package freegraph;

import java.awt.*;
import java.awt.image.*;

/**
 * InvertRectangle is used to draw the zoom rectangle of GraphPlane.  It was
 * originally introduced to work around a stange drawing bug in some old VMs
 * with setXORMode().  However that is fixed, so the work around has been
 * removed, but the class still exists.
 */

class InvertRectangle
{
    public InvertRectangle()
    {
    }

    /**
     * draws an inverted rectangle on the Graphics object
     */
    public void drawRect(Graphics graphics, int x1, int y1,
        int width, int height)
    {
        if (width < 0)
        {
            x1 = x1 + width;
            width = Math.abs(width);
        }
        if (height < 0)
        {
            y1 = y1 + height;
            height = Math.abs(height);
        }
        graphics.setColor(Color.black);
        graphics.setXORMode(Color.white);
        graphics.drawRect(x1, y1, width, height);
        graphics.setPaintMode();
    }
}