Compose PDFs

Register source PDF bytes under a name before appending, inserting, or overlaying pages. Synchronous registration accepts Uint8Array and ArrayBuffer; use registerPdfAsync() for Blob or File.

import { createRecipe } from "@muhammara/wasm";

var Recipe = await createRecipe();
var sourceBytes = new Recipe()
  .createPage(300, 200)
  .text("Source page one", 36, 48)
  .endPage()
  .createPage(300, 200)
  .text("Source page two", 36, 48)
  .endPage()
  .endPDF();

Recipe.registerPdf("appendix", sourceBytes);
var recipe = new Recipe()
  .createPage(612, 792)
  .text("Cover", 72, 72, { size: 30 })
  .overlay("appendix", 72, 140, { page: 1, scale: 0.75 })
  .endPage()
  .appendPage("appendix", 2)
  .insertPage(0, "appendix", 1);

var pdfBytes = recipe.endPDF();
Recipe.unregisterPdf("appendix");

Recipe composition page numbers are one-based. Omit the second appendPage() argument to append every page. A number selects one page; arrays select pages and nested pairs select inclusive ranges. For example, [1, 3] selects pages 1 and 3, while [[1, 3]] selects pages 1 through 3. Selections must be positive integers, ranges must be ascending, and endpoints beyond the source clamp to its final page.

insertPage(afterPageNumber, name, sourcePageNumber) accepts zero as the output position before page one and defers rebuilding until endPDF(). overlay() requires an active created or edited page and supports page, scale, fitWidth, fitHeight, and keepAspectRatio. To place a page like an image, with alignment, rotation, or a frame, pass the registered name to image(); see Place and Transform Images.

Split Into Byte Outputs

split(prefix) ends the Recipe and returns one named Uint8Array per page. It does not write an output directory.

import { createRecipe } from "@muhammara/wasm";

var Recipe = await createRecipe();
var parts = new Recipe()
  .createPage(200, 200)
  .endPage()
  .createPage(200, 200)
  .endPage()
  .split("chapter");

for (var part of parts) {
  console.log(part.name, part.bytes.byteLength);
}

Appending or rebuilding a source page does not retain its existing /Annots graph. Recipe-created annotations in their own output are preserved. See Differences And Restrictions.