Memory: rendered page canvases were never released, so flipping through a
document accumulated one supersampled canvas per page for the lifetime of the
page. Measured on a 30-page PDF this reached 174 MB and stayed there; the figure
grows linearly with page count, which puts a mid-sized catalogue past what a
mobile browser will tolerate. Pages outside a window around the current spread
now have their canvas released (dimensions zeroed so the backing store goes
immediately) and their placeholder restored. Same document now plateaus at
64 MB regardless of reading position.
Supersampling was pinned at 2x even on 1x displays, which costs four times the
memory of a 1x canvas for no visible gain there. It now follows the device pixel
ratio between 1.5x and 2x.
Startup: buildPageDescriptors() walked the entire document calling getPage() on
every page, including when spread splitting was disabled -- the default. On long
PDFs that is hundreds of sequential PDF.js round trips before the first paint.
The walk now happens only when splitting is actually on.
Rendering races: a resize landing while a page was rasterising left that page
with a canvas sized for the previous layout, marked as rendered and therefore
never corrected. Renders now carry a generation stamp and are discarded if the
layout moved underneath them, and the in-flight task is cancelled rather than
left to finish work that is already void. Not reproduced from outside -- the
window is narrow -- but the sequence is plain in the code.
Deployment: asset URLs were absolute from the web root, so the bundle broke
whenever Contao ran in a subdirectory. They now derive from import.meta.url.
Verified under /kunde/shop/ with no failed requests.
Assets moved from the template into the controller via TL_HEAD, keyed so several
flipbooks on one page emit one copy each, in the head rather than after the
content.
Also:
- Front-end strings were hardcoded German despite the bundle shipping de/en.
They now come from TL_LANG and reach the module as data attributes.
- Swallowed errors now reach the console; a failing PDF left no trace before.
- Canvas text is invisible to assistive technology: pages carry aria-labels and
the source PDF is offered as an equivalent download. Honours reduced motion.
- No teardown existed; destroy() plus a MummertPdfFlipbook API for AJAX pages.
- Pages deviating from the document's dominant format were stretched. The
layout ratio is now the median of a leading sample, with object-fit: contain.
- Aspect ratio, pointerdown stealing focus from buttons, single Audio element
cutting itself off on fast flips.
- Vendored PDF.js cmaps and standard fonts: without them, PDFs using CID
encodings or relying on the base-14 fonts render blank.
- Dropped pdf.min.mjs and pdf.worker.min.mjs -- byte-identical copies of the
.js files that nothing referenced (1.7 MB).
- Third-party licence texts were referenced but never shipped. Added, including
the separate Foxit and Liberation terms that come with the fonts. Recorded
that flipbook-js publishes no LICENSE file upstream.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
