Implementation:Microsoft Playwright BidiPdf

Knowledge Sources	Microsoft_Playwright
Domains	BiDi, PDF
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for generating PDF documents from web pages via the WebDriver BiDi protocol provided by the Playwright library.

Description

The `BidiPdf` module provides the `pdfToBuffer` function that generates PDF content from a browsing context using BiDi's `browsingContext.print` command. It handles paper format resolution (letter, A4, legal, etc.), unit conversion (px, in, cm, mm to inches), margin calculation, and print options such as landscape orientation, background graphics, header/footer templates, page ranges, and scale. The `convertPrintParameterToInches` helper converts CSS-style dimension strings into inches for the BiDi print parameters. The module defines standard page paper formats matching common print sizes.

Usage

Use BidiPdf when generating PDF output from pages in BiDi-connected browsers, typically via `page.pdf()` in Firefox or Chromium-via-BiDi mode.

Code Reference

Source Location

• Repository: Microsoft_Playwright
• File: packages/playwright-core/src/server/bidi/bidiPdf.ts

Signature

export async function pdfToBuffer(session: BidiSession, params: channels.PagePdfParams): Promise<Buffer>;

Import

import { pdfToBuffer } from '../server/bidi/bidiPdf';

I/O Contract

Inputs

Name	Type	Required	Description
session	BidiSession	Yes	The BiDi session for the target browsing context
params	channels.PagePdfParams	Yes	PDF generation parameters (format, margins, scale, etc.)

Outputs

Name	Type	Description
buffer	Buffer	The generated PDF content as a Node.js Buffer

Usage Examples

import { pdfToBuffer } from '../server/bidi/bidiPdf';

const pdfBuffer = await pdfToBuffer(bidiSession, {
  format: 'A4',
  landscape: false,
  printBackground: true,
  margin: { top: '1cm', bottom: '1cm', left: '1cm', right: '1cm' },
});
await fs.promises.writeFile('output.pdf', pdfBuffer);

Related Pages

• Environment:Microsoft_Playwright_Node_Runtime_Environment