Google Suite - Apps Script - Download Slides as PNG files via API - google-apps-script

Question

Good Morning All. I have written a short script which batch-creates [single page] Google Slides based on rows from a spreadsheet. While in the loop for each creation, I would like to create a PNG of the Slide in Google Drive (or download on the user's desktop). These pictures should be the same specs as if a user clicked File>Download>PNG - the heavy small text requires full projector HD - so I don't believe I can use the "Thumbnail" function which appears limited to 1600 pixels.
My code below generates the error "Converting from text/html to image/png is not supported" - so I'm not sure if this is a limitation of the API or a problem with my coding. Thank you in advance.
var options =
{
"contentType" : "image/PNG"
};
var url = 'https://docs.google.com/presentation/d/' + presentationCopyId + '/export/PNG';
var response = UrlFetchApp.fetch(url, options);
var image = response.getAs(MimeType.PNG);
image.setName(SlideName);
DriveApp.createFile(image);

Answer 1

Yes, It is possible.
You can use Google slide API and make a PNG file of every page of Google slide.
Here is the code,
BUT first you have to enable API as following
open script editor
click on resources-> Advanced Google Services
Enable Google slide API and Drive API .
click on ok
now copy and paste this code,
and write your slide ID in presentationID.
function generateScreenshots() {
var presentationId = "***ADD YOUR Google Slide ID Only***";
var presentation = SlidesApp.openById(presentationId);
var baseUrl =
"https://slides.googleapis.com/v1/presentations/{presentationId}/pages/{pageObjectId}/thumbnail";
var parameters = {
method: "GET",
headers: { Authorization: "Bearer " + ScriptApp.getOAuthToken() },
contentType: "application/json",
muteHttpExceptions: true
};
// Log URL of the main thumbnail of the deck
Logger.log(Drive.Files.get(presentationId).thumbnailLink);
// For storing the screenshot image URLs
var screenshots = [];
var slides = presentation.getSlides().forEach(function(slide, index) {
var url = baseUrl
.replace("{presentationId}", presentationId)
.replace("{pageObjectId}", slide.getObjectId());
var response = JSON.parse(UrlFetchApp.fetch(url, parameters));
// Upload Googel Slide image to Google Drive
var blob = UrlFetchApp.fetch(response.contentUrl).getBlob();
DriveApp.createFile(blob).setName("Image " + (index + 1) + ".png");
screenshots.push(response.contentUrl);
});
return screenshots;
}

Answer 2

This answer is outdated, leaving up for documentation purposes but please see other answer.
Answer:
Unfortunately it is not possible to export a Slides as a PNG file using the the Slides nor Drive APIs.
More Information:
According to the documentation, there are only four available MimeTypes for exporting Presentations files:
application/vnd.openxmlformats-officedocument.presentationml.presentation
application/vnd.oasis.opendocument.presentation
application/pdf
text/plain
Attempting to export to the image/png MIME Type results in the following error:
Converting from text/html to image/png is not supported
For testing purposes, I tried using the /export/pdf endpoint and making a second conversion to PNG from there like so:
function slidesAsPngAttempt() {
var presentationCopyId = "1Loa...pQs";
var options =
{
"contentType" : "application/pdf"
};
// for exporting to pdf the /export/pdf needs to be all lower case to avoid 404
var url = 'https://docs.google.com/presentation/d/' + presentationCopyId + '/export/pdf';
var response = UrlFetchApp.fetch(url, options);
var pdfAsblob = response.getBlob();
var image = pdfAsblob.getAs('image/png');
image.setName(DriveApp.getFileById(presentationCopyId).getName());
DriveApp.createFile(image);
}
Unfortunately, a similar error occurs when running var image = pdfAsblob.getAs('image/png'):
Converting from application/pdf to image/png is not supported.
From the same export MIME types reference documentation, the only export types available for PDF files are:
text/csv
text/tab-separated-values
application/zip
References:
G Suite documents and corresponding export MIME types
Google Apps Script - method Blob.getAs(contentType)