android中有关图片的处理

 

/**
  * 按照比例放大或者缩小图片
**/
public static Bitmap scaleImage(Bitmap oldImage, int newW, int newH) {
		return scaleImage(oldImage,newW,  newH,false);
	}
	
	public static Bitmap scaleImage(Bitmap oldImage, int newW, int newH,boolean isRecycleOld) {
		if (oldImage == null)
			return null;

		int oldWidth = oldImage.getWidth();
		int oldHeight = oldImage.getHeight();

		Matrix matrix = new Matrix();

		matrix.postScale((float) newW / oldWidth, (float) newH / oldHeight);

		Bitmap resizedBitmap = Bitmap.createBitmap(oldImage, 0, 0, oldWidth,
				oldHeight, matrix, true);
		
		if(isRecycleOld){
			oldImage.recycle();
		}

		return resizedBitmap;
	}	

	
/**
	 * bitmap to byte[]
	 * 
	 * @param bitmap
	 * @return
	 */
	public static byte[] flattenBitmap(Bitmap bitmap) {

		if(bitmap ==null) return null;
		
		int size = bitmap.getWidth() * bitmap.getHeight() * 4;
		ByteArrayOutputStream out = new ByteArrayOutputStream(size);
		try {
			bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
			out.flush();
			out.close();
			return out.toByteArray();
		} catch (IOException e) {
			return null;
		}
	}

	/**
	 * byte[] to bitmap
	 * 
	 * @param bytes
	 * @return
	 */
	public static Bitmap bytesToBitmap(byte[] bytes) {
		if (bytes == null)
			return null;
		return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
	}