// This example is from _Java Examples in a Nutshell_. (http://www.oreilly.com)
// Copyright (c) 1997 by David Flanagan
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for non-commercial purposes.
// For any commercial use, see http://www.davidflanagan.com/javaexamples

import java.applet.*;
import java.awt.*;

/**
 * An applet that demonstrates most of the graphics primitives in java.awt.Graphics.
 **/
public class GraphicsSampler extends Applet
{
  Image image;
  Image background;

  // Initialize the applet
  public void init()
  {
    this.setBackground(Color.lightGray);
    image = this.getImage(this.getDocumentBase(), "tiger.gif");
    background = this.getImage(this.getDocumentBase(), "background.gif");
  }

  // Draw the applet whenever necessary
  public void paint(Graphics g)
  {
    Color fill = new Color(200, 200, 200);
    Color outline = Color.blue;
    Color textcolor = Color.red;
    Font font = new Font("sansserif", Font.BOLD, 14);
    g.setFont(font);

    // get a background image and tile it
    tile(g, this, background);

    // Draw a line
    g.setColor(outline);
    g.drawLine(25, 10, 150, 80);
    centerText("drawLine()", null, g, textcolor, 25, 10, 150, 80);

    // Draw an arc
    g.setColor(fill);
    g.fillArc(225, 10, 150, 80, 90, 135);
    g.setColor(outline);
    g.drawArc(225, 10, 150, 80, 90, 135);
    centerText("fillArc()", "drawArc()", g, textcolor, 225, 10, 150, 80);

    // Draw a rectangle
    g.setColor(fill);
    g.fillRect(25, 110, 150, 80);
    g.setColor(outline);
    g.drawRect(25, 110, 150, 80);
    centerText("fillRect()", "drawRect()", g, textcolor, 25, 110, 150, 80);

    // Draw a rounded rectangle
    g.setColor(fill);
    g.fillRoundRect(225, 110, 150, 80, 20, 20);
    g.setColor(outline);
    g.drawRoundRect(225, 110, 150, 80, 20, 20);
    centerText("fillRoundRect()", "drawRoundRect()", g, textcolor,
               225, 110, 150, 80);

    // Draw a 3D rectangle (clear an area for it first)
    g.setColor(fill);
    g.clearRect(20, 205, 160, 90);
    g.draw3DRect(25, 210, 150, 80, true);
    g.draw3DRect(26, 211, 148, 78, true);
    g.draw3DRect(27, 212, 146, 76, true);
    centerText("draw3DRect()", "x 3", g, textcolor, 25, 210, 150, 80);

    // Draw an oval
    g.setColor(fill);
    g.fillOval(225, 210, 150, 80);
    g.setColor(outline);
    g.drawOval(225, 210, 150, 80);
    centerText("fillOval()", "drawOval()", g, textcolor, 225, 210, 150, 80);

    // Draw a polygon
    int numpoints = 9;
    int[] xpoints = new int[numpoints+1];
    int[] ypoints = new int[numpoints+1];
    for(int i=0; i < numpoints; i++) {
      double angle = 2*Math.PI * i / numpoints;
      xpoints[i] = (int)(100 + 75*Math.cos(angle));
      ypoints[i] = (int)(350 - 40*Math.sin(angle));
    }
    g.setColor(fill);
    g.fillPolygon(xpoints, ypoints, numpoints);
    g.setColor(outline);
    xpoints[numpoints] = xpoints[0];  ypoints[numpoints] = ypoints[0];
    g.drawPolygon(xpoints, ypoints, numpoints+1);
    centerText("fillPolygon()", "drawPolygon()", g, textcolor,
               25, 310, 150, 80);

    // Center and draw an image
    int w = image.getWidth(this);
    int h = image.getHeight(this);
    g.drawImage(image, 225 + (150-w)/2, 310 + (80-h)/2, this);
    centerText("drawImage()", null, g, textcolor,  225, 310, 150, 80);
  }

  // Utility method to tile an image on the background
  protected void tile(Graphics g, Component c, Image i)
  {
    Rectangle r = c.getBounds();  // use c.bounds() in Java 1.0.x
    int iw = i.getWidth(c);
    int ih = i.getHeight(c);
    if ((iw <= 0) || (ih <= 0)) return;
    for(int x=0; x < r.width; x += iw)
      for(int y=0; y < r.height; y += ih)
        g.drawImage(i, x, y, c);
  }

  // Utility method to center text in a rectangle
  protected void centerText(String s1, String s2, Graphics g, Color c,
                            int x, int y, int w, int h)
  {
    Font f = g.getFont();
    FontMetrics fm = Toolkit.getDefaultToolkit().getFontMetrics(f);
    int ascent = fm.getAscent();
    int height = fm.getHeight();
    int width1=0, width2 = 0, x0=0, x1=0, y0=0, y1=0;
    width1 = fm.stringWidth(s1);
    if (s2 != null) width2 = fm.stringWidth(s2);
    x0 = x + (w - width1)/2;
    x1 = x + (w - width2)/2;
    if (s2 == null)
      y0 = y + (h - height)/2 + ascent;
    else {
      y0 = y + (h - (int)(height * 2.2))/2 + ascent;
      y1 = y0 + (int)(height * 1.2);
    }
    g.setColor(c);
    g.drawString(s1, x0, y0);
    if (s2 != null) g.drawString(s2, x1, y1);
  }
}