QuPath-Create concentric rings around an annotation

QuPath-Concentric rings.groovy

/**
 * QuPath script to create concentric rings around an annotation.
 */

// Number of rings to create
int nRings = 5

// Define distance in µm, then convert (or just go straight to defining in pixels)
double distanceMicrons = 100
double distancePixels = distanceMicrons / getCurrentServer().getPixelCalibration().getAveragedPixelSizeMicrons()

def currentROI = getSelectedROI()
def mergedROI = null
def newAnnotations = []
for (int i = 0; i < nRings; i++) {
    // Expand the ROI
    def nextROI = RoiTools.buffer(currentROI, distancePixels)
    // Accumulate all the ROIs so that we can subtract them together
    mergedROI = mergedROI == null ? currentROI : RoiTools.union(mergedROI, currentROI)
    // Subtract the accumulated ROIs to get an outer ring
    nextROI = RoiTools.subtract(nextROI, mergedROI)
    // Create an annotation and add it to a list
    newAnnotations << PathObjects.createAnnotationObject(nextROI)
    // Prepare for the next iteration
    currentROI = nextROI
}
// Add all our annotations
addObjects(newAnnotations)