android图片缩放（指定大小）

	private Drawable zoomDrawable(Drawable drawable, int w, int h) {
		int width = drawable.getIntrinsicWidth();
		int height = drawable.getIntrinsicHeight();
		Bitmap oldbmp = drawableToBitmap(drawable);
		Matrix matrix = new Matrix();
		float scaleWidth = ((float) w / width);
		float scaleHeight = ((float) h / height);
		matrix.postScale(scaleWidth, scaleHeight);
		Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,
				matrix, true);
		return new BitmapDrawable(null, newbmp);
	}

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