly by subordinate widgets.
void	deserialize_leaf (Serializer::Properties &props)
	Deserialize widget properties that require to call overridden methods.
Widget *	find_screen ()
	Starting from this Widget, find the Widget that has a Screen.
EGT_NODISCARD const Widget *	find_screen () const
	Starting from this Widget, find the Widget that has a Screen.
Widget::Flags &	flags ()
	Get a modifiable ref of the flags.
EGT_NODISCARD const Widget::Flags &	flags () const
	Get a const ref of the flags.
virtual bool	internal_drag () const
virtual bool	internal_track_drag () const
EGT_NODISCARD Rect	local_box () const
	Get the local box which is the same size as box(), but with the origin zeroed.
EGT_NODISCARD bool	parent_in_layout ()
	Indicate if our parent is computing the layout.
void	parent_layout ()
	Call our parent to do a layout.
virtual Point	point_from_subordinate (const Widget &subordinate) const
EGT_NODISCARD detail::Range< SubordinatesArray > &	range_from_widget (const Widget &widget)
	Return either components() or children() depending on widget.component()
EGT_NODISCARD const detail::Range< SubordinatesArray > &	range_from_widget (const Widget &widget) const
	Return either components() or children() depending on widget.component()
void	remove_component (Widget *widget)
	Remove a component.
virtual void	set_parent (Widget *parent)
	Set this widget's parent.
void	special_child_draw (Painter &painter, Widget *widget)
	Special draw function that can be invoked when drawing each child.
EGT_NODISCARD ChildDrawCallback	special_child_draw_callback () const
	Get the special child draw callback.
void	special_child_draw_callback (ChildDrawCallback func)
	Set the special child draw callback.
EGT_NODISCARD ChildDrawCallback	special_child_draw_callback (Widget *parent) const
	Get the child draw callback of the parent.
void	start_drag (Event &event)
	Handle 'pointer_drag_start' events and decide whether they are caught by this widget.
virtual Point	to_panel (const Point &p)
	Convert a local point to the coordinate system of the current panel.
virtual EGT_NODISCARD Point	to_subordinate (const Point &p) const
	Convert a point with an origin of the current widget to subordinate origin.
EGT_NODISCARD Rect	to_subordinate (Rect rect) const
bool	track_drag () const
	Tell the continue_drag() method whether the widget tracks 'pointer_drag*' events once they have crossed out the widget boundaries.
void	update_subordinates_ranges ()
	Update the 'm_children' and 'm_components' members.
size_t	zorder (const Widget *widget) const
	Get the zorder of the widget.
void	zorder (const Widget *widget, size_t rank)
	Set the zorder of the widget.
void	zorder_bottom (const Widget *widget)
	Move the specified widget zorder to the bottom of the current list of widgets with the same parent.
void	zorder_down (const Widget *widget)
	Move the specified widget zorder down relative to other widgets with the same parent.
void	zorder_top (const Widget *widget)
	Move the specified widget zorder to the top of the current list of widgets with the same parent.
void	zorder_up (const Widget *widget)
	Move the specified widget zorder up relative to other widgets with the same parent.

Additional Inherited Members
Public Types inherited from Widget
enum class	Flag : uint32_t {   plane_window = detail::bit(0) , window = detail::bit(1) , frame = detail::bit(2) , disabled = detail::bit(3) ,   readonly = detail::bit(4) , active = detail::bit(5) , invisible = detail::bit(6) , grab_mouse = detail::bit(7) ,   no_clip = detail::bit(8) , no_layout = detail::bit(9) , no_autoresize = detail::bit(10) , checked = detail::bit(11) ,   component = detail::bit(12) , user_drag = detail::bit(13) , user_track_drag = detail::bit(14) }
	Common flags used for various widget properties. More...
using	Flags = egt::Flags< Widget::Flag >
	Widget flags.
using	WalkCallback = std::function< bool(Widget *widget, int level)>
	Callback definition used by walk().
using	WidgetId = uint64_t
	Type used to identify a unique Widget ID.
Public Types inherited from Object
using	EventCallback = std::function< void(Event &event)>
	Event handler callback function.
using	FilterFlags = FlagsBase< EventId >
	Event handler EventId filter.
using	RegisterHandle = uint64_t
	Handle type.
Static Public Attributes inherited from Window
static const PixelFormat	DEFAULT_FORMAT
	Default pixel format used for Window.
Protected Types inherited from Widget
using	ChildDrawCallback = std::function< void(Painter &painter, Widget *widget)>
	Helper type that defines the special draw child callback.
using	SubordinatesArray = std::list< std::shared_ptr< Widget > >
	Helper type for an array of subordinate widgets.
Protected Types inherited from Object
using	CallbackArray = std::vector< CallbackMeta >
	Helper type for an array of callbacks.
Protected Attributes inherited from Window
float	m_hscale {1.0}
	Horizontal scale value.
float	m_vscale {1.0}
	Vertical scale value.
Protected Attributes inherited from Widget
Rect	m_box
	Bounding box.
detail::Range< SubordinatesArray >	m_children
	Array of child widgets in the order they were added.
detail::Range< SubordinatesArray >	m_components
	Array of component widgets in the order they were added.
SubordinatesArray::iterator	m_components_begin
	Iterator for the beginning of components which are positionned after children in the subordinates array.
Screen::DamageArray	m_damage
	The damage array for this widget.
bool	m_in_draw {false}
	Status for whether this widget is currently drawing.
bool	m_in_layout {false}
	Status for whether this widget is currently performing layout.
Size	m_min_size
	Minimum size of the widget when not an empty value.
Widget *	m_parent {nullptr}
	Pointer to this widget's parent.
ChildDrawCallback	m_special_child_draw_callback
	Used internally for calling the special child draw function.
SubordinatesArray	m_subordinates
	Array of subordinates widgets split in child widgets and component widgets.
Rect	m_user_requested_box
	Keep track of the box requested by the user.
WidgetId	m_widgetid {0}
	Unique ID of this widget.
Protected Attributes inherited from Object
detail::CopyOnWriteAllocate< CallbackArray >	m_callbacks
	Array of callbacks.
RegisterHandle	m_handle_counter {0}
	Counter used to generate unique handles for each callback registration.
std::string	m_name
	A user defined name for the Object.

Detailed Description

A CameraWindow is a widget to capture image feed from the camera sensor and render it on screen using gstreamer media framework.

It has a bounding rectangle, device, format and WindowHint. These properties can be manipulated to create a camera window either as a basic window or an overlay plane.

Constructor & Destructor Documentation

CameraWindow() [1/6]

CameraWindow ( const std::string &  device = "/dev/video0", PixelFormat  format_hint = PixelFormat::yuyv, WindowHint  hint = WindowHint::overlay  )

explicit

Create a camera window.

Parameters

[in]	device	Camera device node.
[in]	format_hint	Requested format of the Window. This only applies if this Window will be responsible for creating a backing screen. Otherwise, the Window will use whatever format the existing screen has. This is only a hint.
[in]	hint	Requested Window type. This only applies if this Window will be responsible for creating a backing screen. This is only a hint.

Note

Only WindowHint::heo_overlay can use yuyv, nv21 and yuv420 pixel formats.

CameraWindow() [2/6]

CameraWindow ( const Rect &  rect, const std::string &  device = "/dev/video0", PixelFormat  format_hint = PixelFormat::yuyv, WindowHint  hint = WindowHint::overlay  )

explicit

Create a camera window.

Parameters

[in]	rect	Initial rectangle of the widget.
[in]	device	Camera device node.
[in]	format_hint	Requested format of the Window. This only applies if this Window will be responsible for creating a backing screen. Otherwise, the Window will use whatever format the existing screen has. This is only a hint.
[in]	hint	Requested Window type. This only applies if this Window will be responsible for creating a backing screen. This is only a hint.

Note

Only WindowHint::heo_overlay can use yuyv, nv21 and yuv420 pixel formats.

CameraWindow() [3/6]

CameraWindow ( Serializer::Properties &  props )

inline

Construct a camera window.

Parameters

[in]

props

list of widget argument and its properties.

CameraWindow() [4/6]

CameraWindow ( Serializer::Properties &  props, bool  is_derived  )

protected

CameraWindow() [5/6]

CameraWindow ( const CameraWindow &  )

delete

CameraWindow() [6/6]

CameraWindow ( CameraWindow &&  )

default

~CameraWindow()

~CameraWindow ( )

overridenoexcept

Member Function Documentation

device() [1/2]

std::string device

(

)

const

device() [2/2]

void device

(

const std::string &

device

)

do_draw()

void do_draw ( )

inlineoverridevirtual

Perform the actual drawing.

Allocate the Painter and call draw() on each child.

Reimplemented from Window.

draw()

void draw ( Painter &  painter, const Rect &  rect  )

overridevirtual

Draw the widget.

To change how a widget is drawn, this function can be overloaded and changed in a derived class, or it can be changed dynamically with the Theme.

To optimize drawing, a Widget may use the Rect parameter to limit what needs to be redrawn, which may be smaller than the widget's box(), but will never be outside the widget's box().

Painter will always be supplied in a default state to this function, so there is no need to do any cleanup or state saving inside this draw() function.

Warning

Normally this should not be called directly and instead the EventLoop will call this function with an already established Painter when the Widget needs to be drawn.

See also

Color, Palette, and Theme and Drawing

Parameters

[in]	painter	Instance of the Painter for the Screen.
[in]	rect	The rectangle to draw.

Reimplemented from Widget.

list_devices()

std::vector< std::string > list_devices

(

)

operator=() [1/2]

CameraWindow & operator= ( CameraWindow &&  )

default

operator=() [2/2]

CameraWindow & operator= ( const CameraWindow &  )

delete

play()

bool play

(

)

Set the camera pipeline to the play state.

In other words, play the video from the camera.

playing()

EGT_NODISCARD bool playing

(

)

const

Check is the camera pipeline in play state.

Returns

true on success

scale() [1/2]

void scale ( float  hscale, float  vscale  )

overridevirtual

Set the scale of the widget.

Parameters

[in]	hscale	Horizontal scale, with 1.0 being 100%.
[in]	vscale	Vertical scale, with 1.0 being 100%.

Warning

This is experimental.

Reimplemented from Widget.

scale() [2/2]

void scale ( float  hscale, float  vscale  )

overridevirtual

Set the scale of the widget.

Parameters

[in]	hscale	Horizontal scale, with 1.0 being 100%.
[in]	vscale	Vertical scale, with 1.0 being 100%.

Warning

This is experimental.

Reimplemented from Widget.

serialize()

void serialize ( Serializer &  serializer ) const

overridevirtual

Serialize the widget to the specified serializer.

Reimplemented from Widget.

start()

bool start

(

)

Initialize camera pipeline to capture image feed from the camera sensor and render to Window.

Returns

true on success

stop()

void stop

(

)

Stop camera.

Member Data Documentation

on_connect

SignalW<const std::string&> on_connect

Generated when an USB camera connected.

on_disconnect

SignalW<const std::string&> on_disconnect

Generated when an USB camera disconnected.

on_error

SignalW<const std::string&> on_error

Event signal.

Generated when an error occurs.