CTOCanvas

Draw boxes, text and lines on an infinite canvas in the terminal. Scroll in any direction with the mouse or the keys, save the canvas to YAML, or export it as ASCII, PNG, or SVG.

Install

pip install -r requirements.txt

Requires Python 3 with click, Pillow, PyYAML and svgwrite. pytest is only needed to run the tests. A terminal with mouse support is needed for clicking (any xterm-compatible one).

Data

The canvas lives on a grid of terminal cells. x grows to the right and y downwards; both can be negative.

boxes:
  - {x: 2, y: 1, text: Idea}
  - {x: 24, y: 1, text: Plan}
lines:
  - {x1: 10, y1: 2, x2: 24, y2: 2}

A box is three rows high with its top-left corner at x, y; it is as wide as its single-line text plus four. A line runs horizontally from x1, y1 to x2, then vertically to y2. Boxes cover lines, and crossing lines join into ┼ ├ ┬ and friends. Text can contain emoji; PNG export draws them with NotoColorEmoji.ttf if it is installed.

The loader rejects coordinates that are not integers and boxes without a non-empty single-line text. examples/demo.yaml is a full example (see examples/demo.png).

Usage

python ctocanvas.py [canvas.yaml] [--format {interactive,ascii,png,svg}] [-o OUTPUT]

Format	Result
interactive	Full-screen ncurses editor (default). Creates the file on save.
ascii	The canvas printed as text.
png	One image, canvas/<name>.png, cropped to the drawing.
svg	One vector image, canvas/<name>.svg.

Keys and mouse in interactive mode:

Input	Action
Click	Draws with the current tool: a box on empty space (then type its text), or a line (click start, click end). Clicking an item selects it.
Right click	Context menu: choose the tool (Draw boxes / Draw lines; it stays until you pick another), plus Edit text, Move, Delete on an item, or Undo, Save, Export, Go to origin on empty space.
(in the menu)	↑ ↓ Enter, the underlined letter, or the mouse to choose; Esc or a click outside to dismiss.
Box here	Draws a box and asks for its text; the box grows as you type. Enter keeps it, Esc cancels.
Draw lines	Click where the line starts, then where it ends.
Move	Then click the new position. Or just drag an item.
Drag empty space	Pan the canvas.
Wheel / ← → ↑ ↓	Scroll. Shift+wheel scrolls sideways; Shift+arrow scrolls 10 cells.
PgUp PgDn / Home	Scroll a page / back to the origin.
e Enter	Edit the selected box (shortcut for the menu entry).
d Delete	Delete the selected item (shortcut).
u	Undo.
s	Save to the YAML file (shortcut).
x	Export (shortcut): type a file name ending in .txt, .png, .svg or .yaml.
Esc	Cancel a pending line or move, or deselect.
q	Quit (asks first if there are unsaved changes).

When stdin or stdout is not a terminal, or -o is given, interactive falls back to the ascii output. -o sets the output file for every format.

$ python ctocanvas.py examples/demo.yaml --format ascii
┌──────┐              ┌──────┐              ┌─────────┐
│ Idea │──────────────│ Plan │──────────────│ Ship 🚀 │
└──────┘              └──────┘              └─────────┘
      │                   │
…

Tests

python -m pytest