🐛 Fix font selector dropdown takes noticeably long to open when changing font

This commit is contained in:
Luis de Dios 2026-08-04 19:15:13 +02:00
parent 648c8e2152
commit b8a87cfea6
2 changed files with 46 additions and 34 deletions

View File

@ -137,10 +137,10 @@
;; uploads, ones that fail to bake) use the runtime fallback.
;;
;; The sprite is heavy (~2000 nodes), so we DON'T keep it in the DOM: the fetched
;; markup is cached here as a string (`:svg`) and the nodes are materialized only
;; while the picker is open (attach/detach below). `:ids` are the font ids it
;; covers, so the UI can pick sprite vs fallback.
(defonce preview-sprite (l/atom {:status :idle :ids #{} :svg nil}))
;; markup is cached here as a string (`:svg`) and the node is pre-parsed eagerly
;; (`:node`) so attaching is a cheap appendChild. `:ids` are the font ids it
;; covers (also pre-computed), so the UI can pick sprite vs fallback.
(defonce preview-sprite (l/atom {:status :idle :ids #{} :svg nil :node nil}))
;; Id prefix shared with the generator and the UI's `<use href>`; referenced here
;; rather than re-declared so the contract stays in one place.
@ -162,7 +162,7 @@
[]
;; :error → the UI shows plain names (no previews, no per-font load storm); a
;; later `prefetch-preview-sprite!` call can retry.
(reset! preview-sprite {:status :error :ids #{} :svg nil}))
(reset! preview-sprite {:status :error :ids #{} :svg nil :node nil}))
(defn- parse-sprite-svg
"Parse the cached sprite markup as SVG (not HTML, so no innerHTML injection
@ -176,10 +176,10 @@
root)))
(defn prefetch-preview-sprite!
"Fetch the font-preview sprite markup and cache it in memory (no DOM yet — see
`attach-preview-sprite!`). Idempotent: fetches only when nothing is cached yet
(`:idle`) or a previous attempt failed (`:error`); no-op while `:loading` or
`:ready`."
"Fetch the font-preview sprite markup, pre-parse it, and cache both the raw
markup and the parsed DOM node (with collected font ids). Idempotent: fetches
only when nothing is cached yet (`:idle`) or a previous attempt failed
(`:error`); no-op while `:loading` or `:ready`."
[]
(when (and (globals/browser?)
(contains? #{:idle :error} (:status @preview-sprite)))
@ -193,7 +193,20 @@
;; http/send! doesn't reject on non-2xx; guard so an error body isn't
;; cached as the sprite.
(if (http/success? response)
(swap! preview-sprite assoc :status :ready :svg (:body response))
(let [svg (:body response)
svg-el (parse-sprite-svg svg)]
(if-let [node (some-> svg-el (dom/import-node))]
(do
(dom/set-attribute! node "id" "font-preview-sprite")
(let [ids (collect-preview-ids node)]
(swap! preview-sprite assoc
:status :ready
:svg svg
:node node
:ids ids)))
(do
(log/wrn :hint "cannot parse font preview sprite")
(reset-preview-sprite-error!))))
(do
(log/wrn :hint "cannot load font preview sprite" :status (:status response))
(reset-preview-sprite-error!))))
@ -202,30 +215,22 @@
(reset-preview-sprite-error!))))))
(defn attach-preview-sprite!
"Materialize the cached sprite into the DOM (hidden) so rows can reference its
glyph groups via `<use>`, and record the covered font ids. Returns the injected
node (pass it to `detach-preview-sprite!` on close), or nil if not ready / the
markup is invalid. Parsing happens here, not on prefetch, so the cost is paid
only while the picker is open."
"Append the pre-parsed sprite node into the DOM (hidden) so rows can reference
its glyph groups via `<use>`. Returns the node (pass it to
`detach-preview-sprite!` on close), or nil if not ready. Parsing and id
collection happen once during `prefetch-preview-sprite!`, so this is just a
cheap appendChild."
[]
(let [{:keys [status svg]} @preview-sprite]
(when (and (globals/browser?) (= :ready status) (some? svg))
(if-let [node (some-> (parse-sprite-svg svg) (dom/import-node))]
;; The node already carries display:none + aria-hidden from the generator.
(do
(dom/set-attribute! node "id" "font-preview-sprite")
(when-let [body-el (unchecked-get globals/document "body")]
(dom/append-child! body-el node))
(swap! preview-sprite assoc :ids (collect-preview-ids node))
node)
(do
(log/wrn :hint "cannot parse font preview sprite")
(reset-preview-sprite-error!)
nil)))))
(let [{:keys [status node]} @preview-sprite]
(when (and (globals/browser?) (= :ready status) (some? node))
(when-let [body-el (unchecked-get globals/document "body")]
(dom/append-child! body-el node))
node)))
(defn detach-preview-sprite!
"Remove the sprite node injected by `attach-preview-sprite!` from the DOM. The
cached markup and `:ids` stay, so reopening re-attaches without a refetch."
cached markup, parsed node, and `:ids` stay, so reopening re-attaches without
a refetch or re-parse."
[node]
(dom/remove! node))

View File

@ -257,13 +257,20 @@
;; FLAG :font-preview — materialize the preview sprite into the DOM only while
;; the picker is open (markup is prefetched on workspace load), removing it on
;; close so its ~2000 nodes aren't kept around idle. Remove the flag clause to
;; drop the feature.
;; close so its ~2000 nodes aren't kept around idle. The attachment is deferred
;; so the dropdown can paint first with plain names, then the sprite swaps in
;; on the next tick. Remove the flag clause to drop the feature.
(mf/with-effect [sprite-status]
(when (and (contains? cf/flags :font-preview)
(= :ready sprite-status))
(let [node (fonts/attach-preview-sprite!)]
#(fonts/detach-preview-sprite! node))))
(let [node* (volatile! nil)
task (tm/schedule
(fn []
(vreset! node* (fonts/attach-preview-sprite!))))]
(fn []
(tm/dispose! task)
(when-some [n @node*]
(fonts/detach-preview-sprite! n))))))
(mf/with-effect [@selected]
(when-let [inst (mf/ref-val flist)]