PC Active 2001 July/August/PCA1307.ISO/EXTRA/cursus/DrawingApp.java

Java Source | 2001-04-22 | 11.4 KB | 506 lines

// DrawingApp.java

import java.io.*;
import java.util.*;
import java.lang.Math;
import java.awt.*;
import java.awt.event.*;

class DrawingApp extends Frame    implements ActionListener,ItemListener, AdjustmentListener
     {
     static final int RECT = 1;
     static final int CIRCLE = 2;
     static final int LINE = 3;

     Frame        frame;
     MyCanvas    mycanvas;
     Label        y_coor;
     Label        x_coor;
     Panel        panel1;
     Panel        panel2;
     Panel        panel3;
     Button        undo;
     Checkbox    filled;
     CheckboxGroup    shape;
     Checkbox    rectangle;
     Checkbox    circle;
     Checkbox    line;
     MenuBar    bar;
     Menu        mFile;
     Menu        mHelp;
     MenuItem    mLoad;
     MenuItem    mSave;
     MenuItem    mPrint;
     MenuItem    mQuit;
     Rect        r;
     Circle        c;
     Line        l;
     int        x_pos;
     int        y_pos;
     int        iShape = RECT;
     boolean    bFilled = false;
     Color        cColor = Color.black;
     String        fPathname;
     String        sFile;
     Scrollbar    red;
     Scrollbar    blue;
     Scrollbar    green;
     Label        tred;
     Label        tblue;
     Label        tgreen;
     Canvas        clr;
     int        rd;
     int        gr;
     int        bl;

     public static void main (String [] args)
         {
         DrawingApp drawapp = new DrawingApp ();
         drawapp.go ();
         }

     public void go ()
         {
         frame = new Frame ("Untitled");

         bar = new MenuBar ();
         frame.setMenuBar (bar);

         mFile = new Menu ("File");
         bar.add(mFile);
         mSave = new MenuItem ("Save");
         // Register the menu to listen for an actionevent
         mSave.addActionListener (this);

         mLoad = new MenuItem ("Load");
         // Register the menu to listen for an actionevent
         mLoad.addActionListener (this);

         mPrint = new MenuItem ("Print");
         // Register the menu to listen for an actionevent
         mPrint.addActionListener (this);

         mQuit = new MenuItem ("Quit");
         // Register the menu to listen for an actionevent
         mQuit.addActionListener (this);


         mFile.add (mSave);
         mFile.add (mLoad);
         mFile.addSeparator ();
         mFile.add (mPrint);
         mFile.addSeparator ();
         mFile.add (mQuit);

         mycanvas = new MyCanvas ();
         // Register the button to listen for an mouseevent
         mycanvas.addMouseListener (new MouseHandler ());
         mycanvas.addMouseMotionListener (new MouseMotionHandler ());
         frame.add ("Center", mycanvas);

         panel3 = new Panel ();
         panel3.setLayout (new FlowLayout(FlowLayout.LEFT));
         panel3.setBackground (Color.lightGray);

         // Scrollbar color blue
         blue = new Scrollbar (Scrollbar.VERTICAL, 0, 20, 0, 275);
         blue.addAdjustmentListener (this);
         tblue = new Label ();
         tblue.setText ("B");
         panel3.add (blue);
         panel3.add (tblue);

         // Scrollbar color red
         red = new Scrollbar (Scrollbar.VERTICAL, 0, 20, 0, 275);
         red.addAdjustmentListener (this);
         tred = new Label ();
         tred.setText ("R");
         panel3.add (red);
         panel3.add (tred);

         // Scrollbar color green
         green = new Scrollbar (Scrollbar.VERTICAL, 0, 20, 0, 275);
         green.addAdjustmentListener (this);
         tgreen = new Label ();
         tgreen.setText ("G");
         panel3.add (green);
         panel3.add (tgreen);

         // Canvas for drawing
         clr = new Canvas ();
         clr.setBackground (Color.black);
         clr.setSize (25,25);
         panel3.add (clr);

         // X,Y coor
         x_coor = new Label ("X:    ");
         y_coor = new Label ("Y:    ");

         panel3.add (x_coor);
         panel3.add (y_coor);

         panel2 = new Panel ();
         panel2.setLayout (new FlowLayout(FlowLayout.RIGHT));
         panel2.setBackground (Color.lightGray);

         shape = new CheckboxGroup ();
         rectangle = new Checkbox ("Rect", shape, true);
         circle = new Checkbox ("Circle", shape, false);
         line = new Checkbox ("Line", shape, false);
         // Register the choices to listen for an itemevent
         rectangle.addItemListener (this);
         circle.addItemListener (this);
         line.addItemListener (this);

         panel2.add (circle);
         panel2.add (rectangle);
         panel2.add (line);

          filled = new Checkbox ("Filled");
         panel2.add (filled);
         // Register the button to listen for an actionevent
         filled.addItemListener (this);

         undo = new Button ("Undo");
         // Register the button to listen for an actionevent
         undo.addActionListener (this);

         panel2.add (undo);

         panel1 = new Panel ();
         panel1.setLayout (new BorderLayout());
         panel1.add ("North", panel2);
         panel1.add ("South", panel3);

         frame.add ("South", panel1);

         frame.pack ();

         // Register window to listen for a window event
         frame.addWindowListener (new WindowHandler ());
         frame.setSize (500,500);
         frame.setVisible (true);
         }

     public void adjustmentValueChanged (AdjustmentEvent e)
         {
         rd = red.getValue();
         gr = green.getValue();
         bl = blue.getValue();

         // Set new drawing color
         cColor = new Color (rd, gr, bl);
         clr.setBackground (cColor);
         }

     public void itemStateChanged (ItemEvent e)
         {
         // Shape selection
         if (e.getItem () == "Rect")
             {
             iShape = RECT;
             }
         else if (e.getItem () == "Circle")
             {
             iShape = CIRCLE;
             }
         else if (e.getItem () == "Line")
             {
             iShape = LINE;
             filled.setState (false);
             bFilled = false;
             }
         // Filled selection
         else if (e.getStateChange() == ItemEvent.SELECTED)
             {
             // Check for shapes other than a line
             if (iShape != LINE)
                 {
                 bFilled = true;
                 }
             else
                 {
                 // Line
                 bFilled = false;
                 filled.setState (false);
                 }
             }
         else
             {
             // Filled not selected
             bFilled = false;
             }
         }

     public void actionPerformed (ActionEvent e)
         {
         // Menu action load
         if (e.getActionCommand () == "Load"  )
             {
             FileDialog filedialog = new FileDialog (this, "Load", FileDialog.LOAD);
             filedialog.setVisible (true);

             fPathname = filedialog.getDirectory () + filedialog.getFile ();
             sFile = filedialog.getFile ();

             if ( fPathname != null)
                 {
                 File f = new File (fPathname);

                 try
                     {
                     // Create object input stream
                     FileInputStream fIn = new FileInputStream (f);
                     ObjectInputStream in = new ObjectInputStream (fIn);

                     // Read the vector
                     Vector v = (Vector)in.readObject();
                     in.close ();

                     // Clear current drawings
                     mycanvas.removeAll ();

                     // Set vector
                     mycanvas.setVect (v);
                     mycanvas.repaint();
                     }
                 catch (IOException ioe)
                     {
                     ioe.printStackTrace ();
                     }
                 catch (ClassNotFoundException ce)
                     {
                     System.out.println ("Incorrect object type");
                     }
                 }
            }

         // Menu action save
         if (e.getActionCommand () == "Save"  )
             {
             FileDialog filedialog = new FileDialog (this, "Save", FileDialog.SAVE);
             filedialog.setVisible (true);

             fPathname = filedialog.getDirectory () + filedialog.getFile ();
             sFile = filedialog.getFile ();

             if ( fPathname != null)
                 {
                 File f = new File (fPathname);

                 try
                     {
                     // Create a object output stream
                     FileOutputStream fOut = new FileOutputStream (f);
                     ObjectOutputStream out = new ObjectOutputStream (fOut);

                     // Get vector containing the shapes
                     Vector v = mycanvas.getVect();

                     out.writeObject (v);
                     out.close ();
                     }
                 catch (IOException ioe)
                     {
                     ioe.printStackTrace ();
                     }
                 }
             }

         // Menu action quit
         if (e.getActionCommand () == "Quit"  )
               {
             System.exit (0);
             }

         if (e.getActionCommand () == "Undo"  )
             {
             mycanvas.removeLast ();
             }

         if (e.getActionCommand () == "Help"  )
             {
             }

         if (e.getActionCommand () == "Print"  )
             {
             Toolkit t = mycanvas.getToolkit ();

             PrintJob job = t.getPrintJob (this, "Printing....", null);

             if ( job != null )
                 {
                 Graphics page = job.getGraphics ();

                 // Center it on the page and draw a rectangle aroud it
                 Dimension size = mycanvas.getSize ();
                 Dimension pagesize = job.getPageDimension ();
                 page.translate ((pagesize.width - size.width)/2,
                                  (pagesize.height - size.height)/2);
                 page.drawRect (-1, -1, size.width+1, size.height + 1);
                 page.setClip (0, 0, size.width, size.height);

                 mycanvas.printAll (page);
                 page.dispose ();
                 job.end ();
                 }
             }
         }


     class WindowHandler extends WindowAdapter
         {
         public void windowClosing (WindowEvent e)
             {
             System.exit (0);
             }
         }

     class MouseMotionHandler extends MouseMotionAdapter
         {
         // Update mouse coor
         public void mouseMoved (MouseEvent e)
             {
             x_coor.setText ("X: " + e.getX());
             y_coor.setText ("Y: " + e.getY());
             }

         // Update mouse coor
         public void mouseDragged (MouseEvent e)
             {
             x_coor.setText ("X: " + e.getX());
             y_coor.setText ("Y: " + e.getY());
             }
         }

    class MouseHandler extends MouseAdapter
         {
         // Change mouse cursor to crosshair if inside canvase
         public void mouseEntered (MouseEvent e)
             {
             frame.setCursor (Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
             x_coor.setText ("X: " + e.getX());
             y_coor.setText ("Y: " + e.getY());
             }

         // Change mouse cursor to arrow if outside canvas
         public void mouseExited (MouseEvent e)
             {
             frame.setCursor (Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
             x_coor.setText ("X:    ");
             y_coor.setText ("Y:    ");
             }


         public void mousePressed (MouseEvent e)
             {
             // Start of drawing shape
             if ( iShape == RECT)
                 {
                 r = new Rect ();

                 x_pos = e.getX();
                 y_pos = e.getY();
                 }
             else if ( iShape == CIRCLE )
                 {
                 c = new Circle ();

                 x_pos = e.getX();
                 y_pos = e.getY();
                 }
             else if ( iShape == LINE )
                 {
                 l = new Line ();

                 x_pos = e.getX();
                 y_pos = e.getY();
                 }
             else
                 {
                 System.out.println ("Major error");
                 System.exit (0);
                 }
             }

         public void mouseReleased (MouseEvent e)
             {
             int    width;
             int    height;

             // Calculate width and heigt of shape
             width = x_pos - e.getX();
             height = y_pos - e.getY();

             // End drawing a shape
             if (( iShape == RECT ) || ( iShape == CIRCLE ))
                 {
                 /*
                  * If drawing from bottom to top of canvas
                  * width and x_pos needs to be adjusted
                  */
                  if ( width > 0 )
                      {
                      width = Math.abs(width);
                      x_pos = x_pos - width;
                      }
                  else
                      width = Math.abs(width);

                 /*
                  * If drawing from bottom to top of canvas
                  * height and y_pos needs to be adjusted
                  */
                  if ( height > 0 )
                      {
                      height = Math.abs(height);
                      y_pos = y_pos - height;
                      }
                  else
                      height = Math.abs(height);
                  }

              if ( iShape == RECT )
                 {
                 r.setX(x_pos);
                 r.setY(y_pos);
                 r.setWidth(width);
                 r.setHeight(height);
                 r.setClr (cColor);
                 r.setFilled (bFilled);

                 mycanvas.addRect (r);
                 mycanvas.repaint();
                 }
             else if ( iShape == CIRCLE )
                 {
                 c.setX(x_pos);
                 c.setY(y_pos);
                 c.setRadius(width, height);
                 c.setClr (cColor);
                 c.setFilled (bFilled);

                 mycanvas.addCircle (c);
                 mycanvas.repaint();
                 }
             else if ( iShape == LINE )
                 {
                 l.setX(x_pos);
                 l.setY(y_pos);
                 l.setWidth(e.getX());
                 l.setHeight(e.getY());
                 l.setClr (cColor);

                 mycanvas.addLine (l);
                 mycanvas.repaint();
                 }
             else
                 {
                 System.out.println ("Major error");
                 System.exit (0);
                 }
             }
         }
     }