houseplan-card/docs/PDF-EXPORT.md

PDF export

House Plan can save the current space as a one-page A4 architectural PDF. For administrators, the printer button appears in the card header between General settings and Help & feedback. The export is always a flat plan, even when the card currently uses the isometric view.

The PDF always contains the physical architecture: walls, partitions, columns, zero-thickness walls and door, window, gate and passage openings. Device markers, Home Assistant states, Glow, sunlight, vacuum trails, room colours and Zigbee topology are intentionally excluded.

The dialog can additionally include:

• room dimensions and clean floor areas;
• room names;
• furniture and other Background-editor decor;
• the current space backdrop, when one is configured.

The selected options are remembered in this browser. The export reads the current plan but never changes it.

The dialog is designed to remain usable down to a 320 CSS px-wide View area. It does not require horizontal scrolling; on narrow screens its actions stack vertically while retaining touch-sized controls.

Sheet and measurement rules

The output is a single A4 sheet. House Plan builds the complete print scene first — architecture, enabled dimensions, names, decor and backdrop — and then chooses portrait or landscape and the smallest standard scale that fits all of it. The complete scene is centred on the usable sheet, so optional content is not pushed into a fixed reserve or left outside the centred area. The footer shows the scale, a 1 m or 5 ft scale bar, a vector compass when north is configured, the date and the House Plan version. There is no architectural symbol legend.

For unusually large plans, House Plan continues the scale series in steps of 50 until the complete scene fits. If the architecture itself cannot fit on one A4 sheet at any scale, export stops with an error instead of producing a clipped file.

Physical walls, partitions and columns use a #7f7f7f base with a consistent 45-degree hatch. Openings remain clean cut-outs through both the base and the hatch. Zero-thickness walls keep the existing dashed print convention and are not hatched.

Areas use the same clean-floor geometry as the room information card. Internal dimensions follow the inner wall faces; external dimensions follow the outer physical outline. Only horizontal and vertical measurements are printed; genuinely diagonal edges are omitted rather than projected into misleading dimensions. Within one room contour or one connected outer ring, equivalent opposite measurements are shown once on the side with more free space. Equal lengths in different rooms, disconnected rings or unrelated walls are never deduplicated globally. Labels are centred on their measured wall and arranged in consistent lanes clear of the wall body. Units follow Home Assistant. Very short internal edges use a tick instead of unreadable text. A value that has no room beside its own wall is not printed at all: it is never pushed through a wall, a room name or an area, and it is not moved to a separate list beside the plan: a separate list would cost the drawing a whole step of the scale series and turn the sheet sideways.

For a rectangular step in an exterior facade, the chain retains enough horizontal and vertical values to reconstruct the outline: both neighbouring facade sections, the step height and one copy of its depth. An extension line may leave the physical corner to which it belongs, including a short collinear/solid prefix, but it is rejected if it touches architecture again after reaching free space. This narrow source-corner rule prevents both lost step dimensions and dimension lines drawn through another wall.

Images, fonts and limits

Backdrop and decor images are embedded locally in the browser. They are not sent to a conversion service. Embedded image data is limited to 25 MB; an unavailable image or exceeded limit stops the export and leaves the dialog open so the options can be changed.

Text uses an embedded subset of Roboto Regular covering the four House Plan interface languages. The bundled font is distributed under the Apache License 2.0; its license is stored in assets/fonts/LICENSE.

The resulting file is named houseplan-<space-name>-<YYYY-MM-DD>.pdf. Browser and Home Assistant mobile-app download handling determines its final Downloads location.

Implementation boundary

PDF export is a lazy read-only runtime (src/pdf/, lazyPdfFiles); View carries only the administrator trigger and the shared exact-build loader. It reads the already normalised current space through the same physical-geometry resolvers as View, produces one deterministic A4 document and never writes config or layout. Dimension input is normalised before collinear compaction and keeps only canonical horizontal/vertical edges; text bounds use the writer's real font metrics and transform; lanes test exact box/segment intersections against wall rings, never sampled points; parallel facade steps stay in independent collinear groups. Only exterior extension lines use the source-aware collision state machine; dimension lines, shelves, labels and internal dimensions stay on the strict path. Physical walls are even-odd clipped paths with a page-anchored hatch.