/*
* $Id: SimpleTutorial.java,v 1.11 2005/07/08 19:55:00 cxh Exp $
*
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*
*/
package diva.canvas.tutorial;
import java.awt.Color;
import java.awt.geom.GeneralPath;
import javax.swing.SwingUtilities;
import diva.canvas.Figure;
import diva.canvas.FigureLayer;
import diva.canvas.GraphicsPane;
import diva.canvas.JCanvas;
import diva.canvas.toolbox.BasicFigure;
import diva.canvas.toolbox.BasicRectangle;
import diva.gui.BasicFrame;
import diva.util.java2d.Polyline2D;
/**
* <p> This tutorial shows how to construct a JCanvas and place
* figures on it.
* <p>
* <img src="doc-files/SimpleTutorial.gif" align="right">
*
* <P> In this example, we create figures with a few
* different shapes, using the BasicFigure class in
* <b>diva.canvas.toolbox</b>, which takes an instance of Shape (an
* interface defined in the Java AWT) and draws it on the screen using
* given colors and strokes.
*
* <p> Each JCanvas contains by default an instance of GraphicsPane.
* To get the graphics pane from a JCanvas:
*
* <pre>
* GraphicsPane graphicsPane = (GraphicsPane)canvas.getCanvasPane();
* </pre>
*
* The pane contains several layers, one of which is a foreground
* FigureLayer upon which figures are drawn and interacted with. To
* get the figure layer:
*
* <pre>
* FigureLayer layer = graphicsPane.getForegroundLayer();
* </pre>
*
* There are three figures on the screen, each created using a
* different kind of shape. The code to create a rectangle and add it
* to the figure layer is:
*
* <pre>
* Figure rectangle = new BasicRectangle(10,10,100,100,Color.blue);
* layer.add(rectangle);
* </pre>
*
* The code to create the curved shape is more complex, and uses an
* instance of <b>java.awt.geom.GeneralPath</b>.
*
* <pre>
* GeneralPath path = new GeneralPath();
* path.moveTo(120,240);
* path.lineTo(240,240);
* path.quadTo(180,120,120,240);
* path.closePath();
* Figure semi = new BasicFigure(path, Color.green);
* layer.add(semi);
* </pre>
*
* The third figure is much the same, but uses an instance of
* <b>diva.util.java2d.Polyline2D</b>. Polyline2D is more efficient
* than GeneralPath, and should be used anytime only straight-line
* segments are needed.
*
* @author John Reekie
* @version $Id: SimpleTutorial.java,v 1.11 2005/07/08 19:55:00 cxh Exp $ */
public class SimpleTutorial {
// The JCanvas
private JCanvas canvas;
// The GraphicsPane
private GraphicsPane graphicsPane;
/** Create a JCanvas and put it into a window
*/
public SimpleTutorial() {
canvas = new JCanvas();
graphicsPane = (GraphicsPane) canvas.getCanvasPane();
BasicFrame frame = new BasicFrame("Simple canvas tutorial", canvas);
frame.setSize(600, 400);
frame.setVisible(true);
}
/** Create a rectangle figure. The rectangle is an instance of
* the BasicRectangle class. This class, together with a number
* other useful predefined figure classes, is contained in the
* package <b>diva.canvas.toolbox</b>.
*/
public void createBasicRectangle() {
FigureLayer layer = graphicsPane.getForegroundLayer();
Figure rectangle = new BasicRectangle(50, 50, 80, 80, Color.blue);
layer.add(rectangle);
}
/** Create an odd-shaped figure. The rectangle is an instance of
* the BasicShape class, which draws itself using any instance
* of the Java2D interface, <b>java.awt.Shape</b>. In this example,
* we use an instance of GeneralPath.
*/
public void createBasicFigure() {
FigureLayer layer = graphicsPane.getForegroundLayer();
GeneralPath path = new GeneralPath();
path.moveTo(120, 240);
path.lineTo(240, 240);
path.quadTo(180, 120, 120, 240);
path.closePath();
Figure semi = new BasicFigure(path, Color.green);
layer.add(semi);
}
/** Create a polyline. Again, this uses the BasicFigure class,
* but this time the shape is an instance of <b>diva.util.Polyline2D</b>.
*/
public void createPolyline() {
FigureLayer layer = graphicsPane.getForegroundLayer();
Polyline2D path = new Polyline2D.Double();
path.moveTo(240, 120);
path.lineTo(280, 140);
path.lineTo(240, 160);
path.lineTo(280, 180);
path.lineTo(240, 200);
path.lineTo(280, 220);
path.lineTo(240, 240);
Figure line = new BasicFigure(path);
layer.add(line);
}
/** Main function
*/
public static void main(String[] argv) {
// Always invoke graphics code in the event thread
SwingUtilities.invokeLater(new Runnable() {
public void run() {
SimpleTutorial ex = new SimpleTutorial();
ex.createBasicRectangle();
ex.createBasicFigure();
ex.createPolyline();
}
});
}
}