On 31 January 2017 at 11:12, 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.

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).