/** Update the drawableBounds member according to insideBounds and spacing. */
protected void updateDrawableBounds() {
// here, we would like to avoid Rectangle creation
drawableBounds.x = insideBounds.x - spacing.left;
drawableBounds.y = insideBounds.y - spacing.top;
drawableBounds.width = insideBounds.width + spacing.left + spacing.right;
drawableBounds.height = insideBounds.height + spacing.top + spacing.bottom;
Dimension d = getDepth();
backRectangle.setToBackRectangleOf(insideBounds, d);
frontRectangle.setToFrontRectangleOf(insideBounds, d);
}