celebritypainter.java

java编程的一些Applets例子。值得深入研究一下。

     
      optSmall = new Checkbox("Small", grpBrushSize, true);
   
      gblControls.setConstraints(optSmall, gbcControls);

      add(optSmall);


      optMedium = new Checkbox("Medium", grpBrushSize, false);

      gblControls.setConstraints(optMedium, gbcControls);

      add(optMedium);


      optLarge = new Checkbox("Large", grpBrushSize, false);

      gblControls.setConstraints(optLarge, gbcControls);

      add(optLarge);
   }

   //
   //  fillCombo:
   //  Fills the combo box of celebrity brushes with names
   //  given as parameters through the html.
   //  The number of brushes is unlimited.
   //
   public void fillCombo(Choice cboList)
   {
      String sListItem;	// String to add as a combo choice
      int iNum;	// Current parameter to get

      // Look first for parameter brush1.
      iNum = 1;

      while(true)
      {
         sListItem = appParent.getParameter("brush" + iNum);

         // Stop looping when there are no more brush parameters.         
         if(sListItem == null) break;

         cboList.addItem(sListItem);

         // Look for the next brush parameter incrementally.
         iNum++;
      }
   }

   //
   //  action:
   //  Act on the afftected control panel component.
   //
   public boolean action(Event e, Object arg)
   {
      int iSelectedLen;		// Length of selected brush name in combo box
			// Used for erasing.

      // Process celebrity name combo box event.
      if(e.target instanceof Choice)
      {
         // Play sound for changing celebrities.
         appParent.sndChange.play();

         // Tell user that the brush is being loaded. 
         appParent.screenGC.setColor(Color.white);
         appParent.screenGC.fillRect(0, 180, 160, 200);
         appParent.screenGC.setColor(Color.black);
         appParent.screenGC.drawString("Loading Brush.....", 20, 195);

         // Turn off the eraser, in case it was on.
         optEraser.setState(false);

         // Set the thumbnail celebrity image to one matching the selected name.
         bcBrushPic.setImage(convertImageString((String)arg, "BR"));
         sSelected = convertImageString((String)arg, "");

         bcBrushPic.repaint();

         // Load the selected name's celebrity image into the applet's brush.
         appParent.bshCeleb.setImage(sSelected);

         // Erase the loading message by redrawing the applet's screen.
         appParent.screenGC.drawImage(appParent.drawnPic, 0, 0, appParent);
      }

      // Process option event.
      if(e.target instanceof Checkbox)
      {
         // Process eraser event
         if(e.target == optEraser) 
         {
            // Play sound for changing celebrities
            appParent.sndChange.play();

            // Load the eraser
            if(optEraser.getState() == true)
            {
               // Tell user that the eraser is being loaded. 
               appParent.screenGC.setColor(Color.white);
               appParent.screenGC.fillRect(0, 180, 160, 200);
               appParent.screenGC.setColor(Color.black);
               appParent.screenGC.drawString("Loading Eraser.....", 20, 195);

               // Set the thumbnail to image of background.
               bcBrushPic.setImage("ERASERBR.jpg");

               bcBrushPic.repaint();

               // Load the eraser image into the applet's brush.
               appParent.bshCeleb.setImage("ERASER.jpg");

               // Erase the loading message by redrawing the applet's screen.
               appParent.screenGC.drawImage(appParent.drawnPic, 0, 0, appParent);
            }
            // Reload last selected brush.
            else
            {
               // Tell user that the brush is being loaded. 
               appParent.screenGC.setColor(Color.white);
               appParent.screenGC.fillRect(0, 180, 160, 200);
               appParent.screenGC.setColor(Color.black);
               appParent.screenGC.drawString("Loading Brush.....", 20, 195);

               // Get length of string holding name of selected celeb's image file.
               iSelectedLen = sSelected.length();

               // Set the thumbnail celebrity image to one matching the selected name.
               bcBrushPic.setImage(convertImageString(sSelected.substring(0, iSelectedLen - 4), "BR"));

               bcBrushPic.repaint();

               // Load the selected name's celebrity image into the applet's brush.
               appParent.bshCeleb.setImage(sSelected);

               // Erase the loading message by redrawing the applet's screen.
               appParent.screenGC.drawImage(appParent.drawnPic, 0, 0, appParent);
            }
         }

         // Process brush size event
         else
         {
            // Play sound for changing brush size
            appParent.sndBrush.play();     

            // Set the brush size to correspond to the option button set to true.
            if(optSmall.getState() == true) iBrushSize = SMALL;
            else if(optMedium.getState() == true) iBrushSize = MEDIUM;
            else if(optLarge.getState() == true) iBrushSize = LARGE;
         }
      }

      // Process clear button.
      if(e.target instanceof Button)
      { 
         // Clear the applet's screen, setting it back to a blank face.
         appParent.clear();

         appParent.sndClear.play();
      }

      return true;
   }

   // 
   //  convertImageString:
   //  Convert a celebrity name from the combo box into the name
   //  of a jpg file to be loaded.  Do this by stripping spaces, adding
   //  any extra characters, and adding the ".jpg" extension.
   //
   public String convertImageString(String sImageString, String sExt)
   {
      String sImageName = null;	// String to hold the final image name
      int iSpace = 0; 		// Location of current space
      int iLastSpace = (-1);	// Location of last space
      int iNameLength = 0;	// Length of given string

      iNameLength = sImageString.length();

      // Keep stripping spaces until there are no more.
      while(iSpace != (-1))
      {
         iSpace = sImageString.indexOf(" ", iLastSpace + 1);  

         // If a space was found, add the next string segment to the file name.
         if(iSpace != (-1))
         {
            if(sImageName == null) sImageName =  sImageString.substring(iLastSpace + 1, iSpace);
            else sImageName +=  sImageString.substring(iLastSpace + 1, iSpace);

            iLastSpace = iSpace;
         }
      } // end of while

      // Add the string segment found after the last space (or no space). 
      if(sImageName == null) sImageName =  
         sImageString.substring(iLastSpace + 1, iNameLength) + sExt + ".jpg";          
      else sImageName +=  sImageString.substring(iLastSpace + 1, iNameLength) + sExt + ".jpg";          
   
       return sImageName;
   }   
} // end of ControlPanel


//
//  class BrushCanvas:
//  Canvas to paint thumbnail of currently selected celebrity on.
//
class BrushCanvas extends Canvas
{
   // MEMBERS /////////////////////////////////////////////
   Applet appParent;
   Brush bshCelebPic;	// Brush used to hold current celebrity thumbnail
   Image imgCanvasImage;	
   Graphics canvasImageGC;

   public BrushCanvas(String sImageName, Applet ap)
   {
      appParent = ap;

      // Create the canvas' image.
      imgCanvasImage = appParent.createImage(40, 50);
      canvasImageGC = imgCanvasImage.getGraphics();

      // Create a new brush from the given image.
      bshCelebPic = new Brush(sImageName, appParent);

      // Call set image to copy the image to the canvas.
      setImage(sImageName);
   }

   //
   //  setImage:
   //  Copies specified image to canvas by setting it in
   //  the canvas' brush, and copying the pixles.
   //  This process is slow, but produces a better quality image
   //  than simply using getImage() and  drawImage().
   //
   public void setImage(String sImageName)
   {
      // Set the specified image in the canvas' brush.
      bshCelebPic.setImage(sImageName);

      // Copy pixels of the canvas' brush to the canvas.
      for(int x=0; x<40; x++) {
         for(int y=0; y<50; y++) {
            canvasImageGC.setColor(new Color(bshCelebPic.iImgPixels[x][y]));
            canvasImageGC.drawLine(x, y, x, y);         
         }
      }
   }

   //
   //  update:
   //  Call paint without clearing first.
   //
   public void update(Graphics g) {
      paint(g);
   }

   //
   //  paint:
   //  Copy the canvas to the screen.
   //
   public void paint(Graphics g)
   {
      g.drawImage(imgCanvasImage, 0, 0, appParent);         
   }
}  // end of BrushCanvas


//
//  class Brush:
//  Creates an array of pixel values from a given Image.
//
class Brush implements ImageConsumer 
{
   // MEMBERS /////////////////////////////////////////////
   Applet appParent;
   boolean bImgReady;	// Flag set when image has been consumed
   int iImgXSize, iImgYSize;
   int iImgPixels[][];		// Actual pixel values of image

   // 
   //  Brush:
   //  Constructor calls setImage to extract pixels frmo the given image.
   //
   Brush(String sImageName, Applet ap) {
      appParent = ap;      

      // Extract pixels from given image.
      setImage(sImageName);
   }

   //
   //  setImage:
   //  Extracts pixels from a given image.
   //
   public void setImage(String sImageName)
   {
      int iTicks;
      Image imgCopy;

      imgCopy = appParent.getImage(appParent.getDocumentBase(), sImageName);

      bImgReady = false;

      // Get pixles, but give up after 5 minutes.
      imgCopy.getSource().startProduction(this);
      iTicks = 5*60*1000;	// 5 minutes
      while(iTicks>0) {
         try {
             Thread.currentThread().sleep(100);
          } catch (Exception e) {}
          if(this.bImgReady)
              break;
          iTicks -= 100;
      }
   }

   // Function required for Image Consumer.
   public void setProperties(java.util.Hashtable dummy) {
   }

   // Function required for Image Consumer.
   public void setColorModel(ColorModel model) {
   }

   // Function required for Image Consumer.
   public void setHints(int dummy) {
   }

   // 
   //  imageComplete:
   //  Notifies brush that an image has been consumed by
   //  setting the image ready flag to true.
   //
   public void imageComplete(int dummy) {
       bImgReady = true;
   }

   //
   //  setDimensions:
   //  Sets variables for dimensions of given image,
   //  and creates an array to hold the pixels.
   //
   public void setDimensions(int x, int y) {
       iImgXSize = x;
       iImgYSize = y;
       iImgPixels = new int[x][y];
   }

   //
   //  setPixels:
   //  Take pixels from the one dimensional array and put their
   //  RGB lookup values into the two dimensional array of pixels.
   //
   public void setPixels(int x1, int y1, int w, int h,
       ColorModel cmModel, byte byPixels[], int iOff, int iScansize) {
       int x, y, x2, y2, sx, sy;

        x1 = x2 = iOff = 0;

       x2 = x1+w;
       y2 = y1+h;
       sy = iOff;
       for(y=y1; y<y2; y++) {
           sx = sy;
           for(x=x1; x<x2; x++)
               iImgPixels[x][y] = cmModel.getRGB(byPixels[sx++]);
           sy += iScansize;
       }
   }

   //
   //  setPixels:
   //  Take pixels from the one dimensional array and put their
   //  RGB lookup values into the two dimensional array of pixels.
   //
   public void setPixels(int x1, int y1, int w, int h,
      ColorModel cmModel, int iPixels[], int iOff, int iScansize) {
       int x, y, x2, y2, sx, sy;

       x1 = x2 = iOff = 0;

       x2 = x1+w;
       y2 = y1+h;
       sy = iOff;
       for(y=y1; y<y2; y++) {
           sx = sy;
           for(x=x1; x<x2; x++)
               iImgPixels[x][y] = cmModel.getRGB(iPixels[sx++]);
           sy += iScansize;
       }
   }
} // end of Brush