rntviewer/README.md

<img src="example.png" width="500px"/>

## rntviewer
This is an interactive visualization tool for [RNTuple](https://root.cern.ch/doc/v618/md_tree_ntuple_v7_doc_README.html).
It can also be used to read generic TFiles and display some information about them, but it's mostly focused on inspecting
the on-disk structure of RNTuples.

### Getting the repo
Clone this repository with 
```
git clone --recurse-submodules https://codeberg.org/silverweed/rntviewer
```

### Dependencies
rntviewer currently only fully works on Linux, with the terminal-only version working on MacOS as well.

The dependencies are:
  - GLFW3 (`libglfw3-dev` on debian, `glfw-devel` on fedora, `glfw` on arch)
  - ROOT (likely bleeding edge version, compiled from sources)
  - libxxhash3-dev

Other than those, rntviewer depends on Dear ImGui and GLAD (both included in the source tree).

For the graphical version, the OS must support OpenGL 3.3 or higher.

For the terminal-only version you don't need GLFW3, ImGui or OpenGL support.

### Building
Building is done with `make`. Make sure to `source /path/to/root/bin/thisroot.sh` before running it.
You probably want to build the release version:
```
make r
```

You can test that the tool is working properly with:
```
./rntviewer testdata/RNTuple.root
```

To build the terminal-only version:
```
make nogfx_r
```

### Usage
Basic usage is:
```
./rntviewer <ntuple_file.root> [ntuple_name]
```

This will open a window and let you browse the RNTuple, jump around its sections and get some
information about them.
If you don't specify `ntuple_name`, the program will look for the first RNTuple in the file.

There is also a non-interactive non-graphical mode that can be used in a terminal (useful
e.g. for ssh sessions):
```
$ ./rntviewer -t <ntuple_file.root> [ntuple_name]
```

The `-t` flag enables terminal mode. Use `./rntviewer -h` to get a help message about the
other flags that rntviewer accepts and are particularly useful in non-interactive mode.