Add rotating background image to letters

[jo-elimu]

Improve readability when light gameplay background.

Experiment with different levels of opacity and colors for making the contrast as good as possible.

[yorugac]

It seems to me that this issue is dependant on what should be considered as acceptable size of the letters. Right now letters are slightly overlapping each other when they are arranged as triples:

Is that acceptable?

When adding background image to letters, images can create additional overlaps in triples. If background image for letters is of the same size as original zap image, then overlap of background images in triples is negligible though letters themselves still overlap, like in this example:

If background image is made larger, to fit the size of current letters and to improve readability, that will create additional overlaps of background images in triples too.

Downsizing letters will allow to avoid these overlaps but will also make them harder to see / recognize. Some middle ground must be found. Can we downsize letters here and how much?

[jo-elimu]

@yorugac It would be preferred to not reduce the current size of the letters. Is there any way we could increase the minimum spacing between letters when they are grouped together?

[yorugac]

@jogrimst Positions of orbs are hard-coded in levels description. So in order to increase that spacing, either manually alter levels or add some method attempting to locate "triples" and change positions during loading of the level.

There are 10 levels total, I wonder what original authors used to generate them.