Terminal Text Effects

Inline Visual Effects in the Terminal

Table Of Contents

• About
• Requirements
• Installation
• Usage (Application)
• Usage (Library)
• Effect Showcase
• In-Development Preview
• Latest Release Notes
• License

TTE

TerminalTextEffects (TTE) is a terminal visual effects engine. TTE can be installed as a system application to produce effects in your terminal, or as a Python library to enable effects within your Python scripts/applications. TTE includes a growing library of built-in effects which showcase the engine's features. These features include:

• Xterm 256 / RGB hex color support
• Complex character movement via Paths, Waypoints, and motion easing, with support for bezier curves.
• Complex animations via Scenes with symbol/color changes, layers, easing, and Path synced progression.
• Variable stop/step color gradient generation.
• Event handling for Path/Scene state changes with custom callback support and many pre-defined actions.
• Effect customization exposed through a typed effect configuration dataclass that is automatically handled as CLI arguments.
• Runs inline, preserving terminal state and workflow.

Requirements

TerminalTextEffects is written in Python and does not require any 3rd party modules. Terminal interactions use standard ANSI terminal sequences and should work in most modern terminals.

Installation

UV Install

Tool Run

uv tool run terminaltexteffects -h

Application Install

uv tool install terminaltexteffects

Library Install

uv install terminaltexteffects

Pip Install

Application Install

pipx install terminaltexteffects

Library Install

pip install terminaltexteffects

Nix (flakes)

Add it as an input to a flake:

inputs = {
  terminaltexteffects.url = "github:ChrisBuilds/terminaltexteffects/<optional-ref>"
}

Create a shell with it:

nix shell github:ChrisBuilds/terminaltexteffects/<optional-ref>

Or run it directly:

echo 'terminaltexteffects is awesome' | nix run github:ChrisBuilds/terminaltexteffects/<optional-ref> -- beams

Nix (classic)

Fetch the source and add it to, e.g. your shell:

let
  pkgs = import <nixpkgs> {};

  tte = pkgs.callPackage (pkgs.fetchFromGitHub {
    owner = "ChrisBuilds";
    repo = "terminaltexteffects";
    rev = "<revision, e.g. main/v0.13.0/etc.>";
    hash = ""; # Build first, put proper hash in place
  }) {};
in
  pkgs.mkShell {
    packages = [tte];
  }

Usage

View the Documentation for a full installation and usage guide.

Application Quickstart

Options

TTE Command Line Options

  options:
  -h, --help            show this help message and exit
  --input-file, -i INPUT_FILE
                        File to read input from
  --version, -v         show program's version number and exit
  --tab-width (int > 0)
                        Number of spaces to use for a tab character.
  --xterm-colors        Convert any colors specified in 24-bit RBG hex to the closest 8-bit XTerm-256 color.
  --no-color            Disable all colors in the effect.
  --terminal-background-color (XTerm [0-255] OR RGB Hex [000000-ffffff])
                        The background color of you terminal. Used to determine the appropriate color for fade-in/out within effects.
  --existing-color-handling {always,dynamic,ignore}
                        Specify handling of existing 8-bit and 24-bit ANSI color sequences in the input data. 3-bit and 4-bit sequences are not supported. 'always' will always use the
                        input colors, ignoring any effect specific colors. 'dynamic' will leave it to the effect implementation to apply input colors. 'ignore' will ignore the colors in
                        the input data. Default is 'ignore'.
  --wrap-text           Wrap text wider than the canvas width.
  --frame-rate FRAME_RATE
                        Target frame rate for the animation in frames per second. Set to 0 to disable frame rate limiting. Defaults to 60.
  --canvas-width int >= -1
                        Canvas width, set to an integer > 0 to use a specific dimension, use 0 to match the terminal width, or use -1 to match the input text width. Defaults to -1.
  --canvas-height int >= -1
                        Canvas height, set to an integer > 0 to use a specific dimension, use 0 to match the terminal height, or use -1 to match the input text height. Defaults to -1.
  --anchor-canvas {sw,s,se,e,ne,n,nw,w,c}
                        Anchor point for the canvas. The canvas will be anchored in the terminal to the location corresponding to the cardinal/diagonal direction. Defaults to 'sw'.
  --anchor-text {n,ne,e,se,s,sw,w,nw,c}
                        Anchor point for the text within the Canvas. Input text will anchored in the Canvas to the location corresponding to the cardinal/diagonal direction. Defaults to
                        'sw'.
  --ignore-terminal-dimensions
                        Ignore the terminal dimensions and utilize the full Canvas beyond the extents of the terminal. Useful for sending frames to another output handler.
  --reuse-canvas        Do not create new rows at the start of the effect. The cursor will be moved up the number of rows present in the input text in an attempt to re-use the canvas.
                        This option works best when used in a shell script. If used interactively with prompts between runs, the result is unpredictable.
  --no-eol              Suppress the trailing newline emitted when an effect animation completes.
  --no-restore-cursor   Do not restore cursor visibility after the effect.

  Effect:
  Name of the effect to apply. Use <effect> -h for effect specific help.

  {random_effect,beams,binarypath,blackhole,bouncyballs,bubbles,burn,colorshift,crumble,decrypt,dev,dev_worm,errorcorrect,expand,fireworks,highlight,laseretch,matrix,middleout,orbittingvolley,overflow,pour,print,rain,randomsequence,rings,scattered,slice,slide,smoke,spotlights,spray,swarm,sweep,synthgrid,test,thunderstorm,unstable,vhstape,waves,wipe}
                        Available Effects
    random_effect       Randomly select an effect to apply to the input text. All effect and effect-specific options are ignored.
    beams               Create beams which travel over the canvas illuminating the characters behind them.
    binarypath          Binary representations of each character move towards the home coordinate of the character.
    blackhole           Characters are consumed by a black hole and explode outwards.
    bouncyballs         Characters are bouncy balls falling from the top of the canvas.
    bubbles             Characters are formed into bubbles that float down and pop.
    burn                Burns vertically in the canvas.
    colorshift          Display a gradient that shifts colors across the terminal.
    crumble             Characters lose color and crumble into dust, vacuumed up, and reformed.
    decrypt             Display a movie style decryption effect.
    errorcorrect        Some characters start in the wrong position and are corrected in sequence.
    expand              Expands the text from a single point.
    fireworks           Characters launch and explode like fireworks and fall into place.
    highlight           Run a specular highlight across the text.
    laseretch           A laser etches characters onto the terminal.
    matrix              Matrix digital rain effect.
    middleout           Text expands in a single row or column in the middle of the canvas then out.
    orbittingvolley     Four launchers orbit the canvas firing volleys of characters inward to build the input text from the center out.
    overflow            Input text overflows and scrolls the terminal in a random order until eventually appearing ordered.
    pour                Pours the characters into position from the given direction.
    print               Lines are printed one at a time following a print head. Print head performs line feed, carriage return.
    rain                Rain characters from the top of the canvas.
    randomsequence      Prints the input data in a random sequence.
    rings               Characters are dispersed and form into spinning rings.
    scattered           Text is scattered across the canvas and moves into position.
    slice               Slices the input in half and slides it into place from opposite directions.
    slide               Slide characters into view from outside the terminal.
    smoke               Smoke floods the canvas colorizing any characters it crosses.
    spotlights          Spotlights search the text area, illuminating characters, before converging in the center and expanding.
    spray               Draws the characters spawning at varying rates from a single point.
    swarm               Characters are grouped into swarms and move around the terminal before settling into position.
    sweep               Sweep across the canvas to reveal uncolored text, reverse sweep to color the text.
    synthgrid           Create a grid which fills with characters dissolving into the final text.
    thunderstorm        Create a thunderstorm in the terminal.
    unstable            Spawn characters jumbled, explode them to the edge of the canvas, then reassemble them in the correct layout.
    vhstape             Lines of characters glitch left and right and lose detail like an old VHS tape.
    waves               Waves travel across the terminal leaving behind the characters.
    wipe                Wipes the text across the terminal to reveal characters.

  Ex: ls -a | tte decrypt --typing-speed 2 --ciphertext-colors 008000 00cb00 00ff00 --final-gradient-stops eda000 --final-gradient-steps 12 --final-gradient-direction vertical

cat your_text | tte <effect> [options]

OR

cat your_text | python -m terminaltexteffects <effect> [options]

• Use <effect> -h to view options for a specific effect, such as color or movement direction.
  • Ex: tte decrypt -h

For more information, view the Application Usage Guide.

Library Quickstart

All effects are iterators which return a string representing the current frame. Basic usage is as simple as importing the effect, instantiating it with the input text, and iterating over the effect.

from terminaltexteffects.effects import Rain

effect = Rain("your text here")

for frame in effect:
    # do something with the string
    ...

In the event you want to allow TTE to handle the terminal setup/teardown, cursor positioning, and animation frame rate, a terminal_output() context manager is available.

from terminaltexteffects.effects import Rain

effect = Rain("your text here")
with effect.terminal_output() as terminal:
    for frame in effect:
        terminal.print(frame)

For more information, view the Library Usage Guide.

Effect Showcase

Note: Below you'll find a subset of the built-in effects.

View all of the effects and related information in the Effects Showroom.

Effects Demos

Beams

Burn

Decrypt

LaserEtch

Matrix

Spotlights

VHSTape

Latest Release Notes

Visit the ChangeBlog for release write-ups.

0.13.0

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New Features (0.13.0)

---

New Effects (0.13.0)

• Thunderstorm - Rain falls across the canvas. Lightning strikes randomly around the canvas. Lightning flashes after reaching the bottom of the canvas, lighting up the text characters. Sparks explode from lightning impact. Text characters glow when lightning travels through them.
• Smoke - Smoke floods the canvas, colorizing any text it passes over.

---

New Engine Features (0.13.0)

• Added geometry.find_coords_on_rect(), which returns coordinates along the perimeter of a rectangle given a center Coord, width, and height. Results are cached for performance.
• Added --terminal-background-color to the TerminalConfig parser. This will enable terminal themes with background other than black to better display effects with fade in/out components.
• Spanning-tree and search algorithms have been added.
  • PrimsSimple - Unweighted Prims
  • PrimsWeighted
  • RecursiveBacktracker
  • Breadthfirst
• EffectCharacter has a new attribute links to support creating trees using spanning-tree algorithms.

---

New Application Features (0.13.0)

• Support for random effect selection from the command-line. Use effect named random_effect. Global configuration options will apply.
• Support for canvas re-use. Use tte option --reuse-canvas to restore the cursor to the position of the prior effect canvas.
• Added terminaltexteffects entry point.
• --no-eol command-line option. Suppress the trailing newline character after an effect.
• --no-restore-cursor command-line option. Do not restore cursor visibility after an effect ends.

---

Changes (0.13.0)

---

Effects Changes (0.13.0)

• Blackhole - Initial consumption motion modified to create the apperance of an gravitational-wave propagating across the canvas.
• Laseretch - New etch-pattern algorithm uses the link-order of a text-boundary-bound recursive backtracker algorithm.
• Burn - Character ignite order is based on the link-order of a text-boundary-bound prims simple algorithm.
• Pour - Changed --movement-speed to --movement-speed-range to add some variation in character falling speed.
• All effects have been adjusted for visual parity at 60 fps.
• All effects are up-imported into terminaltexteffects.effects to simplify importing to from terminaltexteffects.effects import Burn.

---

Engine Changes (0.13.0)

• animation.set_appearance() symbol argument signature changed from str to str | None, defaulting to the character's input_symbol if not provided.
• Coord objects can be unpacked into (column, row) tuples for multiple assignment.
• motion.activate_path() and animation.activate_scene() accept path_id/scene_id strings OR Path/Scene instances. The Path/Scene corresponding to the provided path_id/scene_id must exist or a SceneNotFoundError/PathNotFoundError will be raised.
• motion.query_path() accepts an argument directing the action to take if a path with the given path_id cannot be found. The default action is to raise a PathNotFoundError, but this behavior can be changed to return None.
• animation.query_scene() accepts an argument directing the action to take if a scene with the given scene_id cannot be found. The default action is to raise a SceneNotFoundError, but this behavior can be changed to return None.
• Events can be registered using path_id/scene_id in place of the Path/Scene for target and caller arguments.
• Frame rate reduced from 100 fps to 60 fps.
• Typed argument parsing and related configuration utilities and classes have been rewritten.
• Terminal distance calculations take into account the cell height/width ratio.
• Completely rewrote modules and classes related to argument parsing and effect/terminal configuration handling. This eliminates the design which forced building multiple configuration objects depending on how the effect was run, and also enabled the random effect option.

Bug Fixes (0.13.0)

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Engine Fixes (0.13.0)

• Fixed duplicate event registrations by adding prevention logic to the EventHandler. The register_event method now raises a DuplicateEventRegistrationError when attempting to register the same event-caller-action-target combination.
• Improved the _handle_event method docstring with comprehensive documentation.
• Scene.reset_scene() now sets easing_current_step to 0.

---

Effect Fixes (0.13.0)

• Unstable - Effect properly uses config values for reassembly/explosion speed. These were not referenced previously.

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License

Distributed under the MIT License. See LICENSE for more information.