/*		JavaDraw
		Troy Downing

  This applet is a simple drawing application. It allows the user
  to select certain drawing tools and paint them to the screen. It
  is intended to demonstrate certain elements of the java.awt.Graphics
  class, so little attention has been put in making it a full-featured
  drawing application.

*/

import java.awt.*;

public class JavaDraw extends java.applet.Applet {

	MyWidgets WControls; // user interface stuff
	MyColors ColorControls;
	static Rectangle DrawSize; // the size of the applet

	public void init() {
	   DrawSize  = bounds(); //get current applet boundary
           setLayout(new BorderLayout()); //use the BorderLayout
           MyCanvas c = new MyCanvas(); //create a new canvas
           add("North", WControls = new MyWidgets(c)); //add controls to 
                                                       //bottom of applet
           add("Center", c); //add new canvas to center of applet
	   add("South", ColorControls = new MyColors(c)); //add Color buttons
	}

    public void start() { //called to start applet
        ColorControls.enable(); //enable the control panel
        WControls.enable(); //enable the control panel
    }
    public void stop() { //called to stop the applet
        ColorControls.disable(); //disable the control panel
        WControls.disable(); //disable the control panel
    }
}

class MyCanvas extends Canvas {

	int drawX; //The X coordinate to draw an object
	int drawY; //The Y coordinate to draw an object
	int drawH; //The height of the object
	int drawW; //The width of the object
	String mt; //Text string

/*
   The following are essentially enums in C. Just makes it easier to
   use the values in the switch statements I'm using in the paint()
   method
*/
	final int RESET = 0; //reset drawing field
	final int RECT = 1; //rectangle
	final int FRECT = 2; //filled rectangle
	final int CIRC	= 3; //circle
	final int FCIRC = 4; //filled circle
	final int LINE = 5; //line
	final int TEXT = 6; //text

	final int BLUE	= 10;
	final int RED = 11;
	final int BLACK = 12;
	final int YELLOW = 13;
	final int GREEN = 14;
	final int GRAY = 15;

	int drawCol = BLACK; //current drawing Color
	int drawAct = LINE; //current drawing mode


/*
   the following is the main drawing routine of the applet.
   There is no persistance of drawn objects, so if the applet
   is obscured, and then brought front again, only the most
   recently drawn object will be redrawn.
*/
	public void paint(Graphics g) {
	   g.setColor(Color.lightGray); //common background color
	   Rectangle r = bounds(); //get the applet dimensions
	   if(drawAct==RESET) //check for a reset, to clear screen
		g.fillRect(0,0,r.width,r.height); //fill screen
	   else {
	   	g.fillRect(0,0,80,15); //cover drawing message
		g.setColor(Color.black);
		g.drawRect(0,0,80,15); //draw black rect around message box
	   }
	   g.setColor(Color.black);
	   g.drawString("JavaDraw",r.width/2-20,15); //print a nice title
	   g.drawRect(0,0,r.width-1,r.height-1); //draw a box around the
						 //drawing area

	   switch (drawCol) { //select the current drawing color
		case BLUE: g.setColor(Color.blue);
			   break;
	        case RED:  g.setColor(Color.red);
			   break;
		case YELLOW: g.setColor(Color.yellow);
			   break;
		case BLACK: g.setColor(Color.black);
			   break;
		case GREEN: g.setColor(Color.green);
			   break;
		case GRAY: g.setColor(Color.gray);
			   break;
	   }
	   switch (drawAct) { //do the selected drawing routing

	      case RECT : g.drawRect(drawX,drawY,drawW, drawH);
		          g.drawString("Rectangle",0,10);
			  break;
	      case FRECT: g.fillRect(drawX,drawY,drawW, drawH);
		          g.drawString("Fill Rectangle",0,10);
			  break;
	      case CIRC: g.drawOval(drawX,drawY,drawW,drawH);
		          g.drawString("Circle",0,10);
			  break;
	      case LINE: g.drawLine(drawX,drawY,drawW,drawH);
		          g.drawString("Line",0,10);
			  break;
	      case FCIRC: g.fillOval(drawX,drawY,drawW,drawH);
		          g.drawString("fill Circle",0,10);
			  break;
	      case TEXT: g.drawString(mt,drawX,drawY);
			  g.drawString(mt,0,10);
			 break;
	   }
	} 

	public void update(Graphics g) { //I'm overriding update so that
					 //the screen doesn't get blanked
					 //between draws
		paint(g);
	}
	public void redraw() {
	      drawX = drawY = drawW = drawH = 0;
	      repaint();
	}
	public boolean mouseDown(Event e, int x, int y) {
	   	drawX=x; //set the start x of the object
		drawY=y; //set the start y of the object
		return true;
	}

	public boolean mouseUp(Event e, int x, int y) {

	   if(drawAct==LINE) { //set the end coords for a line
		drawW=x;
		drawH=y;
		repaint();
		return true;
	   }
		 
	   //if not a line, get x,y,width,height of object	

	   /* the following code extracts the x,y,w,and h
	      based on the current mouse input. In order to 
	      get the correct width and height numbers, you must
	      subtract the lesser from the greater, so I check
	      to see which is greater and switch the values
              if necessary
	   */
	   if(x >= drawX)	
	        drawW = x - drawX;
	   else {
		drawW = drawX - x;
		drawX = x;
	   }
	   if(y >= drawY)
		drawH = y - drawY;
	   else {
		drawH = drawY - y;
		drawY = y;
	   }
	   repaint(); //draw our new object
	   return true;
	}
}

class MyWidgets extends Panel {

	MyCanvas canvas; //canvas that calls this
	TextField mt; //text for drawing to screen


	public MyWidgets(MyCanvas canvas) {
	   this.canvas = canvas; //set canvas to calling class
	   add(mt = new TextField("",10)); //text to draw
	   add(new Button("Text")); //select text tool
	   add(new Button("Line")); //select line tool
	   add(new Button("Rect")); //select rectangle tool
	   add(new Button("FillRect")); //select fillrect tool
	   add(new Button("Circle")); //select circle tool
	   add(new Button("FillCircle")); //select fillcircle tool
	   add(new Button("Reset")); //clear the screen
	}

	//grab events and look for button events. This
	//essentially changes tools and colors

	public boolean action(Event ev, Object arg) {
	   if(ev.target instanceof Button) {
		String label = (String)arg;

	      if(label.equals("Text")){
		 canvas.drawAct = canvas.TEXT;
	         canvas.mt = mt.getText();
	      }
	      if(label.equals("Reset")){
		   canvas.drawAct = canvas.RESET;
		   canvas.repaint(); //clear drawing screen
	      }
	      if(label.equals("Line")) canvas.drawAct = canvas.LINE;
	      if(label.equals("Rect")) canvas.drawAct = canvas.RECT;
	      if(label.equals("FillRect")) canvas.drawAct = canvas.FRECT;
	      if(label.equals("Circle")) canvas.drawAct = canvas.CIRC;
	      if(label.equals("FillCircle")) canvas.drawAct = canvas.FCIRC;

	      canvas.redraw(); //calls paint to show new widget status
	      
	      return true;
	   } 
	   return false;
	}
}
class MyColors extends Panel {

        MyCanvas canvas; //canvas that calls this


        public MyColors(MyCanvas canvas) {
           this.canvas = canvas; //set canvas to calling class
           add(new Button("Blue"));
           add(new Button("Red"));
           add(new Button("Yellow"));
           add(new Button("Black"));
           add(new Button("Green"));
           add(new Button("Gray"));
	}
        public boolean action(Event ev, Object arg) {
           if(ev.target instanceof Button) {
              String label = (String)arg;
              if(label.equals("Blue")) canvas.drawCol = canvas.BLUE;
              if(label.equals("Black")) canvas.drawCol = canvas.BLACK;
              if(label.equals("Yellow")) canvas.drawCol = canvas.YELLOW;
              if(label.equals("Red")) canvas.drawCol = canvas.RED;
              if(label.equals("Green")) canvas.drawCol = canvas.GREEN;
              if(label.equals("Gray")) canvas.drawCol = canvas.GRAY;

	      canvas.redraw(); //calls paint for new color to appear in
			       //tool selection field
              return true;
           }
           return false;
        }
}