wayland_shm_pool_t - Man Page

a shared memory pool

Synopsis

#include <wayland-client-protocol.hpp>

Inherits wayland::proxy_t.

Public Types

enum wrapper_type { wrapper_type::standard, wrapper_type::display, wrapper_type::foreign, wrapper_type::proxy_wrapper }

Public Member Functions

buffer_t create_buffer (int32_t offset, int32_t width, int32_t height, int32_t stride, shm_format const &format)
create a buffer from the pool
void resize (int32_t size)
change the size of the pool mapping
uint32_t get_id () const
Get the id of a proxy object.
std::string get_class () const
Get the interface name (class) of a proxy object.
uint32_t get_version () const
Get the protocol object version of a proxy object.
wrapper_type get_wrapper_type () const
Get the type of a proxy object.
void set_queue (event_queue_t queue)
Assign a proxy to an event queue.
wl_proxy * c_ptr () const
Get a pointer to the underlying C struct.
bool proxy_has_object () const
Check whether this wrapper actually wraps an object.
operator bool () const
Check whether this wrapper actually wraps an object.
bool operator== (const proxy_t &right) const
Check whether two wrappers refer to the same object.
bool operator!= (const proxy_t &right) const
Check whether two wrappers refer to different objects.
void proxy_release ()
Release the wrapped object (if any), making this an empty wrapper.

Static Public Attributes

static constexpr std::uint32_t create_buffer_since_version = 1
Minimum protocol version required for the create_buffer function.
static constexpr std::uint32_t resize_since_version = 1
Minimum protocol version required for the resize function.

Detailed Description

a shared memory pool

The wl_shm_pool object encapsulates a piece of memory shared between the compositor and client. Through the wl_shm_pool object, the client can allocate shared memory wl_buffer objects. All objects created through the same pool share the same underlying mapped memory. Reusing the mapped memory avoids the setup/teardown overhead and is useful when interactively resizing a surface or for many small buffers.

Definition at line 312 of file wayland-client-protocol.hpp.

Member Enumeration Documentation

enum wayland::proxy_t::wrapper_type [strong], [inherited]

Underlying wl_proxy type and properties of a proxy_t that affect construction, destruction, and event handling

Enumerator

standard

C pointer is a standard type compatible with wl_proxy*. Events are dispatched and it is destructed when the proxy_t is destructed. User data is set.

display

C pointer is a wl_display*. No events are dispatched, wl_display_disconnect is called when the proxy_t is destructed. User data is set.

foreign

C pointer is a standard type compatible with wl_proxy*, but another library owns it and it should not be touched in a way that could affect the operation of the other library. No events are dispatched, wl_proxy_destroy is not called when the proxy_t is destructed, user data is not touched. Consequently, there is no reference counting for the proxy_t. Lifetime of such wrappers should preferably be short to minimize the chance that the owning library decides to destroy the wl_proxy.

proxy_wrapper

C pointer is a wl_proxy* that was constructed with wl_proxy_create_wrapper. No events are dispatched, wl_proxy_wrapper_destroy is called when the proxy_t is destroyed. Reference counting is active. A reference to the proxy_t creating this proxy wrapper is held to extend its lifetime until after the proxy wrapper is destroyed.

Definition at line 115 of file wayland-client.hpp.

Member Function Documentation

wl_proxy* wayland::proxy_t::c_ptr () const [inherited]

Get a pointer to the underlying C struct.

Returns

The underlying wl_proxy wrapped by this proxy_t if it exists, otherwise an exception is thrown

buffer_t shm_pool_t::create_buffer (int32_t offset, int32_t width, int32_t height, int32_t stride, shm_format const & format)

create a buffer from the pool

Returns

buffer to create

Parameters

offset buffer byte offset within the pool
width buffer width, in pixels
height buffer height, in pixels
stride number of bytes from the beginning of one row to the beginning of the next row
format buffer pixel format

Create a wl_buffer object from the pool.

The buffer is created offset bytes into the pool and has width and height as specified. The stride argument specifies the number of bytes from the beginning of one row to the beginning of the next. The format is the pixel format of the buffer and must be one of those advertised through the wl_shm.format event.

A buffer will keep a reference to the pool it was created from so it is valid to destroy the pool immediately after creating a buffer from it.

Definition at line 1775 of file wayland-client-protocol.cpp.

std::string wayland::proxy_t::get_class () const [inherited]

Get the interface name (class) of a proxy object.

Returns

The interface name of the object associated with the proxy

uint32_t wayland::proxy_t::get_id () const [inherited]

Get the id of a proxy object.

Returns

The id the object associated with the proxy

Examples dump.cpp.

uint32_t wayland::proxy_t::get_version () const [inherited]

Get the protocol object version of a proxy object. Gets the protocol object version of a proxy object, or 0 if the proxy was created with unversioned API.

A returned value of 0 means that no version information is available, so the caller must make safe assumptions about the object's real version.

display_t will always return version 0.

Returns

The protocol object version of the proxy or 0

wrapper_type wayland::proxy_t::get_wrapper_type () const [inline], [inherited]

Get the type of a proxy object.

Definition at line 301 of file wayland-client.hpp.

wayland::proxy_t::operator bool () const [inherited]

Check whether this wrapper actually wraps an object.

Returns

true if there is an underlying object, false if this wrapper is empty

bool wayland::proxy_t::operator!= (const proxy_t & right) const [inherited]

Check whether two wrappers refer to different objects.

bool wayland::proxy_t::operator== (const proxy_t & right) const [inherited]

Check whether two wrappers refer to the same object.

bool wayland::proxy_t::proxy_has_object () const [inherited]

Check whether this wrapper actually wraps an object.

Returns

true if there is an underlying object, false if this wrapper is empty

void wayland::proxy_t::proxy_release () [inherited]

Release the wrapped object (if any), making this an empty wrapper. Note that display_t instances cannot be released this way. Attempts to do so are ignored.

Examples foreign_display.cpp.

void shm_pool_t::resize (int32_t size)

change the size of the pool mapping

Parameters

size new size of the pool, in bytes

This request will cause the server to remap the backing memory for the pool from the file descriptor passed when the pool was created, but using the new size. This request can only be used to make the pool bigger.

Definition at line 1781 of file wayland-client-protocol.cpp.

void wayland::proxy_t::set_queue (event_queue_t queue) [inherited]

Assign a proxy to an event queue.

Parameters

queue The event queue that will handle this proxy

Assign proxy to event queue. Events coming from proxy will be queued in queue instead of the display's main queue.

See also: display_t::dispatch_queue().

Examples proxy_wrapper.cpp.

Member Data Documentation

constexpr std::uint32_t wayland::shm_pool_t::create_buffer_since_version = 1 [static], [constexpr]

Minimum protocol version required for the create_buffer function.

Definition at line 359 of file wayland-client-protocol.hpp.

constexpr std::uint32_t wayland::shm_pool_t::resize_since_version = 1 [static], [constexpr]

Minimum protocol version required for the resize function.

Definition at line 374 of file wayland-client-protocol.hpp.

Author

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Info

Wed Aug 5 2020 Version 0.2.8 Wayland++