Aligning Zynthian Touchscreens

So you have your zynthian and the display works . . .

But what if your pointer moves left and your cursor goes up...?

Well hopefully this will act as a repository of knowledge for these sorts of problems.

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Well firstly you are going to need to modify files within your zynthian's file system to adjust these things.

predominately files that look like this . . .

The location reveals a little it's within the directory.

/etc/X11/xorg.conf.d/

with this sort of structure....

These are all the files that deal with the X Windows system which is how keyboard, mice, touchscreens, trackballs et al talk to Zynthians and how Zynthians talk back to screens be they great big hdmi one's or tiny touchscreens you need a pin to operate.

What's in these files is defined [1] in ALL it's gore...

But we just want to get a touchscreen the right way up.

Well we need something called a transform matrix, there is one in the screen above.. . .

Its a list of 9 numbers, more frequently laid out in a 3 * 3 grid

 0   1   0
 1   0   0
 0   0   1

for the example above.

This is a way of laying out some numbers that is easily processed by the sort of worlds tht worry about rotating, transforming, scaling, shifting, skewing and goodness knows what other forms of distortion one can apply to a flat surface.

But on startup we really don't have too much in there ...