Rotate-Objects.groovy

/**
 * Rotate annotations or detections in QuPath.
 *
 * This creates new transformed objects that are then added to the current image hierarchy.
 *
 * Note: Tested and working with version 0.5.1.
 * Note: Watch for objects extending beyond image bounds
 * Note: Inspired from: https://gist.github.com/petebankhead/2cab4873e001ab42e03c864666284c5f
 * TODO: Use RoiTools.transformROI(roi, transform.getRotateInstance(-Math.PI/2))
 *
 * @author Ajay Zalavadia
 */

import java.awt.geom.AffineTransform

// Parameters to adjust
// Use positive value for clockwise and negative values for anti-clockwise rotation
// set to zero to disable rotation
var rotate = -25 
boolean keepExisting = false

// Get selected objects & its ROI
def selected = getSelectedObjects().findAll {it.hasROI()}
if (!selected) {
    print 'No objects selected!'
    return
}

def server = getCurrentServer()

def transformedObjects = selected.collect{
    def transform = new AffineTransform()
    if (rotate != 0){
            double theta = Math.toRadians(rotate)
            def roi = it.getROI()
            double centerX = roi.getCentroidX()
            double centerY = roi.getCentroidY()
            transform.rotate(theta, centerX, centerY)
    }

    PathObjectTools.transformObject(it, transform, false)
}

if (!keepExisting)
    removeObjects(selected, true)

addObjects(transformedObjects)
selectObjects(transformedObjects)