layout/shell: Add basic support for split window

This introduces a new set_split request to allow changing the tile
orientation of the window. See the protocol XML for more implementation
details.

Of importance difference from the previous implementation is that
this patch makes use of the xdg-shell protocol, such that orientation
is being handled over the configure event to the client.

The protocol specifies a width to allow the client to control how much
of the output be assign the split window and also a sticky window
functionality.

Bug-AGL: SPEC-4839
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: Ia8b7d04a7514f55d647c3ea76b13bab51a3586aa

1 files changed, 72 insertions, 1 deletions

diff --git a/protocol/agl-shell.xml b/protocol/agl-shell.xml
index b11beb6..f8aee4c 100644
--- a/protocol/agl-shell.xml
+++ b/protocol/agl-shell.xml
@@ -22,7 +22,7 @@
     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     DEALINGS IN THE SOFTWARE.
   </copyright>
-  <interface name="agl_shell" version="10">
+  <interface name="agl_shell" version="11">
     <description summary="user interface for Automotive Grade Linux platform">
       Starting with version 2 of the protocol, the client is required to wait
       for the 'bound_ok' or 'bound_fail' events in order to proceed further.
@@ -67,6 +67,14 @@
       <entry name="deactivated" value="3"/>
     </enum>
 
+    <enum name="tile_orientation" since="11">
+      <entry name="none" value="0"/>
+      <entry name="left" value="1"/>
+      <entry name="right" value="2"/>
+      <entry name="top" value="3"/>
+      <entry name="bottom" value="4"/>
+    </enum>
+
     <request name="ready">
       <description summary="client is ready to be shown">
         Tell the server that this client is ready to be shown. The server
@@ -342,6 +350,69 @@
       <arg name="width" type="int"/>
       <arg name="height" type="int"/>
     </request>
+
+    <request name="set_app_split" since="11">
+      <description summary="set the application split">
+        This requests asks the compositor to change the application from the
+        original mode (whatever that might be) to a split, tiled orientation
+        mode defined in the tile orientation enum.
+        Clients need to implement resizing (to handle xdg-shell configure
+        events) for this to work correctly.
+
+        This request only handles a single level of tiling for practical
+        reasons: to keep implementation simple and straight forward. The
+        compositor will ignore requests if there are already two windows
+        present. The client can verify this request succeed by checking the
+        xdg-shell configure event and with it, the states sent
+        by the compositor.
+
+        If there's no app_id with the supplied name, the compositor will add
+        the app to a pending list in order to be applied when an application
+        gets started, or if the application sets its application after the
+        initial wl_surface.commit request.
+
+        Applications can use this approach if they want to be started in a
+        tiled orientation position, before creating the xdg-shell toplevel role.
+
+        A none orientation type would make the window go back to the original
+        maximized mode. If two windows are side by side, returning one of them
+        back the original mode would mean the other one will be made hidden
+        and the one doing the request for the none orientation will become
+        the currently active window. A further activation, using activate_app
+        request for the other window would make that one active.
+
+        Closing the window in the tiled orientation state implies that either
+        the background surface will displayed, or in case there was another
+        applications being shown at that time, will make that application be
+        returned to the original, maximized state.
+
+        The tiled orientation could be applied independently of each other,
+        such that a client can transition from one tiled orientation to
+        another. Note that any other window already present would literally
+        take the opposite orientation with the one currently being changed. So
+        tiled orientation modification automatically implies a tile orientation
+        for any other application already present/active at that time.
+
+        In case there's already a client active at that time, it will be
+        attributed automatically the opposite tiled orientation, such that two
+        concurrent applications can be displayed at the same time.
+
+        The orientation tiles can not be combined, and only state at a time
+        can be active. Only horizontal and vertical tiling is possible. A
+        horizontal and vertical tile orientation simultaneously is not
+        possible.
+
+        Input focus is being delivered to the last started/activated window,
+        such that users can cycle between that one or the other, assumes there's
+        another window in the first place.
+
+        See xdg_toplevel.set_app_id from the xdg-shell protocol for a
+        description of app_id.
+      </description>
+      <arg name="app_id" type="string"/>
+      <arg name="orientation" type="uint" enum="tile_orientation"/>
+      <arg name="output" type="object" interface="wl_output"/>
+    </request>
   </interface>
 
   <interface name="agl_shell_ext" version="1">