MechPilotPDF export
MechPilot writes sheets as vector PDF: every line, arc, circle, ellipse, filled shape and text of the sheet becomes a PDF path or text object. Nothing is rasterised, so the file stays sharp at any zoom and prints at the size it was drawn.
The code is shared/pdf/index.ts (pdfFromPages), built on pdf-lib (MIT, pure JavaScript). It draws the same display primitives as the screen (shared/draw/primitives.ts), so the PDF shows exactly the geometry of the sheet on screen.
True scale
- One PDF page per sheet. The page size (MediaBox) is the paper size in mm converted with the exact factor 1 mm = 72/25.4 pt (an A4 landscape page is 841.88976… × 595.27559… pt).
- Coordinates are written with full double precision, never rounded: 1 mm on the sheet is 1 mm on paper. Print with "Actual size" (not "Fit to page") to keep the scale.
- Arcs and circles are cubic Bézier curves (at most 90° each) within 0.005 mm of the true circle; ellipses are fine polylines within 0.005 mm.
Black and line widths
- Everything is drawn in black: layer and screen colours are not printed.
- Line widths come from the line type (ISO 128-2). A width of 0 is printed as 0.13 mm, the thinnest line of the ISO 128-2 line-width series. Dashes are written in mm, at true scale.
Text and characters
- Text uses Helvetica, one of the 14 standard PDF fonts that every PDF reader has, so no font is embedded and files stay small. The font size is set so that the cap height equals the text height of the drawing (Helvetica cap height = 0.718 em), and alignment uses Helvetica's real character widths.
- Helvetica in a PDF covers the WinAnsi (Windows-1252) character set: Latin letters with accents and the drawing symbols Ø ° ± × µ are fine. A minus sign (−) is written as a hyphen, ⌀ as Ø, Greek μ as µ; any other character outside the set (Greek, Cyrillic, CJK, emoji, ≤ …) is printed as
?.
Metadata
Title, author and the creating application are written to the document information. Sheet titles appear as page labels in the reader. For tests and CI a deterministic mode gives byte-identical files (fixed dates, uncompressed content).