Add-line seems to sometimes not render line at all.

[dbp]

See the following examples.

[rushsangs]

I changed the x2 for the line and both the start and end changed.

[dbp]

Some testing makes it seems like the arithmetic for add-line is very bizarre, if not just wrong. scene-line seems to work as expected?

[jpolitz]

Thanks for reporting – @blerner is this about pinholes? Seems like the added line (a) calculates its length and angle, then treats that as an image, then (b) overlays that on the background with x1, y1 as the pinhole offset from the center of the background.

[blerner]

Probably, yes. Or rather, that function just looks pretty weird at the moment... I can't even figure out where in the commit history that function's behavior changed, though...

[blerner]

My first instinct is to change the (0,0) at this line (https://github.com/brownplt/pyret-lang/blob/horizon/src/js/trove/make-image.js#L821) to be (x1, y1) -- I'm not at my laptop right now in a state to work on this, but that seems like a quick 1-line fix to try first