PolygonExample.java Source code

Introduction

Here is the source code for PolygonExample.java

Source

//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This class demonstrates drawing polygons
 */
public class PolygonExample {
    private Text txtWidth = null;
    private Text txtHeight = null;

    /**
     * Runs the application
     */
    public void run() {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("Polygon Example");
        createContents(shell);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        display.dispose();
    }

    /**
     * Creates the main window's contents
     * 
     * @param shell the main window
     */
    private void createContents(Shell shell) {
        shell.setLayout(new FillLayout(SWT.VERTICAL));

        // Create the canvas to draw the polygons on
        Canvas drawingCanvas = new Canvas(shell, SWT.NONE);
        drawingCanvas.addPaintListener(new PolygonExamplePaintListener());
    }

    /**
     * This class gets the user input and draws the requested oval
     */
    private class PolygonExamplePaintListener implements PaintListener {
        public void paintControl(PaintEvent e) {
            // Get the canvas for drawing and its dimensions
            Canvas canvas = (Canvas) e.widget;
            int x = canvas.getBounds().width;
            int y = canvas.getBounds().height;

            // Set the drawing color
            e.gc.setBackground(e.display.getSystemColor(SWT.COLOR_BLACK));

            // Create the points for drawing a triangle in the upper left
            int[] upper_left = { 0, 0, 200, 0, 0, 200 };

            // Create the points for drawing a triangle in the lower right
            int[] lower_right = { x, y, x, y - 200, x - 200, y };

            // Draw the triangles
            e.gc.fillPolygon(upper_left);
            e.gc.fillPolygon(lower_right);
        }
    }

    /**
     * The application entry point
     * 
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new PolygonExample().run();
    }
}