Display Class Reference

Represents a display that can be used to display images. More...

Inheritance diagram for Display:

Public Types

using	WindowClosedHandler = std::function< void(Display &display)> Function prototype for window-closed event handlers.
using	NotificationToken = void * Represents a registered callback.

Public Member Functions

bool	displayBuffer (const std::shared_ptr< ic4::ImageBuffer > &buffer, Error &err=Error::Default()) Displays a specific image buffer.
bool	setRenderPosition (DisplayRenderPosition pos, int left=-1, int top=-1, int width=-1, int height=-1, Error &err=Error::Default()) Configure the image scaling and alignment options for a display.
DisplayStatistics	statistics (Error &err=Error::Default()) Queries display statistics.
NotificationToken	eventAddWindowClosed (WindowClosedHandler cb, Error &err=Error::Default()) Registers a new window-closed event handler.
bool	eventRemoveWindowClosed (NotificationToken token, Error &err=Error::Default()) Unregisters a window-closed event handler.

Static Public Member Functions

static std::shared_ptr< Display >

create (DisplayType type, WindowHandle hParent, Error &err=Error::Default())

Creates a new display.

Detailed Description

Represents a display that can be used to display images.

To create a display, call Display::create() or ExternalOpenGLDisplay::create().

Display objects are generally used in two distinct ways:

The display is connected to a data stream when calling Grabber::streamSetup(), automatically displaying all images from the opened device.
ImageBuffer objects are displayed manually by calling Display::displayBuffer().

Display objects are neither copyable nor movable, and are only handled via std::shared_ptr<Display>.

Note: Some functions, such as Grabber::streamSetup(), takes shared ownership of the display object. The display is kept alive by the Grabber instance even if no external reference to the display object exists.

See also: Display::create

Member Typedef Documentation

◆ NotificationToken

using NotificationToken = void*

Represents a registered callback.

When a callback function is registered using Display::eventAddWindowClosed, a token is returned.

The token can then be used to remove the callback using Display::eventRemoveWindowClosed at a later time.

◆ WindowClosedHandler

using WindowClosedHandler = std::function<void(Display& display)>

Function prototype for window-closed event handlers.

Parameters

[in] display The Display on which the event handler was registered.

Member Function Documentation

◆ create()

static std::shared_ptr< Display > create	(	DisplayType	type,
		WindowHandle	hParent,
		Error &	err = `Error::Default()`
	)

inlinestatic

Creates a new display.

Parameters

[in]	type	The type of display to create
[in]	hParent	Handle to the parent window to embed the display into.
[out]	err	Reference to an error handler. See Error Handling for details.

Returns: The new display, or nullptr if an error occurs.

Warning: This function only works in Windows platforms. For other platforms, use ExternalOpenGLDisplay::create().

◆ displayBuffer()

bool displayBuffer	(	const std::shared_ptr< ic4::ImageBuffer > &	buffer,
		Error &	err = `Error::Default()`
	)

inline

Displays a specific image buffer.

Parameters

[in]	buffer	The buffer to display
[out]	err	Reference to an error handler. See Error Handling for details.

Returns: true on success, otherwise false.

Remarks: When buffer is nullptr, the display is cleared and will no longer display the previous buffer.

◆ eventAddWindowClosed()

NotificationToken eventAddWindowClosed	(	WindowClosedHandler	cb,
		Error &	err = `Error::Default()`
	)

inline

Registers a new window-closed event handler.

Parameters

[in]	cb	Callback function to be called when the display window is closed.
[out]	err	Reference to an error handler. See Error Handling for details.

Returns: A token that can be used to unregister the callback using .\n If an error occurrs, the function returns nullptr.

See also: Display::eventRemoveWindowClosed

◆ eventRemoveWindowClosed()

bool eventRemoveWindowClosed	(	NotificationToken	token,
		Error &	err = `Error::Default()`
	)

inline

Unregisters a window-closed event handler.

Parameters

[in]	token	A token that was returned when registering an event handler using Display::eventAddWindowClosed().
[out]	err	Reference to an error handler. See Error Handling for details.

Returns: true on success, otherwise false.

See also: Display::eventAddWindowClosed

◆ setRenderPosition()

bool setRenderPosition	(	DisplayRenderPosition	pos,
		int	left = `-1`,
		int	top = `-1`,
		int	width = `-1`,
		int	height = `-1`,
		Error &	err = `Error::Default()`
	)

inline

Configure the image scaling and alignment options for a display.

Parameters

[in]	pos	The scaling and alignment mode to use
[in]	left	The left coordinate of the target rectangle inside the display window
[in]	top	The top coordinate of the target rectangle inside the display window
[in]	width	The width of the target rectangle inside the display window
[in]	height	The height of the target rectangle inside the display window
[out]	err	Reference to an error handler. See Error Handling for details.

Returns: true on success, otherwise false.

Remarks: The left, top, width and height parameters are ignored unless mode is DisplayRenderPosition::Custom.

◆ statistics()

DisplayStatistics statistics ( Error & err = Error::Default() )

inline

Queries display statistics.

Parameters

[out] err Reference to an error handler. See Error Handling for details.

Returns: A DisplayStatistics structure containing the number of displayed and dropped frames.