One thing that confused me about this slide in particular is what we are considering a point for the endpoints of this line. Like are their coordinates measured in fractions of a pixel? If a pixel is not a unit size, how do we decide how 'large' (if that's the right word) a pixel should be?
@Log Good question. We'll discuss this kind of thing when we cover transformations (in a few lectures). Basically there are a bunch of different coordinate systems you might use while going through the rasterization pipeline. At the end of the day, of course, you do need to have some coordinate system along the lines of 1 pixel=1 unit, so that you can address the right location in memory. But this coordinate system might not be the one you want to work with at earlier stages of the pipeline (since, for instance, it will change depending on the size of your display/window).