Create Thumbnail Showcase Demo Code Sample

Requirements

These packages are required to use these features in production. Trial keys have unlimited access to all features

Web SDKPackage: Page ManipulationLive demo

Easily create high resolution thumbnail images from selected document pages.

This demo allows you to:

• Choose your own document file.

• Create high-resolution thumbnails.

• Define PNG or JPEG image format.

• Specify scale factor [0.1, 10], where low values yield smaller thumbnail sizes .

Implementation steps

To add Thumbnail Creation capability with WebViewer: Step 1: Get started with WebViewer in your preferred web stack. Step 2: Add the ES6 JavaScript sample code provided in this guide.

Once you generate your license key, it will automatically be included in your sample code below.

index.js

// ES6 Compliant Syntax
// GitHub Copilot v1.0, GPT-4.1, October 15, 2025
// File: index.js

import WebViewer from '@pdftron/webviewer';

const licenseKey = 'YOUR_WEBVIEWER_LICENSE_KEY';

// Create Thumbnail Demo
// This code demonstrates how to create a high resolution JPG or PNG thumbnail for a PDF document using the loadCanvas API.

function initializeWebViewer() {

    // This code initializes the WebViewer with the basic settings
    WebViewer({
        path: '/lib',
        licenseKey: licenseKey,
        enableFilePicker: true,
        loadAsPDF: true, // Ensure files are loaded as PDF documents for best thumbnail quality
    }, document.getElementById('viewer')).then((instance) => {
        // Enable the measurement toolbar so it appears with all the other tools, and disable Cloudy rectangular tool
        const cloudyTools = [
            instance.Core.Tools.ToolNames.CLOUDY_RECTANGULAR_AREA_MEASUREMENT,
            instance.Core.Tools.ToolNames.CLOUDY_RECTANGULAR_AREA_MEASUREMENT2,
            instance.Core.Tools.ToolNames.CLOUDY_RECTANGULAR_AREA_MEASUREMENT3,
            instance.Core.Tools.ToolNames.CLOUDY_RECTANGULAR_AREA_MEASUREMENT4,
        ];
        instance.UI.enableFeatures([instance.UI.Feature.Measurement, instance.UI.Feature.Initials]);
        instance.UI.disableTools(cloudyTools);
        // Set default toolbar group to Annotate
        instance.UI.setToolbarGroup('toolbarGroup-Annotate');
        // Set default tool on mobile devices to Pan.
        if (UIElements.isMobileDevice()) {
            instance.UI.setToolMode(instance.Core.Tools.ToolNames.PAN);
        }

        instance.Core.documentViewer.addEventListener('documentUnloaded', () => {
            if (searchParams.has('file')) {
                searchParams.delete('file');
                history.replaceState(null, '', '?' + searchParams.toString());
            }
        });

        instance.Core.annotationManager.enableAnnotationNumbering();
        instance.UI.NotesPanel.enableAttachmentPreview();
        // Add the demo-specific functionality
        customizeUI(instance).then(() => {
            // Create UI controls after demo is initialized
            UIElements.createUIControls(instance);
        });
    });
}

const searchParams = new URLSearchParams(window.location.search);
const history = window.history || window.parent.history || window.top.history;

window.pageNum = 1;
window.scaleNum = 1.0;
window.thumbnailName = 'thumbnail';
window.thumbnailType = 'png';

window.thumbnailOptions = ['PNG', 'JPEG'];


const customizeUI = async (instance) => {
    // Load the default document
    await instance.UI.loadDocument('https://apryse.s3.us-west-1.amazonaws.com/public/files/samples/WebviewerDemoDoc.pdf');
};

// Function to handle the Create Thumbnail button click
window.onThumbnailButtonClick = (instance) => {
    // Get the document
    const doc = instance.Core.documentViewer.getDocument();

    // Get the page number from user input
    let pageNumber = parseInt(window.pageNum, 10);

    // Validate page number
    if (isNaN(pageNumber) || pageNumber < 1 || pageNumber > doc.getPageCount()) {
        alert('Please enter a valid page number between 1 and ' + doc.getPageCount());
        return; // Exit if page number is invalid
    }

    // Clamp the page number to valid range
    pageNumber = isNaN(pageNumber) ? 1 : Math.min(Math.max(pageNumber, 1), doc.getPageCount());

    // Get the scale (zoom level) from user input
    const zoom = parseFloat(window.scaleNum);
    if (isNaN(zoom) || zoom <= 0 || zoom > 10) {
        alert('Please enter a valid zoom level between 0.1 and 10');
        return; // Exit if zoom is invalid
    }
    
    // Compensate for device pixel ratio to ensure consistent output across devices
    // Normalize to standard DPR of 1.0 by dividing by actual DPR
    const devicePixelRatio = window.devicePixelRatio || 1;
    const adjustedZoom = zoom / devicePixelRatio;
    
    console.log(`Device Pixel Ratio: ${devicePixelRatio}`);
    console.log(`Original zoom: ${zoom}, Adjusted zoom: ${adjustedZoom}`);
    console.log(`This should produce thumbnails equivalent to DPR=1.0 environment`);

    // Get the file name and type from user input
    const name = window.thumbnailName;
    const type = window.thumbnailType;

    // Save to blob using the loadCanvas API
    doc.loadCanvas({
        pageNumber,
        zoom: adjustedZoom, // Use DPI-adjusted zoom for consistent output
        drawComplete: async (thumbnail) => {
            // Optionally, comment out "drawAnnotations" to exclude annotations
            await instance.Core.documentViewer
                .getAnnotationManager()
                .drawAnnotations(pageNumber, thumbnail);
            // thumbnail is a HTMLCanvasElement or HTMLImageElement
            thumbnail.toBlob(
                (blob) => {
                    saveAs(blob, name + '.' + type);
                },
                'image/' + type,
                1
            );
        },
    });
};

// Cleanup function for when the demo is closed or page is unloaded
const cleanup = (instance) => {
    if (typeof instance !== 'undefined' && instance.UI) {
        if (instance.Core.documentViewer.getDocument()) {
            // Insert any other cleanup code here
        }
        console.log('Cleaning up demo');
    }
};

// Register cleanup for page unload
window.addEventListener('beforeunload', () => cleanup(instance));
window.addEventListener('unload', () => cleanup(instance));

// UI Elements Script Loader
// Loads the ui-elements.js script
function loadUIElementsScript() {
    return new Promise((resolve, reject) => {
        if (window.UIElements) {
            console.log('UIElements already loaded');
            resolve();
            return;
        }
        const script = document.createElement('script');
        script.src = '/showcase-demos/create-thumbnail/ui-elements.js';
        script.onload = function () {
            console.log('✅ UIElements script loaded successfully');
            resolve();
        };
        script.onerror = function () {
            console.error('Failed to load UIElements script');
            reject(new Error('Failed to load ui-elements.js'));
        };
        document.head.appendChild(script);
    });
}

// Load UIElements script first, then initialize WebViewer
loadUIElementsScript().then(() => {
    initializeWebViewer();
}).catch((error) => {
    console.error('Failed to load UIElements:', error);
});

ui-elements.js

ui-elements.js

// ES6 Compliant Syntax
// GitHub Copilot v1.0, GPT-4.1, October 15, 2025
// File: ui-elements.js

// UI Elements class to create and manage custom UI controls
//
// Helper code to add controls to the viewer holding the buttons
// This code creates a container for the buttons, styles them, and adds them to the viewer
//
class UIElements {
    // Function to check if the user is on a mobile device
    static isMobileDevice = () => {
        return (
            /(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|ipad|iris|kindle|Android|Silk|lge |maemo|midp|mmp|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i.test(
                window.navigator.userAgent
            ) ||
            /1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw-(n|u)|c55\/|capi|ccwa|cdm-|cell|chtm|cldc|cmd-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc-s|devi|dica|dmob|do(c|p)o|ds(12|-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(-|_)|g1 u|g560|gene|gf-5|g-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd-(m|p|t)|hei-|hi(pt|ta)|hp( i|ip)|hs-c|ht(c(-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i-(20|go|ma)|i230|iac( |-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|-[a-w])|libw|lynx|m1-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|-([1-8]|c))|phil|pire|pl(ay|uc)|pn-2|po(ck|rt|se)|prox|psio|pt-g|qa-a|qc(07|12|21|32|60|-[2-7]|i-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h-|oo|p-)|sdk\/|se(c(-|0|1)|47|mc|nd|ri)|sgh-|shar|sie(-|m)|sk-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h-|v-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl-|tdg-|tel(i|m)|tim-|t-mo|to(pl|sh)|ts(70|m-|m3|m5)|tx-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas-|your|zeto|zte-/i.test(
                window.navigator.userAgent.substring(0, 4)
            )
        );
    }

    // Create and return the page number input field
    static pageNumberInputField = () => {
        // Create a container for the input field
        const container = document.createElement('div');
        container.className = 'input-container';
        container.style.display = 'flex';

        // Create and append the label
        const label = document.createElement('label');
        label.className = 'input-label';
        label.textContent = 'Page Number';
        container.appendChild(label);

        // Create and append the input field
        const input = document.createElement('input');
        input.className = 'number-input-field';
        input.type = 'number';
        input.value = window.pageNum;
        input.onchange = (e) => {
            window.pageNum = e.target.value;
        };
        input.min = 1;
        input.pattern = "\d+";
        container.appendChild(input);

        return container;
    }

    // Create and return the scale factor input field
    static scaleFactorInputField = () => {
        // Create a container for the input field
        const container = document.createElement('div');
        container.className = 'input-container';

        // Create and append the label
        const label = document.createElement('label');
        label.className = 'input-label';
        label.textContent = 'Scale Factor';
        container.appendChild(label);

        // Create and append the input field
        const input = document.createElement('input');
        input.className = 'number-input-field';
        input.type = 'number';
        input.value = window.scaleNum;
        input.onchange = (e) => {
            window.scaleNum = e.target.value;
        }
        input.min = 0.1;
        input.step = 0.1;
        input.max = 10;
        container.appendChild(input);

        return container;
    }

    // Create and return the file name input field
    static fileNameInputField = () => {
        // Create a container for the input field
        const container = document.createElement('div');
        container.className = 'input-container';

        // Create and append the label
        const label = document.createElement('label');
        label.className = 'input-label';
        label.textContent = 'File Name';
        container.appendChild(label);

        // Create and append the input field
        const input = document.createElement('input');
        input.className = 'text-input-field';
        input.type = 'text';
        input.value = window.thumbnailName;
        input.onchange = (e) => {
            window.thumbnailName = e.target.value;
        };
        input.required = true;
        input.minLength = 1;
        container.appendChild(input);

        return container;
    }

    // Create and return the image type dropdown field
    static imageTypeInputField = () => {
        // Create a container for the dropdown
        const container = document.createElement('div');
        container.className = 'input-container';

        // Create and append the label
        const label = document.createElement('label');
        label.className = 'input-label';
        label.textContent = 'Image Type';
        container.appendChild(label);

        // Create and append the dropdown
        const select = document.createElement('select');
        select.className = 'dropdown-input-field';
        select.value = window.thumbnailType;
        select.onchange = (e) => {
            window.thumbnailType = e.target.value;
        };

        // Add options to the dropdown
        window.thumbnailOptions.forEach((option) => {
            const optionElement = document.createElement('option');
            optionElement.value = option.toLowerCase();
            optionElement.textContent = option;
            select.appendChild(optionElement);
        });
        container.appendChild(select);

        return container;
    }

    // Create and return the download button
    static downloadButton = (instance) => {
        // Create the button element
        const button = document.createElement('button');
        button.className = 'button';
        button.textContent = 'Download Thumbnail';
        button.onclick = () => window.onThumbnailButtonClick(instance);

        return button;
    }

    static createUIControls = (instance) => {
        // Create a container for all controls
        const controlsContainer = document.createElement('div');
        controlsContainer.className = 'controls-container';

        controlsContainer.appendChild(this.pageNumberInputField());
        controlsContainer.appendChild(this.scaleFactorInputField());
        controlsContainer.appendChild(this.fileNameInputField());
        controlsContainer.appendChild(this.imageTypeInputField());
        controlsContainer.appendChild(this.downloadButton(instance));

        // Add the controls container to the viewer element
        const element = document.getElementById('viewer');
        element.insertBefore(controlsContainer, element.firstChild);

        console.log('✅ UI controls created');
    };
}

// Make UIElements globally available
window.UIElements = UIElements;

index.css

index.css

/* CSS standard Compliant Syntax */
/* GitHub Copilot v1.0, GPT-4.1, October 15, 2025 */
/* File: index.css */

/* Button Styles */
.button {
    background-color: #007bff;
    margin: 0 10px;
    padding: 5px 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    transition: all 0.2s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    color: white;
}

.button:hover {
    background-color: #0056b3;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.button:active {
    transform: translateY(1px);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

/* Text Inputs Container */
.text-inputs-container {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 10px;
}

/* Input Controls */
.input-container {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    margin-bottom: 15px;
}

.input-label {
    display: block;
    text-align: start;
    font-size: 14px;
    margin-inline-end: 12px;
    margin-bottom: 8px;
    font-weight: bold;
    transition: background-color border-color color fill stroke opacity box-shadow transform;
    transition-duration: 200ms;
    opacity: 1;
    color: #485056;
    line-height: 1.5;
    width: 50%;
    white-space: nowrap;
}

.number-input-field,
.text-input-field, 
.dropdown-input-field {
    width: 100%;
    min-width: 0px;
    outline: transparent solid 2px;
    outline-offset: 2px;
    position: relative;
    appearance: none;
    transition: background-color border-color color fill stroke opacity box-shadow transform;
    transition-duration: 200ms;
    border-radius: 6px;
    background-color: white;
    color: #485056;
    border-width: 1px;
    border-style: solid;
    border-image: initial;
    border-color: #cfd4da;
    box-sizing: border-box;
    font-size: 14px;
    padding-inline-start: 16px;
    padding-inline-end: 16px;
    height: 40px;
}

.number-input-field:focus,
.text-input-field:focus,
.dropdown-input-field:focus {
    border-color: #007bff;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}

/* Controls Container */
.controls-container {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 15px;
    margin: 5px 0;
    padding: 16px;
    padding-bottom: 5px;
    border-bottom: 1px solid #DFE1E6;
    background-color: rgba(112, 198, 255, 0.2);
}