pdf-visual-diff/lib/pdf2png/pdf2png.js

Visual Regression Testing for PDFs in JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.pdf2png = pdf2png;
const fs = require("node:fs/promises");
const path = require("node:path");
const jimp_1 = require("jimp");
const types_1 = require("../types");
const conversions_1 = require("../conversions");
// pdfjs location
const PDFJS_DIR = path.join(path.dirname(require.resolve('pdfjs-dist')), '..');
const DOCUMENT_INIT_PARAMS_DEFAULTS = {
    // Where the standard fonts are located.
    standardFontDataUrl: path.join(PDFJS_DIR, 'standard_fonts/'),
    // Some PDFs need external cmaps.
    cMapUrl: path.join(PDFJS_DIR, 'cmaps/'),
    cMapPacked: true,
};
const pdf2PngDefOpts = {
    dpi: types_1.Dpi.High,
};
const PDF_DPI = 72;
function getPageViewPort(page, dpi) {
    const dpiNum = dpi === types_1.Dpi.Low ? PDF_DPI : dpi === types_1.Dpi.High ? 144 : dpi;
    const viewport = page.getViewport({ scale: 1.0 });
    if (dpiNum === PDF_DPI) {
        return viewport;
    }
    // Increase resolution
    const horizontalMm = (0, conversions_1.convertFromPxToMm)(viewport.width, PDF_DPI);
    const verticalMm = (0, conversions_1.convertFromPxToMm)(viewport.height, PDF_DPI);
    const actualWidth = (0, conversions_1.convertFromMmToPx)(horizontalMm, dpiNum);
    const actualHeight = (0, conversions_1.convertFromMmToPx)(verticalMm, dpiNum);
    const scale = Math.min(actualWidth / viewport.width, actualHeight / viewport.height);
    return page.getViewport({ scale });
}
function mkPdfPagesRenderer(pdfDocument, dpi) {
    return async function (toImage, toJimpInstances) {
        const images = [];
        const totalPages = pdfDocument.numPages;
        for (let idx = 1; idx <= totalPages; idx += 1) {
            const page = await pdfDocument.getPage(idx);
            const canvasFactory = pdfDocument.canvasFactory;
            const viewport = getPageViewPort(page, dpi);
            // @ts-expect-error unknown method on Object
            const canvasAndContext = canvasFactory.create(viewport.width, viewport.height);
            const renderParameters = {
                canvasContext: canvasAndContext.context,
                viewport,
            };
            await page.render(renderParameters).promise;
            images.push(toImage(canvasAndContext.canvas));
            page.cleanup();
        }
        return toJimpInstances(images);
    };
}
async function pdf2png(pdf, options = {}) {
    const { getDocument } = await import('pdfjs-dist/legacy/build/pdf.mjs');
    const opts = Object.assign(Object.assign({}, pdf2PngDefOpts), options);
    // Load PDF
    const pdfBuffer = Buffer.isBuffer(pdf) ? pdf : await fs.readFile(pdf);
    const loadingTask = getDocument(Object.assign(Object.assign({}, DOCUMENT_INIT_PARAMS_DEFAULTS), { data: new Uint8Array(pdfBuffer) }));
    const pdfDocument = await loadingTask.promise;
    const renderPdfPages = mkPdfPagesRenderer(pdfDocument, opts.dpi);
    return renderPdfPages((canvas) => canvas.toBuffer('image/png'), (images) => Promise.all(images.map((x) => jimp_1.Jimp.read(x).then((x) => x))));
}
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