android下根据公司需要修改后的能正常使用的坐标校准代码

     用于电子书的屏(具体我也不是很清楚)，故需要在android系统源代码中修改坐标校准算法。

     上层代码应用在其它网页上也有，只是根据网上信息修改了校准算法（可上网查询，这里不再详述），同时将结果保存。代码如下：

package com.;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.util.Log;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;

public class Calibration extends Activity {
 static final int SAMPLE_COUNTS = 5;
 static final int POINT_DEGREE = 2;
 static final int FACTOR_COUNTS = 7;
 static final int TOP_LEFT = 0;
 static final int TOP_RIGHT = 1;
 static final int BOTTOM_RIGHT = 2;
 static final int BOTTOM_LEFT = 3;
 static final int CENTER = 4;
 static final int X_AXIS = 0;
 static final int Y_AXIS = 1;
 static final int EDGE_GAP = 200;

 static final String CALIBRATION_FILE = "/data/pointercal";
 //static final String CALIBRATION_FILE = "/mnt/sdcard/pointercal";
 static final String TAG = "Calibration";
 static final boolean DEBUG = true;

 private int X_RES;
 private int Y_RES;
 
 class calibration {
  int x[] = new int[5];//TouchScreen的x坐标
  int y[] = new int[5];//TouchScreen的y坐标
  int xfb[] = new int[5];//LCD的x坐标
  int yfb[] = new int[5];//LCD的y坐标
//  float a[] = new float[2];
  float a[] = new float[6];
 };

 private calibration cal;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  //Log.d(TAG, "onCreate");
  
  cal = new calibration();

  DisplayMetrics dpm = new DisplayMetrics();
  getWindowManager().getDefaultDisplay().getMetrics(dpm);
  X_RES = dpm.widthPixels;
  Y_RES = dpm.heightPixels;
  String str = String.format("X_RES = %d, Y_RES = %d", X_RES, Y_RES);
  Log.d(TAG, str);

  this.initScreenPoints();

  setContentView(new MyView(this));
 }

 // TopLeft-->TopRight-->BottomRight-->BottomLeft-->Center
 // 为240 * 320分辨率,我们使用50像素作为边缘的差距
 private boolean initScreenPoints() {
  String str;
  
  cal.xfb[TOP_LEFT] = EDGE_GAP; // TopLeft
  cal.yfb[TOP_LEFT] = EDGE_GAP;
  str = String.format("cal.xfb[%d] = %d, cal.yfb[%d] = %d", TOP_LEFT, cal.xfb[TOP_LEFT], TOP_LEFT, cal.yfb[TOP_LEFT]);
  Log.d("zxb", str);

  cal.xfb[TOP_RIGHT] = X_RES - EDGE_GAP; // TopRight
  cal.yfb[TOP_RIGHT] = EDGE_GAP;
  str = String.format("cal.xfb[%d] = %d, cal.yfb[%d] = %d", TOP_RIGHT, cal.xfb[TOP_RIGHT], TOP_RIGHT, cal.yfb[TOP_RIGHT]);
  Log.d("zxb", str);
  
  cal.xfb[BOTTOM_RIGHT] = X_RES - EDGE_GAP; // BottomRight
  cal.yfb[BOTTOM_RIGHT] = Y_RES - EDGE_GAP;
  str = String.format("cal.xfb[%d] = %d, cal.yfb[%d] = %d", BOTTOM_RIGHT, cal.xfb[BOTTOM_RIGHT], BOTTOM_RIGHT, cal.yfb[BOTTOM_RIGHT]);
  Log.d("zxb", str);

  cal.xfb[BOTTOM_LEFT] = EDGE_GAP; // BottomLeft
  cal.yfb[BOTTOM_LEFT] = Y_RES - EDGE_GAP;
  str = String.format("cal.xfb[%d] = %d, cal.yfb[%d] = %d", BOTTOM_LEFT, cal.xfb[BOTTOM_LEFT], BOTTOM_LEFT, cal.yfb[BOTTOM_LEFT]);
  Log.d("zxb", str);

  cal.xfb[CENTER] = X_RES / 2; // Center
  cal.yfb[CENTER] = Y_RES / 2;
  str = String.format("cal.xfb[%d] = %d, cal.yfb[%d] = %d", CENTER, cal.xfb[CENTER], CENTER, cal.yfb[CENTER]);
  Log.d("zxb", str);
  
  return true;
 }

 private boolean perform_calibration() {
  String str;
/*  
  cal.a[0] = ((float)(cal.x[1] - cal.x[0]) / (float)(cal.xfb[1] - cal.xfb[0]) + (float)(cal.x[2] - cal.x[3]) / (float)(cal.xfb[2] - cal.xfb[3])) / 2.0f;
  cal.a[1] = ((float)(cal.y[3] - cal.y[0]) / (float)(cal.yfb[3] - cal.yfb[0]) + (float)(cal.y[2] - cal.y[1]) / (float)(cal.yfb[2] - cal.yfb[1])) / 2.0f;
  
  str = String.format("cal.a[0] = %f, cal.a[1] = %f\n", cal.a[0], cal.a[1]);
  Log.d(TAG, str);
  
  return true;
*/

  int j;
  float n, xt, yt, xt2, yt2, xtyt, xl, xlxt, xlyt, yl, ylxt, ylyt;
  float det, a, b, c, d, e, f;
  float scaling = 65536.0f;

     //Get sums for matrix
  n = xt = yt = xt2 = yt2 = xtyt = xl = xlxt = xlyt = yl = ylxt = ylyt = a = b = c = d = e = f = 0.0f;
  for(j=0; j<5; j++) {
   n += 1.0;
   xt += (float)cal.x[j];
   yt += (float)cal.y[j];
   xt2 += (float)(cal.x[j] * cal.x[j]);
   yt2 += (float)(cal.y[j] * cal.y[j]);
   xtyt += (float)(cal.x[j] * cal.y[j]);
   xl += (float)(cal.xfb[j]);
   xlxt += (float)(cal.xfb[j] * cal.x[j]);
   xlyt += (float)(cal.xfb[j] * cal.y[j]);
   yl += (float)cal.yfb[j];
   ylxt += (float)(cal.yfb[j] * cal.x[j]);
   ylyt += (float)(cal.yfb[j] * cal.y[j]);   
  }

        // Get determinant of matrix -- check if determinant is too small
  det = n * (xt2 * yt2 - xtyt * xtyt) + xt * (xtyt * yt - xt * yt2) + yt * (xt * xtyt - yt * xt2);
  if(det < 0.1 && det > -0.1) {
   str = String.format("ts_calibrate: determinant is too small -- %f\n", det);
   Log.d(TAG, str);
   
   return false;
  }

  a = n*(xlxt * yt2 - xtyt * xlyt) + xl * (xtyt * yt - xt * yt2) - yt * (xlxt * yt - xt * xlyt);  
  cal.a[0] = a / det;
  
  b = n * (xt2 * xlyt - xtyt * xlxt) + xt * (xlxt * yt - xt * xlyt) - xl * (xt2 * yt - xt * xtyt);
  cal.a[1] = b / det;
  
  c = xl * (xt2 * yt2 - xtyt * xtyt) + xt * (xtyt * xlyt - xlxt * yt2) - yt * (xt2 * xlyt - xlxt * xtyt);
  cal.a[2] = c / det;
 
  d = n * (ylxt * yt2 - xtyt * ylyt) + yl * (xtyt * yt - xt * yt2) - yt * (ylxt * yt - xt * ylyt);
  cal.a[3] = d / det;
  
  e = n * (xt2 * ylyt - ylxt * xtyt) + xt * (ylxt * yt - xt * ylyt) - yl * (xt2 * yt - xt * xtyt);
  cal.a[4] = e / det;
  
  f = yl * (xt2 * yt2 - xtyt * xtyt) + xt * (xtyt * ylyt - ylxt * yt2) - yt * (xt2 * ylyt - ylxt * xtyt);
  cal.a[5] = f / det;

  str = String.format("cal.a[0] = %f cal.a[1] = %f cal.a[2] = %f cal.a[3] = %f cal.a[4] = %f cal.a[5] = %f\n",
    cal.a[0], cal.a[1], cal.a[2], cal.a[3], cal.a[4], cal.a[5]);
  Log.d(TAG, str);

  return true;
 }

 private boolean saveCalibrationResult() {
  FileOutputStream os;
  String res = "";

  try {
   os = new FileOutputStream(CALIBRATION_FILE);
   res = String.format("%f %f %f %f %f %f", cal.a[0], cal.a[1], cal.a[2], cal.a[3], cal.a[4], cal.a[5]);

   Log.i(TAG, "calibration result=" + res);

   os.write(res.getBytes());
   os.close();
  } catch (FileNotFoundException e1) {
   // TODO Auto-generated catch block
   e1.printStackTrace();
   Log.w(TAG, "open calibration file write error: " + CALIBRATION_FILE);
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return true;
 }

 public class MyView extends View {
  private Canvas cv;
  private Paint paint;
  private Bitmap bmp;
  private int screen_pos;
  private Context mContext;

  public MyView(Context c) {
   super(c);
   // 镶满屏幕,没有标题
   //Log.d(TAG, "MyView");
   
   requestWindowFeature(Window.FEATURE_NO_TITLE);
   getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
     WindowManager.LayoutParams.FLAG_FULLSCREEN);
   mContext = c;
   paint = new Paint();
   paint.setDither(true);
   paint.setAntiAlias(true);
   paint.setStrokeWidth(2);
   paint.setColor(Color.WHITE);
   paint.setStyle(Paint.Style.STROKE);
   bmp = Bitmap.createBitmap(X_RES, Y_RES, Bitmap.Config.ARGB_8888);
   cv = new Canvas(bmp);
   screen_pos = 0;
   drawCalibrationCross(screen_pos);
  }

  protected void onDraw(Canvas canvas) {
   canvas.drawColor(Color.BLACK);
   canvas.drawBitmap(bmp, 0, 0, null);
  }

  private boolean drawCalibrationCross(int pos) {
   if (DEBUG) {
    Log.i("bigcren", "draw cross at pos " + pos);
   }

   cv.drawColor(Color.BLACK);

   // 画的X线
   cv.drawLine(cal.xfb[pos] - 30, cal.yfb[pos], cal.xfb[pos] - 3,
     cal.yfb[pos], paint);
   cv.drawLine(cal.xfb[pos] + 3, cal.yfb[pos], cal.xfb[pos] + 30,
     cal.yfb[pos], paint);

   // 画的Y线
   cv.drawLine(cal.xfb[pos], cal.yfb[pos] - 30, cal.xfb[pos],
     cal.yfb[pos] - 3, paint);
   cv.drawLine(cal.xfb[pos], cal.yfb[pos] + 3, cal.xfb[pos],
     cal.yfb[pos] + 30, paint);
   invalidate();
   return true;
  }

  public boolean onTouchEvent(MotionEvent event) {
   float tmpx, tmpy;
   boolean ret;
   if (screen_pos > SAMPLE_COUNTS - 1) {
    Log.i("bigcren", "get sample ok");
    return true;
   }

   if (event.getAction() == MotionEvent.ACTION_UP) {
    tmpx = event.getX();
    tmpy = event.getY();
    if (Math.abs(cal.xfb[screen_pos] - tmpx) > 15
      && Math.abs(cal.yfb[screen_pos] - tmpy) > 15) {
     Toast.makeText(mContext, R.string.calibration_error,
       Toast.LENGTH_SHORT).show();
     return false;
    }

    cal.x[screen_pos] = (int) event.getX();//(int) (event.getX() * 4096.0 / (float) X_RES + 0.5);
    cal.y[screen_pos] = (int) event.getY();//(int) (event.getY() * 4096.0 / (float) Y_RES + 0.5);
    String str = String.format("cal.x[%d] = %d, cal.y[%d] = %d", screen_pos, cal.x[screen_pos], screen_pos, cal.y[screen_pos]);
    Log.d(TAG, str);
    /*
    str = String.format("x[%d] = %d, y[%d] = %d", screen_pos, (int)event.getX(), screen_pos, (int)event.getY());
    Log.d(TAG, str);
    */

    if (screen_pos == 4) {
     ret = perform_calibration();
     if (ret) {
      saveCalibrationResult();
      finish();
      return true;
     } else {
      screen_pos = 0;
      Log.w(TAG, "Calibration failed");
     }
    } else {
     Led.ControlLed(Integer.toString(screen_pos));
     screen_pos++;
     drawCalibrationCross(screen_pos);
    }
   }
   return true;
  }
 }
}

 

将校准数据保存到文本文件后，就需要修改android系统源码中的InputDevice.java代码中。下面的代码有些加到MotionEvent generateAbsMotion(InputDevice device, long curTime, long curTimeNano, Display display, int orientation, int metaState)代码中for循环语句的最后面，其它加到该java文件的最后。因为手上暂时没有android的源代码，故无法解释generateAbsMotion函数中每条语句的意思。

//Begin-Modify by zxb for Calibration
                x_tmp = reportData[j + MotionEvent.SAMPLE_X];
                y_tmp = reportData[j + MotionEvent.SAMPLE_Y];
                str = String.format("j = %d MotionEvent.SAMPLE_X = %d MotionEvent.SAMPLE_Y= %d", j,  MotionEvent.SAMPLE_X, MotionEvent.SAMPLE_Y);
        Log.i("zxb", str);
                str = String.format(" 1 reportData[%d] = %f reportData[%d] = %f",  j + MotionEvent.SAMPLE_X, reportData[j + MotionEvent.SAMPLE_X], j + MotionEvent.SAMPLE_Y, reportData[j + MotionEvent.SAMPLE_Y]);
        Log.i("zxb", str);

                if (device.tInfo != null) {
            str = String.format("device.tInfo.x1 = %f device.tInfo.y1 = %f device.tInfo.z1 = %f", device.tInfo.x1, device.tInfo.y1, device.tInfo.z1);
                    Log.i("zxb", str);
                    reportData[j + MotionEvent.SAMPLE_X] =  (device.tInfo.x1 * x_tmp + device.tInfo.y1 * y_tmp + device.tInfo.z1);// / device.tInfo.s;
                    str = String.format("device.tInfo.x2 = %f device.tInfo.y2 = %f device.tInfo.z2 = %f", device.tInfo.x2, device.tInfo.y2, device.tInfo.z2);
                    Log.i("zxb", str);
            reportData[j + MotionEvent.SAMPLE_Y] =  (device.tInfo.x2 * x_tmp + device.tInfo.y2 * y_tmp + device.tInfo.z2);// / device.tInfo.s;
                }
                str = String.format("2 reportData[%d] = %f reportData[%d] = %f",  j + MotionEvent.SAMPLE_X, reportData[j + MotionEvent.SAMPLE_X], j + MotionEvent.SAMPLE_Y, reportData[j + MotionEvent.SAMPLE_Y]);
        Log.i("zxb", str);
                //End-Modify by zxb for Calibration



    //Begin-Add by zxb for Calibration
    static class TransformInfo {
        static float x1;
     static float y1;
     static float z1;
     static float x2;
     static float y2;
     static float z2;
     TransformInfo() {
            x1 = 1.0f;
            y1 = 1.0f;
            z1 = 0.0f;
            x2 = 1.0f;
            y2 = 1.0f;
            z2 = 0.0f;
    }
        
    };
    //End-Add by zxb for Calibration




        //Begin-Add by zxb for Calibration
        readCalibrationResult();
        //End-Add by zxb for Calibration



    //Begin-Add by zxb for Calibration
    private void readCalibrationResult() {
        try {
             FileInputStream is = new FileInputStream(CALIBRATION_FILE);
             Log.d("zxb", String.format("1 tInfo.x1 = %f tInfo.y1 = %f tInfo.z1 = %f tInfo.x2 = %f tInfo.y2 = %f tInfo.z2 = %f", tInfo.x1, tInfo.y1, tInfo.z1, tInfo.x2, tInfo.y2, tInfo.z2));
         byte[] mBuffer = new byte[64];
         int len = is.read(mBuffer);
         is.close();
            if (len > 0) {
             int i;
             for (i = 0; i < len; i++)
             if (mBuffer[i] == '\n' || mBuffer[i] == 0)
                 break;
             len = i;
            }

            if (len > 0) {
         tInfo = new TransformInfo();
         
               StringTokenizer st = new StringTokenizer(new String(mBuffer, 0, len));
               tInfo.x1 = Float.parseFloat(st.nextToken());
               tInfo.y1 = Float.parseFloat(st.nextToken());
               tInfo.z1 = Float.parseFloat(st.nextToken());
               tInfo.x2 = Float.parseFloat(st.nextToken());
               tInfo.y2 = Float.parseFloat(st.nextToken());
               tInfo.z2 = Float.parseFloat(st.nextToken());
               Log.d("zxb", String.format("2 tInfo.x1 = %f tInfo.y1 = %f tInfo.z1 = %f tInfo.x2 = %f tInfo.y2 = %f tInfo.z2 = %f", tInfo.x1, tInfo.y1, tInfo.z1, tInfo.x2, tInfo.y2, tInfo.z2));
        }   
        } catch (java.io.FileNotFoundException e) {
             Log.i("InputDevice", "calibration file not found exception");
        } catch (java.io.IOException e) {
             Log.i("InputDevice", "io exception");
        } catch (java.lang.NumberFormatException e) {
             Log.i("InputDevice", "number format exception");
        }

    }
     //End-Add by zxb for Calibration
};
根据输出坐标值与实际坐标值比较，此校准算法的优缺点是：在坐标不准确时能提高精度，但坐标比较准时会略降低精度；但提高的精度远大于降低的精度。

至于是使用android系统源码自带的校准算法还是采用本文的校准算法，就是仁者见仁智者见智了。因为我没有详细比较两者的优缺点。