android中缩放图片的方法

 static Drawable zoomDrawable(Drawable drawable, int w, int h)      {                int width = drawable.getIntrinsicWidth();                int height= drawable.getIntrinsicHeight();              Log.d("ME", "Width = " + width);              Log.d("ME", "Height = " + height);              Bitmap oldbmp = drawableToBitmap(drawable); // drawable转换成bitmap                Matrix matrix = new Matrix();   // 创建操作图片用的Matrix对象                float scaleWidth = ((float)w / width);   // 计算缩放比例                float scaleHeight = ((float)h / height);                            Log.d("ME", "scaleWidth = " + scaleWidth);              Log.d("ME", "scaleHeight = " + scaleHeight);                            matrix.postScale(scaleWidth, scaleHeight);         // 设置缩放比例                Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height, matrix, true);       // 建立新的bitmap，其内容是对原bitmap的缩放后的图                return new BitmapDrawable(newbmp);       // 把bitmap转换成drawable并返回      }        static Bitmap drawableToBitmap(Drawable drawable) // drawable 转换成bitmap      {                int width = drawable.getIntrinsicWidth();   // 取drawable的长宽                int height = drawable.getIntrinsicHeight();                Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888:Bitmap.Config.RGB_565;         // 取drawable的颜色格式                Bitmap bitmap = Bitmap.createBitmap(width, height, config);     // 建立对应bitmap                Canvas canvas = new Canvas(bitmap);          // 建立对应bitmap的画布                drawable.setBounds(0, 0, width, height);                drawable.draw(canvas);       // 把drawable内容画到画布中                return bitmap;      }
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