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Raspberry pi 4 issue #HowTo #raspberrypi


mikebo21048
 

I have just recently setup a Raspberry pi 4 to run JMRI and xtrkcad. I built my pi using the JMRI Image produced by Steve Todd. I have found a problem using the model 4 that doesn’t exist on a pi3b. On the map, the area that is normally shaded to show the area of your layout that you are working, this area of the map is now blank. That portion of the layout is not visible on the map and if you move the blank area around the map it blanks out any area that it covers. It acts like it is erasing it from the map. If you close the map and reopen it, the blanked area reappears. Also, if you try to setup a print job, the area that would have been shaded as selected to print, is now blanked on the screen. This behavior is only occurring on my Raspberry pi 4. I put the memory card I am I using in in pi 4 in my pi 3b and it worked correctly.

Any help would be greatly appreciated,
Mike


Adam Richards
 

Mike,
I am by no means an expert in Pi, raspberry or otherwise, always thought it would be interesting to use one for running block telegraph equipment, though. 

Anyway - the likeliest culprit is the "screen"/drivers system for the 4 being different than the 3 in a library which I think is called Pi3D?  And it itself is an interface to OpenVG, perhaps?  The rectangle you are talking about is actually a transparent colored overlay, so that's where I would start trying to see what can be done. 

This complaint seems familiar ->  https://www.raspberrypi.org/forums/viewtopic.php?t=254790&p=1554370

Overall It seems like the color depth of the PI display is not the same as that of the Windows/Mac - and so transparent alpha values may not be mapped the same and choices may have been made for the sw platform that alter transparency in particular.   

Sorry I can't be of more help,
Adam


mikebo21048
 

I seem to have resolved the problem by disabling the legacy gl drivers. I have no idea what impact this may have on my system but I haven’t found any I’ll effects yet.

mike