Kontext4J ⚡✨

The Java lib that’s too cool for bloated dependencies. Edits, fills, expands, generates, and low-key judges every other library still downloading 300 MB of JARs.

If other image libs were at a party, they'd still be figuring out Maven while Kontext4J already made your avatar a cyberpunk queen and found a mysterious nano banana in your pocket. 🍌💀

TL;DR

Single-file, dependency-light Java wrapper for BFL/Flux Kontext APIs.
Fluent AF: new Kontext4J().init(key).generate(...).getUrl()
Handles local files, remote URLs, and base64 like a pro.
Polls until server says "Ready" — no email-refreshing required.
Easter egg: sometimes gives you a nano banana. Nobody knows why.

Features 💅

edit(...) — multi-image editing, masks, prompts, negative prompts, seeds, guidance… basically everything you want.
fill(...) — inpainting with optional masks and mask modes.
generate(...) — text → image, also supports reference images.
expand(...) — outpaint top/bottom/left/right like a boss.
Handles paths, URLs, base64 automatically.
Polling included, waits for status == Ready.
Stores multiple result URLs. Use getUrl(), getUrls(), or download(path).
Lightweight JSON parsing with org.json.

Roast Corner 🔥

Other libs be like:

“We need 300 MB of JARs and 12 XML files just to say hi.”
Kontext4J: “Hold my beer 🍺, I’m done in one file.”
“We spin 17 threads to make a 200ms request.”
Kontext4J: single-threaded zen energy.

Install (Maven / Gradle) 💻

Copy Kontext4J.java into your project (src/main/java/io/github/initio/kontext4j/Kontext4J.java).

Dependencies:

Java 11+
org.json:json

Maven snippet:

<dependency>
  <groupId>org.json</groupId>
  <artifactId>json</artifactId>
  <version>20230227</version>
</dependency>

Usage Examples 🚀

Initialize

Kontext4J k = new Kontext4J().init("YOUR_API_KEY_HERE"); 
// no api key? no magic. 💀

Generate (text → image)

k.model("generate")
 .generate(
     "A tiny robot sipping coffee, cinematic lighting, ultra detailed",
     null, "16:9", 42, 30, 7.5, null, null,
     "png", null, null, 1, null, null, null
 );
System.out.println("Image URL: " + k.getUrl());
// other libs would still be configuring XML, we already sipping coffee. ☕🤖

Simple Generate

k.generateSimple("Cyberpunk cat in neon alley");
System.out.println(k.getUrl());
// because we don't need 300 MB of JARs for one cat. 🐱💡

She is now taking a selfie in the streets of Freiburg, it's lovely day out.

It's now snowing, everything is covered in snow

Edit with multiple images

k.edit(
    "/home/me/pic1.jpg",
    "/home/me/pic2.jpg",
    null, null,
    "Make all subjects wear futuristic helmets",
    null, "1:1", 12345, 40, 6.0,
    null, null, "jpg",
    null, null, 2
);
System.out.println(k.getUrls());
// other libs: "please configure 12 XML files." 🤡

Simple Edit

k.editSimple("/home/me/selfie.jpg", "Add sunglasses and party lights");
System.out.println(k.getUrl());

Merge multiple images

k.editMerge(List.of("/pic1.jpg","/pic2.jpg"), "Turn them into a superhero squad");
System.out.println(k.getUrls());

Fill / Inpaint

k.fill(
    "/home/me/photo.jpg",
    "/home/me/mask.png",
    "replace",
    "Make subject wear a futuristic helmet",
    null, "1:1", 12345, 40, 6.0, null, null,
    "jpg", null, null, 1
);
System.out.println(k.getUrls());
// inpainting so smooth, other libs cry into their 17 threads. 😭

Expand / Outpaint

k.expand(
    "https://example.com/input.png",
    200, 0, 0, 200,
    "Extend environment to neon city skyline",
    null, 40, 7.0, null, null, "png", null, null, 1
);
System.out.println(k.getUrl());
// other libs: "Wait… which edge is left again?" 🤔

Download last result

k.download(Paths.get("kontext_result.png"));
// no fuss, no spaghetti code. 🍝

Download a particular result index

k.downloadIndex(Paths.get("kontext_result2.png"), 0);

All Public Methods 🛠

init(String apiKey)
model(String modelName) — "edit" | "fill" | "generate" | "expand"
setRequestTimeout(Duration d)
setPollIntervalMillis(long ms)
setMaxWaitMillis(long ms)
edit(...), editSimple(...), editMerge(...)
fill(...)
generate(...), generateSimple(...)
expand(...)
getUrls(), getUrl(), getLastRawResult()
download(Path), downloadIndex(Path, int)

Nano Banana 🍌

Sometimes, very rarely, a URL or sample might contain a nano banana. No promises. Full giggle guaranteed when it shows up.

Troubleshooting 🛑

No result available — forgot init(apiKey)?
Polling timed out — increase setMaxWaitMillis(...) or check webhook.
Invalid JSON — server sent a JSON-shaped potato 🥔.

License 📝

MIT recommended. Free, petty, and small — like your nano banana.

Contact / Socials 📱

📱 Connect with Me

(Memes > bug reports)

Final Words 🏁

Kontext4J is tiny but opinionated: minimal dependencies, sane defaults, speed > drama. Use it to edit, generate, fill, expand — maybe find a nano banana too. 🍌

FilesExpand file tree

README.md

Latest commit

History