platf::shm_attr_t Struct Reference

X11 shared-memory image dimensions and identifiers. More...

Inheritance diagram for platf::shm_attr_t:

Collaboration diagram for platf::shm_attr_t:

Public Member Functions
std::shared_ptr< img_t >	alloc_img () override
	Allocate an image buffer compatible with this display backend.
capture_e	capture (const push_captured_image_cb_t &push_captured_image_cb, const pull_free_image_cb_t &pull_free_image_cb, bool *cursor) override
	Capture a frame.
void	delayed_refresh ()
	Refresh X11 shared-memory capture after a scheduled delay.
int	dummy_img (platf::img_t *img) override
	Populate a fallback image when real capture data is unavailable.
std::uint32_t	frame_size ()
	Calculate the XCB shared-memory frame size.
int	init (const std::string &display_name, const ::video::config_t &config)
	Initialize X11 shared-memory capture for the selected display.
	shm_attr_t (mem_type_e mem_type)
	Open an X11 shared-memory capture backend.
capture_e	snapshot (const pull_free_image_cb_t &pull_free_image_cb, std::shared_ptr< platf::img_t > &img_out, std::chrono::milliseconds timeout, bool cursor)
	Capture a display frame into the provided image object.
Public Member Functions inherited from platf::x11_attr_t
std::shared_ptr< img_t >	alloc_img () override
	Allocate an image buffer compatible with this display backend.
capture_e	capture (const push_captured_image_cb_t &push_captured_image_cb, const pull_free_image_cb_t &pull_free_image_cb, bool *cursor) override
	Capture a frame.
int	dummy_img (img_t *img) override
	Populate a fallback image when real capture data is unavailable.
int	init (const std::string &display_name, const ::video::config_t &config)
	Open the X11 display and cache capture window attributes.
std::unique_ptr< avcodec_encode_device_t >	make_avcodec_encode_device (pix_fmt_e pix_fmt) override
	Create AVCodec encode device.
void	refresh ()
capture_e	snapshot (const pull_free_image_cb_t &pull_free_image_cb, std::shared_ptr< platf::img_t > &img_out, std::chrono::milliseconds timeout, bool cursor)
	Capture a display frame into the provided image object.
	x11_attr_t (mem_type_e mem_type)
	Open the X11 display and initialize capture attributes.
Public Member Functions inherited from platf::display_t
virtual bool	get_hdr_metadata (SS_HDR_METADATA &metadata)
	Read HDR metadata for the active display mode.
virtual bool	is_codec_supported (std::string_view name, const ::video::config_t &config)
	Check that a given codec is supported by the display device.
virtual bool	is_hdr ()
	Report whether the active display mode is HDR.
virtual std::unique_ptr< nvenc_encode_device_t >	make_nvenc_encode_device (pix_fmt_e pix_fmt)
	Create NVENC encode device.

Public Attributes
shm_data_t	data
	Attached SysV shared-memory data used by XShm.
xcb_screen_t *	display
	XCB screen containing the captured root window.
task_pool_util::TaskPool::task_id_t	refresh_task_id
	Refresh task ID.
std::uint32_t	seg
	XCB shared-memory segment ID attached to the image.
shm_id_t	shm_id
	Shm ID.
x11::xdisplay_t	shm_xdisplay
	X11 display held separately to prevent races with x11_attr_t::xdisplay.
xcb_connect_t	xcb
	XCB connection used by the shared-memory capture path.
Public Attributes inherited from platf::x11_attr_t
std::chrono::nanoseconds	delay
	Delay before the timer task becomes eligible to run.
mem_type_e	mem_type
	Mem type.
XWindowAttributes	xattr
	Cached X11 window attributes used to detect size changes.
x11::xdisplay_t	xdisplay
	X11 display connection used for capture.
Window	xwindow
	Root window being captured.
Public Attributes inherited from platf::display_t
int	env_height {0}
	Height of the full capture environment in physical pixels.
int	env_logical_height {0}
	Height of the full capture environment after display scaling.
int	env_logical_width {0}
	Width of the full capture environment after display scaling.
int	env_width {0}
	Width of the full capture environment in physical pixels.
int	height {0}
	Height of the captured display in physical pixels.
int	logical_height {0}
	Height of the captured display after display scaling.
int	logical_width {0}
	Width of the captured display after display scaling.
int	offset_x {0}
	Horizontal capture offset in physical pixels.
int	offset_y {0}
	Vertical capture offset in physical pixels.
int	width {0}
	Width of the captured display in physical pixels.

Additional Inherited Members
Public Types inherited from platf::display_t
using	pull_free_image_cb_t = std::function<bool(std::shared_ptr<img_t> &img_out)>
	Get free image from pool. Calls must be synchronized. Blocks until there is free image in the pool or capture is interrupted.
using	push_captured_image_cb_t = std::function<bool(std::shared_ptr<img_t> &&img, bool frame_captured)>
	Callback for when a new image is ready. When display has a new image ready or a timeout occurs, this callback will be called with the image. If a frame was captured, frame_captured will be true. If a timeout occurred, it will be false.
Protected Attributes inherited from platf::display_t
logging::time_delta_periodic_logger	sleep_overshoot_logger = {debug, "Frame capture sleep overshoot"}
	Periodic logger for capture sleep overshoot measurements.

Detailed Description

X11 shared-memory image dimensions and identifiers.

Constructor & Destructor Documentation

shm_attr_t()

platf::shm_attr_t::shm_attr_t ( mem_type_e mem_type )

inline

Open an X11 shared-memory capture backend.

Parameters

mem_type

Requested memory path for the capture backend.

Member Function Documentation

alloc_img()

std::shared_ptr< img_t > platf::shm_attr_t::alloc_img ( )

inlineoverridevirtual

Allocate an image buffer compatible with this display backend.

Returns

Allocated img object, or null when unavailable.

Implements platf::display_t.

capture()

capture_e platf::shm_attr_t::capture ( const push_captured_image_cb_t & push_captured_image_cb, const pull_free_image_cb_t & pull_free_image_cb, bool * cursor )

inlineoverridevirtual

Capture a frame.

Parameters

push_captured_image_cb	The callback that is called with captured image, must be called from the same thread as capture()
pull_free_image_cb	Capture backends call this callback to get empty image from the pool. If backend uses multiple threads, calls to this callback must be synchronized. Calls to this callback and push_captured_image_cb must be synchronized as well.
cursor	A pointer to the flag that indicates whether the cursor should be captured as well.

Return values

capture_e::ok	When stopping
capture_e::error	On error
capture_e::reinit	When need of reinitialization

Implements platf::display_t.

dummy_img()

int platf::shm_attr_t::dummy_img ( platf::img_t * img )

inlineoverridevirtual

Populate a fallback image when real capture data is unavailable.

Parameters

img	Image or frame object to read from or populate.

Returns

Capture status reported to the streaming pipeline.

Implements platf::display_t.

frame_size()

std::uint32_t platf::shm_attr_t::frame_size ( )

inline

Calculate the XCB shared-memory frame size.

Returns

Frame size in bytes for BGRA pixels.

init()

int platf::shm_attr_t::init ( const std::string & display_name, const ::video::config_t & config )

inline

Initialize X11 shared-memory capture for the selected display.

Parameters

display_name	Display name.
config	Configuration values to apply.

Returns

0 on success; nonzero or negative platform status on failure.

snapshot()

capture_e platf::shm_attr_t::snapshot ( const pull_free_image_cb_t & pull_free_image_cb, std::shared_ptr< platf::img_t > & img_out, std::chrono::milliseconds timeout, bool cursor )

inline

Capture a display frame into the provided image object.

Parameters

pull_free_image_cb	Callback that provides an available image buffer.
img_out	Shared-memory captured frame returned to the streaming pipeline.
timeout	Maximum time to wait for the operation.
cursor	Cursor image or visibility state to composite.

Returns

Capture status reported to the streaming pipeline.

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

• src/platform/linux/x11grab.cpp