[vlc-devel] [PATCH v3 03/10] vout_window: add visibility reporting callbacks

[Alexandre Janniaux]

Hi,

Fine with a boolean for me. The same naming is ok though?

    vout_window_ReportVisibilityChanged(wnd, true/false);

Regards,
--
Alexandre Janniaux
Videolabs

On Tue, Feb 16, 2021 at 06:46:22PM +0200, Rémi Denis-Courmont wrote:
> Le tiistaina 16. helmikuuta 2021, 17.25.43 EET Alexandre Janniaux a écrit :
> > Those callbacks are meant to be used by vout_window implementations in
> > environment where the rendering is constrained by the application state.
> >
> > The design case for those events is iOS where application must not draw
> > onto its surface when they have been moved to the background, but it
> > should be generalizable to every cases where the window is in a state
> > such as no more rendering is needed for it, like in Wayland when the
> > window is not visible anymore.
> >
> > To handle these other cases, the reporting function might need to also
> > report a callback and better handle state change to notify the callback
> > when the application is back to be visible and has drawn something. This
> > is currently not implemented for iOS, so not done.
> > ---
> >  include/vlc_vout_window.h | 33 +++++++++++++++++++++++++++++++++
> >  1 file changed, 33 insertions(+)
> >
> > diff --git a/include/vlc_vout_window.h b/include/vlc_vout_window.h
> > index ea16d4b414..6e492ce0bd 100644
> > --- a/include/vlc_vout_window.h
> > +++ b/include/vlc_vout_window.h
> > @@ -78,6 +78,16 @@ enum vout_window_state {
> >      VOUT_WINDOW_STATE_BELOW /**< Stacking below (a.k.a. wall paper mode)
> > */, };
> >
> > +/**
> > + * Window visibility state.
> > + *
> > + * See also \ref vout_window_ReportVisibilityChanged.
> > + */
> > +enum vout_window_visibility {
> > +    VOUT_WINDOW_VISIBLE,
> > +    VOUT_WINDOW_NOT_VISIBLE
> > +};
>
> Using a boolean would be far simpler.
>
> And yes, I know that X11 has a partially visible state, but it's pretty much
> unused since everybody and their dog does compositing. It's also dubious that
> VLC would ever be able to handle it any differently from fully visible.
>
> > +
> >  /**
> >   * Window mouse event types.
> >   *
> > @@ -289,6 +299,21 @@ struct vout_window_callbacks {
> >       */
> >      void (*output_event)(struct vout_window_t *,
> >                           const char *id, const char *desc);
> > +
> > +    /**
> > +     * Callback for window visibility signalling.
> > +     *
> > +     * This callback function (if non-NULL) signals that the window is not
> > +     * visible anymore and should not be used for rendering after the end
> > of +     * this function until it is visible again. Typicaly use case of
> > this event +     * is when the application has been moved to the background
> > and should not +     * draw anything, or when the frames being sent to the
> > display won't be +     * used to display anyhting.
> > +     *
> > +     * \param visibility the new visibility state of the window
> > +     */
> > +    void (*visibility_changed)(struct vout_window_t *,
> > +                               enum vout_window_visibility visibility);
> >  };
> >
> >  /**
> > @@ -692,5 +717,13 @@ static inline void
> > vout_window_ReportOutputDevice(vout_window_t *window,
> > window->owner.cbs->output_event(window, id, name);
> >  }
> >
> > +static inline void
> > +vout_window_ReportVisibilityChanged(vout_window_t *window,
> > +                                    enum vout_window_visibility visibility)
> > +{
> > +    if (window->owner.cbs->visibility_changed != NULL)
> > +        window->owner.cbs->visibility_changed(window, visibility);
> > +}
> > +
> >  /** @} */
> >  #endif /* VLC_VOUT_WINDOW_H */
>
>
> --
> Rémi Denis-Courmont
> http://www.remlab.net/
>
>
>
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