Grundlinienraster

Gonna post what I have - it's far simpler than the already available working script but as a lesson maybe I can share what I have and maybe it can be fixed 

So the Cap Height isn't working for me - but I can't figure out why. 

#target indesign
#targetengine "session"

$.writeln("--- Script Start ---");

// Function to safely get document vertical units info (More Robust)
function getDocumentVerticalUnits(doc) {
    var defaultUnitInfo = { type: MeasurementUnits.POINTS, name: "pt" };
    try {
        if (!doc || !doc.isValid || !doc.viewPreferences) {
             $.writeln("Warning: Invalid document or viewPreferences in getDocumentVerticalUnits. Falling back to points.");
             return defaultUnitInfo;
        }
        var unitType = doc.viewPreferences.verticalMeasurementUnits;
        var unitInfo = { type: unitType, name: "" };
        switch (unitType) {
            case MeasurementUnits.POINTS: unitInfo.name = "pt"; break;
            case MeasurementUnits.PICAS: unitInfo.name = "p"; break;
            case MeasurementUnits.INCHES: unitInfo.name = "in"; break;
            case MeasurementUnits.INCHES_DECIMAL: unitInfo.name = "in"; break;
            case MeasurementUnits.MILLIMETERS: unitInfo.name = "mm"; break;
            case MeasurementUnits.CENTIMETERS: unitInfo.name = "cm"; break;
            case MeasurementUnits.CICEROS: unitInfo.name = "c"; break;
            case MeasurementUnits.AGATES: unitInfo.name = "ag"; break;
            case MeasurementUnits.PIXELS: unitInfo.name = "px"; break;
            default: 
                unitInfo.name = "pt"; 
                unitInfo.type = MeasurementUnits.POINTS;
                $.writeln("Warning: Unknown MeasurementUnit encountered (" + unitType + "). Falling back to points.");
        }
         if (typeof unitInfo.name !== 'string' || unitInfo.name === "") {
             $.writeln("Warning: Failed to determine unit name. Falling back to points.");
             return defaultUnitInfo;
         }
        return unitInfo;
    } catch (e) {
        $.writeln("!!! ERROR in getDocumentVerticalUnits: " + e.message + ". Falling back to points.");
        return defaultUnitInfo;
    }
}

// Function to convert points to document units for display (More Robust)
function pointsToDocUnits(points, unitInfo) {
    try {
        if (typeof points !== 'number' || isNaN(points)) {
             $.writeln("Warning: Invalid 'points' value ("+ points +") received in pointsToDocUnits. Returning 0.");
             points = 0;
        }
         if (!unitInfo || typeof unitInfo.name !== 'string' || unitInfo.name === "") {
            $.writeln("Warning: Invalid 'unitInfo' received in pointsToDocUnits. Using points value directly.");
             return points;
         }
        var unitValue = UnitValue(points, "pt");
        return unitValue.as(unitInfo.name);
    } catch (e) {
         $.writeln("!!! ERROR converting points ("+ points +") to doc units ("+ (unitInfo ? unitInfo.name : 'N/A') +"): " + e.message + ". Returning original points value.");
         return points;
    }
}

// Function to convert document units input string to points
function docUnitsInputToPoints(inputString, unitInfo) {
    try {
        var unitValue = UnitValue(inputString);
        // Use unitInfo.name if input is just a number
        if (/^\d+(\.\d+)?$/.test(inputString)) {
             if(unitInfo && unitInfo.name){
                unitValue = UnitValue(parseFloat(inputString), unitInfo.name);
             } else {
                 // If no unitInfo, assume points if just a number
                 unitValue = UnitValue(parseFloat(inputString), "pt");
                 $.writeln("Warning: Assuming points for unitless input due to missing unitInfo.");
             }
        }
        return unitValue.as("pt");
    } catch (e) {
         $.writeln("!!! ERROR converting input string '"+ inputString +"' to points: " + e.message);
        return NaN;
    }
}


function createRealTimeBaselineGridAdjuster() {
    $.writeln("Entering createRealTimeBaselineGridAdjuster function...");

    if (app.documents.length === 0) {
        alert("Please open a document before running this script.");
        $.writeln("No document open. Alert shown. Exiting.");
        return;
    }
    $.writeln("Document found.");

    var doc = app.activeDocument;
    var gridPrefs = doc.gridPreferences;
    $.writeln("Accessing document preferences...");
    var docUnitsInfo = getDocumentVerticalUnits(doc);
    $.writeln("Got document units: " + (docUnitsInfo ? docUnitsInfo.name : 'FAILED TO GET UNITS'));
    var updateFromCheckbox = false;
    var pal, incrementGroup, baselineInput, offsetGroup, firstLineInput;
    var capHeightGroup, capHeightCheckbox, capHeightInfo, closeButton;

    try {
        $.writeln("Attempting to create palette window...");
        pal = new Window("palette", "Live Baseline Grid");
        if (!pal) throw new Error("new Window() failed to return an object.");
        $.writeln(" -> Palette created.");
        pal.orientation = "column";
        pal.alignChildren = "fill";
        pal.spacing = 10;
        pal.margins = 15;
        $.writeln(" -> Palette properties set.");

        // --- Baseline Increment ---
        $.writeln("Adding incrementGroup...");
        incrementGroup = pal.add("group");
        if (!incrementGroup) throw new Error("Failed to add incrementGroup.");
        incrementGroup.orientation = "row";
        incrementGroup.alignChildren = "left";
        incrementGroup.add("statictext", undefined, "Increment (" + docUnitsInfo.name + "):");
        var initialIncrementValue = pointsToDocUnits(gridPrefs.baselineDivision, docUnitsInfo);
        $.writeln(" -> initialIncrementValue = " + initialIncrementValue);
        baselineInput = incrementGroup.add("edittext", undefined, initialIncrementValue.toFixed(3));
        if (!baselineInput) throw new Error("Failed to create baselineInput.");
        baselineInput.characters = 8;
        baselineInput.active = true;

        // --- First Baseline Offset ---
        $.writeln("Adding offsetGroup...");
        offsetGroup = pal.add("group");
        if (!offsetGroup) throw new Error("Failed to add offsetGroup.");
        offsetGroup.orientation = "row";
        offsetGroup.alignChildren = "left";
        offsetGroup.add("statictext", undefined, "Start Offset (" + docUnitsInfo.name + "):");
        var initialOffsetValue = pointsToDocUnits(gridPrefs.baselineStart, docUnitsInfo);
        $.writeln(" -> initialOffsetValue = " + initialOffsetValue);
        firstLineInput = offsetGroup.add("edittext", undefined, initialOffsetValue.toFixed(3));
        if (!firstLineInput) throw new Error("Failed to create firstLineInput.");
        firstLineInput.characters = 8;

        // --- Align to Cap Height ---
        $.writeln("Adding capHeightGroup...");
        capHeightGroup = pal.add("group");
        if (!capHeightGroup) throw new Error("Failed to add capHeightGroup.");
        capHeightGroup.orientation = "column";
        capHeightGroup.alignChildren = "left";
        capHeightCheckbox = capHeightGroup.add("checkbox", undefined, "Align First Line Offset to Cap Height");
        if (!capHeightCheckbox) throw new Error("Failed to create capHeightCheckbox.");
        capHeightCheckbox.helpTip = "Uses Document Text Defaults Font/Size";
        capHeightInfo = capHeightGroup.add("statictext", undefined, "(Uses doc defaults: Font/Size)", { multiline: false, truncate: 'end'});
        if (!capHeightInfo) throw new Error("Failed to create capHeightInfo.");
        capHeightInfo.characters = 30;
        capHeightInfo.enabled = false;

        // --- Update Function ---
        function updateGridSettings(sourceElement) {
            if (updateFromCheckbox) return;
            try {
                var currentIncrementPt = gridPrefs.baselineDivision;
                var currentStartPt = gridPrefs.baselineStart;

                // Apply Increment
                if (sourceElement === baselineInput || !sourceElement) {
                    var newIncrementRaw = baselineInput.text;
                    var newIncrementPt = docUnitsInputToPoints(newIncrementRaw, docUnitsInfo);
                    if (!isNaN(newIncrementPt) && newIncrementPt > 0 && Math.abs(newIncrementPt - currentIncrementPt) > 0.001) {
                        $.writeln("Updating baselineDivision from " + currentIncrementPt + "pt to " + newIncrementPt + "pt");
                        gridPrefs.baselineDivision = newIncrementPt;
                    } else if (isNaN(newIncrementPt)) {
                        $.writeln("Invalid increment input ignored: " + newIncrementRaw);
                    }
                }
                // Apply Start Offset (if checkbox is off)
                if ((sourceElement === firstLineInput || !sourceElement) && !capHeightCheckbox.value) {
                    var newStartRaw = firstLineInput.text;
                    var newStartPt = docUnitsInputToPoints(newStartRaw, docUnitsInfo);
                    if (!isNaN(newStartPt) && newStartPt >= 0 && Math.abs(newStartPt - currentStartPt) > 0.001) {
                        $.writeln("Updating baselineStart from " + currentStartPt + "pt to " + newStartPt + "pt");
                        gridPrefs.baselineStart = newStartPt;
                    } else if (isNaN(newStartPt)) {
                        $.writeln("Invalid start offset input ignored: " + newStartRaw);
                    }
                }
            } catch (e) {
                $.writeln("!!! ERROR in updateGridSettings: " + e.message);
            }
        }
        $.writeln(" -> Update function defined.");

        // Attach event listeners
        baselineInput.onChange = function() { $.writeln("baselineInput onChange triggered."); updateGridSettings(this); };
        firstLineInput.onChange = function() { $.writeln("firstLineInput onChange triggered."); updateGridSettings(this); };

        // Cap Height Checkbox Event
        capHeightCheckbox.onClick = function() {
            $.writeln("capHeightCheckbox onClick triggered. Value: " + this.value);
            if (this.value) {
                try {
                    var mainFont, mainSize;
                    if (doc.textDefaults.appliedFont && typeof doc.textDefaults.appliedFont !== 'string' && doc.textDefaults.pointSize > 0) {
                        mainFont = doc.textDefaults.appliedFont;
                        mainSize = doc.textDefaults.pointSize;
                        $.writeln("Using doc textDefaults: " + mainFont.name + ", " + mainSize + "pt");
                    } else {
                        $.writeln("Doc textDefaults not set or invalid.");
                        alert("Document Text Defaults (Font/Size) are not set or invalid. Cannot calculate Cap Height.");
                        this.value = false;
                        firstLineInput.enabled = true;
                        capHeightInfo.enabled = false;
                        return;
                    }
                    if (typeof mainFont === 'string' || !mainFont.isValid) { 
                        throw new Error("Default font is not valid or missing."); 
                    }
                    var capHeightPt = mainFont.capitalHeight * (mainSize / 1000);
                    $.writeln("Calculated capHeightPt: " + capHeightPt);
                    if (isNaN(capHeightPt) || capHeightPt < 0) { throw new Error("Calculated cap height is invalid."); }
                    updateFromCheckbox = true;
                    $.writeln("Updating baselineStart to capHeight: " + capHeightPt + "pt");
                    gridPrefs.baselineStart = capHeightPt;
                    var capHeightDocUnits = pointsToDocUnits(capHeightPt, docUnitsInfo);
                    $.writeln(" -> capHeight in doc units: " + capHeightDocUnits);
                    firstLineInput.text = capHeightDocUnits.toFixed(3);
                    firstLineInput.enabled = false;
                    capHeightInfo.text = "(Uses: " + mainFont.name + " / " + mainSize + "pt)";
                    capHeightInfo.enabled = true;
                    updateFromCheckbox = false;
                    $.writeln("Cap height applied successfully.");
                } catch (e) {
                    $.writeln("!!! ERROR applying cap height: " + e.message);
                    alert("Could not calculate or apply cap height:\n" + e.message);
                    this.value = false;
                    firstLineInput.enabled = true;
                    capHeightInfo.enabled = false;
                    capHeightInfo.text = "(Uses doc defaults: Font/Size)";
                    updateFromCheckbox = false;
                }
            } else {
                $.writeln("Cap height checkbox unchecked. Enabling manual input.");
                firstLineInput.enabled = true;
                capHeightInfo.enabled = false;
                capHeightInfo.text = "(Uses doc defaults: Font/Size)";
            }
        };

        // Initial state check for checkbox
        if (capHeightCheckbox.value) {
            $.writeln("Triggering initial cap height check...");
            capHeightCheckbox.notify("onClick");
        } else {
            $.writeln("Initial cap height checkbox is not checked.");
        }

        // --- Close Button ---
        $.writeln("Adding Close button...");
        closeButton = pal.add("button", undefined, "Close");
        if (!closeButton) throw new Error("Failed to create Close button.");
        closeButton.onClick = function() { $.writeln("Close button clicked."); pal.close(); };

        // --- Show Palette ---
        $.writeln("Centering palette...");
        pal.center();
        $.writeln("Calling pal.show()...");
        pal.show();
        $.writeln("Palette should now be visible and persistent.");
    } catch (e) {
        $.writeln("\n!!! ERROR during palette creation: " + e.message + " (Line: " + e.line + ")");
        alert("Error creating script window: " + e.message + "\nCheck ESTK Console for details.");
    }
    $.writeln("Exiting createRealTimeBaselineGridAdjuster function.");
}

// --- Run the main function DIRECTLY ---
try {
     $.writeln("Calling createRealTimeBaselineGridAdjuster...");
     createRealTimeBaselineGridAdjuster();
     $.writeln("createRealTimeBaselineGridAdjuster finished.");
} catch(e) {
    $.writeln("!!! FATAL ERROR: " + e.message + " (Line: " + e.line + ")");
    alert("Fatal script error:\n" + e.message);
}

$.writeln("--- Script End ---");