---
name: "wayland_zwp_linux_buffer_params_v1_t"
section: "3"
platform: "linux"
package: "waylandpp-dev"
version: "1.0.0-6+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/wayland_zwp_linux_buffer_params_v1_t"
---

# wayland\_zwp\_linux\_buffer\_params\_v1\_t(3)

parameters for creating a dmabuf-based wl\_buffer

## NAME

wayland::zwp\_linux\_buffer\_params\_v1\_t - parameters for creating a dmabuf-based wl\_buffer

## SYNOPSIS

`#include <wayland-client-protocol-unstable.hpp>`

Inherits **wayland::proxy\_t**.

### Public Types

enum class **wrapper\_type** { **standard**, **display**, **foreign**, **proxy\_wrapper** }\

### Public Member Functions

void **add** (int fd, uint32\_t plane\_idx, uint32\_t offset, uint32\_t stride, uint32\_t modifier\_hi, uint32\_t modifier\_lo)\
 add a dmabuf to the temporary set  void **create** (int32\_t width, int32\_t height, uint32\_t format, zwp\_linux\_buffer\_params\_v1\_flags const &flags)\
 create a wl\_buffer from the given dmabufs  **buffer\_t** **create\_immed** (int32\_t width, int32\_t height, uint32\_t format, zwp\_linux\_buffer\_params\_v1\_flags const &flags)\
 immediately create a wl\_buffer from the given dmabufs  bool **can\_create\_immed** () const\
 Check whether the **create\_immed** function is available with the currently bound version of the protocol.  std::function\< void(**buffer\_t**)\> & **on\_created** ()\
 buffer creation succeeded  std::function\< void()\> & **on\_failed** ()\
 buffer creation failed  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 **add\_since\_version** = 1\
 Minimum protocol version required for the **add** function.  static constexpr std::uint32\_t **create\_since\_version** = 1\
 Minimum protocol version required for the **create** function.  static constexpr std::uint32\_t **create\_immed\_since\_version** = 2\
 Minimum protocol version required for the **create\_immed** function.

## Detailed Description

parameters for creating a dmabuf-based wl\_buffer

This temporary object is a collection of dmabufs and other parameters that together form a single logical buffer. The temporary object may eventually create one wl\_buffer unless cancelled by destroying it before requesting 'create'.

Single-planar formats only require one dmabuf, however multi-planar formats may require more than one dmabuf. For all formats, an 'add' request must be called once per plane (even if the underlying dmabuf fd is identical).

You must use consecutive plane indices ('plane\_idx' argument for 'add') from zero to the number of planes used by the drm\_fourcc format code. All planes required by the format must be given exactly once, but can be given in any order. Each plane index can be set only once.

Definition at line **1670** of file **wayland-client-protocol-unstable.hpp**.

## Member Enumeration Documentation

### enum class 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* **116** *of file* **wayland-client.hpp***.*

## Member Function Documentation

### void zwp\_linux\_buffer\_params\_v1\_t::add (int fd, uint32\_t plane\_idx, uint32\_t offset, uint32\_t stride, uint32\_t modifier\_hi, uint32\_t modifier\_lo)

*add a dmabuf to the temporary set*

**Parameters**

*fd dmabuf fd* \
 *plane\_idx plane index* \
 *offset offset in bytes* \
 *stride stride in bytes* \
 *modifier\_hi high 32 bits of layout modifier* \
 *modifier\_lo low 32 bits of layout modifier*

*This request adds one dmabuf to the set in this zwp\_linux\_buffer\_params\_v1.*

*The 64-bit unsigned value combined from modifier\_hi and modifier\_lo is the dmabuf layout modifier. DRM AddFB2 ioctl calls this the fb modifier, which is defined in drm\_mode.h of Linux UAPI. This is an opaque token. Drivers use this token to express tiling, compression, etc. driver-specific modifications to the base format defined by the DRM fourcc code.*

*Starting from version 4, the invalid\_format protocol error is sent if the format + modifier pair was not advertised as supported.*

*This request raises the PLANE\_IDX error if plane\_idx is too large. The error PLANE\_SET is raised if attempting to set a plane that was already set.*

*Definition at line* **5324** *of file* **wayland-client-protocol-unstable.cpp***.*

### 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*

### bool zwp\_linux\_buffer\_params\_v1\_t::can\_create\_immed () const

*Check whether the* **create\_immed** *function is available with the currently bound version of the protocol.*

*Definition at line* **5342** *of file* **wayland-client-protocol-unstable.cpp***.*

### void zwp\_linux\_buffer\_params\_v1\_t::create (int32\_t width, int32\_t height, uint32\_t format, zwp\_linux\_buffer\_params\_v1\_flags const & flags)

*create a wl\_buffer from the given dmabufs*

**Parameters**

*width base plane width in pixels* \
 *height base plane height in pixels* \
 *format DRM\_FORMAT code* \
 *flags see enum flags*

*This asks for creation of a wl\_buffer from the added dmabuf buffers. The wl\_buffer is not created immediately but returned via the 'created' event if the dmabuf sharing succeeds. The sharing may fail at runtime for reasons a client cannot predict, in which case the 'failed' event is triggered.*

*The 'format' argument is a DRM\_FORMAT code, as defined by the libdrm's drm\_fourcc.h. The Linux kernel's DRM sub-system is the authoritative source on how the format codes should work.*

*The 'flags' is a bitfield of the flags defined in enum 'flags'. 'y\_invert' means the that the image needs to be y-flipped.*

*Flag 'interlaced' means that the frame in the buffer is not progressive as usual, but interlaced. An interlaced buffer as supported here must always contain both top and bottom fields. The top field always begins on the first pixel row. The temporal ordering between the two fields is top field first, unless 'bottom\_first' is specified. It is undefined whether 'bottom\_first' is ignored if 'interlaced' is not set.*

*This protocol does not convey any information about field rate, duration, or timing, other than the relative ordering between the two fields in one buffer. A compositor may have to estimate the intended field rate from the incoming buffer rate. It is undefined whether the time of receiving wl\_surface.commit with a new buffer attached, applying the wl\_surface state, wl\_surface.frame callback trigger, presentation, or any other point in the compositor cycle is used to measure the frame or field times. There is no support for detecting missed or late frames/fields/buffers either, and there is no support whatsoever for cooperating with interlaced compositor output.*

*The composited image quality resulting from the use of interlaced buffers is explicitly undefined. A compositor may use elaborate hardware features or software to deinterlace and create progressive output frames from a sequence of interlaced input buffers, or it may produce substandard image quality. However, compositors that cannot guarantee reasonable image quality in all cases are recommended to just reject all interlaced buffers.*

*Any argument errors, including non-positive width or height, mismatch between the number of planes and the format, bad format, bad offset or stride, may be indicated by fatal protocol errors: INCOMPLETE, INVALID\_FORMAT, INVALID\_DIMENSIONS, OUT\_OF\_BOUNDS.*

*Dmabuf import errors in the server that are not obvious client bugs are returned via the 'failed' event as non-fatal. This allows attempting dmabuf sharing and falling back in the client if it fails.*

*This request can be sent only once in the object's lifetime, after which the only legal request is destroy. This object should be destroyed after issuing a 'create' request. Attempting to use this object after issuing 'create' raises ALREADY\_USED protocol error.*

*It is not mandatory to issue 'create'. If a client wants to cancel the buffer creation, it can just destroy this object.*

*Definition at line* **5330** *of file* **wayland-client-protocol-unstable.cpp***.*

### buffer\_t zwp\_linux\_buffer\_params\_v1\_t::create\_immed (int32\_t width, int32\_t height, uint32\_t format, zwp\_linux\_buffer\_params\_v1\_flags const & flags)

*immediately create a wl\_buffer from the given dmabufs*

**Returns**

*id for the newly created wl\_buffer*

**Parameters**

*width base plane width in pixels* \
 *height base plane height in pixels* \
 *format DRM\_FORMAT code* \
 *flags see enum flags*

*This asks for immediate creation of a wl\_buffer by importing the added dmabufs.*

*In case of import success, no event is sent from the server, and the wl\_buffer is ready to be used by the client.*

*Upon import failure, either of the following may happen, as seen fit by the implementation:*

- •

  *the client is terminated with one of the following fatal protocol errors:*

- •

  *INCOMPLETE, INVALID\_FORMAT, INVALID\_DIMENSIONS, OUT\_OF\_BOUNDS, in case of argument errors such as mismatch between the number of planes and the format, bad format, non-positive width or height, or bad offset or stride.*

- •

  *INVALID\_WL\_BUFFER, in case the cause for failure is unknown or plaform specific.*

- •

  *the server creates an invalid wl\_buffer, marks it as failed and sends a 'failed' event to the client. The result of using this invalid wl\_buffer as an argument in any request by the client is defined by the compositor implementation.*

*This takes the same arguments as a 'create' request, and obeys the same restrictions.*

*Definition at line* **5336** *of file* **wayland-client-protocol-unstable.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*

### 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* **302** *of file* **wayland-client.hpp***.*

### std::function\< void(buffer\_t)\> & zwp\_linux\_buffer\_params\_v1\_t::on\_created ()

*buffer creation succeeded*

**Parameters**

*buffer the newly created wl\_buffer*

*This event indicates that the attempted buffer creation was successful. It provides the new wl\_buffer referencing the dmabuf(s).*

*Upon receiving this event, the client should destroy the zlinux\_dmabuf\_params object.*

*Definition at line* **5348** *of file* **wayland-client-protocol-unstable.cpp***.*

### std::function\< void()\> & zwp\_linux\_buffer\_params\_v1\_t::on\_failed ()

*buffer creation failed This event indicates that the attempted buffer creation has failed. It usually means that one of the dmabuf constraints has not been fulfilled.*

*Upon receiving this event, the client should destroy the zlinux\_buffer\_params object.*

*Definition at line* **5353** *of file* **wayland-client-protocol-unstable.cpp***.*

### 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 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::zwp\_linux\_buffer\_params\_v1\_t::add\_since\_version = 1` [static]`, ` [constexpr]`

*Minimum protocol version required for the* **add** *function.*

*Definition at line* **1724** *of file* **wayland-client-protocol-unstable.hpp***.*

### constexpr std::uint32\_t wayland::zwp\_linux\_buffer\_params\_v1\_t::create\_immed\_since\_version = 2` [static]`, ` [constexpr]`

*Minimum protocol version required for the* **create\_immed** *function.*

*Definition at line* **1835** *of file* **wayland-client-protocol-unstable.hpp***.*

### constexpr std::uint32\_t wayland::zwp\_linux\_buffer\_params\_v1\_t::create\_since\_version = 1` [static]`, ` [constexpr]`

*Minimum protocol version required for the* **create** *function.*

*Definition at line* **1797** *of file* **wayland-client-protocol-unstable.hpp***.*

## Author

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