Code Bazaar: How to automate tasks in Photoshop with JavaScript

I recently learned it is possible to control Adobe Photophop in JavaScript, so I tried it out! From this article, I hope you will learn how to get started with Photoshop scripting.

Photoshop is able to record your manual actions into a JavaScript. To enable this feature:

copy the file ScriptingListenerJS.8LI from C:\Program Files\Adobe\Adobe Photoshop CS5\Scripting\Utilities to C:\Program Files\Adobe\Adobe Photoshop CS5\Plug-ins\Automate
restart Photoshop
start manipulating Photoshop

A file ScriptingListenerJS.txt should be created on your Desktop. I opened an image and resized it, here is the script generated:

// =======================================================
var idOpn = charIDToTypeID( "Opn " );
    var desc1 = new ActionDescriptor();
    var idnull = charIDToTypeID( "null" );
    desc1.putPath( idnull, new File( "C:\\codebazaar\\3x3gifmaker\\input\\IMG_5032.JPG" ) );
executeAction( idOpn, desc1, DialogModes.NO );

// =======================================================
var idImgS = charIDToTypeID( "ImgS" );
    var desc2 = new ActionDescriptor();
    var idWdth = charIDToTypeID( "Wdth" );
    var idPxl = charIDToTypeID( "#Pxl" );
    desc2.putUnitDouble( idWdth, idPxl, 3000.000000 );
    var idscaleStyles = stringIDToTypeID( "scaleStyles" );
    desc2.putBoolean( idscaleStyles, true );
    var idCnsP = charIDToTypeID( "CnsP" );
    desc2.putBoolean( idCnsP, true );
    var idIntr = charIDToTypeID( "Intr" );
    var idIntp = charIDToTypeID( "Intp" );
    var idBcbc = charIDToTypeID( "Bcbc" );
    desc2.putEnumerated( idIntr, idIntp, idBcbc );
executeAction( idImgS, desc2, DialogModes.NO );

A script helps to automate repetitive tasks in Photoshop. You can use the generated code as a starting point to do so.

Adobe also offers an API. For example, I built a script executing the following operations:

ask the user to select a folder
open all the images present in the selected folder
resize all the images
copy/cut and paste all the images into different layers
build a GIF animation

The complete script is available for download here.

To run the script:

open Adobe Extended Toolkit
in the dropdown menu at the top left of the window, select Adobe Photoshop
in the menu, select File, then Open and select the script to execute
in the menu, select Debug, Run (or press F5)
Photoshop will ask to select a folder containing the images to process
then you can see Photoshop executing all the tasks coded in the script

This is a screenshot of Adobe Extended Toolkit. It allows you to set breakpoints, view the local variables as you are debugging and inspect the call stack

I did not find how to automatically set the time interval between each animation frame, so I manually had to do this step and save the animation (File, Save for Web & Device, Save).

The following image has been generated by the script.

The API allows to write a code that is more concise and easier to read than the code generated by Photoshop. In some cases I was not always able to find what method to use from the API to execute a specific action, so I recorded some of these actions and incorporated the generated code into my script.

Here are some web sites I found useful:

Also, if you don't get dizzy by looking at this animation, you can try this one made in HTML 5.

Code Bazaar

Tuesday, March 29, 2011

How to automate tasks in Photoshop with JavaScript

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