Show progress bars in a Google Slides presentation

Coding level: Intermediate
Duration: 15 minutes
Project type: Editor add-on

Objectives

  • Understand what the solution does.
  • Understand what the Apps Script services do within the solution.
  • Set up the script.
  • Run the script.

About this solution

Use this solution to add a progress bar to the bottom of the slides in your presentation.

Screenshot of the progress bar Slides Editor add-on

How it works

The script calculates how many slides are in the presentation and adds a rectangle shape to the bottom of each slide. The script increases the width for each rectangle shape to show progress within the slides.

Apps Script services

This solution uses the following service:

  • Slides service–Gets a presentation's slides and adds a rectangle shape to each one.

Prerequisites

To use this sample, you need the following prerequisites:

  • A Google Account (Google Workspace accounts might require administrator approval).
  • A web browser with access to the internet.

Set up the script

  1. Click the following button to make a copy of the Progress bar Slides presentation. The Apps Script project for this solution is attached to the presentation.
    Make a copy
  2. In the presentation, click Extensions > Progress bar > Show progress bar.

  3. When prompted, authorize the script. If the OAuth consent screen displays the warning, This app isn't verified, continue by selecting Advanced > Go to {Project Name} (unsafe).

  4. Again, click Extensions > Progress bar > Show progress bar.

  5. To remove the progress bar, click Extensions > Progress bar > Hide progress bar.

Review the code

To review the Apps Script code for this solution, click View source code below:

View source code

slides/progress/progress.gs
/**
 * @OnlyCurrentDoc Adds progress bars to a presentation.
 */
const BAR_ID = 'PROGRESS_BAR_ID';
const BAR_HEIGHT = 10; // px

/**
 * Runs when the add-on is installed.
 * @param {object} e The event parameter for a simple onInstall trigger. To
 *     determine which authorization mode (ScriptApp.AuthMode) the trigger is
 *     running in, inspect e.authMode. (In practice, onInstall triggers always
 *     run in AuthMode.FULL, but onOpen triggers may be AuthMode.LIMITED or
 *     AuthMode.NONE.)
 */
function onInstall(e) {
  onOpen();
}

/**
 * Trigger for opening a presentation.
 * @param {object} e The onOpen event.
 */
function onOpen(e) {
  SlidesApp.getUi().createAddonMenu()
      .addItem('Show progress bar', 'createBars')
      .addItem('Hide progress bar', 'deleteBars')
      .addToUi();
}

/**
 * Create a rectangle on every slide with different bar widths.
 */
function createBars() {
  deleteBars(); // Delete any existing progress bars
  const presentation = SlidesApp.getActivePresentation();
  const slides = presentation.getSlides();
  for (let i = 0; i < slides.length; ++i) {
    const ratioComplete = (i / (slides.length - 1));
    const x = 0;
    const y = presentation.getPageHeight() - BAR_HEIGHT;
    const barWidth = presentation.getPageWidth() * ratioComplete;
    if (barWidth > 0) {
      const bar = slides[i].insertShape(SlidesApp.ShapeType.RECTANGLE, x, y,
          barWidth, BAR_HEIGHT);
      bar.getBorder().setTransparent();
      bar.setLinkUrl(BAR_ID);
    }
  }
}

/**
 * Deletes all progress bar rectangles.
 */
function deleteBars() {
  const presentation = SlidesApp.getActivePresentation();
  const slides = presentation.getSlides();
  for (let i = 0; i < slides.length; ++i) {
    const elements = slides[i].getPageElements();
    for (const el of elements) {
      if (el.getPageElementType() === SlidesApp.PageElementType.SHAPE &&
        el.asShape().getLink() &&
        el.asShape().getLink().getUrl() === BAR_ID) {
        el.remove();
      }
    }
  }
}

Contributors

This sample is maintained by Google with the help of Google Developer Experts.

Next steps