Tigma

A terminal-based design tool for creating ASCII diagrams and designs.

Contributing

I'll be honest: mot of this code was written by AI (specifically Opus 4.5). This project is mostly experimental and I do not intend it to become a real production-ready big project. For now, it's fun.

The best way to work with this code right now is with AI assistance. The has low abstractions which is easy to read and debug, but it's more difficult to write manually because of the lack of abstractions. AI will help keep everything consistent.

I specifically used Opus 4.5 to work with this. You may find that to be the best model with this structure, but I haven't tried others. When opening PRs, please don't include a bunch of changes unrelated to the intent.

Running

bunx tigma

Currently this requires bun.

Usage

# Start with a blank canvas
bun run index.ts

# Open an existing file
bun run index.ts mydesign.tigma

Tools

Switch between tools using keyboard shortcuts:

Key	Tool	Description
M	Move	Select, move, and resize objects
T	Text	Create and edit text boxes
R	Rectangle	Draw rectangular shapes with box-drawing characters
L	Line	Draw lines (horizontal, vertical, or diagonal)
P	Freehand	Draw freehand curves with pencil

Controls

General

Key	Action
Ctrl+S	Save file (prompts for filename if new)
Ctrl+Z	Undo
Ctrl+U	Redo
Ctrl+D	Copy selected objects to clipboard
Ctrl+V	Paste at mouse position
Ctrl+X	Cut (copy and delete) selected objects
Ctrl+L	Clear canvas (delete all objects)
Delete / Backspace	Delete selected or hovered object(s)
Escape	Cancel current drawing / exit text editing

Move Tool

• Click on an object to select it
• Shift+Click to add/remove objects from selection (multi-select)
• Click+Drag to move selected objects
• Click on empty space to deselect all
• Click+Drag on empty space to box-select multiple items (hold Shift to add)

Rectangle Resizing

When a single rectangle is selected and hovered, resize handles appear at:

• Corners (NW, NE, SW, SE)
• Edge midpoints (N, S, E, W)

Drag the handles to resize the rectangle.

Layer Ordering

Key	Action
Ctrl+[	Move selected object down one layer
Ctrl+]	Move selected object up one layer

Text Tool

• Click on empty space to create a new text box
• Click on existing text to edit it
• Type to insert characters at cursor
• Arrow keys to move cursor
• Home / End to jump to start/end
• Backspace / Delete to remove characters
• Ctrl+B to toggle bold mode for new characters
• Escape to finish editing

Rectangle Tool

• Click+Drag to draw a rectangle
• Release to commit the shape
• Rectangle uses current stroke and fill colors
• Bold mode affects border thickness

Line Tool

• Click+Drag to draw a line
• Supports horizontal, vertical, and diagonal lines
• Uses Bresenham's algorithm for diagonal rendering
• Line uses current stroke color

Freehand Tool

• Click+Drag to draw freehand curves
• Uses Bresenham interpolation for smooth, continuous strokes
• Renders with directional box-drawing characters (─, │, ╲, ╱)
• Freehand uses current stroke color

Colors

A color picker is displayed at the bottom-right of the canvas.

Stroke Colors

Controls the color of:

• Text characters
• Rectangle borders
• Lines

Available stroke colors: Transparent, Black, White, Red, Green, Blue, Yellow

Fill Colors

Controls the background fill of:

• Rectangles (interior area)
• Text boxes (background)

Available fill colors: Transparent, Black, Gray, Muted Red, Muted Green, Muted Blue, Muted Yellow

Transparent (shown as null) means no color is applied, allowing content beneath to show through.

Click on a color swatch to select it. The selected color applies to:

1. New objects you create
2. Currently selected objects (immediately updates them)

File Format

Designs are saved as .tigma files in JSON format. The file stores:

• Text boxes with per-character styling (bold, color)
• Rectangles with position, stroke color, fill color, and bold state
• Lines with position, stroke color, and bold state
• Freehand curves with point arrays and stroke color
• Z-index ordering for proper layering

Features

• Layered rendering: Objects stack based on z-index; newer objects appear on top by default
• Multi-selection: Select multiple objects with Shift+Click or box-select
• Copy/Paste: Copy objects with Ctrl+D, paste at mouse position with Ctrl+V
• Undo/Redo: Up to 100 history snapshots
• Terminal responsive: Adapts to terminal resize events
• Mouse support: Full mouse interaction including hover highlighting
• Live preview: See rectangles and lines as you draw them

Example Workflow

1. Press R to select the Rectangle tool
2. Click and drag to draw a box
3. Press T to select the Text tool
4. Click inside the box and type a label
5. Press Escape to finish editing
6. Press M to switch to Move tool
7. Select objects and adjust positions
8. Use the color picker to change colors
9. Press Ctrl+S to save your work