several bugs found via in-browser debugging, all in lightbox.js + the
blur-up CSS:
1. DOMRect attribute mismatch: getBoundingClientRect returns .width/
.height, but code read .w/.h -> NaN transforms. map rectOf() to a
uniform {x,y,w,h}.
2. zoom scale base was the huge original natural size (2942px), so the
centered state collapsed to a tiny scale and the open animation ran
backwards (shrink). base the scale on originRect instead: first
frame is the in-article image at scale 1, centered state scales to
target.w/originRect.w. open is always grow, close always shrink.
3. scroll-to-close fired on a phantom scroll jump: the oversized
original img (layout size = naturalW) expanded the document's
scrollable area. set img layout size explicitly and add
overflow:hidden on the (position:fixed) overlay so the img cannot
expand the body.
4. first open animation jumped from the wrong position: a single rAF
was not enough to commit the no-transition first frame. use a forced
reflow (offsetHeight) + double-rAF before starting the transition.
5. blur-up full layer stuck at opacity 0 until a forced reflow (opening
the lightbox) repainted it. drop the opacity transition on .blur-img-
full and set opacity:1 from JS on load (deterministic, no repaint
race). mark the container .is-loaded and hide the placeholder via
the container class.
6. a 16px grey gap above in-article images: .md-content img { margin:
1rem 0 } applied to the absolute .blur-img-full too, pushing it
down. reset margin:0 / max-width:none on the blur-up img layers.
xfy
8bdc3553bd