gcanvas.java

use Java code to draw on pad canvas

   * @param y      Polyline y components.   
   * @param image  Image to render.
   */
  void render (int[] x, int[] y, GImage image)
  {
    Graphics2D  canvas = (Graphics2D) backBuffer_.getGraphics();

    // The image rectangle x,y holds delta values for positioning
    int dx = image.getRectangle().x;
    int dy = image.getRectangle().y;

    int nPoints = x.length;
    for (int i = 0; i < nPoints; i++)
      canvas.drawImage (image.getImage(), x[i] + dx, y[i] + dy, this);
  }

  

  /**
   * Position the specified AWT component within this JPanel.
   * 
   * @param component  AWT component to position.
   */
  void render (GComponent component)
  {
    Component c = component.getComponent();

    c.setLocation (component.getRectangle().x,
                   component.getRectangle().y);

    if (!isAncestorOf (c))
      add (c);
  }
  
  

  /**
   * Utility method for computing the rectangle bounding box of
   * a rendered string using the specified font.
   * 
   * @param string  Sample string.
   * @param font    Font to use.
   * @return        Rectangle bounding box of rendered string.
   */
  Rect getStringBox (String string, Font font)
  {
    Graphics2D graphics = (Graphics2D) getGraphics();

    // For some reason the graphics is not always set
    if (graphics == null)
      return new Rect (0, 0, 0, 0);

    TextLayout textLayout = new TextLayout (string, font, 
                                            graphics.getFontRenderContext());
    Rectangle2D bounds = textLayout.getBounds();

    int width  = (int) Math.ceil (bounds.getWidth());
    int height = (int) Math.ceil (bounds.getHeight());
    
    return new Rect (0, 0, width, height);
  }



  /**
   * From the Printable interface. Print the present canvas.
   * 
   * @param graphics     The paper graphics.
   * @param pageFormat   Page format (not used).
   * @param pageIndex    Page index (not used).
   * @return             Printable.PAGE_EXISTS.
   */
  public int print (Graphics graphics, PageFormat pageFormat, int pageIndex)
  {
    if (pageIndex > 0) return Printable.NO_SUCH_PAGE;  
    
    Graphics2D paper = (Graphics2D) graphics;
    paper.drawImage (backBuffer_, 0, 0, getWidth(), getHeight(), this);

    return Printable.PAGE_EXISTS;
  }
  


  /**
   * Save the current graphics as a gif file.
   * 
   * @param file  File to store in.
   */
  void saveAsGif (File file)
    throws IOException
  {
    try {
      GifEncoder gifEncoder = new GifEncoder (backBuffer_);
      OutputStream stream = new FileOutputStream (file);
      gifEncoder.write (stream);
      stream.close();
    }
    catch (AWTException exception) {
      throw new IOException ("GIF encoder AWT error");
    }
  }



  /**
   * Print the canvas content.
   * 
   * @return  True if no exception was caught, false otherwise.
   */
  boolean print()
  {
    try {
      PrinterJob printerJob = PrinterJob.getPrinterJob();
      printerJob.setPrintable (this);
      printerJob.print();
      return true;
    }
    catch (PrinterException exception) {
      return false;
    }
  }
  

  
  /**
   * Implied by LayoutManager
   * 
   * @param name       Name of component to add.
   * @param component  Component to add.
   */
  public void addLayoutComponent (String name, Component component)
  {
  }

  
  
  /**
   * Implied by LayoutManager. Layout the specified container. All components
   * are positined at thir specified x, y location as determined by
   * the GAnnotator.
   * 
   * @param container  Container to layout.
   */
  public void layoutContainer (Container container)
  {
    Component[] components = container.getComponents();

    for (int i = 0; i < components.length; i++) {
      Component component = components[i];
      
      int x      = component.getX();
      int y      = component.getY();
      int width  = component.getPreferredSize().width;
      int height = component.getPreferredSize().height;

      component.setBounds (x, y, width, height);
    }
  }


  
  /**
   * Implied by LayoutManager. Return minimum layout size.
   * 
   * @param container  Component to return minimum layout size of.
   * @return           Size of canvas window.
   */
  public Dimension minimumLayoutSize (Container container)
  {
    return new Dimension (getWidth(), getHeight());
  }
  

  
  /**
   * Implied by LayoutManager. Return maximum layout size.
   * 
   * @param container  Component to return maximum layout size of.
   * @return           Size of canvas window.
   */
  public Dimension preferredLayoutSize (Container container)
  {
    return new Dimension (getWidth(), getHeight());    
  }


  
  /**
   * Implied by LayoutManager.
   * 
   * @param component  Component to remove.
   */
  public void removeLayoutComponent (Component component)
  {
  }

  


  /**
   * Implied by MouseListener. Not used.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseClicked (MouseEvent event)
  {
  }


  
  /**
   * Method called when the pointer enters this window. If an interaction
   * is installed, pass a FOCUS_IN event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseEntered (MouseEvent event)
  {
    window_.mouseEntered (event.getX(), event.getY());
  }


  
  /**
   * Method called when the pointer exits this window. If an interaction
   * is installed, pass a FOCUS_OUT event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseExited (MouseEvent event)
  {
    window_.mouseExited (event.getX(), event.getY());
  }


  
  /**
   * Method called when a mouse pressed event occurs in this window.
   * If an interaction is installed, pass a BUTTON*_DOWN event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mousePressed (MouseEvent event)
  {
    int modifiers = event.getModifiers();
    int buttonEvent;

    if      (modifiers == event.BUTTON1_MASK)
      buttonEvent = GWindow.BUTTON1_DOWN;
    else if (modifiers == event.BUTTON2_MASK)
      buttonEvent = GWindow.BUTTON2_DOWN;
    else
      buttonEvent = GWindow.BUTTON3_DOWN;

    window_.mousePressed (buttonEvent, event.getX(), event.getY());
  }


  
  /**
   * Method called when a mouse release event occurs in this window.
   * If an interaction is installed, pass a BUTTON*_UP event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseReleased (MouseEvent event)
  {
    int modifiers = event.getModifiers();
    int buttonEvent;

    if      (modifiers == event.BUTTON1_MASK)
      buttonEvent = GWindow.BUTTON1_UP;
    else if (modifiers == event.BUTTON2_MASK)
      buttonEvent = GWindow.BUTTON2_UP;
    else
      buttonEvent = GWindow.BUTTON3_UP;

    window_.mouseReleased (buttonEvent, event.getX(), event.getY());
  }

  

  /**
   * Method called when the mouse is dragged (moved with button pressed) in
   * this window. If an interaction is installed, pass a BUTTON*_DRAG
   * event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseDragged (MouseEvent event)
  {
    int modifiers = event.getModifiers();
    int buttonEvent;

    if      (modifiers == event.BUTTON1_MASK)
      buttonEvent = GWindow.BUTTON1_DRAG;
    else if (modifiers == event.BUTTON2_MASK)
      buttonEvent = GWindow.BUTTON2_DRAG;
    else
      buttonEvent = GWindow.BUTTON3_DRAG;

    window_.mouseDragged (buttonEvent, event.getX(), event.getY());
  }


  
  /**
   * Method called when the mouse is moved inside this window.
   * If an interaction is installed, pass a MOTION event to it.
   * 
   * @param event  Mouse event trigging this method.
   */
  public void mouseMoved (MouseEvent event)
  {
    window_.mouseMoved (event.getX(), event.getY());
  }



  /**
   * Implied by ComponentListener. Not used.
   * 
   * @param event  Event trigging this method.
   */
  public void componentHidden (ComponentEvent event) {}



  /**
   * Implied by ComponentListener. Not used.
   * 
   * @param event  Event trigging this method.
   */
  public void componentMoved (ComponentEvent event) {}


  
  /**
   * Implied by ComponentListener. Not used.
   * 
   * @param event  Event trigging this method.
   */
  public void componentShown (ComponentEvent event) {}


  
  /**
   * Called when the AWT component is resized.
   * 
   * @param event  Resize event.
   */
  public void componentResized (ComponentEvent event)
  {
    createBackBuffer();
    cleared_ = new Rect (0, 0, getWidth(), getHeight());

    window_.resize();
  }
}