import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;

/**
 * Class Canvas - a class to allow for simple graphical 
 * drawing on a canvas.
 * 
 * @author Bruce Quig
 * @author Michael Kolling (mik)
 * @author Dave Musicant - made some local changes
 * @author Amy Csizmar Dalal - more minor local changes
 * @author Jeff Ondich - added setFontSize and getInkColor
 * @author David Liben-Nowell - even more minor local changes
 *
 * @version 1.6.5
 * date:    11.11.2005
 */

public class Canvas
{
    private JFrame frame;
    protected CanvasPane canvas;
    private Graphics2D graphic;
    private Color backgroundColor;
    private Color inkColor;
    private Image canvasImage;


    /**
     * Create a Canvas with default height, width and background color 
     * (300, 300, white).
     * @param title  title to appear in Canvas Frame     
     */
    public Canvas(String title)
    {
        this(title, 300, 300, Color.white);        
    }

    /**
     * Create a Canvas with default title, height, width and background color 
     * ("Canvas", 300, 300, white).
     */
    public Canvas()
    {
        this("Canvas", 300, 300, Color.white);        
    }

    /**
     * Create a Canvas with default background Color (white).
     * @param title  title to appear in Canvas Frame
     * @param width  the desired width for the canvas
     * @param height  the desired height for the canvas
     */
    private Canvas(String title, int width, int height)
    {
        this(title, width, height, Color.white);
    }

    /**
     * Create a Canvas.
     * @param title  title to appear in Canvas Frame
     * @param width  the desired width for the canvas
     * @param height  the desired height for the canvas
     * @param bgColor  the desired background color of the canvas
     */
    private Canvas(String title, int width, int height, Color bgColor)
    {
        frame = new JFrame();
        canvas = new CanvasPane();
        frame.setContentPane(canvas);
        frame.setTitle(title);
        canvas.setPreferredSize(new Dimension(width, height));
        backgroundColor = bgColor;
	inkColor = Color.black;
        frame.pack();

	// Added by acd:  this is a hack that will allow other components,
	// like buttons, to be added to the canvas and be visible.
	// basically, it's saying "when you repaint, don't fill the entire
	// canvas with the background color", i.e. leave the buttons and 
	// stuff alone!
	canvas.setOpaque(false);
	// end of hack

        frame.addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent e) {
                    setVisible(false);
		    System.exit(0);
                }
            });

        if(graphic == null) {
            // first time: instantiate the offscreen image and fill it with
            // the background color
            Dimension size = canvas.getSize();
            canvasImage = canvas.createImage(size.width, size.height);
            graphic = (Graphics2D)canvasImage.getGraphics();
            graphic.setColor(backgroundColor);
            graphic.fillRect(0, 0, size.width, size.height);
            graphic.setColor(inkColor);
        }
    }

    /**
     * Sets the "pen" (outline) color for the Canvas.
     * @param newColor  The color to which to set the pen/drawing tool.
     */
    public void setInkColor(Color newColor)
    {
	inkColor = newColor;
	graphic.setColor(inkColor);
    }

    /**
     * Returns the current pen color.
     */
    public Color getInkColor()
    {
        return inkColor;
    }

    /**
     * Set the canvas visibility and brings canvas to the front of screen
     * when made visible. This method can also be used to bring an already
     * visible canvas to the front of other windows.
     * @param visible  boolean value representing the desired visibility of
     * the canvas (true or false) 
     */
    public void setVisible(boolean visible)
    {
	/*if (visible)
	    frame.show();
	else
	frame.hide();*/
	/* EDITED BY ACD:  show() and hide() are deprecated in 
	   Java 1.5; replace with setVisible(boolean) */
	frame.setVisible(visible);
    }

    /**
     * Provide information on visibility of the Canvas.
     * @return  true if canvas is visible, false otherwise
     */
    public boolean isVisible()
    {
        return frame.isVisible();
    }

    /**
     * Draw a given shape onto the canvas.
     * @param  shape  the shape object to be drawn on the canvas
     */
    private void draw(Shape shape)
    {
        graphic.draw(shape);
        canvas.repaint();
    }
 
    /**
     * Fill the internal dimensions of a given shape with the current 
     * foreground color of the canvas.
     * @param  shape  the shape object to be filled 
     */
    private void fill(Shape shape)
    {
        graphic.fill(shape);
        canvas.repaint();
    }

    /**
     * Erase the whole canvas.
     */
    public void erase()
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        Dimension size = canvas.getSize();
        graphic.fill(new Rectangle(0, 0, size.width, size.height));
        graphic.setColor(original);
        canvas.repaint();
    }

    /**
     * Erase a given shape's interior on the screen.
     * @param  shape  the shape object to be erased 
     */
    private void erase(Shape shape)
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        graphic.fill(shape);              // erase by filling background color
        graphic.setColor(original);
        canvas.repaint();
    }

    /**
     * Erases a given shape's outline on the screen.
     * @param  shape  the shape object to be erased 
     */
    private void eraseOutline(Shape shape)
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        graphic.draw(shape);  // erase by drawing background color
        graphic.setColor(original);
        canvas.repaint();
    }

    /**
     * Draws an image onto the canvas.
     * @param  image   the Image object to be displayed 
     * @param  x       x co-ordinate for Image placement 
     * @param  y       y co-ordinate for Image placement 
     * @return  returns boolean value representing whether the image was 
     *          completely loaded 
     */
    private boolean drawImage(Image image, int x, int y)
    {
        boolean result = graphic.drawImage(image, x, y, null);
        canvas.repaint();
        return result;
    }

    /**
     * Draws a String on the Canvas.
     * @param  text   the String to be displayed 
     * @param  x      x co-ordinate for text placement 
     * @param  y      y co-ordinate for text placement
     */
    public void drawString(String text, int x, int y)
    {
        graphic.drawString(text, x, y);   
        canvas.repaint();
    }

    /**
     * Erases a String on the Canvas.
     * @param  text     the String to be displayed 
     * @param  x        x co-ordinate for text placement 
     * @param  y        y co-ordinate for text placement
     */
    public void eraseString(String text, int x, int y)
    {
        Color original = graphic.getColor();
        graphic.setColor(backgroundColor);
        graphic.drawString(text, x, y);   
        graphic.setColor(original);
        canvas.repaint();
    }

    /**
     * Draws a line on the Canvas.
     * @param  x1   x co-ordinate of start of line 
     * @param  y1   y co-ordinate of start of line 
     * @param  x2   x co-ordinate of end of line 
     * @param  y2   y co-ordinate of end of line 
     */
    public void drawLine(int x1, int y1, int x2, int y2)
    {
        graphic.drawLine(x1, y1, x2, y2);   
        canvas.repaint();
    }
    
    /**
     * Draws a rectangle on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void drawRectangle(int x1, int y1, int x2, int y2)
    {
        graphic.draw(new Rectangle(x1, y1, x2, y2));
        canvas.repaint();
    }

    /**
     * Draws a filled rectangle on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void drawFilledRectangle(int x1, int y1, int x2, int y2)
    {
        graphic.fill(new Rectangle(x1, y1, x2, y2));
        canvas.repaint();
    }

    /**
     * Draws a polygon on the Canvas.
     * @param  x   array of x co-ordinates of polygon points
     * @param  y   array of y co-ordinates of polygon points
     * @param  size the number of points (vertices) in the polygon
     */
    public void drawPolygon(int[] x, int[] y, int size)
    {
	graphic.draw(new Polygon(x,y,size));
        canvas.repaint();
    }

    /**
     * Draws a filled polygon on the Canvas.
     * @param  x   array of x co-ordinates of polygon points
     * @param  y   array of y co-ordinates of polygon points
     * @param  size the number of points (vertices) in the polygon
     */
    public void drawFilledPolygon(int[] x, int[] y, int size)
    {
	graphic.fill(new Polygon(x,y,size));
        canvas.repaint();
    }

    /**
     * Erases a rectangle on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void eraseRectangle(int x1, int y1, int x2, int y2)
    {
        eraseOutline(new Rectangle(x1, y1, x2, y2));
    }


    /**
     * Draws an oval on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void drawOval(int x1, int y1, int x2, int y2)
    {
        graphic.draw(new Ellipse2D.Double(x1, y1, x2, y2));
        canvas.repaint();
    }

    /**
     * Draws a filled oval on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void drawFilledOval(int x1, int y1, int x2, int y2)
    {
        graphic.fill(new Ellipse2D.Double(x1, y1, x2, y2));
        canvas.repaint();
    }

    /**
     * Erases an oval on the Canvas.
     * @param  x1   x co-ordinate of top left corner 
     * @param  y1   y co-ordinate of top left corner
     * @param  x2   width
     * @param  y2   height
     */
    public void eraseOval(int x1, int y1, int x2, int y2)
    {
        eraseOutline(new Ellipse2D.Double(x1, y1, x2, y2));
    }


    /**
     * Sets the foreground color of the Canvas.
     * @param  newColor   the new color for the foreground of the Canvas 
     */
    private void setForegroundColor(Color newColor)
    {
        graphic.setColor(newColor);
    }

    /**
     * Returns the current color of the foreground.
     * @return   the color of the foreground of the Canvas 
     */
    private Color getForegroundColor()
    {
        return graphic.getColor();
    }

    /**
     * Sets the background color of the Canvas.
     * @param  newColor   the new color for the background of the Canvas 
     */
    private void setBackgroundColor(Color newColor)
    {
        backgroundColor = newColor;   
        graphic.setBackground(newColor);
    }

    /**
     * Fills in the Canvas (background) with the specified color.
     * @param newColor  the new color for the background of the Canvas
     */
    public void fillBackground(Color newColor)
    {
	 Dimension size = canvas.getSize();
	 backgroundColor = newColor;
	 graphic.setColor(backgroundColor);
	 graphic.fillRect(0, 0, size.width, size.height);
	 graphic.setColor(inkColor);
    }

    /**
     * Returns the current color of the background
     * @return   the color of the background of the Canvas 
     */
    private Color getBackgroundColor()
    {
        return backgroundColor;
    }

    /**
     * changes the current Font used on the Canvas
     * @param  newFont   new font to be used for String output
     */
    public void setFont(Font newFont)
    {
        graphic.setFont(newFont);
    }

    /**
     * Returns the current font of the canvas.
     * @return     the font currently in use
     **/
    public Font getFont()
    {
        return graphic.getFont();
    }

    /**
     * Sets the point size of the current font to the specified value.
     * The style and font family remain the same.
     *
     * @param  newSize  the new point size
     */
    public void setFontSize( int newSize )
    {
        Font f = graphic.getFont().deriveFont( (float)newSize );
        setFont( f );
    }
    
    /**
     * Sets the size of the canvas.
     * @param  width    new width 
     * @param  height   new height 
     */
    public void setSize(int width, int height)
    {
        canvas.setPreferredSize(new Dimension(width, height));
        Image oldImage = canvasImage;
        canvasImage = canvas.createImage(width, height);
        graphic = (Graphics2D)canvasImage.getGraphics();
	graphic.setColor(backgroundColor);
	graphic.fillRect(0, 0, width, height);
	graphic.setColor(inkColor);
	graphic.drawImage(oldImage, 0, 0, null);
        frame.pack();
    }

    /**
     * Returns the size of the canvas.
     * @return     The current dimension of the canvas
     */
    private Dimension getSize()
    {
        return canvas.getSize();
    }

    /**
     * Waits for a specified number of milliseconds before finishing.
     * This provides an easy way to specify a small delay which can be
     * used when producing animations.
     * @param  milliseconds  the number 
     */
    public void wait(int milliseconds)
    {
        try
        {
            Thread.sleep(milliseconds);
        } 
        catch (Exception e)
        {
            // ignoring exception at the moment
        }
    }
    
    /************************************************************************
     * Nested class CanvasPane - the actual canvas component contained in the
     * Canvas frame. This is essentially a JPanel with added capability to
     * refresh the image drawn on it.
     * MODIFIED by acd:  changed visibility to protected (from private)  
     * to allow subclassing (basically, so we can add mouse listeners to 
     * the canvas), and added the call to super.paint() (an additional hack 
     * to allow us to add components like buttons and menus to the canvas).
     */
    protected class CanvasPane extends JPanel
    {
        public void paint(Graphics g)
        {
            g.drawImage(canvasImage, 0, 0, null);
	    super.paint(g);
        }
    }
}