wayland::serv...g_positioner_t(3)

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version 1.0.1 · 10 versions
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💅 wayland::server::xdg_positioner_t — child surface positioner (Wayland++ 3) 🎀

okay so bestie, gather round, because this one is literally the little rulebook that decides where your popup lands. it's wayland::server::xdg_positioner_t, from the Wayland++ manual, section 3. no cap, it's giving "interior design for floating rectangles" and i'm obsessed 💖

✨ NAME ✨

wayland::server::xdg_positioner_t — child surface positioner 🦋

🌸 SYNOPSIS 🌸

#include <wayland-server-protocol-extra.hpp>

💜 Public Member Functions

  • std::function< void()> & on_destroy () — destroy the xdg_positioner object
  • std::function< void(int32_t, int32_t)> & on_set_size () — set the size of the to-be positioned rectangle
  • std::function< void(int32_t, int32_t, int32_t, int32_t)> & on_set_anchor_rect () — set the anchor rectangle within the parent surface
  • std::function< void(xdg_positioner_anchor)> & on_set_anchor () — set anchor rectangle anchor
  • std::function< void(xdg_positioner_gravity)> & on_set_gravity () — set child surface gravity
  • std::function< void(xdg_positioner_constraint_adjustment)> & on_set_constraint_adjustment () — set the adjustment to be done when constrained
  • std::function< void(int32_t, int32_t)> & on_set_offset () — set surface position offset
  • std::function< void()> & on_set_reactive () — continuously reconstrain the surface
  • std::function< void(int32_t, int32_t)> & on_set_parent_size ()
  • std::function< void(uint32_t)> & on_set_parent_configure () — set parent configure this is a response to
  • void post_invalid_input (std::string const &msg) — Post error: invalid input provided.
  • bool proxy_has_object () const — Check whether this wrapper actually wraps an object.
  • void post_no_memory () const
  • uint32_t get_id () const
  • client_t get_client () const
  • unsigned int get_version () const
  • std::string get_class ()

🦋 Detailed Description 🦋

child surface positioner 💫

so the xdg_positioner is like… a whole collection of rules for where a child surface goes relative to its parent surface. you can define rules so the child surface stays inside the visible area's borders, and you can say how the child surface changes its position — sliding along an axis, flipping around a rectangle, all that main character behavior. ✨

these positioner-created rules are constrained by one requirement that is not optional: a child surface has to intersect with its parent surface, or at least be partially adjacent to it. that's the vibe check, and it does not get skipped 😌

see the various requests for the deets on all the possible rules 👑

okay here's the part people forget: at the time of the request, the compositor makes a copy of the rules specified by the xdg_positioner. so after the request is complete, you can destroy or reuse the xdg_positioner object — further changes to the object will have no effect on previous usages. it's a screenshot, not a live stream, iykyk 💅

and for an xdg_positioner object to be considered complete, it must have:

  1. a non-zero size set by set_size, and
  2. a non-zero anchor rectangle set by set_anchor_rect.
🚨 passing an incomplete xdg_positioner object when positioning a surface raises an error. no exceptions, no grace period, it's giving strict professor energy.

Definition at line 787 of file wayland-server-protocol-extra.hpp.

🎀 Member Function Documentation 🎀

⭐ std::string wayland::server::resource_t::get_class () [inherited]

retrieve the interface name (class) of a resource object 🧚

Returns

  • interface name of the resource object.

⭐ client_t wayland::server::resource_t::get_client () const [inherited]

get the associated client 🫶

Returns

  • the client that owns the resource.

⭐ uint32_t wayland::server::resource_t::get_id () const [inherited]

get the internal ID of the resource 🌈

Returns

  • the internal ID of the resource

⭐ unsigned int wayland::server::resource_t::get_version () const [inherited]

get interface version ⭐

Returns

  • interface version this resource has been constructed with.

⭐ std::function< void()> & xdg_positioner_t::on_destroy ()

destroy the xdg_positioner object — notify the compositor that the xdg_positioner will no longer be used 🗑️✨

Definition at line 1024 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(xdg_positioner_anchor)> & xdg_positioner_t::on_set_anchor ()

set anchor rectangle anchor ⚓

Parameters

  • anchor — anchor

defines the anchor point for the anchor rectangle. the specified anchor is used to derive an anchor point that the child surface will be positioned relative to. if a corner anchor is set (e.g. 'top_left' or 'bottom_right'), the anchor point will be at that specified corner. otherwise, the derived anchor point will be centered on the specified edge — or in the center of the anchor rectangle if no edge is specified. corner girlies get corners, everyone else gets centered 💅

Definition at line 1042 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(int32_t, int32_t, int32_t, int32_t)> & xdg_positioner_t::on_set_anchor_rect ()

set the anchor rectangle within the parent surface 🖼️

Parameters

  • x — x position of anchor rectangle
  • y — y position of anchor rectangle
  • width — width of anchor rectangle
  • height — height of anchor rectangle

specify the anchor rectangle within the parent surface that the child surface will be placed relative to. the rectangle is relative to the window geometry as defined by xdg_surface.set_window_geometry of the parent surface. 📐

when the xdg_positioner object is used to position a child surface, the anchor rectangle may not extend outside the window geometry of the positioned child's parent surface. stay in your lane, rectangle 🤨

🚨 if a negative size is set, the invalid_input error is raised.

Definition at line 1036 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(xdg_positioner_constraint_adjustment)> & xdg_positioner_t::on_set_constraint_adjustment ()

set the adjustment to be done when constrained 🔧

Parameters

  • constraint_adjustment — bit mask of constraint adjustments

specify how the window should be positioned if the originally intended position caused the surface to be constrained — meaning at least partially outside the positioning boundaries set by the compositor. the adjustment is set by constructing a bitmask describing the adjustment to be made when the surface is constrained on that axis. 🎛️

  • if no bit for one axis is set, the compositor will assume that the child surface should not change its position on that axis when constrained.
  • if more than one bit for one axis is set, the order of how adjustments are applied is specified in the corresponding adjustment descriptions.

the default adjustment is none. ✨

Definition at line 1054 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(xdg_positioner_gravity)> & xdg_positioner_t::on_set_gravity ()

set child surface gravity 🪂

Parameters

  • gravity — gravity direction

defines in what direction a surface should be positioned, relative to the anchor point of the parent surface. if a corner gravity is specified (e.g. 'bottom_right' or 'top_left'), then the child surface will be placed towards the specified gravity. otherwise, the child surface will be centered over the anchor point on any axis that had no gravity specified. it's giving "falling with style" 🍓

Definition at line 1048 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(int32_t, int32_t)> & xdg_positioner_t::on_set_offset ()

set surface position offset 📏

Parameters

  • x — surface position x offset
  • y — surface position y offset

specify the surface position offset relative to the position of the anchor on the anchor rectangle and the anchor on the surface. for example, if the anchor of the anchor rectangle is at (x, y), the surface has the gravity bottom|right, and the offset is (ox, oy), the calculated surface position will be (x + ox, y + oy). 🔥

the offset position of the surface is the one used for constraint testing. see set_constraint_adjustment. 👀

an example use case is placing a popup menu on top of a user interface element, while aligning the user interface element of the parent surface with some user interface element placed somewhere in the popup surface. literally the classic dropdown-menu alignment moment, we love to see it 💖

Definition at line 1060 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(uint32_t)> & xdg_positioner_t::on_set_parent_configure ()

set parent configure this is a response to 🎯

Parameters

  • serial — serial of parent configure event

set the serial of an xdg_surface.configure event this positioner will be used in response to. the compositor may use this information together with set_parent_size to determine what future state the popup should be constrained using. 🔮

Definition at line 1078 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(int32_t, int32_t)> & xdg_positioner_t::on_set_parent_size ()

Parameters

  • parent_width — future window geometry width of parent
  • parent_height — future window geometry height of parent

set the parent window geometry the compositor should use when positioning the popup. the compositor may use this information to determine the future state the popup should be constrained using. 📬

💀 if this doesn't match the dimension of the parent the popup is eventually positioned against, the behavior is undefined. read that again. undefined. we do not play with undefined behavior in this house.

the arguments are given in the surface-local coordinate space. 🌍

Definition at line 1072 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void()> & xdg_positioner_t::on_set_reactive ()

continuously reconstrain the surface 🔁

when set reactive, the surface is reconstrained if the conditions used for constraining changed — e.g. the parent window moved. 👑

if the conditions changed and the popup was reconstrained, an xdg_popup.configure event is sent with updated geometry, followed by an xdg_surface.configure event. it's a whole two-step notification choreo and it ate 💅

Definition at line 1066 of file wayland-server-protocol-extra.cpp.

⭐ std::function< void(int32_t, int32_t)> & xdg_positioner_t::on_set_size ()

set the size of the to-be positioned rectangle 📦

Parameters

  • width — width of positioned rectangle
  • height — height of positioned rectangle

set the size of the surface that is to be positioned with the positioner object. the size is in surface-local coordinates and corresponds to the window geometry. see xdg_surface.set_window_geometry. 📐

🚨 if a zero or negative size is set, the invalid_input error is raised. zero is not "basically fine", zero is an error, okay?? 😭

Definition at line 1030 of file wayland-server-protocol-extra.cpp.

⭐ void xdg_positioner_t::post_invalid_input (std::string const & msg)

post error: invalid input provided. 🙈

Definition at line 1084 of file wayland-server-protocol-extra.cpp.

⭐ void wayland::server::resource_t::post_no_memory () const [inherited]

post "not enough memory" error to the client 🫠

if the compositor doesn't have enough memory to fulfill a certain request of the client, this function can be called to notify the client of this circumstance. be nice about it, they're trying their best 🫶

⭐ bool wayland::server::resource_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

literally the "do you actually have a personality or are you just a wrapper" test, iconic 👑

🌈 Author 🌈

generated automatically by Doxygen for Wayland++ from the source code. yes bestie, nobody hand-wrote this, the machine did it and honestly? it ate 🤖✨

okay that's the whole page, go forth and position your popups responsibly 💖

Version 1.0.1 · Fri Mar 27 2026 · wayland::serv...g_positioner_t(3) — mwah, ily, drink some water 🍓🧚‍♀️💜

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