Script logic

[ojodegato]

The basic idea is to prompt the user for a layer name.

If the layer name exists, run an action.

If the layer name does not exists, prompt the user for a layer name.

The next time the script runs in the same open document,

the script does not prompt for a layer name,

it remembers the previously entered layer name and runs an action if the layer exists.

If the layer name does not exists, the script prompts the user for a layer name.

I can manage most of the script behavior with an if else statement and prompt box.

However, I am not sure how to bypass the initial prompt dialog when running the script a second time on the same open document.

That is ,if layer name already exists in the layer pallet.

[Mohit Goyal]

Move to Photoshop Scripting

Thanks,

~Mohit

[Chuck Uebele]

Most likely you should use either an xml or csv file to store the layer name. That way the script can check to see if that layer exists. I use xml files all the time to store UI values, and have one script that does something similar. It checks to see if a value was added to the xml so that editing can be done on a file then the script can be restarted and bypass the ui.

[ojodegato]

I have never used external xml files with photoshop scripts.

Can you please point me to an example, how to use an external xml file for temporary variable storage. 

[Chuck Uebele]

For you purpose, a csv or just a plain text file would work and is easy. here's a sample of what to do.

var infoFile = new File('/c/Images/info.txt')//whatever path and filename you want to use here.

var layerInfo ='layername***docname'//Here put you document name and layer name. Use whatever you want to split up the info.

writeFile (infoFile, layerInfo)



function getInfo(){
    var infoArray = readFile (infoFile).split('***')//use whatever you want to split the array up
    alert(infoArray)
    }

function readFile(file) {
    if (!file.exists) {
        alert( "Cannot find file: " + deodeURI(file.absoluteURI));
        }
    else{
        file.encoding = "UTF8";
        file.lineFeed = "unix";
        file.open("r", "TEXT", "????");
        var str = file.read();
        file.close();

        return str;
        };
};

function writeFile(file, info) {
        file.encoding = "UTF8";
        file.open("w", "TEXT", "????");
        //unicode signature, this is UTF16 but will convert to UTF8 "EF BB BF"
        file.write("\uFEFF");
        file.lineFeed = "unix";
        file.write(info);
        file.close();
    };

[ojodegato]

Thanks for providing the example. Questions about the second line of the sample script

Does docname reference the script name?

[Chuck Uebele]

No, that would be the file name of your image, just to make sure you're using not only the same image but the same layer. It may not be needed. Just thought I'd throw that in.

[ojodegato]

The part, I don't understand is the docname. Will the script work with different files or only with filename specified in the docname.

[ojodegato]

The sample script writes the variable to the external txt file.

The next step is to check if the variable name in the external txt file.

How can the script check if the variable name is in the external txt file?

[Chuck Uebele]

It will work with any file. You don't have to put in the docname. You do that if you want to make sure you are using the same file. You can put whatever you want.

This script isn't meant to be run by itself, meaning that there are parts to write the information to the text file and other parts to read that information back into a variable for you to use with your script. The flow would be:

Check to see if the text file exist, and if it does read the info into a variable/array. Then then the array to see if either the same file is open (the use of docname). Then see if there is the same layer name. If there isn't the proper info or text file. your UI comes up and ask the user to select that info. If the user selects new info, then the scripts rewrites the information to the text file. In line 11, I have an alert showing the contents of the array infoArray. That is the array that was created by reading the information in the text file. So you read the info from the text file, then use that array to get the info for your script to check to see if the file has the same layer name.

The script above just has the building blocks to create your script.

[ojodegato]

Thanks for the explanation. Does this sequence make sense for the script?

1-Declare variables aLayName and infoFile

2-Check if external file exist

3-Read external file variable

4-if external variable exists run action

5-if external variable does not exists prompt user for layer name

6-Write layer name to external file

7- Return to step 2

[Chuck Uebele]

Yes, that makes sense. If at any time you want to reset the text file you can simply remove it or send blank information to it.

[ojodegato]

The script is able to check if the dependency file exists.

Then it checks if the dependency file has a string.

If the string length is grater than 0, it returns the existing string.

If the string is less than 0 it prompts the user for input.

It writes the string input to the dependency file.

Next it reads the and outputs returned string.

For the most part the script works returning the input string.

The second time the script runs it returns undefined as the string.

What can be causing this shift?

var infoFile = new File('~/Desktop/layer-info.txt');

var file = infoFile;

var info;

readFile(file);

getInfo();

writeFile (infoFile, info);

///////////////////////////////////////////////////////////////

// FUNCTIONS

////////////////////////////////////////////////////////////////

//Check if file exist

function readFile(file) { 

    if (!file.exists) { 

        alert( "Cannot find file: " + decodeURI(file.absoluteURI)); 

        } 

    else{ 

        file.encoding = "UTF8"; 

        file.lineFeed = "unix"; 

        file.open("r", "TEXT", "????"); 

        var str = file.read(); 

        file.close();

        return str;        

        }; 

};

//Get file info

function getInfo(){ 

    var infoArray = readFile (infoFile).split('***');

    if(infoFile.length == 0){

        info = prompt ('Enter a Layer Name');

        return; 

      }

    alert(infoArray) 

    }

//Write string to external file

function writeFile(file, info) { 

        file.encoding = "UTF8"; 

        file.open("w", "TEXT", "????"); 

        //unicode signature, this is UTF16 but will convert to UTF8 "EF BB BF" 

        file.write("\uFEFF"); 

        file.lineFeed = "unix"; 

        file.write(info); 

        file.close(); 

    };

[Chuck Uebele · Accepted solution]

Try this. for some reason, the active layer is not highlighted if a layer isn't selected when the script if first run, but it still works. It's better to select some layer first before running the script.

#target photoshop
var infoFile = new File('~/Desktop/layer-info.txt');
// redundant     var file = infoFile;
var info =''
var doc = activeDocument;
var layerName = ''
//not needed       readFile(file);
getInfo();
writeFile (infoFile, info); 

///////////////////////////////////////////////////////////////
// FUNCTIONS
////////////////////////////////////////////////////////////////

//Check if file exist

function readFile(file) { 
    if (!file.exists) { 
        alert( "Cannot find file: " + decodeURI(file.absoluteURI)); 
        } 
    else{ 
        file.encoding = "UTF8"; 
        file.lineFeed = "unix"; 
        file.open("r", "TEXT", "????"); 
        var str = file.read(); 
        file.close();    
        return str;        
        }; 
};

//Get file info
function getInfo(){ 
    info=''//clear variable
    var matchLayer = false;
    if(infoFile.exists){
        info = readFile (infoFile); 
      }//end if for file check
    while(!matchLayer){
        try{
            doc.layers.getByName(info);
            matchLayer = true;
            }
        catch(e){      
            info = prompt ('Layer name does not match any layer.\nEnter a Layer Name');
            }
        }//end while
    }//end function


//Write string to external file
function writeFile(file, info) { 
        file.encoding = "UTF8"; 
        file.open("w", "TEXT", "????"); 
        //unicode signature, this is UTF16 but will convert to UTF8 "EF BB BF" 
        file.write("\uFEFF"); 
        file.lineFeed = "unix"; 
        file.write(info); 
        file.close(); 
    }; 

[ojodegato]

Thanks for reviewing the script. When exiting the prompt via cancel button the script goes into an endless loop.

I try adding the return after line 44 and 46 to exit the loop gracefully. However this disable the loop.

Is there a better way to exit the prompt?

[Chuck Uebele]

Yes, it will keep looping until you type in a correct name for a layer - it has to be exact. I didn't address canceling out out the loop.

[Chuck Uebele]

Change the catch statement to this. This will get it out the of the loop if you press cancel:

catch(e){
info = prompt ('Layer name does not match any layer.\nEnter a Layer Name');
if(info == null){return}
}

[ojodegato]

Yes, that works great. Thank you.

Finally, Is there a method to that can clear the external txt file when the active photoshop document closes?

I am unable to clear the external txt file once it has been written.

[Chuck Uebele]

You most likely need another script to either delete the file or overwrite it. To delete it, it would be something like:

var infoFile = new File(path)

infoFile.remove()

[ojodegato]

Without using the scripts events manager. Can a photoshop script run in the background so that when the active document closes the external txt file is automatically removed?

[Chuck Uebele]

No, if a script runs, it pretty much locks up PS. How often do you need to purge the text file? Is it for each new document? If that is the case, then some code can be added to detect if it's a new document.

[ojodegato]

Actually, there is no need to purge the txt file. I tested the script on documents with different layer structures. If the script does not find the layer name stored in the txt file it prompts for a new layer name overwriting the old one. If it finds the layer name it runs an action on the layer.

Thanks sharing your knowledge and expertise. I truly, appreciate your help. 

[Chuck Uebele]

No problem, glad it's working out for you now.