android 根据固定的宽度或高度等比例缩放图片

public static Bitmap getImageThumbnail(String imagePath, int width,
int height) {
Bitmap bitmap = null;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
// 获取这个图片的宽和高，注意此处的bitmap为null
bitmap = BitmapFactory.decodeFile(imagePath);
options.inJustDecodeBounds = false; // 设为 false
//        bitmap = adjustPhotoRotation(bitmap,1);
//解决三星手机获取系统照片自动横屏显示的问题
int degree = readPictureDegree(imagePath);
bitmap = rotaingImageView(degree,bitmap);

float scale;
if(bitmap.getWidth()>=bitmap.getHeight()){
scale = width/(float)bitmap.getWidth();
}else{
scale = height/(float)bitmap.getHeight();
}

Matrix matrix = new Matrix();
matrix.setScale(scale, scale);

bitmap = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
return bitmap;
}