added PrintWithGraphics::getLayer()

Author: i-make-robots

src/main/java/com/marginallyclever/nodegraphcore/PrintWithGraphics.java

@@ -12,4 +12,10 @@ public interface PrintWithGraphics {
      * @param g the {@link java.awt.Graphics} context.
      */
     void print(java.awt.Graphics g);
+
+    /**
+     * The lowest layer is drawn first.
+     * @return the layer number.
+     */
+    int getLayer();
 }

src/main/java/com/marginallyclever/nodegraphcore/Subgraph.java

@@ -158,4 +158,9 @@ public void print(Graphics g) {
             }
         }
     }
+
+    @Override
+    public int getLayer() {
+        return 0;
+    }
 }