Android bitmap 图片缩放，压缩处理

大家都知道在Android平台上，显示图片时，容易出现bitmap outofmemory除了，对即使的回收bitmap，还有个方法，就是在使用前提前对图片进行处理

对图片进行缩放同时也减小了bitmap的大小

/**
	 * 缩放，压缩图片
	 * @param picPath
	 * @param width
	 * @param height
	 * @return
	 */
	public InputStream revitionPic(String picPath, int width, int height) {
		BitmapFactory.Options options = new BitmapFactory.Options();
		options.inJustDecodeBounds = true;
		BitmapFactory.decodeFile(picPath, options);
		options.inSampleSize = calcRatios(options, width, height);
		options.inJustDecodeBounds = false;
		
		Bitmap bitmap = BitmapFactory.decodeFile(picPath, options);
                //进一步较小图片的大小
		return compressPic(bitmap);
	}

计算缩放尺寸缩放比例

/**
	 * 计算缩放比例
	 * @param options
	 * @param width
	 * @param height
	 * @return
	 */
	protected int calcRatios(BitmapFactory.Options options, int width, int height) {
		int origalWidth = options.outWidth;
		int origalHeight = options.outHeight;
		
		int inSampleSize = 1;
		if(origalHeight > height || origalWidth > width) {
			int heightRatios = Math.round(((float)origalHeight / (float)height));
			int widthRatios = Math.round((float)origalWidth /(float)width);
			inSampleSize = heightRatios > widthRatios ? widthRatios : heightRatios;
		}
		return inSampleSize;
	}

压缩图片

/**
	 * 压缩图片 
	 * @param pic
	 * @return
	 */
	public InputStream compressPic(Bitmap pic) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		pic.compress(CompressFormat.JPEG, 100, baos);
		
		int quality = 100;
		while(quality > 0 && baos.toByteArray().length / 1024 > 100) {
			//大于100k
			baos.reset();
			quality -= 5;
			pic.compress(CompressFormat.JPEG, quality, baos);
		}
		return new ByteArrayInputStream(baos.toByteArray());
	}