Visualization Guide

MahJax exposes two main helpers for SVG output:

• save_svg(...)
• save_svg_animation(...)

If you were looking for save_animation, the current public function name is save_svg_animation.

1. Save a single SVG

The quickest path is:

1. create an environment
2. initialize a state
3. call mahjax.save_svg(...)

Japanese tiles

import jax
import mahjax

env = mahjax.make("no_red_mahjong")
state = env.init(jax.random.PRNGKey(0))

mahjax.save_svg(state, "round-ja.svg", language="ja")

English tiles

import jax
import mahjax

env = mahjax.make("no_red_mahjong")
state = env.init(jax.random.PRNGKey(0))

mahjax.save_svg(state, "round-en.svg", language="en")

The language switch changes the tile art, so en is useful when your audience does not read kanji.

2. Save an SVG animation

save_svg_animation(...) takes a list of states. The simplest way to build that list is to run the environment step by step and append every intermediate state.

Japanese tiles

import jax
import jax.numpy as jnp
import mahjax

env = mahjax.make("no_red_mahjong")
state = env.init(jax.random.PRNGKey(0))
history = [state]

for _ in range(40):
    if bool(state.terminated | state.truncated):
        break
    action = jnp.argmax(state.legal_action_mask).astype(jnp.int32)
    state = env.step(state, action)
    history.append(state)

mahjax.save_svg_animation(
    history,
    "round-ja-animation.svg",
    frame_duration_seconds=0.4,
    language="ja",
)

English tiles

import jax
import jax.numpy as jnp
import mahjax

env = mahjax.make("no_red_mahjong")
state = env.init(jax.random.PRNGKey(0))
history = [state]

for _ in range(40):
    if bool(state.terminated | state.truncated):
        break
    action = jnp.argmax(state.legal_action_mask).astype(jnp.int32)
    state = env.step(state, action)
    history.append(state)

mahjax.save_svg_animation(
    history,
    "round-en-animation.svg",
    frame_duration_seconds=0.4,
    language="en",
)

3. Using the state method directly

For notebooks and quick experiments, the State object also exposes SVG helpers:

svg_text = state.to_svg(language="en")
state.save_svg("snapshot.svg", language="ja")

This is convenient when you already have a state in memory and do not need the top-level helper.

4. Visualization examples

MahJax already includes sample animations in both tile styles.

Japanese tiles	English tiles

These examples are useful when you want to:

• show the same round state to Japanese and non-Japanese readers
• prepare documentation for users who do not know the kanji tile faces
• compare how readable your examples are in ja and en

5. Practical notes

• The output of save_svg_animation(...) is an animated SVG, not a GIF or MP4.
• The same visualization API works for both no_red_mahjong and red_mahjong.
• frame_duration_seconds controls playback speed.
• For riichi mahjong in MahJax, language="en" is the switch you want for non-kanji readers.

For a beginner-facing explanation of the tile set itself, see Mahjong Basics.