Copyright © 2008-2013 Kristian Høgsberg Copyright © 2013 Rafael Antognolli Copyright © 2013 Jasper St. Pierre Copyright © 2010-2013 Intel Corporation Copyright © 2015-2017 Samsung Electronics Co., Ltd Copyright © 2015-2017 Red Hat Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. The xdg_wm_base interface is exposed as a global object enabling clients to turn their wl_surfaces into windows in a desktop environment. It defines the basic functionality needed for clients and the compositor to create windows that can be dragged, resized, maximized, etc, as well as creating transient windows such as popup menus. Destroy this xdg_wm_base object. Destroying a bound xdg_wm_base object while there are surfaces still alive created by this xdg_wm_base object instance is illegal and will result in a defunct_surfaces error. Create a positioner object. A positioner object is used to position surfaces relative to some parent surface. See the interface description and xdg_surface.get_popup for details. This creates an xdg_surface for the given surface. While xdg_surface itself is not a role, the corresponding surface may only be assigned a role extending xdg_surface, such as xdg_toplevel or xdg_popup. It is illegal to create an xdg_surface for a wl_surface which already has an assigned role and this will result in a role error. This creates an xdg_surface for the given surface. An xdg_surface is used as basis to define a role to a given surface, such as xdg_toplevel or xdg_popup. It also manages functionality shared between xdg_surface based surface roles. See the documentation of xdg_surface for more details about what an xdg_surface is and how it is used. A client must respond to a ping event with a pong request or the client may be deemed unresponsive. See xdg_wm_base.ping and xdg_wm_base.error.unresponsive. The ping event asks the client if it's still alive. Pass the serial specified in the event back to the compositor by sending a "pong" request back with the specified serial. See xdg_wm_base.pong. Compositors can use this to determine if the client is still alive. It's unspecified what will happen if the client doesn't respond to the ping request, or in what timeframe. Clients should try to respond in a reasonable amount of time. The “unresponsive” error is provided for compositors that wish to disconnect unresponsive clients. A compositor is free to ping in any way it wants, but a client must always respond to any xdg_wm_base object it created. The xdg_positioner provides a collection of rules for the placement of a child surface relative to a parent surface. Rules can be defined to ensure the child surface remains within the visible area's borders, and to specify how the child surface changes its position, such as sliding along an axis, or flipping around a rectangle. These positioner-created rules are constrained by the requirement that a child surface must intersect with or be at least partially adjacent to its parent surface. See the various requests for details about possible rules. At the time of the request, the compositor makes a copy of the rules specified by the xdg_positioner. Thus, after the request is complete the xdg_positioner object can be destroyed or reused; further changes to the object will have no effect on previous usages. For an xdg_positioner object to be considered complete, it must have a non-zero size set by set_size, and a non-zero anchor rectangle set by set_anchor_rect. Passing an incomplete xdg_positioner object when positioning a surface raises an invalid_positioner error. Notify the compositor that the xdg_positioner will no longer be used. 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. 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. If a negative size is set the invalid_input error is raised. Defines the anchor point for the anchor rectangle. The specified anchor is used 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 the 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. 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. If the gravity is not in the ‘gravity’ enum, an invalid_input error is raised. The constraint adjustment value define ways the compositor will adjust the position of the surface, if the unadjusted position would result in the surface being partly constrained. Whether a surface is considered 'constrained' is left to the compositor to determine. For example, the surface may be partly outside the compositor's defined 'work area', thus necessitating the child surface's position be adjusted until it is entirely inside the work area. The adjustments can be combined, according to a defined precedence: 1) Flip, 2) Slide, 3) Resize. Don't alter the surface position even if it is constrained on some axis, for example partially outside the edge of an output. Slide the surface along the x axis until it is no longer constrained. First try to slide towards the direction of the gravity on the x axis until either the edge in the opposite direction of the gravity is unconstrained or the edge in the direction of the gravity is constrained. Then try to slide towards the opposite direction of the gravity on the x axis until either the edge in the direction of the gravity is unconstrained or the edge in the opposite direction of the gravity is constrained. Slide the surface along the y axis until it is no longer constrained. First try to slide towards the direction of the gravity on the y axis until either the edge in the opposite direction of the gravity is unconstrained or the edge in the direction of the gravity is constrained. Then try to slide towards the opposite direction of the gravity on the y axis until either the edge in the direction of the gravity is unconstrained or the edge in the opposite direction of the gravity is constrained. Invert the anchor and gravity on the x axis if the surface is constrained on the x axis. For example, if the left edge of the surface is constrained, the gravity is 'left' and the anchor is 'left', change the gravity to 'right' and the anchor to 'right'. If the adjusted position also ends up being constrained, the resulting position of the flip_x adjustment will be the one before the adjustment. Invert the anchor and gravity on the y axis if the surface is constrained on the y axis. For example, if the bottom edge of the surface is constrained, the gravity is 'bottom' and the anchor is 'bottom', change the gravity to 'top' and the anchor to 'top'. The adjusted position is calculated given the original anchor rectangle and offset, but with the new flipped anchor and gravity values. If the adjusted position also ends up being constrained, the resulting position of the flip_y adjustment will be the one before the adjustment. Resize the surface horizontally so that it is completely unconstrained. Resize the surface vertically so that it is completely unconstrained. Specify how the window should be positioned if the originally intended position caused the surface to be constrained, meaning at least partially outside 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. 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. 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. 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. The arguments are given in the surface-local coordinate space. 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. An interface that may be implemented by a wl_surface, for implementations that provide a desktop-style user interface. It provides a base set of functionality required to construct user interface elements requiring management by the compositor, such as toplevel windows, menus, etc. The types of functionality are split into xdg_surface roles. Creating an xdg_surface does not set the role for a wl_surface. In order to map an xdg_surface, the client must create a role-specific object using, e.g., get_toplevel, get_popup. The wl_surface for any given xdg_surface can have at most one role, and may not be assigned any role not based on xdg_surface. A role must be assigned before any other requests are made to the xdg_surface object. The client must call wl_surface.commit on the corresponding wl_surface for the xdg_surface state to take effect. Creating an xdg_surface from a wl_surface which has a buffer attached or committed is a client error, and any attempts by a client to attach or manipulate a buffer prior to the first xdg_surface.configure call must also be treated as errors. After creating a role-specific object and setting it up, the client must perform an initial commit without any buffer attached. The compositor will reply with an xdg_surface.configure event. The client must acknowledge it and is then allowed to attach a buffer to map the surface. Mapping an xdg_surface-based role surface is defined as making it possible for the surface to be shown by the compositor. Note that a mapped surface is not guaranteed to be visible once it is mapped. For an xdg_surface to be mapped by the compositor, the following conditions must be met: (1) the client has assigned an xdg_surface-based role to the surface (2) the client has set and committed the xdg_surface state and the role-dependent state to the surface (3) the client has committed a buffer to the surface A newly-unmapped surface is considered to have met condition (1) out of the 3 required conditions for mapping a surface if its role surface has not been destroyed, i.e. the client must perform the initial commit again before attaching a buffer. Destroy the xdg_surface object. An xdg_surface must only be destroyed after its role object has been destroyed, otherwise a defunct_role_object error is raised. This creates an xdg_toplevel object for the given xdg_surface and gives the associated wl_surface the xdg_toplevel role. See the documentation of xdg_toplevel for more details about what an xdg_toplevel is and how it is used. This creates an xdg_popup object for the given xdg_surface and gives the associated wl_surface the xdg_popup role. If null is passed as a parent, a parent surface must be specified using some other protocol, before committing the initial state. See the documentation of xdg_popup for more details about what an xdg_popup is and how it is used. The window geometry of a surface is its "visible bounds" from the user's perspective. Client-side decorations often have invisible portions like drop-shadows which should be ignored for the purposes of aligning, placing and constraining windows. The window geometry is double buffered, and will be applied at the time wl_surface.commit of the corresponding wl_surface is called. When maintaining a position, the compositor should treat the (x, y) coordinate of the window geometry as the top left corner of the window. A client changing the (x, y) window geometry coordinate should in general not alter the position of the window. Once the window geometry of the surface is set, it is not possible to unset it, and it will remain the same until set_window_geometry is called again, even if a new subsurface or buffer is attached. If never set, the value is the full bounds of the surface, including any subsurfaces. This updates dynamically on every commit. This unset is meant for extremely simple clients. The arguments are given in the surface-local coordinate space of the wl_surface associated with this xdg_surface. The width and height must be greater than zero. Setting an invalid size will raise an invalid_size error. When applied, the effective window geometry will be the set window geometry clamped to the bounding rectangle of the combined geometry of the surface of the xdg_surface and the associated subsurfaces. When a configure event is received, if a client commits the surface in response to the configure event, then the client must make an ack_configure request sometime before the commit request, passing along the serial of the configure event. For instance, for toplevel surfaces the compositor might use this information to move a surface to the top left only when the client has drawn itself for the maximized or fullscreen state. If the client receives multiple configure events before it can respond to one, it only has to ack the last configure event. Acking a configure event that was never sent raises an invalid_serial error. A client is not required to commit immediately after sending an ack_configure request - it may even ack_configure several times before its next surface commit. A client may send multiple ack_configure requests before committing, but only the last request sent before a commit indicates which configure event the client really is responding to. Sending an ack_configure request consumes the serial number sent with the request, as well as serial numbers sent by all configure events sent on this xdg_surface prior to the configure event referenced by the committed serial. It is an error to issue multiple ack_configure requests referencing a serial from the same configure event, or to issue an ack_configure request referencing a serial from a configure event issued before the event identified by the last ack_configure request for the same xdg_surface. Doing so will raise an invalid_serial error. The configure event marks the end of a configure sequence. A configure sequence is a set of one or more events configuring the state of the xdg_surface, including the final xdg_surface.configure event. Where applicable, xdg_surface surface roles will during a configure sequence extend this event as a latched state sent as events before the xdg_surface.configure event. Such events should be considered to make up a set of atomically applied configuration states, where the xdg_surface.configure commits the accumulated state. Clients should arrange their surface for the new states, and then send an ack_configure request with the serial sent in this configure event at some point before committing the new surface. If the client receives multiple configure events before it can respond to one, it is free to discard all but the last event it received. This interface defines an xdg_surface role which allows a surface to, among other things, set window-like properties such as maximize, fullscreen, and minimize, set application-specific metadata like title and id, and well as trigger user interactive operations such as interactive resize and move. Unmapping an xdg_toplevel means that the surface cannot be shown by the compositor until it is explicitly mapped again. All active operations (e.g., move, resize) are canceled and all attributes (e.g. title, state, stacking, ...) are discarded for an xdg_toplevel surface when it is unmapped. The xdg_toplevel returns to the state it had right after xdg_surface.get_toplevel. The client can re-map the toplevel by perfoming a commit without any buffer attached, waiting for a configure event and handling it as usual (see xdg_surface description). Attaching a null buffer to a toplevel unmaps the surface. This request destroys the role surface and unmaps the surface; see "Unmapping" behavior in interface section for details. Set the "parent" of this surface. This surface should be stacked above the parent surface and all other ancestor surfaces. Parent surfaces should be set on dialogs, toolboxes, or other "auxiliary" surfaces, so that the parent is raised when the dialog is raised. Setting a null parent for a child surface unsets its parent. Setting a null parent for a surface which currently has no parent is a no-op. Only mapped surfaces can have child surfaces. Setting a parent which is not mapped is equivalent to setting a null parent. If a surface becomes unmapped, its children's parent is set to the parent of the now-unmapped surface. If the now-unmapped surface has no parent, its children's parent is unset. If the now-unmapped surface becomes mapped again, its parent-child relationship is not restored. The parent toplevel must not be one of the child toplevel's descendants, and the parent must be different from the child toplevel, otherwise the invalid_parent protocol error is raised. Set a short title for the surface. This string may be used to identify the surface in a task bar, window list, or other user interface elements provided by the compositor. The string must be encoded in UTF-8. Set an application identifier for the surface. The app ID identifies the general class of applications to which the surface belongs. The compositor can use this to group multiple surfaces together, or to determine how to launch a new application. For D-Bus activatable applications, the app ID is used as the D-Bus service name. The compositor shell will try to group application surfaces together by their app ID. As a best practice, it is suggested to select app ID's that match the basename of the application's .desktop file. For example, "org.freedesktop.FooViewer" where the .desktop file is "org.freedesktop.FooViewer.desktop". Like other properties, a set_app_id request can be sent after the xdg_toplevel has been mapped to update the property. See the desktop-entry specification [0] for more details on application identifiers and how they relate to well-known D-Bus names and .desktop files. [0] https://standards.freedesktop.org/desktop-entry-spec/ Clients implementing client-side decorations might want to show a context menu when right-clicking on the decorations, giving the user a menu that they can use to maximize or minimize the window. This request asks the compositor to pop up such a window menu at the given position, relative to the local surface coordinates of the parent surface. There are no guarantees as to what menu items the window menu contains, or even if a window menu will be drawn at all. This request must be used in response to some sort of user action like a button press, key press, or touch down event. Start an interactive, user-driven move of the surface. This request must be used in response to some sort of user action like a button press, key press, or touch down event. The passed serial is used to determine the type of interactive move (touch, pointer, etc). The server may ignore move requests depending on the state of the surface (e.g. fullscreen or maximized), or if the passed serial is no longer valid. If triggered, the surface will lose the focus of the device (wl_pointer, wl_touch, etc) used for the move. It is up to the compositor to visually indicate that the move is taking place, such as updating a pointer cursor, during the move. There is no guarantee that the device focus will return when the move is completed. These values are used to indicate which edge of a surface is being dragged in a resize operation. Start a user-driven, interactive resize of the surface. This request must be used in response to some sort of user action like a button press, key press, or touch down event. The passed serial is used to determine the type of interactive resize (touch, pointer, etc). The server may ignore resize requests depending on the state of the surface (e.g. fullscreen or maximized). If triggered, the client will receive configure events with the "resize" state enum value and the expected sizes. See the "resize" enum value for more details about what is required. The client must also acknowledge configure events using "ack_configure". After the resize is completed, the client will receive another "configure" event without the resize state. If triggered, the surface also will lose the focus of the device (wl_pointer, wl_touch, etc) used for the resize. It is up to the compositor to visually indicate that the resize is taking place, such as updating a pointer cursor, during the resize. There is no guarantee that the device focus will return when the resize is completed. The edges parameter specifies how the surface should be resized, and is one of the values of the resize_edge enum. Values not matching a variant of the enum will cause a protocol error. The compositor may use this information to update the surface position for example when dragging the top left corner. The compositor may also use this information to adapt its behavior, e.g. choose an appropriate cursor image. The different state values used on the surface. This is designed for state values like maximized, fullscreen. It is paired with the configure event to ensure that both the client and the compositor setting the state can be synchronized. States set in this way are double-buffered. They will get applied on the next commit. The surface is maximized. The window geometry specified in the configure event must be obeyed by the client. The client should draw without shadow or other decoration outside of the window geometry. The surface is fullscreen. The window geometry specified in the configure event is a maximum; the client cannot resize beyond it. For a surface to cover the whole fullscreened area, the geometry dimensions must be obeyed by the client. For more details, see xdg_toplevel.set_fullscreen. The surface is being resized. The window geometry specified in the configure event is a maximum; the client cannot resize beyond it. Clients that have aspect ratio or cell sizing configuration can use a smaller size, however. Client window decorations should be painted as if the window is active. Do not assume this means that the window actually has keyboard or pointer focus. The window is currently in a tiled layout and the left edge is considered to be adjacent to another part of the tiling grid. The window is currently in a tiled layout and the right edge is considered to be adjacent to another part of the tiling grid. The window is currently in a tiled layout and the top edge is considered to be adjacent to another part of the tiling grid. The window is currently in a tiled layout and the bottom edge is considered to be adjacent to another part of the tiling grid. Set a maximum size for the window. The client can specify a maximum size so that the compositor does not try to configure the window beyond this size. The width and height arguments are in window geometry coordinates. See xdg_surface.set_window_geometry. Values set in this way are double-buffered. They will get applied on the next commit. The compositor can use this information to allow or disallow different states like maximize or fullscreen and draw accurate animations. Similarly, a tiling window manager may use this information to place and resize client windows in a more effective way. The client should not rely on the compositor to obey the maximum size. The compositor may decide to ignore the values set by the client and request a larger size. If never set, or a value of zero in the request, means that the client has no expected maximum size in the given dimension. As a result, a client wishing to reset the maximum size to an unspecified state can use zero for width and height in the request. Requesting a maximum size to be smaller than the minimum size of a surface is illegal and will result in an invalid_size error. The width and height must be greater than or equal to zero. Using strictly negative values for width or height will result in a invalid_size error. Set a minimum size for the window. The client can specify a minimum size so that the compositor does not try to configure the window below this size. The width and height arguments are in window geometry coordinates. See xdg_surface.set_window_geometry. Values set in this way are double-buffered. They will get applied on the next commit. The compositor can use this information to allow or disallow different states like maximize or fullscreen and draw accurate animations. Similarly, a tiling window manager may use this information to place and resize client windows in a more effective way. The client should not rely on the compositor to obey the minimum size. The compositor may decide to ignore the values set by the client and request a smaller size. If never set, or a value of zero in the request, means that the client has no expected minimum size in the given dimension. As a result, a client wishing to reset the minimum size to an unspecified state can use zero for width and height in the request. Requesting a minimum size to be larger than the maximum size of a surface is illegal and will result in an invalid_size error. The width and height must be greater than or equal to zero. Using strictly negative values for width and height will result in a invalid_size error. Maximize the surface. After requesting that the surface should be maximized, the compositor will respond by emitting a configure event. Whether this configure actually sets the window maximized is subject to compositor policies. The client must then update its content, drawing in the configured state. The client must also acknowledge the configure when committing the new content (see ack_configure). It is up to the compositor to decide how and where to maximize the surface, for example which output and what region of the screen should be used. If the surface was already maximized, the compositor will still emit a configure event with the "maximized" state. If the surface is in a fullscreen state, this request has no direct effect. It may alter the state the surface is returned to when unmaximized unless overridden by the compositor. Unmaximize the surface. After requesting that the surface should be unmaximized, the compositor will respond by emitting a configure event. Whether this actually un-maximizes the window is subject to compositor policies. If available and applicable, the compositor will include the window geometry dimensions the window had prior to being maximized in the configure event. The client must then update its content, drawing it in the configured state. The client must also acknowledge the configure when committing the new content (see ack_configure). It is up to the compositor to position the surface after it was unmaximized; usually the position the surface had before maximizing, if applicable. If the surface was already not maximized, the compositor will still emit a configure event without the "maximized" state. If the surface is in a fullscreen state, this request has no direct effect. It may alter the state the surface is returned to when unmaximized unless overridden by the compositor. Make the surface fullscreen. After requesting that the surface should be fullscreened, the compositor will respond by emitting a configure event. Whether the client is actually put into a fullscreen state is subject to compositor policies. The client must also acknowledge the configure when committing the new content (see ack_configure). The output passed by the request indicates the client's preference as to which display it should be set fullscreen on. If this value is NULL, it's up to the compositor to choose which display will be used to map this surface. If the surface doesn't cover the whole output, the compositor will position the surface in the center of the output and compensate with with border fill covering the rest of the output. The content of the border fill is undefined, but should be assumed to be in some way that attempts to blend into the surrounding area (e.g. solid black). If the fullscreened surface is not opaque, the compositor must make sure that other screen content not part of the same surface tree (made up of subsurfaces, popups or similarly coupled surfaces) are not visible below the fullscreened surface. Make the surface no longer fullscreen. After requesting that the surface should be unfullscreened, the compositor will respond by emitting a configure event. Whether this actually removes the fullscreen state of the client is subject to compositor policies. Making a surface unfullscreen sets states for the surface based on the following: * the state(s) it may have had before becoming fullscreen * any state(s) decided by the compositor * any state(s) requested by the client while the surface was fullscreen The compositor may include the previous window geometry dimensions in the configure event, if applicable. The client must also acknowledge the configure when committing the new content (see ack_configure). Request that the compositor minimize your surface. There is no way to know if the surface is currently minimized, nor is there any way to unset minimization on this surface. If you are looking to throttle redrawing when minimized, please instead use the wl_surface.frame event for this, as this will also work with live previews on windows in Alt-Tab, Expose or similar compositor features. This configure event asks the client to resize its toplevel surface or to change its state. The configured state should not be applied immediately. See xdg_surface.configure for details. The width and height arguments specify a hint to the window about how its surface should be resized in window geometry coordinates. See set_window_geometry. If the width or height arguments are zero, it means the client should decide its own window dimension. This may happen when the compositor needs to configure the state of the surface but doesn't have any information about any previous or expected dimension. The states listed in the event specify how the width/height arguments should be interpreted, and possibly how it should be drawn. Clients must send an ack_configure in response to this event. See xdg_surface.configure and xdg_surface.ack_configure for details. The close event is sent by the compositor when the user wants the surface to be closed. This should be equivalent to the user clicking the close button in client-side decorations, if your application has any. This is only a request that the user intends to close the window. The client may choose to ignore this request, or show a dialog to ask the user to save their data, etc. The configure_bounds event may be sent prior to a xdg_toplevel.configure event to communicate the bounds a window geometry size is recommended to constrain to. The passed width and height are in surface coordinate space. If width and height are 0, it means bounds is unknown and equivalent to as if no configure_bounds event was ever sent for this surface. The bounds can for example correspond to the size of a monitor excluding any panels or other shell components, so that a surface isn't created in a way that it cannot fit. The bounds may change at any point, and in such a case, a new xdg_toplevel.configure_bounds will be sent, followed by xdg_toplevel.configure and xdg_surface.configure. This event advertises the capabilities supported by the compositor. If a capability isn't supported, clients should hide or disable the UI elements that expose this functionality. For instance, if the compositor doesn't advertise support for minimized toplevels, a button triggering the set_minimized request should not be displayed. The compositor will ignore requests it doesn't support. For instance, a compositor which doesn't advertise support for minimized will ignore set_minimized requests. Compositors must send this event once before the first xdg_surface.configure event. When the capabilities change, compositors must send this event again and then send an xdg_surface.configure event. The configured state should not be applied immediately. See xdg_surface.configure for details. The capabilities are sent as an array of 32-bit unsigned integers in native endianness. A popup surface is a short-lived, temporary surface. It can be used to implement for example menus, popovers, tooltips and other similar user interface concepts. A popup can be made to take an explicit grab. See xdg_popup.grab for details. When the popup is dismissed, a popup_done event will be sent out, and at the same time the surface will be unmapped. See the xdg_popup.popup_done event for details. Explicitly destroying the xdg_popup object will also dismiss the popup and unmap the surface. Clients that want to dismiss the popup when another surface of their own is clicked should dismiss the popup using the destroy request. A newly created xdg_popup will be stacked on top of all previously created xdg_popup surfaces associated with the same xdg_toplevel. The parent of an xdg_popup must be mapped (see the xdg_surface description) before the xdg_popup itself. The client must call wl_surface.commit on the corresponding wl_surface for the xdg_popup state to take effect. This destroys the popup. Explicitly destroying the xdg_popup object will also dismiss the popup, and unmap the surface. If this xdg_popup is not the "topmost" popup, a protocol error will be sent. This request makes the created popup take an explicit grab. An explicit grab will be dismissed when the user dismisses the popup, or when the client destroys the xdg_popup. This can be done by the user clicking outside the surface, using the keyboard, or even locking the screen through closing the lid or a timeout. If the compositor denies the grab, the popup will be immediately dismissed. This request must be used in response to some sort of user action like a button press, key press, or touch down event. The serial number of the event should be passed as 'serial'. The parent of a grabbing popup must either be an xdg_toplevel surface or another xdg_popup with an explicit grab. If the parent is another xdg_popup it means that the popups are nested, with this popup now being the topmost popup. Nested popups must be destroyed in the reverse order they were created in, e.g. the only popup you are allowed to destroy at all times is the topmost one. When compositors choose to dismiss a popup, they may dismiss every nested grabbing popup as well. When a compositor dismisses popups, it will follow the same dismissing order as required from the client. If the topmost grabbing popup is destroyed, the grab will be returned to the parent of the popup, if that parent previously had an explicit grab. If the parent is a grabbing popup which has already been dismissed, this popup will be immediately dismissed. If the parent is a popup that did not take an explicit grab, an error will be raised. During a popup grab, the client owning the grab will receive pointer and touch events for all their surfaces as normal (similar to an "owner-events" grab in X11 parlance), while the top most grabbing popup will always have keyboard focus. This event asks the popup surface to configure itself given the configuration. The configured state should not be applied immediately. See xdg_surface.configure for details. The x and y arguments represent the position the popup was placed at given the xdg_positioner rule, relative to the upper left corner of the window geometry of the parent surface. For version 2 or older, the configure event for an xdg_popup is only ever sent once for the initial configuration. Starting with version 3, it may be sent again if the popup is setup with an xdg_positioner with set_reactive requested, or in response to xdg_popup.reposition requests. The popup_done event is sent out when a popup is dismissed by the compositor. The client should destroy the xdg_popup object at this point. Reposition an already-mapped popup. The popup will be placed given the details in the passed xdg_positioner object, and a xdg_popup.repositioned followed by xdg_popup.configure and xdg_surface.configure will be emitted in response. Any parameters set by the previous positioner will be discarded. The passed token will be sent in the corresponding xdg_popup.repositioned event. The new popup position will not take effect until the corresponding configure event is acknowledged by the client. See xdg_popup.repositioned for details. The token itself is opaque, and has no other special meaning. If multiple reposition requests are sent, the compositor may skip all but the last one. If the popup is repositioned in response to a configure event for its parent, the client should send an xdg_positioner.set_parent_configure and possibly an xdg_positioner.set_parent_size request to allow the compositor to properly constrain the popup. If the popup is repositioned together with a parent that is being resized, but not in response to a configure event, the client should send an xdg_positioner.set_parent_size request. The repositioned event is sent as part of a popup configuration sequence, together with xdg_popup.configure and lastly xdg_surface.configure to notify the completion of a reposition request. The repositioned event is to notify about the completion of a xdg_popup.reposition request. The token argument is the token passed in the xdg_popup.reposition request. Immediately after this event is emitted, xdg_popup.configure and xdg_surface.configure will be sent with the updated size and position, as well as a new configure serial. The client should optionally update the content of the popup, but must acknowledge the new popup configuration for the new position to take effect. See xdg_surface.ack_configure for details.