Le 31 janv. 2017 à 18:18, Bert Freudenberg <bert@freudenbergs.de> a écrit :

On Tue, Jan 31, 2017 at 10:44 AM, Christophe Demarey <christophe.demarey@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.

That seems wrong indeed, since BitBlt can only handle power-of-two depths currently. It should answer 32 or -32 in this case. 

Actually ... is there a difference in pixel layout for 32 bit MSB vs LSB forms? A quick test in SqueakJS suggests there isn’t.