[PATCH weston 5/6] xdg-shell: Rewrite documentation

Jasper St. Pierre jstpierre at mecheye.net
Sat Nov 22 12:28:29 PST 2014


This rewrites basically all of the text inside xdg-shell to be up to
date, clearer, and rid of wl_shell and X11 terminology.
---
 protocol/xdg-shell.xml | 256 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 156 insertions(+), 100 deletions(-)

diff --git a/protocol/xdg-shell.xml b/protocol/xdg-shell.xml
index 360179d..3359cf7 100644
--- a/protocol/xdg-shell.xml
+++ b/protocol/xdg-shell.xml
@@ -31,11 +31,15 @@
 
   <interface name="xdg_shell" version="1">
     <description summary="create desktop-style surfaces">
-      This interface is implemented by servers that provide
-      desktop-style user interfaces.
-
-      It allows clients to associate a xdg_surface with
-      a basic surface.
+      xdg_shell allows clients to turn a wl_surface into a "real window"
+      which can be dragged, resized, stacked, and moved around by the
+      user. Everything about this interface is suited towards traditional
+      desktop environments.
+
+      Destroying a bound xdg_shell object while there are surfaces
+      still alive with roles from this interface is illegal and will
+      result in a protocol error. Make sure to destroy all surfaces
+      before destroying this object.
     </description>
 
     <enum name="version">
@@ -65,33 +69,26 @@
 
     <request name="get_xdg_surface">
       <description summary="create a shell surface from a surface">
-	Create a shell surface for an existing surface.
-
-	This request gives the surface the role of xdg_surface. If the
-	surface already has another role, it raises a protocol error.
-
-	Only one shell or popup surface can be associated with a given
-	surface.
+	This creates an xdg_surface for the given surface and gives it the
+	xdg_surface role. See the documentation of xdg_surface for more details.
       </description>
       <arg name="id" type="new_id" interface="xdg_surface"/>
       <arg name="surface" type="object" interface="wl_surface"/>
     </request>
 
     <request name="get_xdg_popup">
-      <description summary="create a shell surface from a surface">
-	Create a popup surface for an existing surface.
-
-	This request gives the surface the role of xdg_popup. If the
-	surface already has another role, it raises a protocol error.
+      <description summary="create a popup for a surface">
+	This creates an xdg_popup for the given surface and gives it the
+	xdg_popup role. See the documentation of xdg_surface for more details.
 
-	Only one shell or popup surface can be associated with a given
-	surface.
+	This request must be used in response to some sort of user action
+	like a button press, key press, or touch down event.
       </description>
       <arg name="id" type="new_id" interface="xdg_popup"/>
       <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 whose pointer is used"/>
-      <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
+      <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>
@@ -107,7 +104,7 @@
         respond to the ping request, or in what timeframe. Clients should
         try to respond in a reasonable amount of time.
       </description>
-      <arg name="serial" type="uint" summary="pass this to the callback"/>
+      <arg name="serial" type="uint" summary="pass this to the pong request"/>
     </event>
 
     <request name="pong">
@@ -120,8 +117,7 @@
   </interface>
 
   <interface name="xdg_surface" version="1">
-
-    <description summary="desktop-style metadata interface">
+    <description summary="A desktop window">
       An interface that may be implemented by a wl_surface, for
       implementations that provide a desktop-style user interface.
 
@@ -136,20 +132,22 @@
     </description>
 
     <request name="destroy" type="destructor">
-      <description summary="remove xdg_surface interface">
-	The xdg_surface interface is removed from the wl_surface object
-	that was turned into a xdg_surface with
-	xdg_shell.get_xdg_surface request. The xdg_surface properties,
-	like maximized and fullscreen, are lost. The wl_surface loses
-	its role as a xdg_surface. The wl_surface is unmapped.
+      <description summary="Destroy the xdg_surface">
+	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.
       </description>
     </request>
 
     <request name="set_parent">
-      <description summary="surface is a child of another surface">
-	Child surfaces are stacked above their parents, and will be
-	unmapped if the parent is unmapped too. They should not appear
-	on task bars and alt+tab.
+      <description summary="set the parent of this surface">
+	Set the "parent" of this surface. This window should be stacked
+	above a parent. The parent surface must be mapped as long as this
+	surface is mapped.
+
+	Parent windows should be set on dialogs, toolboxes, or other
+	"auxilliary" surfaces, so that the parent is raised when the dialog
+	is raised.
       </description>
       <arg name="parent" type="object" interface="xdg_surface" allow-null="true"/>
     </request>
@@ -168,14 +166,19 @@
     </request>
 
     <request name="set_app_id">
-      <description summary="set surface class">
-	Set an id for the surface.
+      <description summary="set application ID">
+	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
+	applications together, or to determine how to launch a new
+	application.
 
-	The app id identifies the general class of applications to which
-	the surface belongs.
+	See the desktop-entry specification [0] for more details on
+	application identifiers and how they relate to well-known DBus
+	names and .desktop files.
 
-	It should be the ID that appears in the new desktop entry
-	specification, the interface name.
+	[0] http://standards.freedesktop.org/desktop-entry-spec/
       </description>
       <arg name="app_id" type="string"/>
     </request>
@@ -187,29 +190,32 @@
         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 parent surface. There are
-        no guarantees as to what the window menu contains.
+        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.
 
-        Your surface must have focus on the seat passed in to pop up the
-        window menu.
+        This request must be used in response to some sort of user action
+        like a button press, key press, or touch down event.
       </description>
 
-      <arg name="seat" type="object" interface="wl_seat" summary="the seat to pop the window up on"/>
-      <arg name="serial" type="uint" summary="serial of the event to pop up the window for"/>
+      <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" summary="the x position to pop up the window menu at"/>
       <arg name="y" type="int" summary="the y position to pop up the window menu at"/>
     </request>
 
     <request name="move">
       <description summary="start an interactive move">
-	Start a pointer-driven move of the surface.
+	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.
 
-	This request must be used in response to a button press event.
 	The server may ignore move requests depending on the state of
 	the surface (e.g. fullscreen or maximized).
       </description>
-      <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat whose pointer is used"/>
-      <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
+      <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"/>
     </request>
 
     <enum name="resize_edge">
@@ -232,14 +238,16 @@
 
     <request name="resize">
       <description summary="start an interactive resize">
-	Start a pointer-driven resizing of the surface.
+	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.
 
-	This request must be used in response to a button press event.
 	The server may ignore resize requests depending on the state of
 	the surface (e.g. fullscreen or maximized).
       </description>
-      <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat whose pointer is used"/>
-      <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
+      <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="edges" type="uint" summary="which edge or corner is being dragged"/>
     </request>
 
@@ -287,16 +295,21 @@
 
     <event name="configure">
       <description summary="suggest a surface change">
-	The configure event asks the client to resize its surface.
+	The configure event asks the client to resize its surface or to
+	change its state.
 
 	The width and height arguments specify a hint to the window
-        about how its surface should be resized in window geometry
-        coordinates. The states listed in the event specify how the
-        width/height arguments should be interpreted.
+	about how its surface should be resized in window geometry
+	coordinates.
+
+	The states listed in the event specify how the width/height
+	arguments should be interpreted, and possibly how it should be
+	drawn.
 
-        A client should arrange a new surface, and then send a
-        ack_configure request with the serial sent in this configure
-        event before attaching a new surface.
+	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
@@ -311,14 +324,20 @@
 
     <request name="ack_configure">
       <description summary="ack a configure event">
-        When a configure event is received, a client should then ack it
-        using the ack_configure request to ensure that the compositor
-        knows the client has seen the event.
-
-        By this point, the state is confirmed, and the next attach should
-        contain the buffer drawn for the configure event you are acking.
+        When a configure event is received, if a client is updating
+        and redrawing its state in response to the configure event,
+        then the client needs to make an ack_configure request before
+        point the commit to mark this next commit as being a
+        reaction to the configure.
+
+        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.
       </description>
-      <arg name="serial" type="uint" summary="a serial to configure for"/>
+      <arg name="serial" type="uint" summary="the serial from the configure event"/>
     </request>
 
     <request name="set_window_geometry">
@@ -328,15 +347,20 @@
         portions like drop-shadows which should be ignored for the
         purposes of aligning, placing and constraining windows.
 
-        The default value is the full bounds of the surface, including any
-        subsurfaces. Once the window geometry of the surface is set once,
-        it is not possible to unset it, and it will remain the same until
+        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 width and height must be greater than zero.
       </description>
       <arg name="x" type="int"/>
       <arg name="y" type="int"/>
@@ -359,7 +383,18 @@
     </request>
     <request name="unset_fullscreen" />
 
-    <request name="set_minimized" />
+    <request name="set_minimized">
+      <description summary="set the window as minimized">
+	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.
+      </description>
+    </request>
 
     <event name="close">
       <description summary="surface wants to be closed">
@@ -376,26 +411,48 @@
   </interface>
 
   <interface name="xdg_popup" version="1">
-    <description summary="desktop-style metadata interface">
-      An interface that may be implemented by a wl_surface, for
-      implementations that provide a desktop-style popups/menus. A popup
-      surface is a transient surface with an added pointer grab.
-
-      An existing implicit grab will be changed to owner-events mode,
-      and the popup grab will continue after the implicit grab ends
-      (i.e. releasing the mouse button does not cause the popup to be
-      unmapped).
-
-      The popup grab continues until the window is destroyed or a mouse
-      button is pressed in any other clients window. A click in any of
-      the clients surfaces is reported as normal, however, clicks in
-      other clients surfaces will be discarded and trigger the callback.
-
-      The x and y arguments specify the locations of the upper left
-      corner of the surface relative to the upper left corner of the
-      parent surface, in surface local coordinates.
-
-      xdg_popup surfaces are always transient for another surface.
+    <description summary="short-lived, popup surfaces for menus">
+      A popup surface is a short-lived, temporary surface that can be
+      used to implement menus. It takes an explicit grab on the surface
+      that will be dismissed when the user dismisses the 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.
+
+      When the popup is dismissed, a popup_done event will be sent out,
+      and at the same time the surface will be unmapped. The xdg_popup
+      object is now inert and cannot be reactivated, so clients should
+      destroy it. Explicitly destroying the xdg_popup object will also
+      dismiss the popup, and unmap the surface.
+
+      Clients will receive events for all their surfaces during this
+      grab (which is an "owner-events" grab in X11 parlance). This is
+      done so that users can navigate through submenus and other
+      "nested" popup windows without having to dismiss the topmost
+      popup.
+
+      Clients that want to dismiss the popup when another surface of
+      their own is clicked should dismiss the popup using the destroy
+      request.
+
+      The parent surface must have either an xdg_surface or xdg_popup
+      role.
+
+      Specifying an xdg_popup for the parent 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.
+
+      If there is an existing popup when creating a new popup, the
+      parent must be the current topmost popup.
+
+      When compositors choose to dismiss a popup if the user clicks
+      outside the window, they will likely dismiss every nested popup
+      as well.
+
+      The x and y arguments specify where the top left of the popup
+      should be placed, relative to the local surface coordinates of the
+      parent surface.
     </description>
 
     <enum name="error">
@@ -407,19 +464,18 @@
 
     <request name="destroy" type="destructor">
       <description summary="remove xdg_surface interface">
-	The xdg_surface interface is removed from the wl_surface object
-	that was turned into a xdg_surface with
-	xdg_shell.get_xdg_surface request. The xdg_surface properties,
-	like maximized and fullscreen, are lost. The wl_surface loses
-	its role as a xdg_surface. The wl_surface is unmapped.
+	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.
       </description>
     </request>
 
     <event name="popup_done">
       <description summary="popup interaction is done">
-	The popup_done event is sent out when a popup grab is broken,
-	that is, when the users clicks a surface that doesn't belong
-	to the client owning the popup surface.
+	The popup_done event is sent out when a popup is dismissed
+	by the compositor.
       </description>
     </event>
 
-- 
2.1.0



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