flash摄像头拍照实现原理分析

最近一段时间，由于网站的需要，做了一个在线拍照的flash，刚开始的时候也是什么都不懂，对flash也是了解点皮毛，经过不断的在网上查阅资料。经过一周的努力，终于被我搞定了。

主要用到Camera类，MovieClip 类，BitmapData类，LoadVars类，如果要实现这个功能，必须先去了解这几个类

实现的过程如下。

1，先在库中新建一个视频元件，把视频元件拖放到场景中，取名为my_video，新建一个按纽元件，取名为btn_print.

2，加入以下代码实现视频的播放
myCam = Camera.get();
myCam.setMode(266,200,10);
my_video.attachVideo(myCam);

3 ，以下代码实现图片的获得和上传
import flash.display.BitmapData;
import flash.geom.Rectangle;
import flash.geom.ColorTransform;

class PrintScreen {
 
 public var addListener:Function
 public var broadcastMessage:Function
 
 private var id:   Number;
 public  var record:LoadVars;
 
 function PrintScreen(){
  AsBroadcaster.initialize( this );
 }
 public function print(mc:MovieClip, w:Number, h:Number){
  broadcastMessage("onStart", mc);
  w = Math.floor(w);
  h = Math.floor(h);
  var bmp:BitmapData = new BitmapData(w, h, false);
  record = new LoadVars();
  record.width  = w
  record.height = h
  record.cols   = 0
  record.rows   = 0
  bmp.draw(mc);
  id = setInterval(copysource, 1, this, mc, bmp);
 }
 
 private function copysource(scope, movie, bit){
  var pixel:Number
  var str_pixel:String
  scope.record["px" + scope.record.rows] = new Array();
  for(var a = 0; a < bit.width; a++){
   pixel     = bit.getPixel(a, scope.record.rows )
   str_pixel = pixel.toString(16)
   scope.record["px" + scope.record.rows].push(str_pixel)
  }
 
  scope.record.rows += 1
  if(scope.record.rows >= bit.height){
   clearInterval(scope.id)
   bit.dispose();
  }
 }
}

4 以下代码在服务器段接受数据，生成图片(jsp版)
String width = request.getParameter("width");
 String height = request.getParameter("height");
int w = Integer.parseInt(width);
  int h = Integer.parseInt(height);
try {
   OutputStream fos = response.getOutputStream();
   BufferedImage bf = new BufferedImage(w, h,
     BufferedImage.TYPE_INT_RGB);

   for (int i = 0; i < bf.getHeight(); i++) {
    String data = request.getParameter("px" + i);
    String[] ds = data.split(",");
    for (int j = 0; j < bf.getWidth(); j++) {
     int d = Integer.parseInt(ds[j], 16);
     bf.setRGB(j, i, d);
    }
   }

   ImageWriter writer = null;
   ImageTypeSpecifier type = ImageTypeSpecifier
     .createFromRenderedImage(bf);
   Iterator iter = ImageIO.getImageWriters(type, "jpg");
   if (iter.hasNext()) {
    writer = (ImageWriter) iter.next();
   }
   if (writer == null) {
    return null;
   }
   IIOImage iioImage = new IIOImage(bf, null, null);
   ImageWriteParam param = writer.getDefaultWriteParam();

   param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);

   param.setCompressionQuality(0.2f);

   // save to file
   ImageOutputStream outputStream2 = ImageIO
     .createImageOutputStream(response.getOutputStream());
   writer.setOutput(outputStream2);
   writer.write(null, iioImage, param);

   fos.close();

  } catch (Exception e) {
   e.printStackTrace();
  }
System.out.println("w = " + w + ",h=" + h);
 response.setContentType("image/jpeg");
 return null;