pdfcpu & wasm update, server side functions init, README.md, CONTRIBUTE.md

functions/extractPages.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+
+export const extractPages = async (snapshot, pagesToExtractArray) => {
+    const pdfDoc = await PDFDocument.load(snapshot)
+
+    // TODO: invent a better format for pagesToExtractArray and convert it.
+    return createSubDocument(pdfDoc, pagesToExtractArray);
+};
+
+export async function createSubDocument(pdfDoc, pagesToExtractArray) {
+    const subDocument = await PDFDocument.create();
+
+    // Check that array max number is not larger pdf pages number
+    if(Math.max(...pagesToExtractArray) >= pdfDoc.getPageCount()) {
+        throw new Error(`The PDF document only has ${pdfDoc.getPageCount()} pages and you tried to extract page ${Math.max(...pagesToExtractArray)}`);
+    }
+
+    const copiedPages = await subDocument.copyPages(pdfDoc, pagesToExtractArray);
+
+    for (let i = 0; i < copiedPages.length; i++) {
+        subDocument.addPage(copiedPages[i]);
+    }
+
+    return subDocument.save();
+}

functions/impose.js

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+import * as pdfcpuWraopper from "../public/wasm/pdfcpu-wrapper-node.js";
+
+export async function impose(snapshot, nup, format) {
+    return await pdfcpuWraopper.oneToOne([
+            "pdfcpu.wasm",
+            "nup",
+            "-c",
+            "disable",
+            'f:' + format,
+            "/output.pdf",
+            String(nup),
+            "input.pdf",
+        ], snapshot);
+}
+

functions/mergePDFs.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+
+export const mergePDFs = async (snapshots) => {
+
+    const mergedPdf = await PDFDocument.create(); 
+
+    for (let i = 0; i < snapshots.length; i++) {
+        const pdfToMerge = await PDFDocument.load(snapshots[i]);
+
+        const copiedPages = await mergedPdf.copyPages(pdfToMerge, pdfToMerge.getPageIndices());
+        copiedPages.forEach((page) => mergedPdf.addPage(page));
+    }
+
+    return mergedPdf.save();
+};

functions/rotatePDF.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+
+export const rotatePages = async (snapshot, rotation) => {
+    // Load the original PDF file
+    const pdfDoc = await PDFDocument.load(snapshot, {
+        parseSpeed: ParseSpeeds.Fastest,
+    });
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        // Change page size
+        page.setRotation(degrees(rotation))
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};

functions/scaleContent.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+
+export const scaleContent = async (snapshot, scale_factor) => {
+    // Load the original PDF file
+    const pdfDoc = await PDFDocument.load(snapshot, {
+        parseSpeed: ParseSpeeds.Fastest,
+    });
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        const width = page.getWidth();
+        const height = page.getHeight();
+        
+        // Scale content
+        page.scaleContent(scale_factor, scale_factor);
+        const scaled_diff = {
+            width: Math.round(width - scale_factor * width),
+            height: Math.round(height - scale_factor * height),
+        };
+
+        // Center content in new page format
+        page.translateContent(Math.round(scaled_diff.width / 2), Math.round(scaled_diff.height / 2));
+
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};

functions/scalePage.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+
+export const scalePage = async (snapshot, page_size) => {
+    // Load the original PDF file
+    const pdfDoc = await PDFDocument.load(snapshot, {
+        parseSpeed: ParseSpeeds.Fastest,
+    });
+
+    const new_size = page_size;
+
+    const pages = pdfDoc.getPages();
+
+    pages.forEach(page => {
+        // Change page size
+        page.setSize(new_size.width, new_size.height);
+    });
+
+    // Serialize the modified document
+    return pdfDoc.save();
+};
+
+export const PageSize = {
+    a4: {
+        width: 594.96,
+        height: 841.92
+    },
+    letter: {
+        width: 612,
+        height: 792
+    }
+};

functions/splitPDF.js

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+import { PDFDocument, ParseSpeeds } from 'pdf-lib'
+import { createSubDocument } from "./extractPages.js";
+
+export const splitPDF = async (snapshot, splitAfterPageArray) => {
+    const pdfDoc = await PDFDocument.load(snapshot)
+
+    const numberOfPages = pdfDoc.getPages().length;
+
+    let pagesArray = [];
+    let splitAfter = splitAfterPageArray.shift();
+    const subDocuments = [];
+
+    for (let i = 0; i < numberOfPages; i++) {
+        if(i > splitAfter && pagesArray.length > 0) {
+            subDocuments.push(await createSubDocument(pdfDoc, pagesArray));
+            splitAfter = splitAfterPageArray.shift();
+            pagesArray = [];
+        }
+        pagesArray.push(i);        
+    }
+    subDocuments.push(await createSubDocument(pdfDoc, pagesArray));
+    pagesArray = [];
+
+    return subDocuments;
+};