Doesn't work for 28x14 panels

[rgweaver]

This library is great and I appreciate you sharing it. But I'm getting some errors, which I'm pretty sure boil down to the fact that the library presumes each panel is 28x7, or at least that the height is exactly 7.

Unfortunately this isn't the case for my display, which is comprised of 18 panels, each 28x14 pixels. (These are AlfaZeta panels -- the XY5 comes in multiple sizes.) My configuration is 3 rows and 6 columns, such that the entire display is 28x3 = 84 pixels wide and 14x6 = 84 pixels high.

I know that the display.Display object allows you to specify arbitrary configurations so long as the panels (and the overall display?) are rectangular. But it looks like other aspects of the code require each panel's height to be 7. For example:

• sim.DisplaySim.update warns you if h is not 7, and contains the comment "note that h should always be 7".
• display.Display.to_bytes similarly warns you if h isn't 7.
• In that same to_bytes() function, I'm getting a ValueError from result.append(b) because my "byte" is out of range. In fact the value it's trying to append is 8192.

From your Readme file, I gather the essence of the problem is contained in your description of the underlying control protocol: "Essentially each column of 7 pixels (in a 7x28 board) is a controlled by a single byte, using the lower seven bits." Obviously you can't represent a 14-bit column in a single byte. Presumably for the 28w x 14h panels the protocol uses two bytes for each column, ignoring the highest bit of each.

Anyway, I'm not expecting you to update the library right away to enable the use of 28x14 panels. But I'd be grateful if:

1. You can confirm I'm on the right track here, and not screwing something else up.
2. You can provide any guidance (general and specific) on how one might modify the library to support 28x14 panels. (I could probably get there eventually, but alas I am an intermediate coder at best.)
3. If you do want to go ahead and update the library to support 28x14 panels, that would be amazing.