A slideshow template is the Playback (not "prepare previews"), Layout /
Options / Backdrop, Overlays and Titles settings as one versioned JSON
document (format lightcraft.slideshowTemplate, version 1).
- Engine: slide_template (SlideLook, Template, built-ins, user template
files in <settings>/slideshow-templates read through each section's own
merged() validation; size and count caps; newer versions refused; bad
files reported and skipped; file names sanitised so ids never leave the
folder). Applying replaces the four settings in one step and keeps the
replaced ones as "previous" for the session (prefs have no undo).
- Five built-ins of our own: Plain Black, Gallery Wall, Edge to Edge,
Cinema Wide, Shooting Data (no Lightroom names or designs, no images).
- Commands slideshow.templates.list/apply/save/update/rename/delete/
import/export; slideshow.preview {template} previews without applying.
- UI: Template Browser at the top of Settings > Slideshow (built-in, user,
previous settings; click applies, hover previews on the selected photo,
right-click update / rename / export / delete; save and import), file
dialogs on the desktop; strings in the nine locales.
- Docs: parity row (partial), whats-new, control protocol and MCP.
- Engine: slide_overlay (OverlaySettings in prefs.json, the new slideshow.overlays
command): identity plate (text, or a PNG/JPEG file with its transparency; size,
colour, opacity; render behind image), rating stars (own vector stars), up to 16
text overlays with tokens ({caption}, {exposure}, {file}, {date}, {focal}… plus
every rename token; unknown tags show as typed and are reported) and a drop
shadow, each at one of nine anchors of the slide or photo plus an offset, kept on
the slide; the export watermark on the photo. Sizes relative to the slide's
shorter side; validated and clamped.
- Drawn by the engine as a second pass over lightcraft_slideshow::compose_with
(new behind hook for "render behind image"); the watermark's text renderer moved
to engine text.rs (TextLayout, Inter + craft-fonts CJK) and is shared; glyphs
off the image are skipped so huge text stays cheap.
- rename::expand_tokens_with lets overlays add tokens without changing rename.
- Playback composes slides when overlays are on; slideshow.preview returns each
overlay's box. Settings > Slideshow > Overlays section with live preview.
- Docs: parity row (partial), whats-new, control/MCP docs, nine locale catalogs.
- Tests: tokens, nine anchors, star count, plate image opacity and missing file,
text shadow, resolution independence, hostile input, big-slide cost, CJK with
craft-fonts, prefs persistence, preview and headless playback pixel checks.
- New crate lightcraft-slideshow (L1, no UI): SlideSettings (margins linked or
independent, guides, aspect preview, zoom to fill, stroke border, cast shadow,
backdrop colour, colour wash, background image; lengths relative to the slide's
shorter side; validated and clamped) and a CPU compose() used by playback, the
Settings preview and slideshow.preview.
- Engine: slideshow.layout (partial merge, saved in prefs.json) and
slideshow.preview {id?, width?, height?, path?} (PNG to path or base64);
RenderJob::with_slide composes on the render worker; the background photo is
rendered once and shared.
- Playback: with a non-default layout each slide is the composed screen-sized
slide, prepared ahead like before; the default layout plays as before.
- Settings > Slideshow: Layout, Options and Backdrop sections and a debounced
live preview of the active photo's slide (with margin guides).
- Tests: composer geometry/pixels/hostile input, command get/set/persist/preview,
headless playback of a composed slide and of the default layout.
Jason Baldwin