[PATCH wayland] cursor: add wl_cursor_frame_and_duration

[Pekka Paalanen]

On Tue,  3 Mar 2015 15:24:13 -0600
Derek Foreman <derekf at osg.samsung.com> wrote:

> It's useful to know how long the current cursor frame should be displayed
> so we can wait that long to change it.
> 
> Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
> ---
> 
> In a follow up weston patch I use this to let toytoolkit set the cursor
> with a timerfd instead of using a frame callback.
> 
>  cursor/wayland-cursor.c | 29 ++++++++++++++++++++++++++---
>  cursor/wayland-cursor.h |  4 ++++
>  2 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/cursor/wayland-cursor.c b/cursor/wayland-cursor.c
> index dba3b51..d5c8221 100644
> --- a/cursor/wayland-cursor.c
> +++ b/cursor/wayland-cursor.c
> @@ -458,22 +458,28 @@ wl_cursor_theme_get_cursor(struct wl_cursor_theme *theme,
>  }
>  
>  /** Find the frame for a given elapsed time in a cursor animation
> + *  as well as the time left until next cursor change.
>   *
>   * \param cursor The cursor
> - * \param time Elapsed time since the beginning of the animation
> + * \param time Elapsed time in ms since the beginning of the animation
> + * \param duration pointer to uint32_t to store time left for this image

I think you'd want to document the special duration time of zero
meaning "forever", right?

>   *
>   * \return The index of the image that should be displayed for the
>   * given time in the cursor animation.
>   */
>  WL_EXPORT int
> -wl_cursor_frame(struct wl_cursor *_cursor, uint32_t time)
> +wl_cursor_frame_and_duration(struct wl_cursor *_cursor, uint32_t time,
> +			     uint32_t *duration)
>  {
>  	struct cursor *cursor = (struct cursor *) _cursor;
>  	uint32_t t;
>  	int i;
>  
> -	if (cursor->cursor.image_count == 1)
> +	if (cursor->cursor.image_count == 1) {
> +		if (*duration)
> +			duration = 0;
>  		return 0;
> +	}
>  
>  	i = 0;
>  	t = time % cursor->total_delay;
> @@ -481,5 +487,22 @@ wl_cursor_frame(struct wl_cursor *_cursor, uint32_t time)
>  	while (t - cursor->cursor.images[i]->delay < t)
>  		t -= cursor->cursor.images[i++]->delay;
>  
> +	if (duration)
> +		*duration = cursor->cursor.images[i]->delay - t;

This can never produce zero duration, right?

I think it can't, and it's certainly logical to never produce zero, but
I didn't rigorously think it through. So, we don't accidentally hit the
special zero here.

> +
>  	return i;
>  }
> +
> +/** Find the frame for a given elapsed time in a cursor animation
> + *
> + * \param cursor The cursor
> + * \param time Elapsed time in ms since the beginning of the animation
> + *
> + * \return The index of the image that should be displayed for the
> + * given time in the cursor animation.
> + */
> +WL_EXPORT int
> +wl_cursor_frame(struct wl_cursor *_cursor, uint32_t time)
> +{
> +	return wl_cursor_frame_and_duration(_cursor, time, NULL);
> +}
> diff --git a/cursor/wayland-cursor.h b/cursor/wayland-cursor.h
> index c7548ae..c3884a0 100644
> --- a/cursor/wayland-cursor.h
> +++ b/cursor/wayland-cursor.h
> @@ -63,6 +63,10 @@ wl_cursor_image_get_buffer(struct wl_cursor_image *image);
>  int
>  wl_cursor_frame(struct wl_cursor *cursor, uint32_t time);
>  
> +int
> +wl_cursor_frame_and_duration(struct wl_cursor *cursor, uint32_t time,
> +			     uint32_t *duration);
> +
>  #ifdef  __cplusplus
>  }
>  #endif

With that one documentation bit fixed:
Reviewed-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>


Thanks,
pq