JAnim Stdio Interact

A utility library for interacting with JAnim GUI and managing windows via standard input/output

Basic Usage

Interact with the JAnim GUI by passing JSON commands via stdio to open and close specific instances.

First, start the janim-stdio-i program:

janim-stdio-i host

For example, to compile a code snippet and build the Timeline within it for display in a preview window, send the following to stdin:

{"type": "execute", "key": "id1", "source": "from janim.examples import *\nclass A(HelloJAnimExample): pass"}

You will see a preview window open displaying the classic HelloJAnimExample.

[!WARNING]
All commands sent to stdin must be on a single line. Multi-line commands will be truncated.

Here, "key": "id1" is used for window reuse. If you send an execute command with the same key, the Timeline in the existing window will be replaced without opening a new window.

{"type": "execute", "key": "id1", "source": "from janim.examples import *\nclass A(RotatingPieExample): ..."}

Sending the command above replaces the HelloJAnimExample in the original window with RotatingPieExample.

[!NOTE]
If a code snippet contains multiple Timelines, the first one is used for the initial build.
> On subsequent rebuilds (replacements), it attempts to find a Timeline with the same name as the previous one; if not found, it defaults to the first one.

If we use a different key, for example:

{"type": "execute", "key": "id2", "source": "from janim.examples import *\nclass A(ArrowPointingExample): ..."}

A new window will open. Essentially, one key corresponds to one window.

In addition to compiling and building Timelines via stdin, information generated by the GUI is returned via stdout. See below for details.

API Reference

stdin

• "type": "execute"

Required parameters:

• "key": Unique identifier for the window.

• "source": Source code for compilation.

Compiles and builds the Timeline to display in the preview window.

If the window corresponding to key already exists, the original Timeline in that window is replaced with the new one.

Example:

{"type": "execute", "key": "id1", "source": "from janim.examples import *\nclass A(HelloJAnimExample): pass"}

• "type": "close"

Required parameters:

• "key": Unique identifier for the window.

Closes the window corresponding to key.

Example:

{"type": "close", "key": "id1"}

stdout

{"type": "viewer-msg", "key": "...", "from": "...", "janim": { ... }}

Field	Type	Description
type	string	Fixed as "viewer-msg", identifying the message category
key	string	Corresponds to the identifier key used during creation
from	string	Sender source. Possible values: "execute", "close", "gui"
janim	object	The specific event payload, containing the event type and data

When "from": "execute", it represents the result of the execute command sent to stdin:

• When source code compilation fails, the payload is

"janim": {"type": "error", "reason": "compile-failed"}

• When the source code contains no usable Timeline, the payload is:

"janim": {"type": "error", "reason": "no-timeline"}

• When the Timeline build fails, the payload is:

"janim": {"type": "error", "reason": "build-failed"}

• When execution is successful, the payload is:

"janim": {"type": "success"}

When "from": "close", it represents the result of the close command sent to stdin:

• When no preview interface is found for the identifier, the payload is:

"janim": {"type": "error", "reason": "not-found"}

• When executed successfully, the payload is:

"janim": {"type": "success"}

When "from": "gui", it represents information generated by the GUI:

• When the interface is created, the payload is:

"janim": {"type": "created"}

• When the interface content is replaced, the payload is:

"janim": {"type": "rebuilt"}

• When the preview progress changes, the payload is:

"janim": {"type": "lineno", "data": <current_line_number>}

• When the interface is closed, the payload is:

"janim": {"type": "close_event"}