fix(studio): canvas selection, drag and resize correctness - #3146
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…ally paints under The box around a text layer inside the playground card stopped mid-word. The layer is 260px wide and paints 313, because its parent carries `scale(1.2)`, and the chrome read only the element's OWN transform. The top-left looked right, since the corners are anchored to the real bounding rect, so only the right and bottom edges fell short, by exactly 1/1.2. The same read decides whether to draw the box rotated at all, so an element whose parent is rotated got an upright box over a rotated one. The transform is now accumulated from the element up to the composition root. Only the linear part matters: each transform's origin contributes translation, and translation is already discarded by matching the corners to the element's bounding rect, so composing the matrices is enough and no per-ancestor origin has to be unpicked. The walk stops inside the composition document, because the canvas zoom lives on the iframe in Studio's own document and is applied separately. The fake DOMMatrix the geometry tests use gained the `multiply` it now needs.
… one assumed An element that had never been dragged skipped the movement measurement and took the canvas zoom as the whole screen mapping. Nothing above the element was considered, so any parent transform broke the drag: a card at rotationY 180 with scale 1.2 maps a rightward drag to -1.2x the zoom, meaning the text walked LEFT while the overlay followed the pointer, and the overlay only snapped onto the text at drop, when it re-measured. Measured on the live element in that card: one unit of drag offset moved it -0.757 px on x and +0.757 on y, where the skipped path assumed +0.631 on both. The measurement it skipped already handles this — it moves the element, watches where it lands, and inverts that, which is right for rotation, mirroring, scale and perspective alike. So the special case is gone and every drag measures. Same element after: a 120x80 pointer drag moves it 120.3x80.2. Rewrote the test that asserted the skipped path's identity matrix for an unmovable element. It now asserts the honest outcome: an element with no measurable movement is reported unmeasurable whether or not it carries a path offset, and the caller's existing fallback covers it.
…last one hovered Shift-click read the hover cache and used it without checking what it described. That cache is filled asynchronously as the pointer moves, so passing over one element on the way to another leaves it naming the element you left. The shift-click then added THAT element, and because the same branch prevented the default and set the suppression flags, the mousedown path that would have resolved the point correctly never ran. Multi-select looked like it grabbed things at random, or like it did nothing. Reproduced on the canvas with a trace: hover #card, shift-click #dot-b, and the group gained #card. Same gesture after: the guard rejects the cache, the mousedown path resolves the point, and the group gains #dot-b. The cache is still used when it is provably about the point clicked, including when it names a clip ancestor of the element there, so the fast path survives for the common case of clicking straight at something. Adds `hf-select-debug` (localStorage, off by default) recording which selection branch ran and what it decided, and pulls the flag/format shared with `hf-reload-debug` into one place rather than copying it.
The marquee built the group correctly and then threw it away. It announced only the primary to the timeline, and the timeline is the source of truth for what is selected: the sync back to the canvas saw one selected id against a group of several, decided the canvas was stale, and replaced the group with that single element a moment after the drop. Drag a box around four things, get one. The whole set is announced now, and the primary goes in as its anchor rather than as a new single selection, so the set it just joined survives. This is the same reason the single-select path already anchors with preserveSet. A test drives applyMarqueeSelection with two elements and asserts both reach the timeline; it fails against the old single-id announce.
Every canvas selection is mirrored onto the timeline, and the timeline syncs back — whatever it holds replaces the canvas selection a moment later. The mirror announced only the primary and anchored it with preserveSet, but preserving a set that does not contain the id empties the set, and an empty set syncs back as "nothing is selected". Adding a second element, or re-resolving a group after moving it, could therefore drop the whole selection rather than keep it. One helper now owns the mirror: publish the members, then anchor. A single selection keeps the previous contract deliberately, so a late async primary still cannot collapse a live group and a fresh click still collapses a stale one. The group re-resolve path also gains the ancestor id fallback the other callers already had — without it a member with no direct timeline row resolved to null and deselected everything. Two tests: a second element joining a selection, and a marquee, both assert the full set reaches the timeline. Both fail against the announce-the-primary-only version.
A drag that jumps is a position that changed without the pointer asking for it, and nothing on that path says anything today, so the frame it diverges can only be guessed at. `hf-drag-debug` (localStorage, off by default) records the whole gesture: the mapping and start position each member got, the pointer delta against the delta actually applied on every eighth move, what each member was told to commit, and where they all sit at the drop, once the commit resolves, and 120/400/900ms later. That last group is the point of it. The source write, the preview reload and the timeline resume all land within a few frames of the drop, and any of them can put the elements back where they started before the new position arrives — a snap-back shows up as a settle sample reverting to the gesture-start reading. A gap between `pointer` and `applied` instead means snapping pulled the group off the cursor, which is a different fault with a different fix.
The drag trace showed the group landing exactly where it was dropped and staying there — no snap-back at any settle sample, and the pointer and the applied delta never more than 2px apart — but two milliseconds after the drop the selection was cleared with seven members still in it. The clear comes from the timeline sync deciding the timeline holds nothing, and that branch said nothing. It says so now, along with whether it is about to act on it. The mirror alongside it reports how many members it managed to publish and whether the anchor was among them, because a member with no timeline row of its own resolves to null and is dropped silently — publish none and the sync reads it back as an empty selection.
After a move the preview re-syncs and the selection is re-resolved against the new document. When the primary could not be found there, both re-resolve paths cleared the entire selection — so a group of five, all still on screen, was deselected because one of them failed to resolve. The trace showed the clear landing 600ms after the drop with five members still held, and the timeline sync running afterwards on an already-empty canvas, which ruled it out as the cause. A live group now re-resolves as a group and keeps whoever survived, picking a new primary from them; it only clears when nobody did. That is what refreshDomEditGroupSelectionsFromPreview was written for — it existed and was never called. Both clears also say which one they are and how many members were held, so if this is not the last of it the next trace names the path immediately.
… that breaks away A link to a bug hit with several elements selected only reproduced one of them, so the report read as "works for me". The hash now carries the rest as selGroup and reopens the whole selection; members whose element is gone are dropped rather than failing the others. Verified end to end in a real browser: select three, copy the hash, open it fresh, the same three come back. The drag trace also gains a rigidity check. A group moves as one object, so every member travels the same distance; one that does not IS the fault. Drift was being computed but only printed on every eighth frame, which is exactly how a single-frame divergence hides — it now prints on the frame it happens. The frame handler moves to its own module on the way past. It had grown a snap block and a trace block inside a function already juggling four gesture kinds, and it was over both the complexity and file-size gates. Not fixed: the jump itself. Two headful runs driving a real group drag showed the members staying rigid to the pixel, at the drop and 900ms after, so I have not reproduced it yet and will not guess at a fix.
…ed yet Your log caught it on the first frame of the drag: pointer "0,0", applied "4,-3", and all four members jumped 12,-8 composition px before the pointer had moved at all. An element resting within the 6px snap threshold of a guide is already snappable, so the snap computed on frame one closes that gap immediately — picking the selection up moves it. Snapping now sits out until the gesture has travelled the same 4px a drag needs to count as a drag rather than a click, on both the group and single-element paths. Nothing below that distance moves anything, and a real drag snaps exactly as before. The test builds a box resting 4px from a guide and asserts the ungated call still returns dx 4 — the very displacement from your log — while the gated one returns 0 for a pointer that has not moved.
Your Jam confirmed the first-frame jump is gone — pointer "0,0" now reads applied "0,0" — and caught what was left: two milliseconds after each drop, a `[hf-select] clear` with the group still holding three, then four members. Every pointerup trails a click. The group gesture ref is cleared before the commit runs, so by the time that click arrives the box no longer looks busy and it reaches the canvas as an ordinary click — landing in the gap between the members, resolving to nothing, and clearing the selection the drag just moved. The under-threshold path already ate that click; the committed path never did. The flag is now set before the two paths diverge, so neither can forget it. The test drives a real pointerup through the handlers and fails on the committed path with the flag moved back down.
…the frame An element dragged past the edge sits out in the grey, and the rubber band refused to start there — it only began when the press landed inside the composition rect. The one gesture that could reach those elements could not be begun near them, so the timeline was the only way to select something plainly visible on screen. The collecting half never had that limit: it compares rects in overlay space and never clipped to the frame, so those elements have always been selectable once the band could begin. Only the start gate had to go. A press in the grey that never travels still commits an empty selection, which is the deselect it used to be, so the old behaviour of clicking out there to clear is unchanged.
The selection work above pushed four files past the 600-line gate. Same split the branch made later, landed with the changes that caused it.
Dragging several elements at once and dropping them made one of them snap back to where it started for a frame or two, then jump forward again. Each member of the group is written separately, and every write patched the live GSAP tween in place and then seeked the player. A seek re-renders the WHOLE timeline, not the tween that changed, so the members still queued behind that write got repainted from their un-patched tweens: back to their pre-drag position, where they sat until their own write landed. Only members whose tween actually renders at the playhead showed it, which is why a group of three flashed one element and left the others still. The group commit now defers the seek for every member but the last, so the queued members keep the transform the gesture left on them and the whole group repaints once, from the fully patched timeline.
Dragging N elements cost N writes and 9 reads for a three-element group: each member fetched the composition's parse to preflight, fetched it again to resolve its tween, then wrote the file on its own round trip. Every one of those writes re-read, re-parsed and re-serialized the whole composition. Three changes, same behaviour: - The parse endpoint shares an in-flight request per file, so callers asking for the same composition at the same moment get one request. Only overlapping calls share — the entry is dropped as soon as it settles, so a read after a write still gets a fresh parse. - The group preflight runs its members together instead of one at a time. A preflight writes nothing, so there is nothing to order. - Members' mutations are queued and sent as one batch write. Anything that re-reads the file flushes the queue first, so a member resolving a shared or stale tween never reads a composition missing writes it is about to build on. The batch carries each member's runtime patch, and only the last one re-renders. A three-element group drag now issues 2 reads and 1 write, down from 9 and 3.
Resizing the card commits correctly — the source and a fresh load both read 273x181 — but 200ms after the drop, mid-commit, the element renders at 395x261 with the studio size vars still holding 273x181. Something writes the pre-gesture size back inline while the reload is still in flight, and every writer of that size was silent. Both are traced now under the existing hf-resize-debug flag, each with the size going in, the size being replaced, and a short stack. Restoring the pre-gesture size is right on a cancel and wrong after a successful commit, and the function doing it cannot tell the two apart from the inside — so the caller has to be named before this can be fixed at the right end.
Your log caught it across two resizes. The first commits 305x202 and the element is 305x202 at the drop; 200ms later it renders 395x261, its stylesheet size, while --hf-studio-width still reads 305. The second gesture then starts with `actual` at 305 against a live box of 395, and its very first move — a pointer delta of 0.1px — snaps the element back to 305. That snap is the jump. The gap belongs to the soft reload: it reverts the old timeline before building the new one, and GSAP hands back each tween's recorded starting width on the way out. Nothing held the size in between, because the seek reapply that exists for exactly this stands aside for elements GSAP animates. Standing aside is right for the offset — those channels compose, and applying both doubles the move — and wrong for size, where both channels write width and height so the later write simply wins on the same committed number. It applies now. Only an element mid-edit carries the vars, so nothing else is touched. A test seeks an element whose size GSAP owns after the revert put the stylesheet size back, and fails with the skip restored.
Selecting a rotated element drew upright dashed boxes across its children: the chrome co-rotated with the element and the child outlines did not, so a text layer inside a rotated card got a square outline lying across the rotated glyphs. The chrome already measures an oriented box; the child outlines were still measured axis-aligned. They now use the same oriented measurement and render with the same rotation. An unrotated element measures identically to before, since the oriented rect returns the plain bounding box at angle 0.
This was referenced Aug 9, 2026
This was referenced Aug 9, 2026
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What
The three bugfix seams from the #3137 stack, landed together: canvas selection (#3138), drag correctness (#3139) and resize hold (#3140). Same commits, on a branch that is not part of a GitHub stack.
Why
GitHub refuses base retargeting and admin merge on a stacked PR — the only endpoint it permits is the asynchronous merge, which does not apply the ruleset bypass. The three PRs are reviewed and green but cannot be landed in place.
How
Nothing here is new. This branch is
stack/resize-holdrebased onto main after #3137 merged: 26 commits covering multi-selection (shift-click, marquee, timeline sync, share URLs), drag correctness (the group-drag jump, one batched write per drag), the resize size-hold, and the child-outline rotation fix. It contains no rich-text feature files — the feature half stays in #3141-#3144.Test plan
Supersedes #3138, #3139 and #3140, which are closed in favour of this.