Replacing shapes by colour in Google Slides & Google Apps Script

Question

I am attempting to replace shapes color in a Google Slide presentation, using Google Apps Script.

function changeColors() {
  const objectId = "#an-id#";  // Please set the object ID.

  const slides = SlidesApp.openById(objectId).getSlides();
  slides.forEach(loopSlides);
  
}

function loopSlides(slide){

  var shapes = slide.getShapes();
  if (shapes.length > 0) {
    shapes.forEach(myFunction);
  }
}

function myFunction(shape) {
  try{
    var st = shape.getShapeType();
  if (st != SlidesApp.ShapeType["RECTANGLE"] && 
      st != SlidesApp.ShapeType["ROUND_RECTANGLE"] &&
      st != SlidesApp.ShapeType["UNSUPPORTED"]){
          Logger.log("Not a box!!");
          Logger.log(st);
          Logger.log(shape.getText());
        return;
      }
  }
  catch(err) {
    Logger.log("Not a Shape!!");
   return; // not a shape!
}
  var hexColor = shape.getFill().getSolidFill();
  Logger.log(hexColor);
  switch (hexColor){
    case "#f16727ff": // Computer Science
      shape.getFill().setSolidFill("#413c73ff");
    case "#0b9faeff": // Information technology
      shape.getFill().setSolidFill("#d90368ff");
    case "#d71b55ff": // Digital Literacy
      shape.getFill().setSolidFill("#aa968aff");    
      }

}

The above code will never run the replacement code (Basically it will never reach the Logger.log(hexColor); instruction

Answer 1

When I run your code it reaches Logger.log(hexColor);. The issue in your code is that your hexColor variable is actually a SolidFill object since you used getSolidFill().

If you want to get the RGB hexstring of the current shape, You need to first check if the ColorType is RGB using getColorType(). Then use asRgbColor() to get the RgbColor object. Lastly, use asHexString() to get the rgb color hex string.

Sample Code:

function myFunction(shape) {
  try{
    var st = shape.getShapeType();
    if (st != SlidesApp.ShapeType["RECTANGLE"] && 
        st != SlidesApp.ShapeType["ROUND_RECTANGLE"] &&
        st != SlidesApp.ShapeType["UNSUPPORTED"]){
        Logger.log("Not a box!!");
        Logger.log(st);
        Logger.log(shape.getText());
        return;
    }
  }
  catch(err) {
    Logger.log("Not a Shape!!");
    return; // not a shape!
  }
  var colorType = shape.getFill().getSolidFill().getColor().getColorType();
  if(colorType != SlidesApp.ColorType.RGB ){
    Logger.log("TYPE: "+colorType);
    Logger.log("ColorType not RGB");
    return;
  }
  var hexColor = shape.getFill().getSolidFill().getColor().asRgbColor().asHexString().toLowerCase();
  Logger.log(hexColor);
  switch (hexColor){
    case "#f16727": // Computer Science
      shape.getFill().setSolidFill("#413c73");
      break;
    case "#0b9fae": // Information technology
      shape.getFill().setSolidFill("#d90368");
      break;
    case "#d71b55": // Digital Literacy
      shape.getFill().setSolidFill("#aa968a");  
      break; 
  }
  
}

Sample Output:

Note:

• I used String.toLowerCase() to change the rgb hex string into lowercase for your switch statement
• Your rgb hex strings is incorrect. (I removed trailing ff). RGB hex string should only consist of 6 characters.
• Your switch cases has missing break for each cases. If you don't include a break the shape color will always be set to the last solid fill setting which is #aa968a