From aaa189cad4ed907310fbd2491ccdac545c6ed1df Mon Sep 17 00:00:00 2001 From: PolyMeilex Date: Tue, 10 Sep 2024 19:47:22 +0200 Subject: [PATCH] Update wayland.xml to 1.23 --- wayland-client/CHANGELOG.md | 2 + wayland-client/wayland.xml | 215 ++++++++++++++++++++++++++---------- wayland-server/CHANGELOG.md | 2 + wayland-server/wayland.xml | 215 ++++++++++++++++++++++++++---------- 4 files changed, 316 insertions(+), 118 deletions(-) diff --git a/wayland-client/CHANGELOG.md b/wayland-client/CHANGELOG.md index b07612a9773..c189b73a5a8 100644 --- a/wayland-client/CHANGELOG.md +++ b/wayland-client/CHANGELOG.md @@ -2,6 +2,8 @@ ## Unreleased +- Updated Wayland core protocol to 1.23 + ## 0.31.2 -- 2024-01-29 #### Additions diff --git a/wayland-client/wayland.xml b/wayland-client/wayland.xml index 10e039d6ecc..9418c62f3f6 100644 --- a/wayland-client/wayland.xml +++ b/wayland-client/wayland.xml @@ -46,7 +46,7 @@ compositor after the callback is fired and as such the client must not attempt to use it after that point. - The callback_data passed in the callback is the event serial. + The callback_data passed in the callback is undefined and should be ignored. @@ -212,7 +212,7 @@ - + The wl_shm_pool object encapsulates a piece of memory shared between the compositor and client. Through the wl_shm_pool @@ -262,17 +262,17 @@ 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. + 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. - + A singleton global object that provides support for shared memory. @@ -419,6 +419,21 @@ + + + + + + + + + + + + + + + @@ -442,6 +457,17 @@ + + + + + + Using this request a client can tell the server that it is not going to + use the shm object anymore. + + Objects created via this interface remain unaffected. + + @@ -453,9 +479,11 @@ client provides and updates the contents is defined by the buffer factory interface. - If the buffer uses a format that has an alpha channel, the alpha channel - is assumed to be premultiplied in the color channels unless otherwise - specified. + Color channels are assumed to be electrical rather than optical (in other + words, encoded with a transfer function) unless otherwise specified. If + the buffer uses a format that has an alpha channel, the alpha channel is + assumed to be premultiplied into the electrical color channel values + (after transfer function encoding) unless otherwise specified. Note, because wl_buffer objects are created from multiple independent factory interfaces, the wl_buffer interface is frozen at version 1. @@ -847,6 +875,7 @@ + @@ -868,7 +897,7 @@ The icon surface is an optional (can be NULL) surface that provides an icon to be moved around with the cursor. Initially, the top-left corner of the icon surface is placed at the cursor - hotspot, but subsequent wl_surface.attach request can move the + hotspot, but subsequent wl_surface.offset requests can move the relative position. Attach requests must be confirmed with wl_surface.commit as usual. The icon surface is given the role of a drag-and-drop icon. If the icon surface already has another role, @@ -876,6 +905,10 @@ The input region is ignored for wl_surfaces with the role of a drag-and-drop icon. + + The given source may not be used in any further set_selection or + start_drag requests. Attempting to reuse a previously-used source + may send a used_source error. @@ -889,6 +922,10 @@ to the data from the source on behalf of the client. To unset the selection, set the source to NULL. + + The given source may not be used in any further set_selection or + start_drag requests. Attempting to reuse a previously-used source + may send a used_source error. @@ -1411,7 +1448,7 @@ + summary="surface was destroyed before its role object"/> @@ -1440,9 +1477,9 @@ When the bound wl_surface version is 5 or higher, passing any non-zero x or y is a protocol violation, and will result in an - 'invalid_offset' error being raised. The x and y arguments are ignored - and do not change the pending state. To achieve equivalent semantics, - use wl_surface.offset. + 'invalid_offset' error being raised. The x and y arguments are ignored + and do not change the pending state. To achieve equivalent semantics, + use wl_surface.offset. Surface contents are double-buffered state, see wl_surface.commit. @@ -1479,6 +1516,13 @@ If wl_surface.attach is sent with a NULL wl_buffer, the following wl_surface.commit will remove the surface content. + + If a pending wl_buffer has been destroyed, the result is not specified. + Many compositors are known to remove the surface content on the following + wl_surface.commit, but this behaviour is not universal. Clients seeking to + maximise compatibility should not destroy pending buffers and should + ensure that they explicitly remove content from surfaces, even after + destroying buffers. @@ -1618,16 +1662,18 @@ Surface state (input, opaque, and damage regions, attached buffers, etc.) is double-buffered. Protocol requests modify the pending state, - as opposed to the current state in use by the compositor. A commit - request atomically applies all pending state, replacing the current - state. After commit, the new pending state is as documented for each - related request. + as opposed to the active state in use by the compositor. - On commit, a pending wl_buffer is applied first, and all other state - second. This means that all coordinates in double-buffered state are - relative to the new wl_buffer coming into use, except for - wl_surface.attach itself. If there is no pending wl_buffer, the - coordinates are relative to the current surface contents. + A commit request atomically creates a content update from the pending + state, even if the pending state has not been touched. The content + update is placed in a queue until it becomes active. After commit, the + new pending state is as documented for each related request. + + When the content update is applied, the wl_buffer is applied before all + other state. This means that all coordinates in double-buffered state + are relative to the newly attached wl_buffers, except for + wl_surface.attach itself. If there is no newly attached wl_buffer, the + coordinates are relative to the previous content update. All requests that need a commit to become effective are documented to affect double-buffered state. @@ -1666,10 +1712,12 @@ - This request sets an optional transformation on how the compositor - interprets the contents of the buffer attached to the surface. The - accepted values for the transform parameter are the values for - wl_output.transform. + This request sets the transformation that the client has already applied + to the content of the buffer. The accepted values for the transform + parameter are the values for wl_output.transform. + + The compositor applies the inverse of this transformation whenever it + uses the buffer contents. Buffer transform is double-buffered state, see wl_surface.commit. @@ -1725,11 +1773,11 @@ a buffer that is larger (by a factor of scale in each dimension) than the desired surface size. - If scale is not positive the invalid_scale protocol error is + If scale is not greater than 0 the invalid_scale protocol error is raised. + summary="scale for interpreting buffer contents"/> @@ -1802,10 +1850,15 @@ This event indicates the preferred buffer scale for this surface. It is sent whenever the compositor's preference changes. + Before receiving this event the preferred buffer scale for this surface + is 1. + It is intended that scaling aware clients use this event to scale their content and use wl_surface.set_buffer_scale to indicate the scale they have rendered with. This allows clients to supply a higher detail buffer. + + The compositor shall emit a scale value greater than 0. @@ -1815,9 +1868,12 @@ This event indicates the preferred buffer transform for this surface. It is sent whenever the compositor's preference changes. - It is intended that transform aware clients use this event to apply the - transform to their content and use wl_surface.set_buffer_transform to - indicate the transform they have rendered with. + Before receiving this event the preferred buffer transform for this + surface is normal. + + Applying this transformation to the surface buffer contents and using + wl_surface.set_buffer_transform might allow the compositor to use the + surface buffer more efficiently. @@ -1992,9 +2048,9 @@ where (x, y) are the coordinates of the pointer location, in surface-local coordinates. - On surface.attach requests to the pointer surface, hotspot_x + On wl_surface.offset requests to the pointer surface, hotspot_x and hotspot_y are decremented by the x and y parameters - passed to the request. Attach must be confirmed by + passed to the request. The offset must be applied by wl_surface.commit as usual. The hotspot can also be updated by passing the currently set @@ -2248,7 +2304,7 @@ - + Discrete step information for scroll and other axes. @@ -2374,6 +2430,16 @@ The wl_keyboard interface represents one or more keyboards associated with a seat. + + Each wl_keyboard has the following logical state: + + - an active surface (possibly null), + - the keys currently logically down, + - the active modifiers, + - the active group. + + By default, the active surface is null, the keys currently logically down + are empty, the active modifiers and the active group are 0. @@ -2408,10 +2474,15 @@ The compositor must send the wl_keyboard.modifiers event after this event. + + In the wl_keyboard logical state, this event sets the active surface to + the surface argument and the keys currently logically down to the keys + in the keys argument. The compositor must not send this event if the + wl_keyboard already had an active surface immediately before this event. - + @@ -2422,8 +2493,10 @@ The leave notification is sent before the enter notification for the new focus. - After this event client must assume that all keys, including modifiers, - are lifted and also it must stop key repeating if there's some going on. + In the wl_keyboard logical state, this event resets all values to their + defaults. The compositor must not send this event if the active surface + of the wl_keyboard was not equal to the surface argument immediately + before this event. @@ -2448,6 +2521,15 @@ If this event produces a change in modifiers, then the resulting wl_keyboard.modifiers event must be sent after this event. + + In the wl_keyboard logical state, this event adds the key to the keys + currently logically down (if the state argument is pressed) or removes + the key from the keys currently logically down (if the state argument is + released). The compositor must not send this event if the wl_keyboard + did not have an active surface immediately before this event. The + compositor must not send this event if state is pressed (resp. released) + and the key was already logically down (resp. was not logically down) + immediately before this event. @@ -2459,6 +2541,17 @@ Notifies clients that the modifier and/or group state has changed, and it should update its local state. + + The compositor may send this event without a surface of the client + having keyboard focus, for example to tie modifier information to + pointer focus instead. If a modifier event with pressed modifiers is sent + without a prior enter event, the client can assume the modifier state is + valid until it receives the next wl_keyboard.modifiers event. In order to + reset the modifier state again, the compositor can send a + wl_keyboard.modifiers event with no pressed modifiers. + + In the wl_keyboard logical state, this event updates the modifiers and + group. @@ -2566,6 +2659,8 @@ currently active on this client's surface. The client is responsible for finalizing the touch points, future touch points on this surface may reuse the touch point ID. + + No frame event is required after the cancel event. @@ -2665,10 +2760,9 @@ - - This describes the transform that a compositor will apply to a - surface to compensate for the rotation or mirroring of an - output device. + + This describes transformations that clients and compositors apply to + buffer contents. The flipped values correspond to an initial flip around a vertical axis followed by rotation. @@ -2700,6 +2794,10 @@ The geometry event will be followed by a done event (starting from version 2). + Clients should use wl_surface.preferred_buffer_transform instead of the + transform advertised by this event to find the preferred buffer + transform to use for a surface. + Note: wl_output only advertises partial information about the output position and identification. Some compositors, for instance those not implementing a desktop-style output layout or those exposing virtual @@ -2722,7 +2820,7 @@ + summary="additional transformation applied to buffer contents during presentation"/> @@ -2795,8 +2893,9 @@ This event contains scaling geometry information that is not in the geometry event. It may be sent after binding the output object or if the output scale changes - later. If it is not sent, the client should assume a - scale of 1. + later. The compositor will emit a non-zero, positive + value for scale. If it is not sent, the client should + assume a scale of 1. A scale larger than 1 means that the compositor will automatically scale surface buffers by this amount @@ -2804,12 +2903,9 @@ displays where applications rendering at the native resolution would be too small to be legible. - It is intended that scaling aware clients track the - current output of a surface, and if it is on a scaled - output it should use wl_surface.set_buffer_scale with - the scale of the output. That way the compositor can - avoid scaling the surface, and the client can supply - a higher detail image. + Clients should use wl_surface.preferred_buffer_scale + instead of this event to find the preferred buffer + scale to use for a surface. The scale event will be followed by a done event. @@ -3035,6 +3131,11 @@ If the parent wl_surface object is destroyed, the sub-surface is unmapped. + + A sub-surface never has the keyboard focus of any seat. + + The wl_surface.offset request is ignored: clients must use set_position + instead to move the sub-surface. @@ -3060,9 +3161,7 @@ surface area. Negative values are allowed. The scheduled coordinates will take effect whenever the state of the - parent surface is applied. When this happens depends on whether the - parent surface is in synchronized mode or not. See - wl_subsurface.set_sync and wl_subsurface.set_desync for details. + parent surface is applied. If more than one set_position request is invoked by the client before the commit of the parent surface, the position of a new request always @@ -3085,9 +3184,7 @@ The z-order is double-buffered. Requests are handled in order and applied immediately to a pending state. The final pending state is copied to the active state the next time the state of the parent - surface is applied. When this happens depends on whether the parent - surface is in synchronized mode or not. See wl_subsurface.set_sync and - wl_subsurface.set_desync for details. + surface is applied. A new sub-surface is initially added as the top-most in the stack of its siblings and parent. diff --git a/wayland-server/CHANGELOG.md b/wayland-server/CHANGELOG.md index f9543418d2b..4eee50392d8 100644 --- a/wayland-server/CHANGELOG.md +++ b/wayland-server/CHANGELOG.md @@ -2,6 +2,8 @@ ## Unreleased +- Updated Wayland core protocol to 1.23 + ## 0.31.2 -- 2024-05-30 #### Additions diff --git a/wayland-server/wayland.xml b/wayland-server/wayland.xml index 10e039d6ecc..9418c62f3f6 100644 --- a/wayland-server/wayland.xml +++ b/wayland-server/wayland.xml @@ -46,7 +46,7 @@ compositor after the callback is fired and as such the client must not attempt to use it after that point. - The callback_data passed in the callback is the event serial. + The callback_data passed in the callback is undefined and should be ignored. @@ -212,7 +212,7 @@ - + The wl_shm_pool object encapsulates a piece of memory shared between the compositor and client. Through the wl_shm_pool @@ -262,17 +262,17 @@ 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. + 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. - + A singleton global object that provides support for shared memory. @@ -419,6 +419,21 @@ + + + + + + + + + + + + + + + @@ -442,6 +457,17 @@ + + + + + + Using this request a client can tell the server that it is not going to + use the shm object anymore. + + Objects created via this interface remain unaffected. + + @@ -453,9 +479,11 @@ client provides and updates the contents is defined by the buffer factory interface. - If the buffer uses a format that has an alpha channel, the alpha channel - is assumed to be premultiplied in the color channels unless otherwise - specified. + Color channels are assumed to be electrical rather than optical (in other + words, encoded with a transfer function) unless otherwise specified. If + the buffer uses a format that has an alpha channel, the alpha channel is + assumed to be premultiplied into the electrical color channel values + (after transfer function encoding) unless otherwise specified. Note, because wl_buffer objects are created from multiple independent factory interfaces, the wl_buffer interface is frozen at version 1. @@ -847,6 +875,7 @@ + @@ -868,7 +897,7 @@ The icon surface is an optional (can be NULL) surface that provides an icon to be moved around with the cursor. Initially, the top-left corner of the icon surface is placed at the cursor - hotspot, but subsequent wl_surface.attach request can move the + hotspot, but subsequent wl_surface.offset requests can move the relative position. Attach requests must be confirmed with wl_surface.commit as usual. The icon surface is given the role of a drag-and-drop icon. If the icon surface already has another role, @@ -876,6 +905,10 @@ The input region is ignored for wl_surfaces with the role of a drag-and-drop icon. + + The given source may not be used in any further set_selection or + start_drag requests. Attempting to reuse a previously-used source + may send a used_source error. @@ -889,6 +922,10 @@ to the data from the source on behalf of the client. To unset the selection, set the source to NULL. + + The given source may not be used in any further set_selection or + start_drag requests. Attempting to reuse a previously-used source + may send a used_source error. @@ -1411,7 +1448,7 @@ + summary="surface was destroyed before its role object"/> @@ -1440,9 +1477,9 @@ When the bound wl_surface version is 5 or higher, passing any non-zero x or y is a protocol violation, and will result in an - 'invalid_offset' error being raised. The x and y arguments are ignored - and do not change the pending state. To achieve equivalent semantics, - use wl_surface.offset. + 'invalid_offset' error being raised. The x and y arguments are ignored + and do not change the pending state. To achieve equivalent semantics, + use wl_surface.offset. Surface contents are double-buffered state, see wl_surface.commit. @@ -1479,6 +1516,13 @@ If wl_surface.attach is sent with a NULL wl_buffer, the following wl_surface.commit will remove the surface content. + + If a pending wl_buffer has been destroyed, the result is not specified. + Many compositors are known to remove the surface content on the following + wl_surface.commit, but this behaviour is not universal. Clients seeking to + maximise compatibility should not destroy pending buffers and should + ensure that they explicitly remove content from surfaces, even after + destroying buffers. @@ -1618,16 +1662,18 @@ Surface state (input, opaque, and damage regions, attached buffers, etc.) is double-buffered. Protocol requests modify the pending state, - as opposed to the current state in use by the compositor. A commit - request atomically applies all pending state, replacing the current - state. After commit, the new pending state is as documented for each - related request. + as opposed to the active state in use by the compositor. - On commit, a pending wl_buffer is applied first, and all other state - second. This means that all coordinates in double-buffered state are - relative to the new wl_buffer coming into use, except for - wl_surface.attach itself. If there is no pending wl_buffer, the - coordinates are relative to the current surface contents. + A commit request atomically creates a content update from the pending + state, even if the pending state has not been touched. The content + update is placed in a queue until it becomes active. After commit, the + new pending state is as documented for each related request. + + When the content update is applied, the wl_buffer is applied before all + other state. This means that all coordinates in double-buffered state + are relative to the newly attached wl_buffers, except for + wl_surface.attach itself. If there is no newly attached wl_buffer, the + coordinates are relative to the previous content update. All requests that need a commit to become effective are documented to affect double-buffered state. @@ -1666,10 +1712,12 @@ - This request sets an optional transformation on how the compositor - interprets the contents of the buffer attached to the surface. The - accepted values for the transform parameter are the values for - wl_output.transform. + This request sets the transformation that the client has already applied + to the content of the buffer. The accepted values for the transform + parameter are the values for wl_output.transform. + + The compositor applies the inverse of this transformation whenever it + uses the buffer contents. Buffer transform is double-buffered state, see wl_surface.commit. @@ -1725,11 +1773,11 @@ a buffer that is larger (by a factor of scale in each dimension) than the desired surface size. - If scale is not positive the invalid_scale protocol error is + If scale is not greater than 0 the invalid_scale protocol error is raised. + summary="scale for interpreting buffer contents"/> @@ -1802,10 +1850,15 @@ This event indicates the preferred buffer scale for this surface. It is sent whenever the compositor's preference changes. + Before receiving this event the preferred buffer scale for this surface + is 1. + It is intended that scaling aware clients use this event to scale their content and use wl_surface.set_buffer_scale to indicate the scale they have rendered with. This allows clients to supply a higher detail buffer. + + The compositor shall emit a scale value greater than 0. @@ -1815,9 +1868,12 @@ This event indicates the preferred buffer transform for this surface. It is sent whenever the compositor's preference changes. - It is intended that transform aware clients use this event to apply the - transform to their content and use wl_surface.set_buffer_transform to - indicate the transform they have rendered with. + Before receiving this event the preferred buffer transform for this + surface is normal. + + Applying this transformation to the surface buffer contents and using + wl_surface.set_buffer_transform might allow the compositor to use the + surface buffer more efficiently. @@ -1992,9 +2048,9 @@ where (x, y) are the coordinates of the pointer location, in surface-local coordinates. - On surface.attach requests to the pointer surface, hotspot_x + On wl_surface.offset requests to the pointer surface, hotspot_x and hotspot_y are decremented by the x and y parameters - passed to the request. Attach must be confirmed by + passed to the request. The offset must be applied by wl_surface.commit as usual. The hotspot can also be updated by passing the currently set @@ -2248,7 +2304,7 @@ - + Discrete step information for scroll and other axes. @@ -2374,6 +2430,16 @@ The wl_keyboard interface represents one or more keyboards associated with a seat. + + Each wl_keyboard has the following logical state: + + - an active surface (possibly null), + - the keys currently logically down, + - the active modifiers, + - the active group. + + By default, the active surface is null, the keys currently logically down + are empty, the active modifiers and the active group are 0. @@ -2408,10 +2474,15 @@ The compositor must send the wl_keyboard.modifiers event after this event. + + In the wl_keyboard logical state, this event sets the active surface to + the surface argument and the keys currently logically down to the keys + in the keys argument. The compositor must not send this event if the + wl_keyboard already had an active surface immediately before this event. - + @@ -2422,8 +2493,10 @@ The leave notification is sent before the enter notification for the new focus. - After this event client must assume that all keys, including modifiers, - are lifted and also it must stop key repeating if there's some going on. + In the wl_keyboard logical state, this event resets all values to their + defaults. The compositor must not send this event if the active surface + of the wl_keyboard was not equal to the surface argument immediately + before this event. @@ -2448,6 +2521,15 @@ If this event produces a change in modifiers, then the resulting wl_keyboard.modifiers event must be sent after this event. + + In the wl_keyboard logical state, this event adds the key to the keys + currently logically down (if the state argument is pressed) or removes + the key from the keys currently logically down (if the state argument is + released). The compositor must not send this event if the wl_keyboard + did not have an active surface immediately before this event. The + compositor must not send this event if state is pressed (resp. released) + and the key was already logically down (resp. was not logically down) + immediately before this event. @@ -2459,6 +2541,17 @@ Notifies clients that the modifier and/or group state has changed, and it should update its local state. + + The compositor may send this event without a surface of the client + having keyboard focus, for example to tie modifier information to + pointer focus instead. If a modifier event with pressed modifiers is sent + without a prior enter event, the client can assume the modifier state is + valid until it receives the next wl_keyboard.modifiers event. In order to + reset the modifier state again, the compositor can send a + wl_keyboard.modifiers event with no pressed modifiers. + + In the wl_keyboard logical state, this event updates the modifiers and + group. @@ -2566,6 +2659,8 @@ currently active on this client's surface. The client is responsible for finalizing the touch points, future touch points on this surface may reuse the touch point ID. + + No frame event is required after the cancel event. @@ -2665,10 +2760,9 @@ - - This describes the transform that a compositor will apply to a - surface to compensate for the rotation or mirroring of an - output device. + + This describes transformations that clients and compositors apply to + buffer contents. The flipped values correspond to an initial flip around a vertical axis followed by rotation. @@ -2700,6 +2794,10 @@ The geometry event will be followed by a done event (starting from version 2). + Clients should use wl_surface.preferred_buffer_transform instead of the + transform advertised by this event to find the preferred buffer + transform to use for a surface. + Note: wl_output only advertises partial information about the output position and identification. Some compositors, for instance those not implementing a desktop-style output layout or those exposing virtual @@ -2722,7 +2820,7 @@ + summary="additional transformation applied to buffer contents during presentation"/> @@ -2795,8 +2893,9 @@ This event contains scaling geometry information that is not in the geometry event. It may be sent after binding the output object or if the output scale changes - later. If it is not sent, the client should assume a - scale of 1. + later. The compositor will emit a non-zero, positive + value for scale. If it is not sent, the client should + assume a scale of 1. A scale larger than 1 means that the compositor will automatically scale surface buffers by this amount @@ -2804,12 +2903,9 @@ displays where applications rendering at the native resolution would be too small to be legible. - It is intended that scaling aware clients track the - current output of a surface, and if it is on a scaled - output it should use wl_surface.set_buffer_scale with - the scale of the output. That way the compositor can - avoid scaling the surface, and the client can supply - a higher detail image. + Clients should use wl_surface.preferred_buffer_scale + instead of this event to find the preferred buffer + scale to use for a surface. The scale event will be followed by a done event. @@ -3035,6 +3131,11 @@ If the parent wl_surface object is destroyed, the sub-surface is unmapped. + + A sub-surface never has the keyboard focus of any seat. + + The wl_surface.offset request is ignored: clients must use set_position + instead to move the sub-surface. @@ -3060,9 +3161,7 @@ surface area. Negative values are allowed. The scheduled coordinates will take effect whenever the state of the - parent surface is applied. When this happens depends on whether the - parent surface is in synchronized mode or not. See - wl_subsurface.set_sync and wl_subsurface.set_desync for details. + parent surface is applied. If more than one set_position request is invoked by the client before the commit of the parent surface, the position of a new request always @@ -3085,9 +3184,7 @@ The z-order is double-buffered. Requests are handled in order and applied immediately to a pending state. The final pending state is copied to the active state the next time the state of the parent - surface is applied. When this happens depends on whether the parent - surface is in synchronized mode or not. See wl_subsurface.set_sync and - wl_subsurface.set_desync for details. + surface is applied. A new sub-surface is initially added as the top-most in the stack of its siblings and parent.