Demonstrates drawing an Arc : 2D « SWT JFace Eclipse « Java

Demonstrates drawing an Arc

Demonstrates drawing an Arc

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

//Rob Warner (
//Robert Harris (

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

 * This class demonstrates drawing an Arc
public class ArcExample {
  private Text txtWidth = null;
  private Text txtHeight = null;
  private Text txtBeginAngle = null;
  private Text txtAngle = null;

   * Runs the application
  public void run() {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Arc Example");

    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {

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

    // Create the composite that holds the input fields
    Composite widgetComposite = new Composite(shell, SWT.NONE);
    widgetComposite.setLayout(new GridLayout(2, false));

    // Create the input fields
    new Label(widgetComposite, SWT.NONE).setText("Width:");
    txtWidth = new Text(widgetComposite, SWT.BORDER);

    new Label(widgetComposite, SWT.NONE).setText("Height");
    txtHeight = new Text(widgetComposite, SWT.BORDER);

    new Label(widgetComposite, SWT.NONE).setText("Begin Angle:");
    txtBeginAngle = new Text(widgetComposite, SWT.BORDER);

    new Label(widgetComposite, SWT.NONE).setText("Angle:");
    txtAngle = new Text(widgetComposite, SWT.BORDER);

    // Create the button that launches the redraw
    Button button = new Button(widgetComposite, SWT.PUSH);

    // Create the canvas to draw the arc on
    final Canvas drawingCanvas = new Canvas(shell, SWT.NONE);
    drawingCanvas.addPaintListener(new ArcExamplePaintListener());

    // Add a handler to redraw the arc when pressed
    button.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent e) {

   * This class gets the user input and draws the requested arc
  private class ArcExamplePaintListener 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;

      // Determine user input, defaulting everything to zero.
      // Any blank fields are converted to zero
      int width = 0;
      int height = 0;
      int begin = 0;
      int angle = 0;

      try {
        width = txtWidth.getText().length() == 0 ? 0 : Integer.parseInt(txtWidth
        height = txtHeight.getText().length() == 0 ? 0 : Integer
        begin = txtBeginAngle.getText().length() == 0 ? 0 : Integer
        angle = txtAngle.getText().length() == 0 ? 0 : Integer.parseInt(txtAngle
      } catch (NumberFormatException ex) {
        // Any problems, reset them all to zero
        width = 0;
        height = 0;
        begin = 0;
        angle = 0;
      // Set the drawing color to black

      // Draw the arc, centered on the canvas
          .fillArc((x - width) / 2, (y - height) / 2, width, height, begin, angle);

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


Related examples in the same category

1.SWT 2D Chart: FlowchartSWT 2D Chart: Flowchart
2.Use of Java2D on SWT or Draw2D graphical contextUse of Java2D on SWT or Draw2D graphical context
3.SWT 2D UnicodeSWT 2D Unicode
4.SWT 2D Simple DemoSWT 2D Simple Demo
5.SWT Draw 2DSWT Draw 2D
6.SWT Draw2D Example
8.Animations ExampleAnimations Example
9.Alpha Fade InAlpha Fade In
11.Draw Text DemoDraw Text Demo
12.GC Creation
15.Draw2D SampleDraw2D Sample
16.Class AnalyzerClass Analyzer
17.Demonstrates animation. It uses double buffering.Demonstrates animation. It uses double buffering.
18.Demonstrates drawing polygonsDemonstrates drawing polygons
19.Demonstrates drawing points. It draws a sine waveDemonstrates drawing points. It draws a sine wave
20.Draw Round RectangleDraw Round Rectangle
21.Displays information about the display deviceDisplays information about the display device
22.Demonstrates the effects of the flags on the constructorDemonstrates the effects of the flags on the constructor
23.Demonstrates how to draw vertical textDemonstrates how to draw vertical text
24.Utility methods for drawing graphics
25.Demonstrates drawing linesDemonstrates drawing lines
26.Demonstrates animationDemonstrates animation
27.Demonstrates how to draw textDemonstrates how to draw text
28.Demonstrates drawing ovalsDemonstrates drawing ovals
29.Demonstrates how to draw text in colorsDemonstrates how to draw text in colors
30.SWT Paint Example
31.SWT Graphics ExampleSWT Graphics Example
32.SWT OpenGL snippet: draw a square
33.Drawing with transformations, paths and alpha blendingDrawing with transformations, paths and alpha blending
34.Draw lines and polygons with different cap and join stylesDraw lines and polygons with different cap and join styles
35.GC: implement a simple scribble programGC: implement a simple scribble program
36.GC: measure a stringGC: measure a string
37.GC example: draw a thick lineGC example: draw a thick line
38.How to draw directly on an SWT ControlHow to draw directly on an SWT Control
39.SWT useful utilities