How do you center a layer in a Photoshop script?

Question

My Photoshop Canvas is 900X600.

The function below takes Layer X and makes Layer X copy .

It takes Layer X copy and while maintaining the ratio adjusts the height to 600px. var newdLayer

It takes Layer X and while maintaining the ratio adjusts the width to 900px and applies the Gaussian Blur. var blur .

It then merges Layer X and Layer X copy .

The problem is that if Layer X is not centered in the beginning of the script then it malfunctions.

How to add center layer to Layer X in the beginning of the script?

 (function (){ var docRef = activeDocument var blur = docRef.activeLayer; var newdLayer = blur.duplicate(); var startRulerUnits = app.preferences.rulerUnits; app.preferences.rulerUnits = Units.PIXELS; // since we resize based on the initial size of the source layer, // we don't need to get the bounds twice var bounds = blur.bounds; var height = bounds[3].value - bounds[1].value; var width = bounds[2].value - bounds[0].value; // declare 2 different vars for your sizes (there are better ways to do this, but // since you say you aren't a JavaScript pro, I figured I'd keep it simple) var newSize600 = (100 / height) * 600; var newSize900 = (100 / width) * 900; // resize your layers newdLayer.resize(newSize600, newSize600, AnchorPosition.MIDDLECENTER); blur.resize(newSize900, newSize900, AnchorPosition.MIDDLECENTER); // apply blur blur.applyGaussianBlur(5); // below creates the group, moves the layers to it and merges them. Feel free to just include this part // at the end of your function if you don't want to use the modified code above. // create a new layer set var groupOne = docRef.layerSets.add(); // move the blur layer inside the layer set and name the layer for posterity blur.move(groupOne, ElementPlacement.INSIDE); blur.name = "blur"; // move the newdLayer inside and rename newdLayer.move(groupOne, ElementPlacement.INSIDE); newdLayer.name = "newdLayer"; // merge the layer set and name the new layer var mergedGroup = groupOne.merge(); mergedGroup.name = "newdLayer + blur"; app.preferences.rulerUnits = startRulerUnits; })(); 

Answer 1

What you need to do is to calculate difference between layer center and document center and then translate the blur layer by that difference before making a copy.

To calculate the layer center you take bound[0].value and bound[1].value (distances from the left top corner of the document to the top left corner of the layer) and add half of the width and half of the height . And then to calculate the deltas you subtract layer center coordinates from document center coordinate.

Here's the code:

(function()
{

    var startRulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;

    var docRef = activeDocument;
    var blur = docRef.activeLayer;

    // since we resize based on the initial size of the source layer, 
    // we don't need to get the bounds twice
    var bounds = blur.bounds;
    var height = bounds[3].value - bounds[1].value;
    var width = bounds[2].value - bounds[0].value;

    /////////////////////////////////////////////////////////////////////////////////////
    // Centering the layer

    // Getting center coordinates of the document
    var docCenterW = docRef.width.as("px") / 2;
    var docCenterH = docRef.height.as("px") / 2;

    // getting values to translate the layer. 
    var deltaX = Math.round(docCenterW - (bounds[0].value + width / 2));
    var deltaY = Math.round(docCenterH - (bounds[1].value + height / 2));

    blur.translate(deltaX, deltaY);
    /////////////////////////////////////////////////////////////////////////////////////

    var newdLayer = blur.duplicate();

    // declare 2 different vars for your sizes (there are better ways to do this, but
    // since you say you aren't a JavaScript pro, I figured I'd keep it simple)
    var newSize600 = (100 / height) * 600;
    var newSize900 = (100 / width) * 900;
    // resize your layers
    newdLayer.resize(newSize600, newSize600, AnchorPosition.MIDDLECENTER);
    blur.resize(newSize900, newSize900, AnchorPosition.MIDDLECENTER);
    // apply blur
    blur.applyGaussianBlur(5);

    // below creates the group, moves the layers to it and merges them. Feel free to just include this part
    // at the end of your function if you don't want to use the modified code above. 

    // create a new layer set
    var groupOne = docRef.layerSets.add();

    // move the blur layer inside the layer set and name the layer for posterity
    blur.move(groupOne, ElementPlacement.INSIDE);
    blur.name = "blur";

    // move the newdLayer inside and rename
    newdLayer.move(groupOne, ElementPlacement.INSIDE);
    newdLayer.name = "newdLayer";

    // merge the layer set and name the new layer
    var mergedGroup = groupOne.merge();
    mergedGroup.name = "newdLayer + blur";

    app.preferences.rulerUnits = startRulerUnits;

})();