//Print the flag by pressing the "Print Screen" key; then paste the
//clipboard into another document.

//The following two lines are needed to open and close a window.
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

//The following two lines are needed to let the window repaint itself.
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;

//The following two lines are needed for what we want to draw in the window.
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;

public class FlagSWT {
	public static void main(String[] args) {

		// The following two lines are needed to open the window.
		final Display display = new Display();
		final Shell shell = new Shell(display);

		// Everything from Point A to Point B will be executed
		// whenever the window needs to be redrawn.
		shell.addPaintListener(new PaintListener() {
			public void paintControl(PaintEvent e) {

				// Point A
				GC gc = e.gc; // Graphics Context: the pen you draw with
				final int nrows = 200; // number of rows of pixels
				final int ncols = 300; // number of columns of pixels

				for (int row = 0; row < nrows; ++row) {
					for (int col = 0; col < ncols; ++col) {
						Color color;

						// The last three arguments of Color are the amount of
						// red, green, blue:
						// minimum amount is zero, maximum is 255.
						// The && means "and".
						if (row < nrows / 2 && col < ncols / 2) {
							// blue union jack in upper left corner.
							color = new Color(display, 0, 0, 255);
						} else if (row % 20 < 10) {
							// red horizontal stripe
							color = new Color(display, 255, 0, 0);
						} else {
							// white horizontal stripe
							color = new Color(display, 255, 255, 255);
						}

						gc.setForeground(color);

						// Change the pixel at location col, row to the
						// foreground color.
						gc.drawPoint(col, row);

						color.dispose(); // don't need this color any more
					}
				}

				gc.dispose(); // don't need gc any more
				// Point B
			}
		});

		shell.setText("American flag");
		shell.open();

		// The following six lines are needed to close the window.
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}
}