Today I learned Javascript in Photoshop

[dmcantrell]

Wow, this is some powerful stuff. I guess I just eeked about $100 of value out of Photoshop that was previously going unused.

[RKEnnis]

Sweet! You were automating something, I take it?

JavaScript may be the best scripting language ever...

[dmcantrell]

Yes I automated some task that I found myself doing over and over.

Like resizing the image down to 800 longest edge at 300dpi, and saving jpeg quality 9 with a <image_name)_c1_800.jpg extension in a particular folder.

[Jake]

Cool, now explain everything you learned in a way a 5yr old could understand.
I'm ready and taking notes.......

[dmcantrell]

Sure thing, I will post the actual code later on tonight when I get home.

I made two scripts to do two specific things that I do -alot-. I seem to spend quite a bit of time doing these repetitive tasks and click click clicking in the dialog boxes.

1) Resize images to 800px / 300dpi.
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I do this all the time. I save a full-sized version in .psd format with layers, then resize down to 800px / 300dpi for web-posting. The problem is that the 800px is the long edge, so the user needs to know which of the fields in the resize dialog box to change the 800. Also, the aspect ratio needs to be considered. My script will compare the height and width to determine which is larger, calculate the aspect ratio, then call the image resizer with the results of the calculations. The result is a 300dpi image with the same aspect ratio as the original, sized down so that the longest edge is 800px after one click.

2) Save As JPEG (quality 9) with my own naming convention
----
This is another task I find myself doing a lot. Change mode to 8-bit, save-as jpeg, change the file name, choose 9 quality, click click click. My script will determine if the image is in 8 or 16-bit, change it to 8-bit, call the 'Save As' dialog, change the filename to <original_name>c1_800.jpg (my naming convention), and save the file as JPEG with quality 9 with one click.

I wrote the scripts by hand in a text editor (VIM), and saved them with a .jsx file extension. I put them in the /Scripts folder (see the Photoshop documentation) so that they can be accessed via the File-->Scripts--> menu. Then, I made some new actions that executed the scripts so that I could have a one-click solution without having to go two menus deep to get to them.

[dmcantrell]

-------------- resize_to_800.jsx -----------------

// the active document
var AD=activeDocument;

if (AD.width.value > AD.height.value) {
  // process width
  var currentAspectRatio = AD.width.value / AD.height.value;
  alert (currentAspectRatio);
  var newHeight = 800 / currentAspectRatio;
  var newWidth = 800;
  AD.resizeImage (newWidth, newHeight, 300, ResampleMethod.BILINEAR);
} 
else {
  // process height
  var currentAspectRatio = AD.height.value / AD.width.value;
  alert (currentAspectRatio);
  var newHeight = 800;
  var newWidth = 800 / currentAspectRatio;
  AD.resizeImage (newWidth, newHeight, 300, ResampleMethod.BILINEAR);
}

----------------- save_as_jpg_9.jsx --------------------

// the active document
var AD=activeDocument;

// set to 8-bit depth for saving
var currentBitsPerChannel = AD.bitsPerChannel;
AD.bitsPerChannel = BitsPerChannelType.EIGHT ;

// If any documentes are open
if (app.documents.length >=1) {
  // create a variable to get the current document name
  myDoc = app.activeDocument.name;
}
  else {
  sampleDoc = "There are no documents open.";
}

// add the desired file name extension
var newFileName = myDoc.slice(0,-4) + "_c1_800"

alert (newFileName)

saveFile = new File(decodeURI(app.activeDocument.path)+'/'+newFileName+'.jpg')
saveOptions = new JPEGSaveOptions()
saveOptions.embedColorProfile = true
saveOptions.formatOptions = FormatOptions.STANDARDBASELINE
saveOptions.matte = MatteType.NONE
saveOptions.quality = 9
AD.saveAs(saveFile, saveOptions, true, Extension.LOWERCASE)

AD.bitsPerChannel = currentBitsPerChannel;

I put both of these files into C:/Program Files/Adobe/Adobe Photoshop CS4/Presets/Scripts

[RKEnnis]

Thanks for posting the code!

Whats up those alerts - don't you know your supposed to remove them from all production code? hehehe j/k!

Seriously, you've inspired me to get back into automating PS. There's some stuff I've wanted to do, but I've been too lazy. Plus I've taken too long a break from coding...

[dmcantrell]

Originally Posted by RKEnnis

Thanks for posting the code!

no problem!

Whats up those alerts - don't you know your supposed to remove them from all production code? hehehe j/k!