KMUTNB Physics Lab Plotter

A terminal UI graph plotter for physics lab data. It works like a small lab notebook plus graph-paper viewer inside the terminal: enter x-y values, edit the table, and see the plot, best-fit equation, slope, intercept, and R^2 update immediately.

The app stores data as plain CSV. No database is required.

Install And Run

On NixOS or any system with Nix:

nix-shell
cargo run -- samples/ohms_law.csv

Without entering a shell:

nix-shell --run "cargo run -- samples/ohms_law.csv"

A flake.nix is also included for projects that prefer flakes. In a Git worktree, Nix flakes only see files tracked by Git, so use nix-shell while working with newly created untracked files.

With a normal Rust toolchain:

cargo run -- samples/ohms_law.csv

Start without a file to create a blank dataset:

cargo run

Keybindings

Key	Action
h / j / k / l	Move table cursor, or move graph crosshair when graph focus and crosshair are enabled
i	Edit current cell
a	Add row
A	Add column
d	Delete selected row
r	Rename selected column
g	Focus graph panel
t	Focus table panel
s	Save CSV
o	Open/load CSV
f	Toggle best-fit line
X	Swap plotted x-axis and y-axis mapping
G	Toggle graph paper mode
S	Open manual scale dialog
u	Return to auto scale from the scale dialog
c	Toggle crosshair cursor
?	Help screen
Esc	Cancel current mode / return to normal mode
q	Quit

Example Workflow

1. Run cargo run -- samples/ohms_law.csv.
2. Use j/k to move through rows and h/l to move between columns.
3. Press i, type a value, then press Enter.
4. Press a to add another measurement row.
5. Press G for graph-paper mode.
6. Press S to set manual graph-paper scale, such as fixed min/max, major divisions, and minor divisions per major square.
7. Press f to toggle the best-fit line.
8. Press g, then c, then move the crosshair with h/j/k/l to read estimated graph coordinates.
9. Press s to save.

CSV Format

The first row contains column names. The default columns are x and y; extra columns are preserved.

x,y
1,2.1
2,4.0
3,6.2
4,8.1

Invalid or blank values in x or y are kept in the table but excluded from plotting and regression. Invalid x-y cells are highlighted in the table.

Graph Paper View

Graph paper mode prioritizes a clean grid for physics lab work:

• subtle minor grid divisions
• stronger major grid divisions every 10 minor divisions by default
• stronger x/y axes
• numeric labels at major divisions
• selected point marker
• optional best-fit line extended across the visible graph
• manual scale fields for x min, x max, y min, y max, x major division, y major division, and minor divisions

Unicode Braille characters are used when the terminal reports UTF-8 support, giving each terminal cell a 2x4 virtual pixel grid. Otherwise the plot falls back to a cleaner major-grid-only ASCII view.

Tests

nix-shell --run "cargo test"

The test suite covers CSV loading/saving, linear regression, invalid value handling, and row editing operations.