I've been trying to do some precision graphic work and have come across a problem that's been bugging me, so I hope someone can help.
I've attached a sample screenshot, an example PDF, and the original SLA.
When placing some coloured blocks next to and on top of other coloured blocks there is sometimes a visible gap or line where they "touch" even though the blocks are positioned with exact coordinates and sizes.
If you look at the PDF you can see a blue line "poking through" between the top green blocks and a green one between the right-hand blue blocks. However, if you look at the SLA, you'll see that the positions and sizes of the blocks are such that there shouldn't - in common sense terms - be a gap.
Also, at certain zoom levels the problem disappears but it comes back when zooming further in. The same effect occurs both in Scribus and some of my PDF readers. (Adobe reader looks to be better than others.)
Can anyone explain why this happens?
(I've a feeling it's got something to do with floating point arithmetic precision and differences in rendering mechanisms but that's just a guess.)
And, more importantly, can anyone give me a good - easily achieved - solution or work-around that will work both on-screen and when printed so that the "gap" won't appear?
Or is this just one of those things that we've got to live with?
(Obviously in this simple scenario I could just create a big green block and put a smaller blue block over the top of it but that won't work for more complex work. Or at least I don't want to have to put the effort in to create lots of bespoke shapes.)