[igt-dev] [PATCH i-g-t] tests/kms_plane_alpha_blend: Paint FBs with cairo source operator

[Wentland, Harry]

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>>
>>>
>>> However, this patch would still be needed since the fill will still be
>>> blended by default. When creating transparent or semi-transparent
>>> buffers they should be filled in with the cairo source operator or the
>>> alpha channel won't be set to the correct value.
>>
>> AFAICS if the dest alpha and color are both 0.0 the only fb that is
>> wrong is argb_fb_0 since the current code will in fact give us
>> alpha of 1.0. draw_squares() with OVER should still give us the
>> same results as we'd get with SOURCE.
>>
>> I guess this means any test which is currently using argb_fb_0
>> is definitely not testing per-pixel alpha.
>>
>> So argb_transparant() and basic_alpha() are simply useless atm?
>>
>> constant_alpha_min() sets pixel_blend_mode to None anyway so
>> doesn't really matter what we have in the alpha channel.
>>
>> Not sure why those tests aren't doing the gray_fb thing the other tests
>> are using...
>>
>> Anyways, no point in blending when you don't have to so
>> the patch seems to make sense to me either way:
>> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Thanks for the review. Like you said, the main problem is with argb_fb_0 
> and argb_transparent and basic_alpha but it's better to be explicit 
> about intent with the square filling too IMO.
> 

Merged.

> Nicholas Kazlauskas
> 

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