Android 图片处理，缩放、Drawable->Bitmap

//放大缩小图片

public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){  
      int width = bitmap.getWidth();  
      int height = bitmap.getHeight();  
      Matrix matrix = new Matrix();  
      float scaleWidht = ((float)w / width);  
      float scaleHeight = ((float)h / height);  
      matrix.postScale(scaleWidht, scaleHeight);  
      Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);  
      return newbmp;  
  }  

//将Drawable转化为Bitmap

     public static Bitmap drawableToBitmap(Drawable drawable){  
            int width = drawable.getIntrinsicWidth();  
            int height = drawable.getIntrinsicHeight();  
            Bitmap bitmap = Bitmap.createBitmap(width, height,  
                    drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888  
                            : Bitmap.Config.RGB_565);  
            Canvas canvas = new Canvas(bitmap);  
            drawable.setBounds(0,0,width,height);  
            drawable.draw(canvas);  
            return bitmap;  
              
        }  

//获得圆角图片的方法

  public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){

       Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
               .getHeight(), Bitmap.Config.ARGB_8888);
       Canvas canvas = new Canvas(output);

       final int color = 0xff424242;
       final Paint paint = new Paint();
       final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
       final RectF rectF = new RectF(rect);

       paint.setAntiAlias(true);
       canvas.drawARGB(0, 0, 0, 0);
       paint.setColor(color);
       canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

       paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
       canvas.drawBitmap(bitmap, rect, rect, paint);

       return output;
   }

//获得带倒影的图片方法

    public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){  
        final int reflectionGap = 4;  
        int width = bitmap.getWidth();  
        int height = bitmap.getHeight();  
          
        Matrix matrix = new Matrix();  
        matrix.preScale(1, -1);  
          
        Bitmap reflectionImage = Bitmap.createBitmap(bitmap,   
                0, height/2, width, height/2, matrix, false);  
          
        Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB_8888);  
          
        Canvas canvas = new Canvas(bitmapWithReflection);  
        canvas.drawBitmap(bitmap, 0, 0, null);  
        Paint deafalutPaint = new Paint();  
        canvas.drawRect(0, height,width,height + reflectionGap,  
                deafalutPaint);  
          
        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);  
          
        Paint paint = new Paint();  
        LinearGradient shader = new LinearGradient(0,  
                bitmap.getHeight(), 0, bitmapWithReflection.getHeight()  
                + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);  
        paint.setShader(shader);  
        // Set the Transfer mode to be porter duff and destination in  
        paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));  
        // Draw a rectangle using the paint with our linear gradient  
        canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()  
                + reflectionGap, paint);  
   
        return bitmapWithReflection;  
    }