=============
Read / Write
=============

.. contents:: :local:

Create and read a Pointcloud from file
=======================================
To read a cloud from a file, the following function can be used :

.. code-block:: c
	:linenos:

	pcl::PointCloud<pcl::PointXYZ>::Ptr mynewcloud(new pcl::PointCloud <pcl::PointXYZ>);
	pcl::io::loadPCDFile("file/path/filename.pcd", *mynewcloud);

| The type of cloud can be any of pcl::Pointxxxx. pcl::PointXYZ is a simple cloud file with (x,y,z) positions. If you need color handling, pcl::PointXYZRGB can be used.
| Read the PCL documentation for more information.


Read from a file (FileExplorer (Windows))
==========================================
For quick use while testing on multiple files, the following method allows to pick a file from FileExplorer on Windows :

.. code-block:: c
	:linenos:

	/**
	 * @brief Get cloud from file explorer
	 * @tparam PointT Should be a pcl::PointXYZxxx
	 * @param emp_cloud Cloud to fill with file
	 * @param verbose If has to output debug on console
	*/
	template <typename PointT>
	void getCloud(typename pcl::PointCloud<PointT>::Ptr& emp_cloud, bool verbose = false);

To use it, do as follow :

.. code-block:: c
	:linenos:

	pcl::PointCloud<pcl::PointXYZ>::Ptr mynewcloud(new pcl::PointCloud <pcl::PointXYZ>);
	getCloud(mynewcloud);

Write to file
==============
To write a cloud to a file, the following function can be used :

.. code-block:: c
	:linenos:

	pcl::io::savePCDFileASCII("file/path/filename.pcd", *mynewcloud);

Center cloud
=============
If your cloud has an offset, it can be centered with the following function :

.. code-block:: c
	:linenos:

	/**
	 * @brief Center given cloud to (0,0,0) based on closest points to center
	 * @tparam PointT Should be a pcl::PointXYZxxx
	 * @param emp_cloud Cloud to center
	 * @param verbose If has to output debug on console
	*/
	template <typename  PointT>
	void centerCloud(typename pcl::PointCloud<PointT>::Ptr& emp_cloud, bool verbose = false);

What this function does is looking for the point with the smallest x (can be negative) from the center, same with the point with the smallest y and the one with the smallest z value. It then moves the whole cloud by the inverted values to have it lying around the origin.

To use it, do as follow :

.. code-block:: c
	:linenos:

	centerCloud<pcl::PointXYZ>(mynewcloud);

Get and center cloud
=====================
Combining the two last functions, the following one load a file thanks to the FileExplorer and then center it :

.. code-block:: c
	:linenos:

	/**
	* @brief Get cloud from file explorer and center it
	* @tparam PointT Should be a pcl::PointXYZxxx
	* @param emp_cloud Cloud to fill and center with file
	* @param verbose If has to output debug on console
	* @example
	* pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
	* getAndCenterCloud<pcl::PointXYZ>(cloud,true);
	*/
	template <typename  PointT>
	void getAndCenterCloud(typename pcl::PointCloud<PointT>::Ptr& emp_cloud, bool verbose = false);

:tag:`Algorithm`
:tag:`3D Algorithm`
:tag:`PCL`
:tag:`Point Cloud`