Reader Node
============

Overview
------------

The **Reader node** read files from the designated path. 
There are three modes of reading files are available.

.. image:: Images/reader/reader_overview_1.png
   :align: center

.. image:: Images/reader/reader_overview_2.png
   :align: center

|

Output
----------

+-------------------------+-------------------+------------------------------------------------------------------------+
| Output                  | Type              | Description                                                            |
+=========================+===================+========================================================================+
| index                   | int               | The index of the file if loading from a folder or from numbered files. |
+-------------------------+-------------------+------------------------------------------------------------------------+
| numOfFiles              | int               | The number of files.                                                   |
+-------------------------+-------------------+------------------------------------------------------------------------+
| outputBag               | AssembledBagData  | Data read as a bag data object.                                        |
+-------------------------+-------------------+------------------------------------------------------------------------+
| outputCloud             | Cloud             | Data read as a point cloud.                                            |
+-------------------------+-------------------+------------------------------------------------------------------------+
| outputImage             | Image             | Data read as an image.                                                 |
+-------------------------+-------------------+------------------------------------------------------------------------+
| outputMesh              | Mesh              | Data read as a mesh.                                                   |
+-------------------------+-------------------+------------------------------------------------------------------------+
| status                  | int               | Status code, 0 if successful.                                          |
+-------------------------+-------------------+------------------------------------------------------------------------+

|

Node Settings
----------------

.. image:: Images/reader/reader_node_settings.png
   :align: center

**Source Type**

    - From File:
        Read the same file from the path. 

    - From Folder:
        Read from files inside a folder.        

    - From Numbered:
        Reads from files with the same naming scheme ending with a number.

- File Path / Folder Path: 
    The path the read files from.

- Forward Traversal (Default: True): 
    Files are read in non-decreasing index if true. Available in From Folder and From Numbered mode.

- File Prefix (Default: "daoai\_"): 
    Appended to the start of the file name. Available in From Numbered mode.

- Index (Default: 0 to 10000): 
    The start index and the end index to consider. Available in From Numbered mode.

|

Procedure to Use
-------------------

You only want to read image_20 to image_30 from this folder.

.. image:: Images/reader/reader_procedure_0.png
   :scale: 80%

1. Insert a Reader node.

.. image:: Images/reader/reader_procedure_1.png
   :scale: 80%

2. Select "From Numbered" mode for Source Type. Click Browse to select the folder path.

.. image:: Images/reader/reader_procedure_2.png
   :scale: 80%

3. Change File Prefix to "image\_", and change start index to 20 and end index to 30.

.. image:: Images/reader/reader_procedure_3.png
   :scale: 80%

4. Run the node. You can see that only the files with index 20 to 30 will be read. 

.. image:: Images/reader/reader_procedure_4.png
   :scale: 80%