android图片压缩

/**
* 从文件解析出Bitmap格式的图片
*
* @param path
* @param maxWidth
* @param maxHeight
* @return
*/
public static Bitmap decodeFile(String path, int maxWidth, int maxHeight){
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
Bitmap image = null;
image = BitmapFactory.decodeFile(path, options);
double ratio = 1D;
if (maxWidth > 0 && maxHeight <= 0) {
// 限定宽度，高度不做限制
ratio = Math.ceil(options.outWidth / maxWidth);
} else if (maxHeight > 0 && maxWidth <= 0) {
// 限定高度，不限制宽度
ratio = Math.ceil(options.outHeight / maxHeight);
} else if (maxWidth > 0 && maxHeight > 0) {
// 高度和宽度都做了限制，这时候我们计算在这个限制内能容纳的最大的图片尺寸，不会使图片变形
double _widthRatio = Math.ceil(options.outWidth / maxWidth);
double _heightRatio = (double) Math.ceil(options.outHeight / maxHeight);
ratio = _widthRatio > _heightRatio ? _widthRatio : _heightRatio;
}
if (ratio > 1) {
options.inSampleSize = (int) ratio;
}
options.inSampleSize = calcScaleRatio(maxWidth, maxHeight, options.outWidth, options.outHeight);
options.inJustDecodeBounds = false;
options.inPreferredConfig = Bitmap.Config.RGB_565;
image = BitmapFactory.decodeFile(path, options);
return image;
}