Hi, I think it is time to take the next step regarding xdg_shell: declaring it stable. The current unstable version (xdg_shell unstable v6) has been implemented in multiple code bases, used by multiple desktop environments for quite some time, and I think this proves it is time to take the next step.
While it has indeed been implemented and used, there has been various issues raised regarding the protocol, but I believe all of these qualify as minor enough not requiring a new unstable release. I'll go through them here in this E-mail, but please do read the actual commits for the actual change. 1) Renaming the main global interface It is not possible to just strip the unstable protocol prefix/postfix of the global interface name, so it had to be renamed. The reason for this is that up until the unstable version 6, the global interface name of the protocol was simply "xdg_shell". This means that without clever version hackery, we can not make the it discoverable that this is indeed the new stable interface and not an old unstable one. The new name has been discussion previously on #wayland, and at one point Pekka came up with "xdg_wm_base" as xdg_shell really is about the window management basics. I chose this name for this patch series, but it is not set in stone. Other suggestions include "wp_shell", "wp_desktop_shell", "xdg_desktop_shell". 2) The anchor rectangle of a xdg_positioner may now be empty If one wants to position a menu against corner of a pixel and have it flip in any direction, this was not possible due to the requirement that a anchor rectangle of a xdg_positioner had to be non-empty. Allowing an empty anchor rectangle fixes this without any down sides. 3) More forgiving managing of stacking relationships The set_parent request of xdg_toplevel was specified to require unmapping the parent before the child. This was poorly enforced in various implementations, and making it an error will have serious consequences when the relationship crosses client boundaries, as is possible using xdg_foreign (used by xdg-desktop-portal, i.e. sandboxed clients using portals). Make things a bit more forgiving, while at the same time more predictable. For example, unmapping a parent that itself has a parent, will turn its children children of its own parent. 4) Allowing external protocols to define popup parent relationships To use xdg_popup for things such as a window menu implemented in westons desktop shell client, we must allow passing null as a parent, relying on some external protocol for setting up this relationship. Allowing this also makes it possible to extend xdg_foreign with foreign popup menus in case this is ever needed. 5) Define behaviour when attaching a null buffer to a surface The behaviour of attaching a null buffer was previously undefined. Some compositors just didn't render the surface, some assumed it was invalid behaviour and sent an error. In short, the now defined behavior depends on the role; it'll either permanently unmap the surface (xdg_popup), or unmap it and reset all attributes as if the xdg_surface and role objects was just created (xdg_toplevel). See corresponding patch (xdg-shell: clarify map/unmap wording) for details. 6) Misc minor changes/clarification/rewording Other changes are best read in the actual patches, but just to make things more complete, they include some rewording of the documentation of the global interface, clarification of maintaining window positions in relation to window management changes and terminology corrections. The maintainers listed in the README has also changed to be me and Mike Blumenkrantz. So these are the changes that should provide us on a good base shell protocol. If we can agree on making this, we can later start adding more extensions, both externally (as separate protocols) or inside xdg_shell (as global interfaces, or new requests/events). There are already plans and ideas of additions that has been discussed at various places, but I believe we should not try to introduce any new features to the base protocol before having something we can rely on for backward compatibility. So in other words, proposing to make xdg_shell stable does not mean it defines everything that needs to be defined; it means that it defines the bare minimum a compositor must implement to support clients that use xdg_shell in a way that can be extended in the future. If there is something missing for implementing a certain feature, that is expected; if there is something that makes extending the protocol to implement a certain feature impossible, that should be fixed. Jonas Jonas Ådahl (10): Add xdg-shell to stable/ xdg-shell: Rename interfaces xdg-shell: Update copyright notices xdg-shell: Reword the xdg_wm_base introduction xdg-shell/positioner: Allow empty anchor_rect xdg-shell: Replace 'monitor' with 'output' xdg-shell/surface: Add note about window position and geometry xdg-shell/toplevel: Clarify xdg_toplevel.set_parent(null) xdg-shell/toplevel: Chain multiple parent-child relationships xdg-shell/popup: Allow custom parent by passing null as parent Mike Blumenkrantz (1): xdg-shell: clarify map/unmap wording stable/xdg-shell/README | 5 + stable/xdg-shell/xdg-shell.xml | 1080 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 1085 insertions(+) create mode 100644 stable/xdg-shell/README create mode 100644 stable/xdg-shell/xdg-shell.xml -- 2.13.0 _______________________________________________ wayland-devel mailing list wayland-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/wayland-devel
