Function buildSyntheticPdf

benchmarks/fixtures.ts:82–119

* Build a synthetic PDF with the given number of pages by copying * pages from sample.pdf. Each page gets unique text to simulate * real-world content variation.

(pageCount: number)

 * real-world content variation.
 */
async function buildSyntheticPdf(pageCount: number): Promise<Uint8Array> {
  const sourceBytes = await loadFixture(mediumPdfPath);
  const source = await PDF.load(sourceBytes);
  const sourcePageCount = source.getPageCount();

  // Start by copying the source pages
  const pdf = await PDF.load(sourceBytes);

  // Copy pages from source repeatedly until we reach the target count
  const pagesNeeded = pageCount - sourcePageCount;

  if (pagesNeeded > 0) {
    // Build an array of source page indices to copy in bulk
    const indices: number[] = [];

    for (let i = 0; i < pagesNeeded; i++) {
      indices.push(i % sourcePageCount);
    }

    await pdf.copyPagesFrom(source, indices);
  }

  // Add unique text to each page so content varies
  for (let i = 0; i < pdf.getPageCount(); i++) {
    const page = pdf.getPage(i);

    if (page) {
      page.drawText(`Page ${i + 1} of ${pageCount}`, {
        x: 50,
        y: 20,
        font: "Helvetica",
        size: 8,
      });
    }
  }

  return pdf.save();
}

/**
 * Get or create a synthetic PDF cached to disk.