Create a png file from a Google Drawing using App Script

Question

I've got a folder full of Google Drawings. I've got the filenames of the Google Drawings in a Google spreadsheet. I can extract the filenames from the Google spreadsheet, iterate through the filenames, find all the Google drawings and ... this is where I get stuck. I'd like to convert the drawings into PNG files and store the PNG files in a separate drive folder.

This is the script I have so far ...

function load_list_of_images() {
  var course_workbook_name = "SPREADSHEET"; // Title of spreadsheet to download files
  var course_workbooks = DriveApp.getFilesByName(course_workbook_name); // There may be more than one!
  try{
    var course_workbook_id = course_workbooks.next();
    Logger.log("Spreadsheet ID : " + course_workbook_id);    
  } catch(error) {
    Logger.log("Spreadsheet doesn't exist");
    return(null);
  }
  var course_workbook = SpreadsheetApp.open(course_workbook_id);
  var image_list_sheet = course_workbook.getSheetByName("image_list");
  // Get list of image names (without extensions)
  var list_of_images = [];
  var images = image_list_sheet.getRange(1,1,1000).getValues();
  for (var row in images) {
    for (var col in images[row]) {
      if (images[row][col] == "") {
        return(list_of_images);
      }
      list_of_images.push(images[row][col]);
    }
  }
}

function download_images() {
  var list = load_list_of_images();
  if (list == null){
    return(null);
  }
  for (var row in list){
    var image_name = list[row];
    var image_exists = DriveApp.getFilesByName(image_name);
    // There may be more than one
    if (image_exists.hasNext()) {
      var image = image_exists.next()
      var gDraw_file = DriveApp.getFileById(image.getId());
      DriveApp.createFile(gDraw_file.getBlob());
    }
  }
}

When I run this, all the Google drawings are converted to PDF files and stored in my drive folder.

Answer 1

You need to specify to which mimeType you want to convert the drawing

However, converting from drawings to png is not possible directly, you need to perform the following steps:

• Create an export link for exporting the file as image/png
• Fetch this link with the UrlFetchApp
• Create a file from the blob of the result

Sample

  var id = image.getId(); 
  var exportUrl = "https://www.googleapis.com/drive/v3/files/" + id + "/export?mimeType=image/png";
  var urlFetchOptions = {
    headers: {Authorization : "Bearer " + ScriptApp.getOAuthToken()}
  };
  var blob= UrlFetchApp.fetch(exportUrl, urlFetchOptions).getBlob();
  DriveApp.createFile(blob);