[Vm-dev] [Pharo-dev] pb with primitive #primitiveScreenDepth on Linux ?

Igor Stasenko siguctua at gmail.com
Thu Feb 2 20:57:04 UTC 2017

On 31 January 2017 at 11:12, Christophe Demarey <christophe.demarey at inria.fr
> wrote:

> Hello,
> With Pavel, we discovered a strange behavior of the primitive
> #primitiveScreenDepth on Linux. It returns a value of 24 bits per pixel
> (True colors) that looks valid but not supported (at least by Pharo).
> DisplayScreen actualScreenDepth "(calling the primitive screenDepth)"
>         => 32 on OS X [OK]
>         => 24 on Linux [KO]
> Also, it is not consistent with the primitive 91
> DisplayScreen new supportsDisplayDepth: DisplayScreen actualScreenDepth
>         => true on OS X
>         => false on Linux
> There are some safeguard image-side but it would be great if someone could
> check that vm side.
> Christophe.

IIRC in Pharo, we purposedly decided to support only single screen depth
internally for Display.
It is then the headache of VM driver to convert 32bpp to anything that
suitable to deliver it on screen.

The problem with this prim, is that it doesn't really tells you anything,
especially since Pharo started using SDL.
Also IIRC Squeak/Pharo doesn't forcing you to use native bitmaps (or only
those that supported
on platform it runs).

Best regards,
Igor Stasenko.
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