GroupTest.java

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.*;
import javafx.scene.paint.*;
import javafx.scene.shape.*;
import javafx.geometry.Bounds;
import javafx.collections.*;
import java.util.List;
import java.lang.Math;

public class GroupTest extends Application {
    public void start(Stage stage) {
        Group grp = new Group();
        Scene scene = new Scene(grp, 400, 400);

	grp.setTranslateX(scene.getWidth()/2);
	grp.setTranslateY(scene.getHeight()/2);
	double res = 96;
	grp.setScaleX(res);
	grp.setScaleY(res);

	//grp.setRotate(10.0);

	Grid.draw(grp);

	List<String> args = getParameters().getRaw();
	int mode = 0;
	if (args.size()>0) mode = Integer.parseInt(args.get(0));
	System.out.println("mode " + mode);


	drawTest(grp,mode);

	

        stage.setTitle("Group Test");
        stage.setScene(scene);
        stage.show();
    }

   
	void show_elements(Group grp) {
		ObservableList<Node> ol = grp.getChildren();
		for (Node n: ol) System.out.println(n);
	}

   void show_bounds(Group grp) {
	double xcen, ycen;
	Bounds b1 = grp.getBoundsInLocal();
	//System.out.println("BoundsInLocal: " + b1);
	xcen = 0.5*(b1.getMinX()+b1.getMaxX());
	ycen = 0.5*(b1.getMinY()+b1.getMaxY());
	System.out.format("\nBoundsInLocal: xcen %g ycen %g width %g height %g\n",
	xcen, ycen, b1.getWidth(), b1.getHeight());
	Bounds b2 = grp.getBoundsInParent();
	xcen = 0.5*(b2.getMinX()+b2.getMaxX());
	ycen = 0.5*(b2.getMinY()+b2.getMaxY());
	//System.out.println("BoundsInParent: " + b2);
	System.out.format("BoundsInParent: xcen %g ycen %g width %g height %g\n",
	xcen, ycen, b2.getWidth(), b2.getHeight());
   }



   void drawTest(Group parent, int mode)
   {

	Group grp = new Group();
	double resc = 0.1;
	grp.setScaleX(resc);
	grp.setScaleY(resc);


	double res = parent.getScaleX();
	Rectangle r = new Rectangle(-3,-2,6,4);
	r.setFill(null);
	r.setStrokeWidth(10/res);
	r.setStroke(Color.RED);
	if (mode>1) grp.getChildren().add(r);
	double xoff = 0.0;
	if (mode>0) xoff = -1.00;
	Circle cir= new Circle(xoff,0.0,2.0);
	cir.setFill(null);
	cir.setStrokeWidth(10/res);
	cir.setStroke(Color.BLACK);
	grp.getChildren().add(cir);
	
	


	ObservableList<Node> ol = grp.getChildren();

	// mark origin with orange X
	Line g = new Line(-0.5,0.5,0.5,-0.5);
	g.setStroke(Color.ORANGE);
	g.setStrokeWidth(20/res);
	ol.add(g);
	g = new Line(-0.5,-0.5,0.5,0.5);
	g.setStroke(Color.ORANGE);
	g.setStrokeWidth(20/res);
	ol.add(g);

	parent.getChildren().add(grp);

	double xpos = 0.0, ypos = 0.0;
	grp.setTranslateX(xpos);
	grp.setTranslateY(-ypos);

	show_bounds(grp);

   }
}