[PATCH weston 1/6] xdg-shell: define the present/present_from_event() requests

Bill Spitzak spitzak at gmail.com
Tue Sep 29 10:47:44 PDT 2015


Another important point is that the compositor can check what *type* of
event was used for the raise. It could accept press/release and ignore move
events, for instance. Keyboard events could be ignored if the client no
longer has keyboard focus, while clicks are ignored if the client no longer
has mouse focus.

I would really like to suggest two modifications:

1. Merge these two requests into one that always takes an event. Make a way
of saying "no event" as the event serial. The Wayland api is getting really
bloated with unnecessary duplicate functions and it would be nice to make
an effort to keep it small in really obvious cases like this.

2. Call the function "xdg_surface_raise". Because raising is exactly what
the client expects. It does not mean that it *has* to raise the window. If
you don't do this, lots of programmers are going to ask where the raise
function is, let's stop that from being added as another call and get this
right now into a single api.


On Tue, Sep 29, 2015 at 12:53 AM, Manuel Bachmann <manuel.bachmann at iot.bzh>
wrote:

> Hi Derek, and thanks a lot for your feedback,
>
> I think it makes sense if you consider the compositor can know if a past
> input event could have happened "not long ago" or "a very long time ago"
> (if the event happened not long ago, raise the window, otherwise blink). It
> is really a matter of policy, but the idea was to let the shell know some
> details on user interactions, so it can decide what to do. What do you
> think of this ?
>
> PS : I  rebased the patches on top of Weston 1.9 *. I am also preparing a
> demonstration using well-known applications with external toolkits, but it
> takes some time.
>
> * : https://github.com/Tarnyko/weston-xdg_surface_present
>
> Regards,
>
> *Manuel Bachmann, Graphics Engineer www.iot.bzh <http://iot.bzh> *
>
>
> 2015-09-28 22:41 GMT+02:00 Derek Foreman <derekf at osg.samsung.com>:
>
>> On 09/04/15 11:22 AM, Manuel Bachmann wrote:
>> > xdg_surface_present() and xdg_surface_present_from_event()
>> > are new requests supposed to be called on an existing
>> > xdg_surface. They tell the compositor that the surface
>> > has new content which may be of interest to the user.
>> > The compositor may then choose to notify the user.
>> >
>> > xdg_surface_present_from_event() takes a serial coming
>> > from an input (wl_keyboard, wl_pointer, wl_touch) event as
>> > an argument. If the serial is valid and sufficiently recent,
>> > we can suppose the new content has been issued at the user's
>> > request ; the compositor may then choose to raise the
>> > surface directly. Otherwise, it just behaves like present().
>>
>> I'm having a hard time thinking of a use case for
>> xdg_surface_present_from_event()...  Picking an arbitrary motion event
>> from the past seems odd - the compositor probably won't keep track of
>> input serials in any way that makes this useful?
>>
>> > Signed-off-by: Manuel Bachmann <manuel.bachmann at open.eurogiciel.org>
>> > ---
>> >  desktop-shell/shell.c  | 15 +++++++++++++++
>> >  protocol/xdg-shell.xml | 20 ++++++++++++++++++++
>> >  2 files changed, 35 insertions(+)
>> >
>> > diff --git a/desktop-shell/shell.c b/desktop-shell/shell.c
>> > index f7c928e..d1d3f3c 100644
>> > --- a/desktop-shell/shell.c
>> > +++ b/desktop-shell/shell.c
>> > @@ -3923,6 +3923,19 @@ xdg_surface_set_minimized(struct wl_client
>> *client,
>> >       set_minimized(shsurf->surface);
>> >  }
>> >
>> > +static void
>> > +xdg_surface_present(struct wl_client *client,
>> > +                 struct wl_resource *resource)
>> > +{
>> > +}
>> > +
>> > +static void
>> > +xdg_surface_present_from_event(struct wl_client *client,
>> > +                            struct wl_resource *resource,
>> > +                            uint32_t serial)
>> > +{
>> > +}
>> > +
>> >  static const struct xdg_surface_interface xdg_surface_implementation =
>> {
>> >       xdg_surface_destroy,
>> >       xdg_surface_set_parent,
>> > @@ -3938,6 +3951,8 @@ static const struct xdg_surface_interface
>> xdg_surface_implementation = {
>> >       xdg_surface_set_fullscreen,
>> >       xdg_surface_unset_fullscreen,
>> >       xdg_surface_set_minimized,
>> > +     xdg_surface_present,
>> > +     xdg_surface_present_from_event,
>> >  };
>> >
>> >  static void
>> > diff --git a/protocol/xdg-shell.xml b/protocol/xdg-shell.xml
>> > index 68cf469..10f82c5 100644
>> > --- a/protocol/xdg-shell.xml
>> > +++ b/protocol/xdg-shell.xml
>> > @@ -396,6 +396,26 @@
>> >        </description>
>> >      </request>
>> >
>> > +    <request name="present">
>> > +      <description summary="the window wants attention from the user">
>> > +     The surface has new content and would like the compositor
>> > +     to notify the user.
>> > +      </description>
>> > +    </request>
>> > +
>> > +    <request name="present_from_event">
>> > +      <description summary="the window needs attention from the user">
>> > +     The surface has new content and would like the compositor
>> > +     to notify the user.
>> > +
>> > +     If a valid and sufficiently recent serial coming from an
>> > +     input (keyboard, pointer, touch) event is passed as an
>> > +     argument, the compositor may want to raise the surface.
>> > +     Otherwise, the request just behaves like the "present" one.
>> > +      </description>
>> > +      <arg name="serial" type="uint" summary="serial of an input
>> event"/>
>> > +    </request>
>> > +
>> >      <event name="close">
>> >        <description summary="surface wants to be closed">
>> >          The close event is sent by the compositor when the user
>> >
>>
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>>
>
>
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