[PATCH] xdg-shell: add draw states for xdg_surface

[Benoit Gschwind]

Hello Mike and Jonas,

I wonder why ?

I do not saying you proposal is useless, but any proposal should solve
an issue or add a feature to be discussed. In both case, I think a
proposal must provide an explanation of why this proposal.

This may be obvious for you but it might be not so obvious. And also
people can check for consistency between the issues/features described
and the solution proposed. Thus, please, describe the issue you trying
to address.

Best regards.

On 27/05/2016 17:29, Mike Blumenkrantz wrote:
> this adds a method for compositors to change various draw attributes
> for a surface
> 
> Signed-off-by: Mike Blumenkrantz <zmike at osg.samsung.com>
> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> ---
>  unstable/xdg-shell/xdg-shell-unstable-v6.xml | 69 ++++++++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
> 
> diff --git a/unstable/xdg-shell/xdg-shell-unstable-v6.xml b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> index dfd7e84..0fa76d4 100644
> --- a/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> +++ b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
> @@ -843,6 +843,75 @@
>        </description>
>      </request>
>  
> +    <enum name="draw_state">
> +      <description summary="draw states for the surface">
> +        The draw state enum defines optional states which describe how
> +        a client should draw a surface. A client must at least support the
> +        default state, and support for optional draw states is explicitly
> +        advertised using xdg_toplevel.set_available_draw_states.
> +
> +        The default draw state implies that the client draws the surface
> +        with complete window decorations.
> +        This may include, e.g., window frame and drop shadow.
> +
> +        Each draw state defines an alteration to the default. Some draw
> +        states may be combined, while some are mutually exclusive. See
> +        each draw state for details.
> +
> +        Desktop environments may extend this enum by taking up a range of
> +        values and documenting the range they chose in this description.
> +        They are not required to document the values for the range that they
> +        chose. Ideally, any good extensions from a desktop environment should
> +        make its way into standardization into this enum.
> +
> +        The current reserved ranges are:
> +
> +        0x0000 - 0x0FFF: xdg-shell core values, documented below.
> +        0x1000 - 0x1FFF: EFL
> +      </description>
> +      <entry name="no_shadow" value="1" summary="no dropshadow">
> +        <description summary="the surface without a dropshadow">
> +          The "no_shadow" draw state implies that the client must not draw
> +          drop shadow around the surface. This may have side effects
> +          on usability, e.g., the inability to activate client-initiated
> +          interactive resize.
> +        </description>
> +      </entry>
> +    </enum>
> +
> +    <event name="configure_draw_states">
> +      <description summary="set the draw state(s) of the surface">
> +        Set the draw state(s) which the client should use to draw a given
> +        surface. The absence of this event prior to an xdg_surface.configure
> +        event indicates that no change has occurred in the draw state since the
> +        previous xdg_surface.configure.
> +
> +        Sending an empty array of states with this method resets a surface to the
> +        default draw state.
> +
> +        This event is not sent by itself but as a latched state sent prior to
> +        the xdg_surface.configure event. When received, a client should adapt
> +        the drawing of the surface according to the state and respond to the
> +        configure event accordingly. See xdg_surface.ack_configure for
> +        details.
> +
> +        A compositor will only configure a client to draw with optional states on a
> +        given surface using the states which were advertised by that surface using
> +        xdg_toplevel.set_available_draw_states.
> +      </description>
> +      <arg name="states" type="array" enum="draw_state"/>
> +    </event>
> +
> +    <request name="set_available_draw_states">
> +      <description summary="advertise optional draw states for the window">
> +        Inform the compositor of optional draw states which are available
> +        for the xdg_toplevel.
> +
> +        Calling this after an xdg_toplevel's first commit will raise a client error.
> +      </description>
> +      <arg name="states" type="array" enum="draw_state"/>
> +    </request>
> +
>      <event name="configure">
>        <description summary="suggest a surface change">
>  	This configure event asks the client to resize its toplevel surface or
>