Thanks, I’ll take a look at your 2d viewer repo.
Yes, I mean the SVG viewport. I generally set that so that in a normal (not-zoomed) drawing, its size is 1:1 with the pixel size it is being rendered. The drawing may extend over a much larger area of which only a smaller viewport is being shown. If the zoom changes, then obviously the size will no longer be 1:1 with the pixels.