Keyslide

Preview animated Beamer presentations while you edit. Open a .tex that uses the keyslide LaTeX package, run Keyslide: Open Preview, and every save rebuilds the deck into the side panel — keeping your slide position, keeping the last good render when a build fails (error banner + OUTPUT "keyslide"), and warning when variable fonts would make the HTML differ from the PDF.

Requires a local TeX Live (latex / dvilualatex) and a Ghostscript-enabled dvisvgm (brew install dvisvgm). The keyslide .sty is bundled and injected automatically. Limitation: only saves of the previewed file itself trigger a rebuild (\input parts do not).

Partial preview

Most saves only rebuild the frame that was actually edited since the last save — not the frame under the cursor, which stays wrong under Find&Replace, format-on-save, multi-cursor edits, and split-pane focus — and splice just that slide into the preview (only that one frame is typeset, faster than a full rebuild), showing a partial preview — only slide N is fresh badge. It automatically falls back to a full render, with a banner explaining why, on: unsupported constructs (\againframe, noframenumbering, \maketitle, \frame{...} shorthand, allowframebreaks — these produce slides with no matching \begin{frame} in the source or split one frame into several slides, breaking the mapping) or a partial build/splice failure (banner text partial preview unavailable (...) or partial preview could not splice — rendering the full deck). The first build, changes in frame count, no edit detected (e.g. a re-save with no changes), an edit outside any frame (e.g. the preamble) or spanning more than one frame (e.g. a multi-slide Find&Replace), and a partial build displaced from the queue by a newer save also fall back silently to a full render (expected behavior). If the partial build fails because of a LaTeX compile error, the full deck is not re-rendered — the last good render is kept with a red error banner, same as any other build failure. Forward search (Reveal Current Frame) stays cursor-based — navigation is exactly what the cursor is for. Both forward search and inverse search (Alt+click) share the same frame-mapping assumption and silently do nothing when the source scan can't be trusted against the built deck.

Commands and keybindings

Active only when the editor has LaTeX focus.

Inverse search: Alt+click a slide in the preview to move the cursor to its \begin{frame} line. A plain click is left alone for advancing the deck.

Present button

The preview's bottom-right ▶ Present button does a full render, writes a self-contained <name>.html next to the .tex (doubling as an export), and opens it in a browser. Nothing is written if the build fails. The exported HTML has no VS Code integration or Present button — it's the plain player.

Settings

Using alongside LaTeX Workshop

If the same .tex is also built to PDF by LaTeX Workshop, its save-triggered auto-build can compete with keyslide's rebuild. Add to the workspace .vscode/settings.json to build PDFs manually only:

{ "latex-workshop.latex.autoBuild.run": "never" }