IPENtool/js/pdf.js

/*
 * Copyright 2021 Netsyms Technologies.
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

const {jsPDF} = window.jspdf;

var pdfPageScale = 4;
var pdfAssumedDPI = 72;
var pdfDoc = null;
var pageNumber = 0;

function addPDF() {
    openFileDialog(function (path) {
        var filedata = getFileAsUint8Array(path);

        /**
         * Asynchronously downloads PDF.
         */
        pdfjsLib.getDocument(filedata).promise.then(function (pdfDoc_) {
            pdfDoc = pdfDoc_;

            renderAllPages(pdfDoc);
            pdfZoom("fitwidth");
            // Initial/first page rendering
            //renderPage(pageNum);
        });
    });
}

function savePDF() {
    var canvases = $("#page-canvas-container .page-canvas");
    const pdf = new jsPDF({
        unit: "in",
        compress: true
    });
    // creating a PDF creates a blank page that we don't want to use,
    // as we haven't done the calculations yet
    pdf.deletePage(1);
    for (var i = 0; i < canvases.length; i++) {
        var canvas = $("#page-canvas-container .page-canvas")[i];
        var widthpx = canvas.getContext("2d").canvas.width;
        var heightpx = canvas.getContext("2d").canvas.height;
        var pageWidthInches = widthpx / (pdfAssumedDPI * pdfPageScale);
        var pageHeightInches = heightpx / (pdfAssumedDPI * pdfPageScale);
        console.log(pageWidthInches + " x " + pageHeightInches);
        var pageFormat = [pageWidthInches, pageHeightInches];
        var pageOrientation = (pageWidthInches > pageHeightInches ? "landscape" : "portrait");
        pdf.addPage(pageFormat, pageOrientation);
        pdf.addImage($("#page-canvas-container .page-canvas")[i].toDataURL(), 0, 0, pageWidthInches, pageHeightInches);
    }
    pdf.save("signed.pdf");
}

function pdfZoom(str) {
    disableGuideBox();
    var widthpx = $("#page-canvas-container .page-canvas").css("width").replace("px", "") * 1;
    var zoomstep = 100;
    console.log(widthpx);
    switch (str) {
        case "out":
            $("#page-canvas-container .page-canvas").css("height", "auto");
            widthpx -= zoomstep;
            $("#page-canvas-container .page-canvas").css("width", widthpx + "px");
            break;
        case "in":
            $("#page-canvas-container .page-canvas").css("height", "auto");
            widthpx += zoomstep;
            $("#page-canvas-container .page-canvas").css("width", widthpx + "px");
            break;
        case "fitwidth":
            $("#page-canvas-container .page-canvas").css("width", "100%");
            $("#page-canvas-container .page-canvas").css("height", "auto");
            break;
        case "fitheight":
            $("#page-canvas-container .page-canvas").css("height", "100%");
            $("#page-canvas-container .page-canvas").css("width", "auto");
            break;
    }
}

function getNewCanvas(pagenumber) {
    var canvas = document.createElement('canvas');
    canvas.id = "pdf-canvas-page-" + pagenumber;
    canvas.className = "page-canvas";
    return canvas;
}

function addPage() {
    pageNumber++;
    var canvas = getNewCanvas(pageNumber);
    var prevPageCanvas = $("#page-canvas-container .page-canvas#pdf-canvas-page-" + (pageNumber - 1))[0];
    canvas.width = prevPageCanvas.getContext("2d").canvas.width;
    canvas.height = prevPageCanvas.getContext("2d").canvas.height;
    $("#page-canvas-container").append(canvas);
}

function renderAllPages() {
    var startingPageNumber = pageNumber;
    var thisDocPageCount = pdfDoc.numPages;
    for (var i = 1; i <= pdfDoc.numPages; i++) {
        pdfDoc.getPage(i).then(function (page) {
            var viewport = page.getViewport({scale: pdfPageScale});
            var canvas = getNewCanvas(page.pageNumber + startingPageNumber);
            canvas.height = viewport.height;
            canvas.width = viewport.width;
            $("#page-canvas-container").append(canvas);

            // Render PDF page into canvas context
            var renderContext = {
                canvasContext: canvas.getContext("2d"),
                viewport: viewport
            };

            page.render(renderContext);
        });
    }
    pageNumber = pageNumber + thisDocPageCount;
    document.getElementById('page_count').textContent = pageNumber;
}