[solved] Demo's "U-mapper" uses wrong order. how to swap?

1

According to the docs, the “U-mapper” assumes this config when using 4 panels:

So the following chain (Viewed looking at the LED-side of the panels)
    [<][<][<][<] }- Raspbery Pi connector

is arranged in this U-shape (on its side)
    [<][<] }----- Raspberry Pi connector
    [>][>]

I am using this, where the first two panels are at the top and the other two below.

However, when I run the “-D0” demo, the image is so that the upper and lower panels are vertically reversed. Instead of seeing

 /\
 \/

I see:

 \/
 /\

Which means that the demo uses the first 2 panels as the last 2.

Is there a way to fix this, without (a) changing the panel arrangement and without (b) changing the code?

I don’t think so, but I wonder if others have run into this as well?

2

Huh - as usual, you just have to formulate the question and the answer comes on its own :grinning_face_with_smiling_eyes:

I have to use: “Rotate:180;U-mapper”

3

Oh, I’m glad that worked, but there are indeed combinations where re-wiring/re-ordering panels is the way to go.
while what you have works, if you physically reorder/rotate the panels and wiring, you can avoid the rotate which does add extra compute work, and in some cases, will make things slower in a way that is visible (it’s more true for bigger displays than yours that is small, so it may be ok as is)