[ Processing for Android ] A Camera example for prior ICS

ketai library目前提供的KetaiCamera範例應該只適用於Android ICS之後的版本,如果想在ICS之前的版本執行的話,在http://www.akeric.com/blog/?p=1342提供一份很詳細的原始碼範例,不過畢竟作者是在2010年寫出的,有一小部份的code已不適用目前的Processing for Android 2.x版本,所以我稍微調整了幾行code,就可以在舊平板上跑起來

import processing.core.*; 
import processing.data.*; 
import processing.event.*; 
import processing.opengl.*; 

import android.content.Context; 
import android.hardware.Camera; 
import android.hardware.Camera.PreviewCallback; 
import android.view.*;

import java.util.*; 
import java.io.*; 

public class camera extends PApplet {


CameraSurfaceView gCamSurfView;

PImage gBuffer;

public void setup() {
  //用不到
}

public void draw() {
  //用不到
}


public void onResume() {
  super.onResume();
  orientation(LANDSCAPE);
  gCamSurfView = new CameraSurfaceView(this.getApplicationContext());
}


class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Camera.PreviewCallback {

  SurfaceHolder mHolder;
  Camera camera = null;
  Camera.Size prevSize;

  CameraSurfaceView(Context context) {
    super(context);

    mHolder = getSurfaceHolder();

    mHolder.addCallback(this);
  }

  public void surfaceCreated (SurfaceHolder holder) {

    camera = Camera.open();
    camera.setPreviewCallback(this);
    
    
    Camera.Parameters parameters = camera.getParameters();
    parameters.setPreviewSize(800,800); 
    camera.setParameters(parameters);


    prevSize = parameters.getPreviewSize();
    gBuffer = createImage(prevSize.width, prevSize.height, RGB);
  }  

  public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    camera.startPreview();
  }

  public void surfaceDestroyed (SurfaceHolder holder) {
    camera.stopPreview();
    camera.release();
    camera = null;
  }


  public void onPreviewFrame(byte[] data, Camera cam) {
    gBuffer.loadPixels();
    decodeYUV420SP(gBuffer.pixels, data, prevSize.width, prevSize.height);
    gBuffer.updatePixels();
    image(gBuffer, 0, 0);
  }

  public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {
    // 原作者改自 Pulled directly from:
    // http://ketai.googlecode.com/svn/trunk/ketai/src/edu/uic/ketai/inputService/KetaiCamera.java
    final int frameSize = width * height;

    for (int j = 0, yp = 0; j < height; j++) {       int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
      for (int i = 0; i < width; i++, yp++) {
        int y = (0xff & ((int) yuv420sp[yp])) - 16;
        if (y < 0)
          y = 0;
        if ((i & 1) == 0) {
          v = (0xff & yuv420sp[uvp++]) - 128;
          u = (0xff & yuv420sp[uvp++]) - 128;
        }

        int y1192 = 1192 * y;
        int r = (y1192 + 1634 * v);
        int g = (y1192 - 833 * v - 400 * u);
        int b = (y1192 + 2066 * u);

        if (r < 0)
           r = 0;
        else if (r > 262143)
           r = 262143;
        if (g < 0)
           g = 0;
        else if (g > 262143)
           g = 262143;
        if (b < 0)
           b = 0;
        else if (b > 262143)
           b = 262143;

        rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
      }
    }
  }
}

  public int sketchWidth() { return displayWidth; }
  public int sketchHeight() { return displayHeight; }
}