I'm trying to write a script in Photoshop using JavaScript. The goal for this script is to automatically convert from RGB to Bitmap mode. I don't want use the manual way: image->mode->greyscale->image->mode->bitmap.

After reading the “JavaScript Scripting Reference” I understand that I need to do it the same as the manual way but using code.

1. I convert the RGB image to grayscale using the changeMode method. This works:

   app.activeDocument.changeMode(ChangeMode.GRAYSCALE)
   

2. But, when I try to change from greyscale to bitmap I just can´t. The document does not explain clearly how it works. I did try to follow the document but I don't have a lot of experience in JavaScript.

   // Save the current preferences
   var startRulerUnits = app.preferences.rulerUnits
   var startTypeUnits = app.preferences.typeUnits
   var startDisplayDialogs = app.displayDialogs
   // Set Adobe Photoshop to use pixels and display no dialogs
   app.preferences.rulerUnits = Units.PIXELS
   app.preferences.typeUnits = TypeUnits.PIXELS
   app.displayDialogs = DialogModes.NO
   
   app.activeDocument.changeMode(ChangeMode.GRAYSCALE)
   app.activeDocument.changeMode(ChangeMode.Bitmap)
   // app.activeDocument.close()
   

I appreciate your help with providing a simple example about how to do it.