faceDetectionToRoi function
Implementation
RectF faceDetectionToRoi(RectF bbox, {double expandFraction = 0.6}) {
final e = bbox.expand(expandFraction);
final cx = (e.xmin + e.xmax) * 0.5;
final cy = (e.ymin + e.ymax) * 0.5;
final s = math.max(e.w, e.h) * 0.5;
return RectF(cx - s, cy - s, cx + s, cy + s);
}