diva.canvas.tutorial
Class CompositeFigureTutorial

java.lang.Object
  diva.canvas.tutorial.CompositeFigureTutorial

public class CompositeFigureTutorial
extends java.lang.Object

This tutorial demonstrates how to use composite figures.

It instantiates a composite figure which contains a square (which represents the body of a component) and four circles (which represents "ports" on the component). The ports can be moved and scaled independently of the body, and when the body is scaled, the ports are scaled proportionally.

In general, it would be better to create a custom class for something like a component with port -- the purpose here is simply to illustrate how to use this class. The way that the composite figure is created is straight-forward:

     CompositeFigure tc = new CompositeFigure();
 

Adding child figures to the composite figure is also straight-forward. For example,

     Figure p1 = new BasicEllipse(150.0, 100.0, 20.0, 20.0, Color.red);
     p1.translate(-10,-10);
     tc.add(p1);
 

(The call to translate is there simply because it was easier to figure out the coordinates of all the figures relative to their centers. The translate() moves the center to the coordinates set in the call to the constructor.)

In this tutorial we also introduce the notion of controllers and interactors. Any but the simplest interactive graphical applications should have a controller object that takes care of managing user interaction. The class diva.canvas.toolbox.BasicController is a very basic interaction controller that we use in some of the tutorials. It contains an object called a DragInteractor that is used to move figures about on the screen:

     BasicController controller = new BasicController(graphicsPane);
     Interactor defaultInteractor = controller.getSelectionInteractor();
 

To make each figure respond to the mouse, we just give it the interactor. For example,

     p1.setInteractor(defaultInteractor);
 

In this example, an interactor is set up on each port so that they can be dragged independently, and an interactor is set up on the composite figure itself, so dragging on any figure that is not part of the background itself will drag the whole figure and its contents.

Version:

$Id: CompositeFigureTutorial.java 38798 2005-07-08 20:00:01Z cxh $

Author:

John Reekie, Michael Shilman

Accepted Rating:

Red

Field Summary

private JCanvas	canvas
(package private) BasicController	controller
(package private) Interactor	defaultInteractor
private GraphicsPane	graphicsPane
(package private) FigureLayer	layer

Constructor Summary

CompositeFigureTutorial()
Create a JCanvas and put it into a window.

Method Summary

void	addPorts(CompositeFigure tc) Utility function to add the "ports" to the composite figure.
void	createBackgroundedCompositeFigure() Create a composite figure that uses the background facility.
void	createCompositeFigure() Create a composite figure that does not have a background
static void	main(java.lang.String[] argv) Main function

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

canvas

private JCanvas canvas

graphicsPane

private GraphicsPane graphicsPane

layer

FigureLayer layer

controller

BasicController controller

defaultInteractor

Interactor defaultInteractor

Constructor Detail

CompositeFigureTutorial

public CompositeFigureTutorial()

Create a JCanvas and put it into a window.

Method Detail

main

public static void main(java.lang.String[] argv)

Main function

createCompositeFigure

public void createCompositeFigure()

Create a composite figure that does not have a background

createBackgroundedCompositeFigure

public void createBackgroundedCompositeFigure()

Create a composite figure that uses the background facility. Generally, for figures of this nature, this is a better thing to do.

addPorts

public void addPorts(CompositeFigure tc)

Utility function to add the "ports" to the composite figure.