html2deck

html2deck

What it does

Given an HTML page, html2deck renders it in headless Chromium at exactly 1280x720 (16:9), walks the page's top-level "units" (each --unit-selector match), projects a slide face (visual-first; excess prose → speaker notes), and decides — per unit — whether it fits on one slide or must be split. It then writes one PNG per slide, a contact sheet for approval, and finally a .pptx and .pdf.

Fixed title bar (PowerPoint-master style)

The heading is pulled OUT of the flowing content into a pinned top zone — same Y and same font size on EVERY content slide, like a PowerPoint master. Only the content below it (figure / table / lead) is scaled to fit; the title never moves or resizes from slide to slide. On a split unit the N / M part label sits top-right of that title bar.

Fit equation (hard — never overflow):

[ s_{\mathrm{fit}}=\min!\Big(1,\ \tfrac{H_c}{h},\ \tfrac{W_c}{w}\Big),\quad s=\begin{cases} s_{\mathrm{fit}} & h>H_c\ \min(s_{\max},,0.72,H_c/h) & \text{visual, under-filled}\ 1 & \text{otherwise} \end{cases} ]

Readability floors (0.90 / 0.80) decide whether to split, never whether to spill. Content is clipped in #__fit under the title; the title zone is z-stacked with an opaque background so transforms cannot paint over it. Content stays top-aligned under the title.

Title page exception: the first unit's first slide uses a PowerPoint title layout — title + optional lead stacked and centered on the full canvas (no pinned title bar). Never a graphic, table, card, or figure on a title page. If the opener needs a visual, the title page stays text-only and the visual lands on the next slide (master title bar), or under the next section header. The same title-page layout may be reused as a section header before a graphic-heavy unit — title alone (or title + one lead), then the chart/table.

Layout contract: best-fit equation

The height budget alone prevents overflow. Composition fit prevents awkward slides (sparse, text-walled, or chart-crushed-by-prose).