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import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class MainClass {
public static void main(String[] a) {
Display display = new Display();
final Shell shell = new Shell(display);
Region region = new Region();
region.add(createCircle(50, 50, 50));
region.subtract(createCircle(50, 50, 20));
shell.setRegion(region);
shell.setSize(region.getBounds().width, region.getBounds().height);
shell.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
static int[] createCircle(int xOffset, int yOffset, int radius) {
int[] circlePoints = new int[10 * radius];
for (int loopIndex = 0; loopIndex < 2 * radius + 1; loopIndex++) {
int xCurrent = loopIndex - radius;
int yCurrent = (int) Math.sqrt(radius * radius - xCurrent * xCurrent);
int doubleLoopIndex = 2 * loopIndex;
circlePoints[doubleLoopIndex] = xCurrent + xOffset;
circlePoints[doubleLoopIndex + 1] = yCurrent + yOffset;
circlePoints[10 * radius - doubleLoopIndex - 2] = xCurrent + xOffset;
circlePoints[10 * radius - doubleLoopIndex - 1] = -yCurrent + yOffset;
}
return circlePoints;
}
}
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