Ajustar tamaño de texto a una caja de tamaño fijo

Hi @MMAJORAL, I've written a script to get you started. You have to put in the names of the character style(s). Let me know if it's useful. I've also attached a demo .indd so you can see it working.

- Mark

/**
 * @file Fit Text By CharacterStyle.js
 *
 * Usage:
 * 
 *  1. First configure the script by editing the `fittings` array.
 *     - each fitting object must have a `characterStyleName` property
 *       that matches a character style in the document.
 *     - each fitting object has switches for `enlargeToFit` and/or `reduceToFit`
 * 
 *  2. Run script - will search whole document for those-character-styled texts.
 *
 * @author m1b
 * @version 2025-05-08
 * @discussion https://community.adobe.com/t5/indesign-discussions/ajustar-tamaño-de-texto-a-una-caja-de-tamaño-fijo/m-p/15308760
 */
function main() {

    /** 
     * Edit the `fittings` array to suit your needs:
     *   - add or remove fittings objects
     *   - set the enlarge/reduce options on each fitting
     */
    var fittings = [

        // example fitting 1
        {
            characterStyleName: 'Reduce Or Enlarge To Fit',
            enlargeToFit: true,
            reduceToFit: true,
        },

        // example fitting 2
        {
            characterStyleName: 'Reduce To Fit',
            enlargeToFit: false,
            reduceToFit: true,
        },

        // example fitting 3
        {
            characterStyleName: 'Enlarge To Fit',
            enlargeToFit: true,
            reduceToFit: false,
        },
    ];

    var doc = app.activeDocument,
        counter = 0;

    for (var i = 0, style, found; i < fittings.length; i++) {

        style = getThing(doc.allCharacterStyles, 'name', fittings[i].characterStyleName);

        if (!style) {
            alert('Character Style "' + fittings[i].characterStyleName + '" not found.');
            continue;
        }

        app.findGrepPreferences = NothingEnum.NOTHING;
        app.changeGrepPreferences = NothingEnum.NOTHING;
        app.findGrepPreferences.properties = {
            appliedCharacterStyle: style,
        };

        found = doc.findGrep();

        foundLoop:
        for (var j = 0; j < found.length; j++) {

            if (!found[j].parent.hasOwnProperty('overflows'))
                continue foundLoop;

            if (fittings[i].enlargeToFit) {

                while (!found[j].parent.overflows) {
                    found[j].pointSize = found[j].characters[0].pointSize + 1;
                    found[j].parent.recompose()
                }

            }

            if (
                fittings[i].reduceToFit
                || fittings[i].enlargeToFit
            ) {

                while (found[j].parent.overflows) {
                    found[j].pointSize = found[j].characters[0].pointSize - 0.1;
                    found[j].parent.recompose()
                }

            }

            counter++;

        }

    }

    alert('Adjusted ' + counter + ' texts.');

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Do Script');

/**
 * Returns a thing with matching property.
 * If `key` is undefined, evaluate the object itself.
 * @author m1b
 * @version 2024-04-21
 * @param {Array|Collection} things - the things to look through.
 * @param {String} [key] - the property name (default: undefined).
 * @param {*} value - the value to match.
 * @returns {*?} - the thing, if found.
 */
function getThing(things, key, value) {

    for (var i = 0; i < things.length; i++)
        if ((undefined == key ? things[i] : things[i][key]) == value)
            return things[i];

};