IDL-Java Bridge Examples

public class array2d { 
   short[][] m_as; 
   long[][] m_aj; 
 
   // ctor 
   public array2d() { 
      int SIZE1 = 3; 
      int SIZE2 = 4; 
 
      // default ctor creates a fixed number of elements 
      m_as = new short[SIZE1][SIZE2]; 
      m_aj = new long[SIZE1][SIZE2]; 
 
      for (int i=0; i<SIZE1; i++) { 
        for (int j=0; j<SIZE2; j++) { 
          m_as[i][j] = (short)(i*10+j); 
          m_aj[i][j] = (long)(i*10+j); 
         } 
      } 
    
 } 
 
   public void setShorts(short[][] _as) { 
      m_as = _as; 
   } 
 
    public short[][] getShorts() {return m_as;} 
 
    public short getShortByIndex(int i, int j) { 
      return m_as[i][j]; 
   } 
 
   public void setLongs(long[][] _aj) { 
      m_aj = _aj; 
   } 
 
   public long[][] getLongs() {return m_aj;} 
   public long getLongByIndex(int i, int j) {return m_aj[i][j];} 
 
} 

PRO ArrayDemo 
 
; The Java class array2d creates 2 initial arrays, one 
; of longs and one of shorts. We can interrogate and 
; change this array. 
oJArr = OBJ_NEW('IDLJavaObject$ARRAY2D', 'array2d') 
 
; First, let's see what is in the short array at index 
; (2,3). 
PRINT, 'array2d short(2, 3) = ', $ 
   oJArr -> GetShortByIndex(2, 3), $ 
   '    (should be 23)' 
 
; Now, let's copy the entire array from Java to IDL. 
shortArrIDL = oJArr->GetShorts() 
HELP, shortArrIDL 
PRINT, 'shortArrIDL[2, 3] = ', shortArrIDL[2, 3], $ 
   '    (should be 23)' 
 
; Let's change this value... 
shortArrIDL[2, 3] = 999 
; ...and copy it back to Java... 
oJArr->SetShorts, shortArrIDL 
; ...now its value should be different. 
PRINT, 'array2d short(2, 3) = ', $ 
   oJArr->GetShortByIndex(2, 3), '    (should be 999)' 
 
; Let's set our array to something different. 
oJArr -> SetShorts, INDGEN(10, 8) 
PRINT, 'array2d short(0, 0) = ', $ 
   oJArr->GetShortByIndex(0, 0), '    (should be 0)' 
PRINT, 'array2d short(1, 0) = ', $ 
   oJArr->GetShortByIndex(1, 0), '    (should be 1)' 
PRINT, 'array2d short(2, 0) = ', $ 
   oJArr->GetShortByIndex(2, 0), '    (should be 2)' 
PRINT, 'array2d short(0, 1) = ', $ 
   oJArr->GetShortByIndex(0, 1), '    (should be 10)' 
 
; Array2d has a setLongs method, but b/c arrays do not 
; (currently) promote, the first call to setLongs works 
; but the second fails. 
oJArr->SetLongs, L64INDGEN(10, 8) 
PRINT, 'array2d long(0, 1) = ', $ 
   oJArr->GetLongByIndex(0, 1), '    (should be 10)' 
 
;PRINT, '(expecting an error on the next line...)' 
;oJArr->SetLongs, INDGEN(10,8) 
 
; Cleanup our object. 
OBJ_DESTROY, oJArr 
 
END 

array2d short(2, 3) = 23 (should be 23) 
SHORTARRIDL   INT = Array[3, 4] 
shortArrIDL[2, 3] = 23 (should be 23) 
array2d short(2, 3) = 999 (should be 999) 
array2d short(0, 0) = 0 (should be 0) 
array2d short(1, 0) = 1 (should be 1) 
array2d short(2, 0) = 2 (should be 2) 
array2d short(0, 1) = 10 (should be 10) 
array2d long(0, 1) = 10 (should be 10) 

import java.io.*; 
import java.net.*; 
 
public class URLReader 
{ 
   private ByteArrayOutputStream m_buffer; 
 
  // ******************************************************** 
  // 
  // Constructor.  Create the reader 
  // 
  // ******************************************************** 
   public URLReader() { 
      m_buffer = new ByteArrayOutputStream(); 
   } 
          
  // ******************************************************** 
  // 
  // readURL: read the data from the URL into our buffer 
  // 
  //    returns: number of bytes read (0 if invalid URL) 
  // 
  // NOTE: reading a new URL clears out the previous data 
  // 
  // ******************************************************** 
   public int readURL(String sURL) { 
      URL url; 
      InputStream in = null; 
 
m_buffer.reset();  // reset our holding buffer to 0 bytes 
 
      int total_bytes = 0; 
      byte[] tempBuffer = new byte[4096]; 
      try { 
         url = new URL(sURL); 
         in = url.openStream(); 
 
         int bytes_read; 
         while ((bytes_read = in.read(tempBuffer)) != -1) { 
            m_buffer.write(tempBuffer, 0, bytes_read); 
            total_bytes += bytes_read; 
         } 
      } catch (Exception e) { 
         System.err.println("Error reading URL: "+sURL); 
         total_bytes = 0; 
      } finally { 
         try {  
            in.close();  
            m_buffer.close();  
         } catch (Exception e) {} 
      } 
 
      return total_bytes; 
   } 
 
  // ******************************************************** 
  // 
  // getData: return the array of bytes 
  // 
  // ******************************************************** 
   public byte[] getData() { 
     return m_buffer.toByteArray(); 
   } 
 
  // ******************************************************** 
  // 
  // main: reads URL and reports # of byts reads 
  // 
  //   Usage: java URLReader <URL> 
  // 
  // ******************************************************** 
 
  public static void main(String[] args) {   
     if (args.length != 1) 
        System.err.println("Usage: URLReader <URL>"); 
     else { 
        URLReader o = new URLReader(); 
        int b = o.readURL(args[0]); 
        System.out.println("bytes="+b); 
     } 
  } 
 
} 

FUNCTION URLRead, sURLName 
 
; Create an URLReader. 
oJURLReader = OBJ_NEW('IDLjavaObject$URLReader', 'URLReader') 
 
; Read the URL data into our Java-side buffer. 
nBytes = oJURLReader->ReadURL(sURLName) 
 
;PRINT, 'Read ', nBytes, ' bytes' 
 
; Pull the data into IDL. 
byteArr = oJURLReader->GetData() 
 
; Cleanup Java object. 
OBJ_DESTROY, oJURLReader 
 
; Return the data. 
RETURN, byteArr 
 
END 

address = 'http://www.ittvis.com' 
data = URLRead(address) 

import java.awt.*; 
import java.awt.image.*; 
 
public class GreyBandsImage extends BufferedImage 
{ 
 // Members 
 private int m_height; 
 private int m_width; 
 
 
 // 
 // ctor 
 // 
 public GreyBandsImage() { 
    super(100, 100, BufferedImage.TYPE_INT_ARGB); 
    generateImage(); 
    m_height = 100; 
    m_width = 100; 
 } 
 
 // 
 // private method to generate the image 
 // 
 private void generateImage() { 
    Color c; 
    int width  = getWidth(); 
    int height = getHeight(); 
    WritableRaster raster = getRaster(); 
    ColorModel model = getColorModel(); 
 
    int BAND_PIXEL_WIDTH = 5; 
    int nBands = width/BAND_PIXEL_WIDTH; 
    int greyDelta = 255 / nBands; 
    for (int i=0 ; i < nBands; i++) { 
          c = new Color(i*greyDelta, i*greyDelta, i*greyDelta); 
          int argb = c.getRGB(); 
          Object colorData = model.getDataElements(argb, null); 
 
          for (int j=0; j < height; j++)  
             for (int k=0; k < BAND_PIXEL_WIDTH; k++)  
                raster.setDataElements(j, (i*5)+k, colorData); 
           
    } 
 } 
 
 // 
 // mutators 
 // 
 public int[] getRawData() { 
   Raster oRaster = getRaster(); 
   Rectangle oBounds = oRaster.getBounds();  
   int[] data = new int[m_height * m_width * 4]; 
 
   data = oRaster.getPixels(0,0,100,100, data); 
   return data; 
 } 
 public int getH() {return m_height; } 
 public int getW() {return m_width; } 
 
} 

PRO ShowGreyImage 
 
; Construct the GreyBandImage in Java. This is a sub-class of 
; BufferedImage. It is actually a 4 band image that happens to 
display bands in greyscale. It is 100x100 pixels. 
oGrey = OBJ_NEW('IDLjavaObject$GreyBandsImage', 'GreyBandsImage') 
 
; Get the 4 byte pixel values. 
data = oGrey -> GetRawData() 
 
; Get the height and width. 
h = oGrey -> GetH() 
w = oGrey -> GetW() 
 
; Display the graphic in an IDL window 
WINDOW, 0, XSIZE = 100, YSIZE = 100 
TV, REBIN(data, h, w) 
 
; Cleanup 
OBJ_DESTROY, oGrey 
 
END 

import java.awt.*; 
import java.awt.image.*; 
import java.awt.event.*; 
import javax.swing.*; 
import javax.swing.event.*; 
import java.io.File; 
 
public class FrameTest extends JFrame { 
 
 RSIImageArea c_imgArea; 
 int m_xsize; 
 int m_ysize; 
 Box c_controlBox; 
     
 public FrameTest() { 
 
  super("This is a JAVA Swing Program called from IDL"); 
  // Dispose the frame when the sys close is hit 
  setDefaultCloseOperation(DISPOSE_ON_CLOSE); 
  m_xsize = 350; 
  m_ysize = 371; 
  buildGUI(); 
 
 } 
 
 public void buildGUI() { 
 
  c_controlBox = Box.createVerticalBox(); 
 
  JLabel l1 = new JLabel("Example Java/IDL Interaction"); 
  JButton bLoadFile = new JButton("Load new file"); 
  bLoadFile.addActionListener(new ActionListener() { 
   public void actionPerformed(ActionEvent e) { 
    JFileChooser chooser = new JFileChooser(new 
     File("c:\\ITT\\IDL63\\EXAMPLES\\DATA")); 
    chooser.setDialogTitle("Enter a JPEG file"); 
    if (chooser.showOpenDialog(FrameTest.this) == 
     JFileChooser.APPROVE_OPTION) { 
 
      java.io.File fname = chooser.getSelectedFile(); 
      String filename = fname.getPath(); 
      System.out.println(filename); 
      c_imgArea.setImageFile(filename); 
    } 
   } 
  }); 
 
  JButton b1 = new JButton("Close this example"); 
  b1.addActionListener(new ActionListener() { 
   public void actionPerformed(ActionEvent e) { 
    dispose(); 
   } 
  }); 
 
  c_imgArea = new 
   RSIImageArea("c:\\itt\\idl63\\examples\\data\\glowing_gas.jpg", 
    new Dimension(m_xsize,m_ysize)); 
 
  Box mainBox = Box.createVerticalBox(); 
  Box rowBox = Box.createHorizontalBox();        
  rowBox.add(b1); 
  rowBox.add(bLoadFile); 
 
  c_controlBox.add(l1); 
  c_controlBox.add(rowBox); 
  mainBox.add(c_controlBox); 
  mainBox.add(c_imgArea); 
 
  getContentPane().add(mainBox); 
 
  pack(); 
  setVisible(true); 
  c_imgArea.displayImage(); 
  c_imgArea.addResizeListener(new RSIImageAreaResizeListener() { 
   public void areaResized(int newx, int newy) { 
    Dimension cdim = c_controlBox.getSize(null); 
    Insets i = getInsets(); 
    newx = i.left + i.right + newx; 
    newy = i.top + cdim.height + newy + i.bottom; 
    setSize(new Dimension(newx, newy)); 
   } 
  }); 
 } 
 
 public void setImageData(int [] imgData, int xsize, int ysize) { 
  MemoryImageSource ims = new MemoryImageSource(xsize, ysize,  
   imgData, 0, ysize); 
  Image imgtmp = createImage(ims); 
  Graphics g = c_imgArea.getGraphics(); 
  g.drawImage(imgtmp, 0, 0, null); 
 
 } 
 
 public void setImageData(byte [][][] imgData, int xsize,  
  int ysize) { 
 
  System.out.println("SIZE = "+xsize+"x"+ysize); 
  int newArray [] = new int[xsize*ysize]; 
  int pixi = 0; 
  int curpix = 0; 
  short [] currgb = new short[3]; 
  for (int i=0;i<m_xsize;i++) { 
   for (int j=0;j<m_ysize;j++) { 
    for (int k=0;k<3;k++) { 
     currgb[k] = (short) imgData[k][i][j]; 
     currgb[k] = (currgb[k] < 128) ? (short) currgb[k] : (short) 
      (currgb[k]-256); 
    } 
    curpix = (int) currgb[0] *  + 
     ((int) currgb[1] * (int) Math.pow(2,8)) + 
      ((int) currgb[2] * (int) Math.pow(2,16)); 
    if (pixi % 1000 == 0) 
     System.out.println("PIXI = "+pixi+" "+curpix); 
    newArray[pixi++] = curpix; 
   } 
  } 
 
  MemoryImageSource ims = new MemoryImageSource(xsize, ysize,  
   newArray, 0, ysize); 
  c_imgArea.setImageObj(c_imgArea.createImage(ims)); 
 
 } 
 
 public byte[][][] getImageData()  
 { 
  int width = 1; 
  int height = 1; 
  PixelGrabber pGrab; 
 
  width = m_xsize; 
  height = m_ysize; 
                  
  // pixarray for the grab - 3D bytearray for display 
  int [] pixarray = new int[width*height]; 
  byte [][][] bytearray = new byte[3][width][height]; 
 
 
  // create a pixel grabber 
  pGrab = new PixelGrabber(c_imgArea.getImageObj(),0,0,  
  width,height, pixarray, 0, width); 
 
  // grab the pixels from the image 
  try { 
   boolean b = pGrab.grabPixels(); 
  } catch (InterruptedException e) { 
   System.err.println("pixel grab interrupted"); 
   return bytearray; 
  } 
 
  // break down the 32-bit integers from the grab into 8-bit bytes 
  // and fill the return 3D array 
  int pixi = 0; 
  int curpix = 0; 
  for (int j=0;j<m_ysize;j++) { 
   for (int i=0;i<m_xsize;i++) { 
    curpix = pixarray[pixi++]; 
    bytearray[0][i][j] = (byte) ((curpix >> 16) & 0xff); 
    bytearray[1][i][j] = (byte) ((curpix >>  8) & 0xff); 
    bytearray[2][i][j]  = (byte) ((curpix      ) & 0xff); 
   } 
  } 
  return bytearray; 
 } 
 
 
 public static void main(String [] args) { 
  FrameTest f = new FrameTest(); 
 } 
 
} 
 


Note

The above text is for the FrameTest class that accesses the glowing_gas.jpg file in the examples/data directory of a default installation of IDL on a Windows system. The file's location is specified as c:\\ITT\\IDL70\\EXAMPLES\\DATA in the above text. If the glowing_gas.jpg file is not in the same location on system, edit the text to change the location of this file to match your system.

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.util.Vector; 
import java.io.File; 
 
public class RSIImageArea extends JComponent implements 
 MouseMotionListener, MouseListener { 
 
 
 Image c_img; 
 int m_boxw = 100; 
 int m_boxh = 100; 
 Dimension c_dim; 
 boolean m_pressed = false; 
 int m_button = 0; 
 Vector c_resizelisteners = null; 
 
 public RSIImageArea(String imgFile, Dimension dim) { 
 
  c_img = getToolkit().getImage(imgFile); 
  c_dim = dim; 
  setPreferredSize(dim); 
  setSize(dim); 
  addMouseMotionListener(this); 
  addMouseListener(this); 
 
 } 
 
 public void addResizeListener(RSIImageAreaResizeListener l) { 
  if (c_resizelisteners == null) c_resizelisteners = new Vector(); 
  if (! c_resizelisteners.contains(l))  c_resizelisteners.add(l); 
 }  
 public void removeResizeListener(RSIImageAreaResizeListener l) { 
  if (c_resizelisteners == null) return; 
  if (c_resizelisteners.contains(l)) c_resizelisteners.remove(l); 
 } 
 
 public void displayImage() { 
  repaint(); 
 } 
 
 public void paint(Graphics g) { 
 
  int xsize = c_img.getWidth(null); 
  int ysize = c_img.getHeight(null); 
  if (xsize != -1 && ysize != -1) { 
   if (xsize != c_dim.width || ysize != c_dim.height) { 
    c_dim.width = xsize; 
    c_dim.height = ysize; 
    setPreferredSize(c_dim); 
    setSize(c_dim); 
    if (c_resizelisteners != null) { 
     RSIImageAreaResizeListener l = null; 
     for (int j=0;j<c_resizelisteners.size();j++) { 
      l = (RSIImageAreaResizeListener) 
       c_resizelisteners.elementAt(j); 
      l.areaResized(xsize, ysize); 
     } 
    } 
   } 
  } 
  g.drawImage(c_img, 0, 0, null); 
 } 
 
 public void setImageFile(String fileName) {	   
  c_img = null; 
  c_img = getToolkit().getImage(fileName); 
  repaint();	 
 } 
 
 
 public Image getImageObj() { 
  return c_img; 
 } 
 
 public void setImageObj(Image img) { 
  c_img = img; 
  repaint(); 
 } 
 
 public void drawZoomBox(MouseEvent e) { 
  int bx = e.getX() - m_boxw/2;	     
  bx = (bx >=0) ? bx :0; 
  int by = e.getY() - m_boxh/2; 
  by = (by >=0) ? by :0; 
  int ex = bx + m_boxw; 
  if (ex > c_dim.width) { 
   ex = c_dim.width; 
   bx = c_dim.width-m_boxw; 
  } 
  int ey = by + m_boxh; 
  if (ey > c_dim.height) { 
   ey = c_dim.height; 
   by = c_dim.height-m_boxh; 
  } 
 
  repaint(); 
  Graphics g = getGraphics(); 
  g.drawImage(c_img, bx, by, ex, ey, bx+(m_boxw/4), by+(m_boxh/4), 
   ex-(m_boxw/4),ey-(m_boxh/4), null); 
  g.setColor(Color.white); 
  g.drawRect(bx, by, m_boxw, m_boxh); 
 
 } 
 
 public void mouseDragged(MouseEvent e) { 
  drawZoomBox(e); 
 } 
 
 public void mouseMoved(MouseEvent e) { 
 
  Graphics g = getGraphics(); 
  if (m_pressed && (m_button == 1)) { 
   drawZoomBox(e);		 
   g.setColor(Color.white); 
   g.drawString("DRAG", 10,10); 
  } else { 
 
   g.setColor(Color.white); 
   String s = "("+e.getX()+","+e.getY()+")"; 
   repaint(); 
   g.drawString(s, e.getX(), e.getY()); 
  } 
 
 } 
 
 public void mouseClicked(MouseEvent e) {} 
 public void mouseEntered(MouseEvent e) {} 
 public void mouseExited(MouseEvent e) {} 
 
 public void mousePressed(MouseEvent e) { 
  m_pressed = true; 
  m_button = e.getButton(); 
  repaint(); 
  if (m_button == 1) drawZoomBox(e); 
 } 
 
 public void mouseReleased(MouseEvent e) { 
  m_pressed = false; 
  m_button = 0; 
 }        	 
} 

public interface RSIImageAreaResizeListener { 
 public void areaResized(int newx, int newy); 
} 

PRO ImageFromJava 
; Create a Swing Java object and have it load image data 
; into IDL. 
 
; Create the Java object first. 
oJSwing = OBJ_NEW('IDLjavaObject$FrameTest', 'FrameTest') 
 
; Get the image from the Java object. 
image = oJSwing -> GetImageData() 
PRINT, 'Loaded Image Information:' 
HELP, image 
 
; Delete the Java object. 
OBJ_DESTROY, oJSwing 
 
; Interactively display the image. 
IIMAGE, image 
 
END