// file:    testGraphics6.java
// author:  Robert Keller
// purpose: faster animation
//          

/* This program is similar to testGraphics5.  However, rather than redraw
   the logo image by drawing its components each time, we make one image
   then draw that.  This makes the update considerable faster.
*/

import java.awt.*;                      // to get awt (abstract window toolkit)
import java.lang.Thread;

class testGraphics6 extends Frame       // needed to allow over-ride of paint
{                                       // consider this to be magic for now

Image image;                            // image provides graphics buffer

Image logo;				// Logo to be displayed

// paint(Graphics) will be called by the system to paint the Frame when 
// necessary.  At that time, the Graphics of the frame will be passed as 
// an argument.

public void paint(Graphics g)
  {
  g.drawImage(image, 0, 0, null);
  }


public void update(Graphics g)
  {
  paint(g);
  }

// draw stuff at position x, y

void drawStuff(int x, int y)
  {
  Graphics g = image.getGraphics();
  g.drawImage(logo, x, y, null);
  }


// Draw Logo on indicate graphics

static void drawLogoOn(Graphics g)		
  {
  g.setColor(Color.black);                        // set the color for drawing
  g.drawRect(50, 50, 400, 300);                   // draw a rectangle

  g.setColor(Color.blue);
  g.fillOval(100, 100, 300, 200);                 // fill an oval

  g.setColor(Color.yellow);
  g.drawOval(100, 100, 300, 200)    ;             // draw an oval

  g.setFont(new Font("Times", Font.BOLD, 28));  
  g.drawString("Harvey Mudd College", 140, 210);  // draw a string
  }


public static void main(String[] arg)
  {
  testGraphics6 frame = new testGraphics6();      // create the frame

  frame.setBackground(Color.white);               // avoid startup flicker

  frame.reshape(50, 50, 600, 500);                // set the location and size

  frame.show();                                   // show the frame 

  // Note: the following must be done AFTER the frame is shown.

  frame.image = frame.createImage(frame.size().width, frame.size().height);

  frame.logo = frame.createImage(frame.size().width, frame.size().height);

  drawLogoOn(frame.logo.getGraphics());		  // draw logo
  
  for( int i = 0; i < 100; i += 1 )
    { 
    frame.drawStuff(i, i);
    try{Thread.sleep(5);} catch(Exception e){}  // delay 5 milliseconds
    frame.repaint();
    }
  }
}