import java.awt.*; import java.awt.event.*; import java.applet.Applet; import java.awt.image.*; public class BufferedShapeMover extends Applet{ static protected Label label; public void init(){ //Initialize the layout. setLayout(new BorderLayout()); add(new BSMCanvas()); label = new Label("Drag rectangle around within the area"); add("South", label); } public static void main(String s[]) { Frame f = new Frame("BufferedShapeMover"); f.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) {System.exit(0);} }); Applet applet = new BufferedShapeMover(); f.add("Center", applet); applet.init(); f.pack(); f.setSize(new Dimension(550,250)); f.show(); } } class BSMCanvas extends Canvas implements MouseListener, MouseMotionListener{ Rectangle rect = new Rectangle(0, 0, 100, 50); BufferedImage bi; Graphics2D big; // Holds the coordinates of the user's last mousePressed event. int last_x, last_y; boolean firstTime = true; TexturePaint fillPolka, strokePolka; Rectangle area; // True if the user pressed, dragged or released the mouse outside of the rectangle; false otherwise. boolean pressOut = false; public BSMCanvas(){ setBackground(Color.white); addMouseMotionListener(this); addMouseListener(this); // Creates the fill texture paint pattern. bi = new BufferedImage(5, 5, BufferedImage.TYPE_INT_RGB); big = bi.createGraphics(); big.setColor(Color.pink); big.fillRect(0, 0, 7, 7); big.setColor(Color.cyan); big.fillOval(0, 0, 3, 3); Rectangle r = new Rectangle(0,0,5,5); fillPolka = new TexturePaint(bi, r); big.dispose(); //Creates the stroke texture paint pattern. bi = new BufferedImage(5, 5, BufferedImage.TYPE_INT_RGB); big = bi.createGraphics(); big.setColor(Color.cyan); big.fillRect(0, 0, 7, 7); big.setColor(Color.pink); big.fillOval(0, 0, 3, 3); r = new Rectangle(0,0,5,5); strokePolka = new TexturePaint(bi, r); big.dispose(); } // Handles the event of the user pressing down the mouse button. public void mousePressed(MouseEvent e){ last_x = rect.x - e.getX(); last_y = rect.y - e.getY(); // Checks whether or not the cursor is inside of the rectangle while the user is pressing themouse. if(rect.contains(e.getX(), e.getY())){ updateLocation(e); } else { BufferedShapeMover.label.setText("First position the cursor on the rectangle and then drag."); pressOut = true; } } // Handles the event of a user dragging the mouse while holding down the mouse button. public void mouseDragged(MouseEvent e){ if(!pressOut){ updateLocation(e); } else { BufferedShapeMover.label.setText("First position the cursor on the rectangle and then drag."); } } // Handles the event of a user releasing the mouse button. public void mouseReleased(MouseEvent e){ // Checks whether or not the cursor is inside of the rectangle when the user releases the // mouse button. if(rect.contains(e.getX(), e.getY())){ updateLocation(e); } else { BufferedShapeMover.label.setText("First position the cursor on the rectangle and then drag."); pressOut = false; } } // This method required by MouseListener. public void mouseMoved(MouseEvent e){} // These methods are required by MouseMotionListener. public void mouseClicked(MouseEvent e){} public void mouseExited(MouseEvent e){} public void mouseEntered(MouseEvent e){} public void updateLocation(MouseEvent e){ rect.setLocation(last_x + e.getX(), last_y + e.getY()); /* * Updates the label to reflect the location of the * current rectangle * if checkRect returns true; otherwise, returns error message. */ if (checkRect()) { BufferedShapeMover.label.setText("Rectangle located at " + rect.getX() + ", " + rect.getY()); } else { BufferedShapeMover.label.setText("Please don't try to "+ " drag outside the area."); } repaint(); } public void paint(Graphics g){ update(g); } public void update(Graphics g){ Graphics2D g2 = (Graphics2D)g; if(firstTime){ Dimension dim = getSize(); int w = dim.width; int h = dim.height; area = new Rectangle(dim); bi = (BufferedImage)createImage(w, h); big = bi.createGraphics(); rect.setLocation(w/2-50, h/2-25); big.setStroke(new BasicStroke(8.0f)); firstTime = false; } // Clears the rectangle that was previously drawn. big.setColor(Color.white); big.clearRect(0, 0, area.width, area.height); // Draws and fills the newly positioned rectangle to the buffer. big.setPaint(strokePolka); big.draw(rect); big.setPaint(fillPolka); big.fill(rect); // Draws the buffered image to the screen. g2.drawImage(bi, 0, 0, this); } /* * Checks if the rectangle is contained within the applet window. If the rectangle * is not contained withing the applet window, it is redrawn so that it is adjacent * to the edge of the window and just inside the window. */ boolean checkRect(){ if (area == null) { return false; } if(area.contains(rect.x, rect.y, 100, 50)){ return true; } int new_x = rect.x; int new_y = rect.y; if((rect.x+100)>area.width){ new_x = area.width-99; } if(rect.x < 0){ new_x = -1; } if((rect.y+50)>area.height){ new_y = area.height-49; } if(rect.y < 0){ new_y = -1; } rect.setLocation(new_x, new_y); return false; } }