Amey-Thakur PDF generation
PDF is a fixed-layout format, which makes it excellent for documents that must look identical everywhere and awkward for content whose length varies. Most generation bugs are page breaks and fonts.
Method
- Choose the approach by document complexity. HTML rendered to PDF suits document-like output and reuses web skills; a PDF library suits precise layout and forms.
- Embed fonts explicitly. A font available on the developer's machine and missing on the server produces silently substituted output (see format-selection).
- Design for variable content length. Tables that span pages need repeated headers, and fixed positioning breaks the moment content grows (see text-expansion-layout).
- Control page breaks deliberately. Keep headings with their content and avoid orphaned rows, since default breaking produces documents that look careless.
- Generate asynchronously for anything large. PDF rendering is slow enough that it belongs in a queue rather than a request (see media-processing-queue).
- Make it accessible where it matters. Tagged structure, reading order, and text rather than images of text, which is a legal requirement in many contexts (see accessibility-review).
- Store the rendered file, not just the data. Regenerating an old document from current templates produces something different from what was issued (see invoicing-and-receipts).
Boundaries
PDF is fixed layout and reads badly on small screens, so it is often the wrong choice for content that could be a web page. Rendering engines differ in support, particularly for newer CSS. Extracting data back out is unreliable (see document-parsing).