docs/: Added docsjellyfish_10.0.1jellyfish/10.0.110.0.1

This adds the documentations bits, most, if not all, extracted from
the original wayland-ivi-plugins repository.

It describes the waltham-transmiter-plugin, and the receiver side, how
to configure and run them. It also removes any ivi-shell and with it,
any menton about LayoutManagerControls.

Bug-AGL: SPEC-3601

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: I2f900f7eee34c431cc8d601131c5925c31280425

1 files changed, 156 insertions, 0 deletions

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+**Table of Content**
+
+1. TOC
+{:toc}
+
+## waltham-client-server-applications
+
+![image](./images/Waltham_Architecture.jpg)
+
+### waltham-transmitter-plugin
+
+*waltham-transmitter-plugin* provides an API to create remote connections and
+push surfaces over the network and handles remote input.  It is loaded
+automatically at start-up, by the compositor. The (remote) outputs are streamed
+to the remote side by using the remoting plug-in.
+
+### waltham-receiver
+
+waltham-receiver is a sample implementation of the receiver app which should be
+running at the remote side. It is developed based on [waltham
+server](https://github.com/waltham/waltham/tree/master/tests), using Waltham
+protocol to obtain and process remote input -- handled by
+waltham-transmitter-plugin, with the remote output handled by the remoting
+plugin.  This component is designed to be used for evaluating the functionality
+of waltham-transmitter plugin.
+
+## How it works
+
+### 1. Loading and initialization
+
+As the compositor is starting up, it loads the waltham-transmitter plugin.
+
+![image](./images/01_Load_transmitter.jpg)
+
+### 2. Establishing connection
+
+At `transmitter_create_remote()`, waltham-transmitter creates
+`weston_transmitter_remote` object which expresses the receiver object at
+remote side, and it is created for each receiver.
+
+*waltham-transmitter* uses `wth_display_get_registry()` and `wth_display_sync()`
+for the receiver applications in the same manner as the Wayland protocol
+would retrieve the interfaces. Then, the receiver applications sends back
+the resource list to the waltham-transmitter.
+
+![image](./images/02_Establish_connection.jpg)
+
+### 3. Forwarding surface
+
+A fake mechanism of sending the buffer attachments was previously in place. The
+following protocol messages to the receiver app were added to notify about
+surface updates. 
+
+`wthp_surface_attach()`, `wthp_surface_damage()` and `wthp_surface_commit()`
+correspond to `wl_surface_attach()`, `wl_surface_damage()` and
+`wl_surface_commit()` message in wayland protocol.
+
+- `wthp_surface_attach()` - Send wthp_buffer as a buffer handling. This is not
+the actual buffer which contains the data to be rendered but the handle of an
+actual buffer. It abstracts the differences of buffer type.
+- `wthp_surface_damage()` - Tell the updated region to receiver app.
+- `wthp_surface_commit()` - Tell surface gets updated to receiver app.
+
+These are no longer in place, as the remoting output is being handled entirely
+by the remoting plugin.
+
+![image](./images/03_Forward_surface.jpg)
+
+### 4. Rendering using GStreamer
+
+![image](./images/04_Rendering_using_gstreamer.jpg)
+
+### 5. Input handling
+
+For handling input events, waltham-transmitter has 2 ways to secure seat.
+
+1. Use `wl_seat` as weston has.
+2. Create a new `wl_seat`.
+
+Second case is applicable in case the transmitter side does not have an input
+device but the receiver at remote side has one. After `wl_seat` is created,
+waltham-transmitter sends input events to the client application when
+it gets an input event from the receiver via the Waltham protocol.
+
+The message wthp_send_XXX shows you that input event is forwarded from the
+receiver to the transmitter, XXX is filled by the input event name.
+
+![image](./images/05_Input_handling.jpg)
+
+### 6. Retry connection
+
+In case the connection gets disconnected during surface sharing,
+waltham-transmitter shall re-establish the connection. The `waltham_display`
+objects represents the connection between the transmitter and the receiver,
+and contains a flag that can be used to detect a disconnect.
+
+That happens in `connection_handle_data()` in case a disconnect is detected.
+This flag is checked at every call of `transmitter_surface_gather_state`. When
+running is in false state, waltham-transmitter starts to retry the handling
+sequence.
+
+It release the waltham protocol objects then it goes to establish a connection
+sequence mentioned in 2. Establishing connection.
+
+![image](./images/06_Retry_connection.jpg)
+
+## Waltham in practice
+
+Here is the example how waltham can be used in hypervisor use case of real
+project.
+
+* Weston is used as the wayland compositor.
+* waltham-client is implemented for Weston which acts as a Waltham  virtual
+  display.
+* Application surface is assigned to Waltham virtual display and it's sent to
+  the other ECU/OS.  Buffers of surface are transferred via GStreamer(UDP),
+  since transferring raw pixel data via Waltham(TCP) is not fast enough.
+* Controlling input events (pointer, keyboard, touch) for the surface is
+  handled by Waltham.
+
+![image](./images/Waltham_In_Practice.jpg)
+
+## How Waltham can be integrated
+
+Some possible integration examples of waltham follow.
+
+### As an EGL backend (theoretical possibility)
+
+Similarly to Wayland back-end for EGL, Waltham client could be a back-end in
+the compositor.  For better performance, a generic surface sharing mechanism is
+needed in a hypervisor environment.  Applications need to adapt to Waltham.
+As waltham is not designed with this use in mind this usage is just a
+theoretical possibility.
+
+![image](./images/Waltham_Integration_Possibility-01.jpg)
+
+### As a GStreamer sink (theoretical possibility)
+
+Similarly to Wayland sink, a Waltham sink GStreamer plugin can be implemented
+which sends the buffers to a receiver on another domain/OS.  Waltham sink can
+utilize frame synchronization and a presentation feedback protocols for video
+synchronization.  For better performance, a generic surface sharing mechanism
+is needed in a hypervisor environment.  As Waltham is not designed with this
+use in mind this usage is just a theoretical possibility.
+
+![image](./images/Waltham_Integration_Possibility-02.jpg)
+
+### As a virtual display in compositor
+
+Virtual display plugin can be implemented in the compositor. This plugin sends
+client buffers to waltham-receiver in another domain.  No changes to
+applications.  For good performance, a generic surface sharing mechanism is
+needed in hypervisor environment.  This is the intended use in mind during
+design.
+
+![image](./images/Waltham_Integration_Possibility-03.jpg)