Snippet134.java Source code

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Here is the source code for Snippet134.java

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/*
 * Shell example snippet: create a non-rectangular window
 *
 * For a list of all SWT example snippets see
 * http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-swt-home/dev.html#snippets
 */
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;

public class Snippet134 {

    static int[] circle(int r, int offsetX, int offsetY) {
        int[] polygon = new int[8 * r + 4];
        // x^2 + y^2 = r^2
        for (int i = 0; i < 2 * r + 1; i++) {
            int x = i - r;
            int y = (int) Math.sqrt(r * r - x * x);
            polygon[2 * i] = offsetX + x;
            polygon[2 * i + 1] = offsetY + y;
            polygon[8 * r - 2 * i - 2] = offsetX + x;
            polygon[8 * r - 2 * i - 1] = offsetY - y;
        }
        return polygon;
    }

    public static void main(String[] args) {
        final Display display = new Display();
        // Shell must be created with style SWT.NO_TRIM
        final Shell shell = new Shell(display, SWT.NO_TRIM | SWT.ON_TOP);
        shell.setBackground(display.getSystemColor(SWT.COLOR_RED));
        // define a region that looks like a key hole
        Region region = new Region();
        region.add(circle(67, 67, 67));
        region.subtract(circle(20, 67, 50));
        region.subtract(new int[] { 67, 50, 55, 105, 79, 105 });
        // define the shape of the shell using setRegion
        shell.setRegion(region);
        Rectangle size = region.getBounds();
        shell.setSize(size.width, size.height);
        // add ability to move shell around
        Listener l = new Listener() {
            Point origin;

            public void handleEvent(Event e) {
                switch (e.type) {
                case SWT.MouseDown:
                    origin = new Point(e.x, e.y);
                    break;
                case SWT.MouseUp:
                    origin = null;
                    break;
                case SWT.MouseMove:
                    if (origin != null) {
                        Point p = display.map(shell, null, e.x, e.y);
                        shell.setLocation(p.x - origin.x, p.y - origin.y);
                    }
                    break;
                }
            }
        };
        shell.addListener(SWT.MouseDown, l);
        shell.addListener(SWT.MouseUp, l);
        shell.addListener(SWT.MouseMove, l);
        // add ability to close shell
        Button b = new Button(shell, SWT.PUSH);
        b.setBackground(shell.getBackground());
        b.setText("close");
        b.pack();
        b.setLocation(10, 68);
        b.addListener(SWT.Selection, new Listener() {
            public void handleEvent(Event e) {
                shell.close();
            }
        });
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        region.dispose();
        display.dispose();
    }
}