如何裁剪圖像？

Question

我用矩陣類來縮放我的圖像。 但我不知道如何裁剪縮放的圖像。

我想我應該在ZOOM模式下修正偏移量。

請幫我

public class PP2cropActivity extends Activity implements OnTouchListener { 

     private static final String TAG = "Touch"; 


     Button cropbtn; 
     float offx, offy; 
     float addX2, addY2; 
     float sx, sy, ex, ey; 
     float scale; 

     Matrix matrix = new Matrix(); 
     Matrix savedMatrix = new Matrix(); 
     static final int NONE = 0; 
     static final int DRAG = 1; 
     static final int ZOOM = 2; 
     int mode = NONE; 

     PointF start = new PointF(); 
     PointF mid = new PointF(); 
     PointF end = new PointF(); 

     float oldDist = 1f; 
     Bitmap bPhoto; 
     String mImgpath; 

     @Override 
     public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.main); 

      Intent intent = getIntent(); 
      mImgpath = intent.getStringExtra("mImgpath"); 

      bPhoto = BitmapFactory.decodeFile(mImgpath); 
      bPhoto = Bitmap.createScaledBitmap(bPhoto, 400, 600, true); 

      cropbtn = (Button)findViewById(R.id.confirmbtn); 

      cropbtn.setOnClickListener(new OnClickListener(){ 
       public void onClick(View arg0) { 

        PP2mainActivity.mCropedImage = Bitmap.createBitmap(bPhoto, (int)addX2, (int)addY2, 100, 100); 
        Intent intent = new Intent(PP2cropActivity.this, PP2mainActivity.class); 
        startActivity(intent); 

       } 
      }); 

      ImageView view = (ImageView) findViewById(R.id.matrixview); 
      view.setImageBitmap(bPhoto); 
      view.setOnTouchListener(this); 
     } 


     public boolean onTouch(View v, MotionEvent event) { 
      ImageView view = (ImageView) v; 

      // Dump touch event to log 


      // Handle touch events here... 
       switch (event.getAction() & MotionEvent.ACTION_MASK) { 
       case MotionEvent.ACTION_DOWN: 
        savedMatrix.set(matrix); 
        start.set(event.getX(), event.getY()); 
        Log.d(TAG, "mode=DRAG"); 
        sx = event.getX(); 
        sy = event.getY(); 

        mode = DRAG; 
        break; 

       case MotionEvent.ACTION_POINTER_DOWN: 
        oldDist = spacing(event); 
        Log.d(TAG, "oldDist=" + oldDist); 
        if (oldDist > 10f) { 
         savedMatrix.set(matrix); 
         midPoint(mid, event); 
         mode = ZOOM; 
          Log.d(TAG, "mode=ZOOM"); 
        } 
        break; 
       case MotionEvent.ACTION_UP: 
        if(mode ==DRAG) { 
        addX2 = -offx +10; 
        addY2 = -offy +10; 
        mode = NONE; 
        Log.d("point", "addX2 : " + addX2 + "addY2 : " + addY2); 
        } else if(mode ==ZOOM) 
        { 
         addX2 = (-offx+10)*scale; 
         addY2 = (-offy+10)*scale; 
        } 
        break; 
       case MotionEvent.ACTION_POINTER_UP: 
         mode = NONE; 
         Log.d(TAG, "mode=NONE"); 
         break; 
       case MotionEvent.ACTION_MOVE: 
        if (mode == DRAG) { 
         // ... 
         matrix.set(savedMatrix); 
         ex = event.getX(); 
         ey = event.getY(); 

         offx +=(int)(ex-sx); 
         offy +=(int)(ey-sy); 
         sx = ex; 
         sy = ey; 

         Log.d("off", "offx : " + offx+ " , offy : " + offy); 
         matrix.postTranslate(event.getX()- start.x, event.getY()- start.y); 


        } 
        else if (mode == ZOOM) { 

          float newDist = spacing(event); 
          Log.d(TAG, "newDist=" + newDist); 
          if (newDist > 10f) { 
            matrix.set(savedMatrix); 
           scale = newDist/oldDist; 
            matrix.postScale(scale, scale, mid.x, mid.y); 
          } 
          offx += (int)(ex-sx) /scale; 
          offy += (int)(ey-sy) /scale; 
          sx = ex; 
          sy = ey; 
        } 
        break; 
       } 

       view.setImageMatrix(matrix); 
       return true; // indicate event was handled 
     } 


     /** Determine the space between the first two fingers */ 
     private float spacing(MotionEvent event) { 
      float x = event.getX(0) - event.getX(1); 
      float y = event.getY(0) - event.getY(1); 
      return FloatMath.sqrt(x * x + y * y); 
     } 

     /** Calculate the mid point of the first two fingers */ 
     private void midPoint(PointF point, MotionEvent event) { 
      float x = event.getX(0) + event.getX(1); 
      float y = event.getY(0) + event.getY(1); 
      point.set(x/2, y/2); 
     } 
} 

Answer 1

要裁剪圖像：

Bitmap originalBitmap = BitmapFactory.decodeResource(getResources(), 
       R.drawable.test_image); 
Bitmap croppedBitmap = Bitmap.createBitmap(originalBitmap, x, y, width, height);