collegeshala-beta/pdf.html at master · collegeshala/collegeshala-beta · GitHub

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<!doctype html>

<html lang="en">

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>My PDF Viewer</title>
    <style>
        #canvas_container {
            width: 1000px;
            height: 800px;
            overflow: auto;
        }

        #canvas_container {
            background: #333;
            text-align: center;
            border: solid 3px;
        }
    </style>
</head>

<body onload="onload()">
    <div id="my_pdf_viewer">
        <div id="canvas_container">
            <canvas id="pdf_renderer"></canvas>
        </div>
    </div>
    <div id="navigation_controls">
        <button id="go_previous">Previous</button>
        <input id="current_page" value="1" type="number" />
        <button id="go_next">Next</button>
    </div>
    <div id="zoom_controls">
        <button id="zoom_in">+</button>
        <button id="zoom_out">-</button>
    </div>
    <canvas id="the-canvas"></canvas>
    <!-- <script src="/script.js"></script> -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.0.943/pdf.min.js">
    </script>

    <script>
        var myState = {
            pdf: null,
            currentPage: 1,
            zoom: 1,
            noteurl: "https://collegeshala-notes.s3.ap-south-1.amazonaws.com/" + localStorage.getItem("noteId") + ".pdf"
        }

        function onload() {
            myState.noteurl = "https://collegeshala-notes.s3.ap-south-1.amazonaws.com/" + localStorage.getItem("noteId") + ".pdf";
            render();
        }
        // https://collegeshala-notes.s3.ap-south-1.amazonaws.com/c59b7dbd-fd6b-400e-a173-156ace07a56f.pdf
        pdfjsLib.getDocument(myState.noteurl)
            .then((pdf) => {

                myState.pdf = pdf;
                render();

            });

        function render() {
            myState.pdf.getPage(myState.currentPage).then((page) => {

                var canvas = document.getElementById("pdf_renderer");
                var ctx = canvas.getContext('2d');

                var viewport = page.getViewport(myState.zoom);
                canvas.width = viewport.width;
                canvas.height = viewport.height;

                page.render({
                    canvasContext: ctx,
                    viewport: viewport
                });

            });
        }

        document.getElementById('go_previous')
            .addEventListener('click', (e) => {
                if (myState.pdf == null
                    || myState.currentPage == 1) return;
                myState.currentPage -= 1;
                document.getElementById("current_page")
                    .value = myState.currentPage;
                render();
            });

        document.getElementById('go_next')
            .addEventListener('click', (e) => {
                if (myState.pdf == null
                    || myState.currentPage > myState.pdf
                        ._pdfInfo.numPages)
                    return;

                if (myState.currentPage == 2) {
                    alert("Preview ended!")
                } else {
                    myState.currentPage += 1;
                    document.getElementById("current_page")
                        .value = myState.currentPage;
                    render();
                }
            });

        document.getElementById('current_page')
            .addEventListener('keypress', (e) => {
                if (myState.pdf == null) return;

                // Get key code
                var code = (e.keyCode ? e.keyCode : e.which);

                // If key code matches that of the Enter key
                if (code == 13) {
                    var desiredPage =
                        document.getElementById('current_page')
                            .valueAsNumber;

                    if (desiredPage >= 1
                        && desiredPage <= myState.pdf
                            ._pdfInfo.numPages) {
                        if (desiredPage > 2) {
                            alert("Preview ended!");
                        } else {
                            myState.currentPage = desiredPage;
                            document.getElementById("current_page")
                                .value = desiredPage;
                            render();
                        }
                    }
                }
            });

        document.getElementById('zoom_in')
            .addEventListener('click', (e) => {
                if (myState.pdf == null) return;
                myState.zoom += 0.5;
                render();
            });

        document.getElementById('zoom_out')
            .addEventListener('click', (e) => {
                if (myState.pdf == null) return;
                myState.zoom -= 0.5;
                render();
            });

    </script>
</body>

</html>