365 lines
10 KiB
Java
Executable File
365 lines
10 KiB
Java
Executable File
import javax.swing.*;
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import java.awt.*;
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import java.awt.geom.*;
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/**
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* Class Canvas - a class to allow for simple graphical
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* drawing on a canvas.
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*
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* @author Michael Kölling (mik)
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* @author Bruce Quig
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*
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* @version 2016.02.29
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*/
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public class Canvas
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{
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private JFrame frame;
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private CanvasPane canvas;
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private Graphics2D graphic;
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private Color backgroundColor;
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private Image canvasImage;
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/**
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* Create a Canvas with default height, width and background color
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* (300, 300, white).
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* @param title title to appear in Canvas Frame
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*/
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public Canvas(String title)
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{
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this(title, 300, 300, Color.white);
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}
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/**
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* Create a Canvas with default background color (white).
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* @param title title to appear in Canvas Frame
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* @param width the desired width for the canvas
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* @param height the desired height for the canvas
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*/
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public Canvas(String title, int width, int height)
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{
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this(title, width, height, Color.white);
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}
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/**
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* Create a Canvas.
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* @param title title to appear in Canvas Frame
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* @param width the desired width for the canvas
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* @param height the desired height for the canvas
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* @param bgClour the desired background color of the canvas
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*/
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public Canvas(String title, int width, int height, Color bgColor)
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{
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frame = new JFrame();
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canvas = new CanvasPane();
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frame.setContentPane(canvas);
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frame.setTitle(title);
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canvas.setPreferredSize(new Dimension(width, height));
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backgroundColor = bgColor;
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frame.pack();
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setVisible(true);
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}
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/**
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* Set the canvas visibility and brings canvas to the front of screen
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* when made visible. This method can also be used to bring an already
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* visible canvas to the front of other windows.
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* @param visible boolean value representing the desired visibility of
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* the canvas (true or false)
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*/
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public void setVisible(boolean visible)
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{
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if(graphic == null) {
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// first time: instantiate the offscreen image and fill it with
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// the background color
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Dimension size = canvas.getSize();
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canvasImage = canvas.createImage(size.width, size.height);
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graphic = (Graphics2D)canvasImage.getGraphics();
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graphic.setColor(backgroundColor);
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graphic.fillRect(0, 0, size.width, size.height);
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graphic.setColor(Color.black);
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}
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frame.setVisible(true);
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}
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/**
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* Provide information on visibility of the Canvas.
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* @return true if canvas is visible, false otherwise
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*/
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public boolean isVisible()
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{
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return frame.isVisible();
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}
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/**
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* Draw the outline of a given shape onto the canvas.
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* @param shape the shape object to be drawn on the canvas
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*/
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public void draw(Shape shape)
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{
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graphic.draw(shape);
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canvas.repaint();
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}
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/**
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* Fill the internal dimensions of a given shape with the current
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* foreground color of the canvas.
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* @param shape the shape object to be filled
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*/
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public void fill(Shape shape)
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{
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graphic.fill(shape);
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canvas.repaint();
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}
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/**
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* Fill the internal dimensions of the given circle with the current
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* foreground color of the canvas.
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* @param xPos The x-coordinate of the circle center point
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* @param yPos The y-coordinate of the circle center point
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* @param diameter The diameter of the circle to be drawn
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*/
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public void fillCircle(int xPos, int yPos, int diameter)
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{
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Ellipse2D.Double circle = new Ellipse2D.Double(xPos, yPos, diameter, diameter);
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fill(circle);
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}
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/**
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* Fill the internal dimensions of the given rectangle with the current
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* foreground color of the canvas. This is a convenience method. A similar
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* effect can be achieved with the "fill" method.
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*/
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public void fillRectangle(int xPos, int yPos, int width, int height)
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{
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fill(new Rectangle(xPos, yPos, width, height));
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}
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/**
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* Erase the whole canvas.
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*/
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public void erase()
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{
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Color original = graphic.getColor();
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graphic.setColor(backgroundColor);
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Dimension size = canvas.getSize();
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graphic.fill(new Rectangle(0, 0, size.width, size.height));
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graphic.setColor(original);
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canvas.repaint();
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}
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/**
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* Erase the internal dimensions of the given circle. This is a
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* convenience method. A similar effect can be achieved with
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* the "erase" method.
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*/
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public void eraseCircle(int xPos, int yPos, int diameter)
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{
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Ellipse2D.Double circle = new Ellipse2D.Double(xPos, yPos, diameter, diameter);
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erase(circle);
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}
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/**
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* Erase the internal dimensions of the given rectangle. This is a
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* convenience method. A similar effect can be achieved with
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* the "erase" method.
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*/
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public void eraseRectangle(int xPos, int yPos, int width, int height)
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{
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erase(new Rectangle(xPos, yPos, width, height));
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}
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/**
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* Erase a given shape's interior on the screen.
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* @param shape the shape object to be erased
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*/
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public void erase(Shape shape)
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{
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Color original = graphic.getColor();
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graphic.setColor(backgroundColor);
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graphic.fill(shape); // erase by filling background color
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graphic.setColor(original);
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canvas.repaint();
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}
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/**
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* Erases a given shape's outline on the screen.
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* @param shape the shape object to be erased
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*/
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public void eraseOutline(Shape shape)
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{
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Color original = graphic.getColor();
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graphic.setColor(backgroundColor);
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graphic.draw(shape); // erase by drawing background color
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graphic.setColor(original);
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canvas.repaint();
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}
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/**
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* Draws an image onto the canvas.
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* @param image the Image object to be displayed
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* @param x x co-ordinate for Image placement
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* @param y y co-ordinate for Image placement
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* @return returns boolean value representing whether the image was
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* completely loaded
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*/
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public boolean drawImage(Image image, int x, int y)
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{
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boolean result = graphic.drawImage(image, x, y, null);
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canvas.repaint();
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return result;
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}
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/**
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* Draws a String on the Canvas.
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* @param text the String to be displayed
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* @param x x co-ordinate for text placement
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* @param y y co-ordinate for text placement
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*/
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public void drawString(String text, int x, int y)
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{
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graphic.drawString(text, x, y);
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canvas.repaint();
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}
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/**
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* Erases a String on the Canvas.
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* @param text the String to be displayed
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* @param x x co-ordinate for text placement
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* @param y y co-ordinate for text placement
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*/
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public void eraseString(String text, int x, int y)
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{
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Color original = graphic.getColor();
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graphic.setColor(backgroundColor);
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graphic.drawString(text, x, y);
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graphic.setColor(original);
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canvas.repaint();
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}
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/**
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* Draws a line on the Canvas.
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* @param x1 x co-ordinate of start of line
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* @param y1 y co-ordinate of start of line
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* @param x2 x co-ordinate of end of line
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* @param y2 y co-ordinate of end of line
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*/
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public void drawLine(int x1, int y1, int x2, int y2)
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{
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graphic.drawLine(x1, y1, x2, y2);
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canvas.repaint();
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}
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/**
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* Sets the foreground color of the Canvas.
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* @param newColor the new color for the foreground of the Canvas
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*/
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public void setForegroundColor(Color newColor)
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{
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graphic.setColor(newColor);
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}
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/**
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* Returns the current color of the foreground.
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* @return the color of the foreground of the Canvas
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*/
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public Color getForegroundColor()
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{
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return graphic.getColor();
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}
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/**
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* Sets the background color of the Canvas.
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* @param newColor the new color for the background of the Canvas
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*/
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public void setBackgroundColor(Color newColor)
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{
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backgroundColor = newColor;
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graphic.setBackground(newColor);
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}
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/**
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* Returns the current color of the background
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* @return the color of the background of the Canvas
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*/
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public Color getBackgroundColor()
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{
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return backgroundColor;
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}
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/**
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* changes the current Font used on the Canvas
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* @param newFont new font to be used for String output
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*/
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public void setFont(Font newFont)
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{
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graphic.setFont(newFont);
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}
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/**
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* Returns the current font of the canvas.
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* @return the font currently in use
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**/
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public Font getFont()
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{
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return graphic.getFont();
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}
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/**
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* Sets the size of the canvas.
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* @param width new width
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* @param height new height
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*/
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public void setSize(int width, int height)
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{
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canvas.setPreferredSize(new Dimension(width, height));
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Image oldImage = canvasImage;
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canvasImage = canvas.createImage(width, height);
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graphic = (Graphics2D)canvasImage.getGraphics();
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graphic.setColor(backgroundColor);
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graphic.fillRect(0, 0, width, height);
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graphic.drawImage(oldImage, 0, 0, null);
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frame.pack();
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}
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/**
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* Returns the size of the canvas.
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* @return The current dimension of the canvas
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*/
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public Dimension getSize()
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{
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return canvas.getSize();
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}
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/**
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* Waits for a specified number of milliseconds before finishing.
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* This provides an easy way to specify a small delay which can be
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* used when producing animations.
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* @param milliseconds the number
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*/
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public void wait(int milliseconds)
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{
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try
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{
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Thread.sleep(milliseconds);
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}
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catch (InterruptedException e)
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{
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// ignoring exception at the moment
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}
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}
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/************************************************************************
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* Inner class CanvasPane - the actual canvas component contained in the
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* Canvas frame. This is essentially a JPanel with added capability to
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* refresh the image drawn on it.
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*/
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private class CanvasPane extends JPanel
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{
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public void paint(Graphics g)
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{
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g.drawImage(canvasImage, 0, 0, null);
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}
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}
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}
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