wayland::shm_pool_t(3) Wayland++ wayland::shm_pool_t(3)

wayland::shm_pool_t - a shared memory pool

#include <wayland-client-protocol.hpp>

Inherits wayland::proxy_t.


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


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 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.

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.

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

Enumerator

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.
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.
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.
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 116 of file wayland-client.hpp.

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.

Examples
shm.cpp.

Definition at line 1816 of file wayland-client-protocol.cpp.

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

Returns

The interface name of the object associated with the proxy

Get the id of a proxy object.

Returns

The id the object associated with the proxy

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 302 of file wayland-client.hpp.

Check whether this wrapper actually wraps an object.

Returns

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

Check whether two wrappers refer to different objects.

Check whether two wrappers refer to the same object.

Check whether this wrapper actually wraps an object.

Returns

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

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.

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.

This request only changes the amount of bytes that are mmapped
by the server and does not touch the file corresponding to the
file descriptor passed at creation time. It is the client's
responsibility to ensure that the file is at least as big as
the new pool size.

Definition at line 1823 of file wayland-client-protocol.cpp.

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.

Minimum protocol version required for the create_buffer function.

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

Minimum protocol version required for the resize function.

Definition at line 380 of file wayland-client-protocol.hpp.

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Mon Apr 22 2024 09:52:15 Version 1.0.0