[PATCH weston 08/12 v2] weston: Port Wayland backend to new output handling API

[Armin Krezović]

On 18.08.2016 12:31, Pekka Paalanen wrote:
> On Wed, 17 Aug 2016 19:49:06 +0200
> Armin Krezović <krezovic.armin at gmail.com> wrote:
> 
>> On 17.08.2016 17:07, Pekka Paalanen wrote:
>>> On Sun, 14 Aug 2016 17:28:17 +0200
>>> Armin Krezović <krezovic.armin at gmail.com> wrote:

SNIP

>>>> +static int
>>>> +wayland_output_configure_hotplug(struct weston_output *base)
>>>> +{
>>>> +	struct wayland_output *output = to_wayland_output(base);
>>>> +	struct wayland_parent_output *poutput = output->user_data;
>>>>  
>>>>  	if (poutput->current_mode) {
>>>> -		mode = poutput->current_mode;
>>>> +		output->poutput_mode = poutput->current_mode;
>>>>  	} else if (poutput->preferred_mode) {
>>>> -		mode = poutput->preferred_mode;
>>>> +		output->poutput_mode = poutput->preferred_mode;
>>>>  	} else if (!wl_list_empty(&poutput->mode_list)) {
>>>> -		mode = container_of(poutput->mode_list.next,
>>>> -				    struct weston_mode, link);
>>>> -	} else {
>>>> -		weston_log("No valid modes found.  Skipping output\n");
>>>> -		return NULL;
>>>> -	}
>>>> -
>>>> -	if (!wl_list_empty(&b->compositor->output_list)) {
>>>> -		output = container_of(b->compositor->output_list.prev,
>>>> -				      struct wayland_output, base.link);
>>>> -		x = output->base.x + output->base.current_mode->width;
>>>> +		output->poutput_mode = container_of(poutput->mode_list.next,
>>>> +						    struct weston_mode, link);
>>>>  	} else {
>>>> -		x = 0;
>>>> +		weston_log("No valid modes found. Cannot configure an output.\n");
>>>> +		return -1;
>>>>  	}
>>>>  
>>>> -	output = wayland_output_create(b, x, 0, mode->width, mode->height,
>>>> -				       NULL, 0,
>>>> -				       WL_OUTPUT_TRANSFORM_NORMAL, 1);
>>>> -	if (!output)
>>>> -		return NULL;
>>>> +	if (wayland_output_configure(&output->base, output->poutput_mode->width,
>>>> +				     output->poutput_mode->height) < 0)  
>>>
>>> If wayland_output_configure() multiplies by scale and applies
>>> transformation, then passing mode->width and mode->height directly here
>>> is wrong.
>>>
>>> The "video mode" is given in output pixels, so it is already multiplied
>>> by scale and rotated by transform.
>>>
>>> I see the old code was equally wrong, particularly if the output was
>>> rotated 90 degrees it would create a window with inverted aspect ratio.
>>> Ok, so if this keeps the old broken behaviour, it's fine.
>>>
>>> Testing the upstream x11-backend, it looks like we expect to put the
>>> logical output size (in global coordinates) in weston.ini, and then
>>> expect the scale and transform to be applied on that to get the output
>>> resolution in output pixels.
>>>   
>>
>> This is for parent output (fs shell and sprawl). You can't change the size
>> here. Scale and transform are also hardcoded to "scale = 1, transform = WL_OUTPUT_TRANSFORM_NORMAL"
>> (well, they used to be and I let them remain that way).
>>
>> See:
>>
>> https://cgit.freedesktop.org/wayland/weston/tree/libweston/compositor-wayland.c#n1148
>>
>> and:
>>
>> https://github.com/krezovic/weston/blob/gsoc-v10/compositor/main.c#L1545
>>
>> Those values are set just for sake of it, it's not that anything uses them.
> 
> Yes, but ideally we might use also the scale and transform from the
> parent output.
> 

But, if parent output was transformed, wouldn't that display the surface
just as it should be? Applying transform might further scale/rotate it. If
it were to be used for "show off" (in weston-info, for example), we could
do that. But I doubt we want any additional transformations if parent output
is already transformed.

So, for *_for_parent_output case, I've hardcoded transform and scale values
in the backend, just before calls to wayland_output_set_size().

> Those values are no longer hardcoded in this site here, which makes
> things harder to follow, and wayland_output_configure() does use them.
> 
> However, that doesn't really affect this patch. Except maybe needing a
> comment about scale and transform.
> 
> Btw. wayland_output_configure() forgets to apply transform, but that's
> how it was already.
> 

Backend functions don't do that. It's done in libweston, (current) weston_output_init, rather.

>>>> +		return -1;
>>>>  
>>>>  	output->parent.output = poutput->global;
>>>>  
> 
> 
> Thanks,
> pq
> 

Cheers.

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