[PATCH wayland-protocols v3 1/7] xdg-shell: Turn xdg_surface into a generic base interface

Jonas Ådahl jadahl at gmail.com
Mon Jun 13 19:58:04 UTC 2016


On Wed, Jun 08, 2016 at 04:45:28PM +0200, Benoit Gschwind wrote:
> Hello Jonas,
> 
> On 08/06/2016 03:18, Jonas Ådahl wrote:
> > On Wed, Jun 08, 2016 at 12:37:01AM +0200, Benoit Gschwind wrote:
> >> Hello,
> >>
> >> This proposal look good, few optional comments following.
> >>
> >> On 26/05/2016 06:32, Jonas Ådahl wrote:
> >>> Split out toplevel window like requests and events into a new interface
> >>> called xdg_toplevel, and turn xdg_surface into a generic base interface
> >>> which others extends.
> >>>
> >>> xdg_popup is changed to extend the xdg_surface.
> >>>
> >>> The configure event in xdg_surface was split up making
> >>> xdg_surface.configure an event only carrying the serial number, while a
> >>> new xdg_toplevel.configure event carries the other data previously sent
> >>> via xdg_surface.configure. xdg_toplevel.configure is made to extend,
> >>> via the latch-state mechanism, xdg_surface.configure and depends on
> >>> that event to synchronize state.
> >>>
> >>> Other future xdg_surface based extensions are meant to also extend
> >>> xdg_surface.configure for relevant window type dependend state
> >>> synchronization.
> >>>
> >>> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> >>> Signed-off-by: Mike Blumenkrantz <zmike at samsung.com>
> >>> ---
> >>>
> >>> Changes since v2:
> >>>   - Grammar, typos and spelling fixes
> >>>   - Tried to clarify the latched state configure events sequence
> >>>   - Clarified window geometry constraints and semantics
> >>>
> >>>
> >>>  unstable/xdg-shell/xdg-shell-unstable-v6.xml | 275 ++++++++++++++++-----------
> >>>  1 file changed, 165 insertions(+), 110 deletions(-)
> >>>
> >>> diff --git a/unstable/xdg-shell/xdg-shell-unstable-v6.xml b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> >>> index ce57153..fa838f9 100644
> >>> --- a/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> >>> +++ b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> >>> @@ -54,11 +54,9 @@
> >>>  
> >>>      <request name="get_xdg_surface">
> >>>        <description summary="create a shell surface from a surface">
> >>> -	This creates an xdg_surface for the given surface and gives it the
> >>> -	xdg_surface role. A wl_surface can only be given an xdg_surface role
> >>> -	once. If get_xdg_surface is called with a wl_surface that already has
> >>> -	an active xdg_surface associated with it, or if it had any other role,
> >>> -	an error is raised.
> >>> +	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.
> >>>  
> >>
> >> I think the 3 line above are more confusing than useful and may be
> >> replaced by the single sentence:
> >> This creates an xdg_surface for the given surface.
> > 
> > I think it helps describing the expectations here.
> 
> Then something like that:
> 
> xdg_surface are used as basis to define a role to a given surface, such
> as xdg_toplevel or xdg_popup. It's also the basis of the management of
> xdg's surfaces states.

Sure, that sounds reasonable.


Jonas

> 
> > 
> >>
> >>>  	See the documentation of xdg_surface for more details about what an
> >>>  	xdg_surface is and how it is used.
> >>> @@ -67,29 +65,6 @@
> >>>        <arg name="surface" type="object" interface="wl_surface"/>
> >>>      </request>
> >>>  
> >>> -    <request name="get_xdg_popup">
> >>> -      <description summary="create a popup for a surface">
> >>> -	This creates an xdg_popup for the given surface and gives it the
> >>> -	xdg_popup role. A wl_surface can only be given an xdg_popup role
> >>> -	once. If get_xdg_popup is called with a wl_surface that already has
> >>> -	an active xdg_popup associated with it, or if it had any other role,
> >>> -	an error is raised.
> >>> -
> >>> -	This request must be used in response to some sort of user action
> >>> -	like a button press, key press, or touch down event.
> >>> -
> >>> -	See the documentation of xdg_popup for more details about what an
> >>> -	xdg_popup is and how it is used.
> >>> -      </description>
> >>> -      <arg name="id" type="new_id" interface="zxdg_popup_v6"/>
> >>> -      <arg name="surface" type="object" interface="wl_surface"/>
> >>> -      <arg name="parent" type="object" interface="wl_surface"/>
> >>> -      <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat of the user event"/>
> >>> -      <arg name="serial" type="uint" summary="the serial of the user event"/>
> >>> -      <arg name="x" type="int"/>
> >>> -      <arg name="y" type="int"/>
> >>> -    </request>
> >>> -
> >>>      <event name="ping">
> >>>        <description summary="check if the client is alive">
> >>>  	The ping event asks the client if it's still alive. Pass the
> >>> @@ -117,13 +92,23 @@
> >>>    </interface>
> >>>  
> >>>    <interface name="zxdg_surface_v6" version="1">
> >>> -    <description summary="A desktop window">
> >>> +    <description summary="desktop user interface surface base interface">
> >>>        An interface that may be implemented by a wl_surface, for
> >>>        implementations that provide a desktop-style user interface.
> >>>  
> >>> -      It provides requests to treat surfaces like windows, allowing to set
> >>> -      properties like maximized, fullscreen, minimized, and to move and resize
> >>> -      them, and associate metadata like title and app id.
> >>> +      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, create a role-specific object using, e.g.,
> >>
> >> In order to map an xdg_surface, the client must create a role-specific ...
> > 
> > Sure.
> > 
> >>
> >>> +      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.
> >>> @@ -133,12 +118,146 @@
> >>>        manipulate a buffer prior to the first xdg_surface.configure call must
> >>>        also be treated as errors.
> >>>  
> >>> -      For a surface to be mapped by the compositor the client must have
> >>> -      committed both an xdg_surface state and a buffer.
> >>> +      For a surface to be mapped by the compositor the client must have assigned
> >>> +      one of the xdg_surface based roles, it must have committed both the
> >>> +      xdg_surface state and the role dependent state, and it must have committed
> >>> +      a buffer.
> >>
> >> For a surface to be mapped by the compositor, the following conditions
> >> must be met: (1) the client has assigned a xdg_surface based role to the
> >> surface, (2) the client has set the xdg_surface state and the role
> >> dependent state to the surface and (3) the client has committed a buffer
> >> to the surface.
> > 
> > Sure, that makes it a bit clearer.
> > 
> >>
> >>> +    </description>
> >>> +
> >>> +    <enum name="error">
> >>> +      <entry name="not_constructed" value="1"/>
> >>> +      <entry name="already_constructed" value="2"/>
> >>> +    </enum>
> >>> +
> >>> +    <request name="destroy" type="destructor">
> >>> +      <description summary="destroy the xdg_surface">
> >>> +	Destroy the xdg_surface object. An xdg_surface must only be destroyed
> >>> +	after its role object has been destroyed.
> >>> +      </description>
> >>> +    </request>
> >>> +
> >>> +    <request name="get_toplevel">
> >>> +      <description summary="assign the xdg_toplevel surface role">
> >>> +	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.
> >>> +      </description>
> >>> +      <arg name="id" type="new_id" interface="zxdg_toplevel_v6"/>
> >>> +    </request>
> >>> +
> >>> +    <request name="get_popup">
> >>> +      <description summary="assign the xdg_popup surface role">
> >>> +	This creates an xdg_popup object for the given xdg_surface and gives the
> >>> +	associated wl_surface the xdg_popup role.
> >>> +
> >>> +	This request must be used in response to some sort of user action like a
> >>> +	button press, key press, or touch down event.
> >>> +
> >>> +	See the documentation of xdg_popup for more details about what an
> >>> +	xdg_popup is and how it is used.
> >>> +      </description>
> >>> +      <arg name="id" type="new_id" interface="zxdg_popup_v6"/>
> >>> +      <arg name="parent" type="object" interface="wl_surface"/>
> >>> +      <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat of the user event"/>
> >>> +      <arg name="serial" type="uint" summary="the serial of the user event"/>
> >>> +      <arg name="x" type="int"/>
> >>> +      <arg name="y" type="int"/>
> >>> +    </request>
> >>> +
> >>> +    <request name="set_window_geometry">
> >>> +      <description summary="set the new window geometry">
> >>> +	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.
> >>> +
> >>> +	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.
> >>
> >> This sentence was from the previous spec. but I would use :
> >>
> >> This defaults behavior is meant for simplest clients.
> >>
> >> maybe could be done in another patch.
> > 
> > Yea, lets that would be better as a follow up.
> > 
> >>
> >>
> >>> +
> >>> +	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 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.
> >>> +      </description>
> >>> +      <arg name="x" type="int"/>
> >>> +      <arg name="y" type="int"/>
> >>> +      <arg name="width" type="int"/>
> >>> +      <arg name="height" type="int"/>
> >>> +    </request>
> >>> +
> >>> +    <request name="ack_configure">
> >>> +      <description summary="ack a configure event">
> >>> +	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.
> >>> +
> >>> +	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.
> >>> +      </description>
> >>> +      <arg name="serial" type="uint" summary="the serial from the configure event"/>
> >>> +    </request>
> >>> +
> >>> +    <event name="configure">
> >>> +      <description summary="suggest a surface change">
> >>> +	The configure event marks the end of a configure sequence. A configure
> >>> +	sequence is a set of zero or more events configuring the drawing of the
> >>> +	surface, finalized by this event.
> >>
> >> 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.
> > 
> > Yes, that sounds better.
> > 
> >>
> >>> +
> >>> +	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.
> >>
> >> I tried to figure out what the paragraph above explain. Here is my
> >> rewording, If I'm wrong please correct myself and feel free to pick my
> >> wording to improve this paragraph.
> >>
> >> The client must freeze the state of a window until a configure sequence
> >> is completed. During the configure sequence the client accumulate state
> >> changes. When and only when the client receive a xdg_surface.configure
> >> event, the client can apply accumulated changes of the surface state.
> >> During the configure sequence, a newer events override all previous
> >> event of the same type.
> > 
> > Yes, except I would assume a client wouldn't "freeze" anything, but
> > would rather accumulate the changes in a "pending state" container
> > similar to how the compositor handles surface state changes before
> > wl_surface.commit.
> > 
> >>
> >>> +
> >>> +	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.
> >>> +      </description>
> >>> +      <arg name="serial" type="uint" summary="serial of the configure event"/>
> >>> +    </event>
> >>> +  </interface>
> >>> +
> >>> +  <interface name="zxdg_toplevel_v6" version="1">
> >>> +    <description summary="toplevel surface">
> >>> +      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.
> >>>      </description>
> >>>  
> >>>      <request name="destroy" type="destructor">
> >>> -      <description summary="Destroy the xdg_surface">
> >>> +      <description summary="destroy the xdg_toplevel">
> >>>  	Unmap and destroy the window. The window will be effectively
> >>>  	hidden from the user's point of view, and all state like
> >>>  	maximization, fullscreen, and so on, will be lost.
> >>> @@ -155,7 +274,7 @@
> >>>  	"auxiliary" surfaces, so that the parent is raised when the dialog
> >>>  	is raised.
> >>>        </description>
> >>> -      <arg name="parent" type="object" interface="zxdg_surface_v6" allow-null="true"/>
> >>> +      <arg name="parent" type="object" interface="zxdg_toplevel_v6" allow-null="true"/>
> >>>      </request>
> >>>  
> >>>      <request name="set_title">
> >>> @@ -348,8 +467,10 @@
> >>>  
> >>>      <event name="configure">
> >>>        <description summary="suggest a surface change">
> >>> -	The configure event asks the client to resize its surface or to
> >>> -	change its state.
> >>> +	This configure event asks the client to resize its toplevel surface or
> >>> +	to change its state. It is not sent by itself but as a latched state
> >>> +	sent prior to the xdg_surface.configure event. See xdg_surface.configure
> >>> +	for details.
> >>
> >> This configure event asks the client to resize or to change states of
> >> the client surface. This event is not applied immediately, see
> >> xdg_surface.configure for details.
> > 
> > Maybe "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
> >>> @@ -364,81 +485,15 @@
> >>>  	arguments should be interpreted, and possibly how it should be
> >>>  	drawn.
> >>>  
> >>> -	Clients should arrange their surface for the new size and
> >>> -	states, and then send a 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.
> >>> +	Clients must send an ack_configure in response to this event. See
> >>> +	xdg_surface.configure and xdg_surface.ack_configure for details.
> >>>        </description>
> >>>  
> >>>        <arg name="width" type="int"/>
> >>>        <arg name="height" type="int"/>
> >>>        <arg name="states" type="array"/>
> >>> -      <arg name="serial" type="uint"/>
> >>>      </event>
> >>>  
> >>> -    <request name="ack_configure">
> >>> -      <description summary="ack a configure event">
> >>> -	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, 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.
> >>> -
> >>> -	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.
> >>> -
> >>> -	The compositor expects that the most recently received
> >>> -	ack_configure request at the time of a commit indicates which
> >>> -	configure event the client is responding to.
> >>> -      </description>
> >>> -      <arg name="serial" type="uint" summary="the serial from the configure event"/>
> >>> -    </request>
> >>> -
> >>> -    <request name="set_window_geometry">
> >>> -      <description summary="set the new window geometry">
> >>> -	The window geometry of a window 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.
> >>> -
> >>> -	Once the window geometry of the surface is set once, 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 mode is meant for extremely simple clients.
> >>> -
> >>> -	If responding to a configure event, the window geometry in here
> >>> -	must respect the sizing negotiations specified by the states in
> >>> -	the configure event.
> >>> -
> >>> -	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.
> >>> -      </description>
> >>> -      <arg name="x" type="int"/>
> >>> -      <arg name="y" type="int"/>
> >>> -      <arg name="width" type="int"/>
> >>> -      <arg name="height" type="int"/>
> >>> -    </request>
> >>> -
> >>>      <request name="set_max_size">
> >>>        <description summary="set the maximum size">
> >>>  	Set a maximum size for the window.
> >>> @@ -447,7 +502,7 @@
> >>>  	not try to configure the window beyond this size.
> >>>  
> >>>  	The width and height arguments are in window geometry coordinates.
> >>> -	See set_window_geometry.
> >>> +	See xdg_surface.set_window_geometry.
> >>>  
> >>>  	Values set in this way are double-buffered. They will get applied
> >>>  	on the next commit.
> >>> @@ -488,7 +543,7 @@
> >>>  	not try to configure the window below this size.
> >>>  
> >>>  	The width and height arguments are in window geometry coordinates.
> >>> -	See set_window_geometry.
> >>> +	See xdg_surface.set_window_geometry.
> >>>  
> >>>  	Values set in this way are double-buffered. They will get applied
> >>>  	on the next commit.
> >>> @@ -631,7 +686,7 @@
> >>>        their own is clicked should dismiss the popup using the destroy
> >>>        request.
> >>>  
> >>> -      The parent surface must have either an xdg_surface or xdg_popup
> >>> +      The parent surface must have either the xdg_toplevel or xdg_popup surface
> >>>        role.
> >>>  
> >>>        Specifying an xdg_popup for the parent means that the popups are
> >>> @@ -653,7 +708,7 @@
> >>>        The x and y arguments passed when creating the popup object specify
> >>>        where the top left of the popup should be placed, relative to the
> >>>        local surface coordinates of the parent surface. See
> >>> -      xdg_shell.get_xdg_popup.
> >>> +      xdg_surface.get_popup.
> >>>  
> >>>        The client must call wl_surface.commit on the corresponding wl_surface
> >>>        for the xdg_popup state to take effect.
> >>>
> >>
> >> Best regards
> > 
> > Thanks for taking a look
> > 
> > 
> > Jonas
> > 
> >> --
> >> Benoit Gschwind
> >>
> 
> Best regards
> --
> Benoit Gschwind


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