DocsBlogPricingEnterpriseCareersResearch Grants
Log-inSign-up

Chain Of Zoom Image to Image

fal-ai/chain-of-zoom
Extreme Super-Resolution via Scale Autoregression and Preference Alignment
Inference
Commercial use
PlaygroundAPI

About

Perform extreme zoom into an image region.

Each zoom step:

  • Crops the center 1/4 area (1/2 width, 1/2 height)
  • Upscales it back to original size (4x zoom)
  • Applies AI super-resolution with context-aware prompts

1. Calling the API#

Install the client#

The client provides a convenient way to interact with the model API.

npm install --save @fal-ai/client

Setup your API Key#

Set FAL_KEY as an environment variable in your runtime.

export FAL_KEY="YOUR_API_KEY"

Submit a request#

The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.

import { fal } from "@fal-ai/client";

const result = await fal.subscribe("fal-ai/chain-of-zoom", {
  input: {
    image_url: "https://storage.googleapis.com/falserverless/example_inputs/coz_example_input"
  },
  logs: true,
  onQueueUpdate: (update) => {
    if (update.status === "IN_PROGRESS") {
      update.logs.map((log) => log.message).forEach(console.log);
    }
  },
});
console.log(result.data);
console.log(result.requestId);

2. Authentication#

The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.

API Key#

In case your app is running in an environment where you cannot set environment variables, you can set the API Key manually as a client configuration.
import { fal } from "@fal-ai/client";

fal.config({
  credentials: "YOUR_FAL_KEY"
});

3. Queue#

Submit a request#

The client API provides a convenient way to submit requests to the model.

import { fal } from "@fal-ai/client";

const { request_id } = await fal.queue.submit("fal-ai/chain-of-zoom", {
  input: {
    image_url: "https://storage.googleapis.com/falserverless/example_inputs/coz_example_input"
  },
  webhookUrl: "https://optional.webhook.url/for/results",
});

Fetch request status#

You can fetch the status of a request to check if it is completed or still in progress.

import { fal } from "@fal-ai/client";

const status = await fal.queue.status("fal-ai/chain-of-zoom", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true,
});

Get the result#

Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.

import { fal } from "@fal-ai/client";

const result = await fal.queue.result("fal-ai/chain-of-zoom", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);

4. Files#

Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.

Data URI (base64)#

You can pass a Base64 data URI as a file input. The API will handle the file decoding for you. Keep in mind that for large files, this alternative although convenient can impact the request performance.

Hosted files (URL)#

You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.

Uploading files#

We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.

import { fal } from "@fal-ai/client";

const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);

Read more about file handling in our file upload guide.

5. Schema#

Input#

image_url string* required

Input image to zoom into

scale float

Zoom scale in powers of 2 Default value: 5

center_x float

X coordinate of zoom center (0-1) Default value: 0.5

center_y float

Y coordinate of zoom center (0-1) Default value: 0.5

user_prompt string

Additional prompt text to guide the zoom enhancement Default value: ""

sync_mode boolean

If set to true, the function will wait for the image to be generated and uploaded before returning the response. This will increase the latency of the function but it allows you to get the image directly in the response without going through the CDN.

{
  "image_url": "https://storage.googleapis.com/falserverless/example_inputs/coz_example_input",
  "scale": 5,
  "center_x": 0.5,
  "center_y": 0.5
}

Output#

images list<Image>* required

List of intermediate images

scale float* required

Actual linear zoom scale applied

zoom_center list<float>* required

Center coordinates used for zoom

{
  "images": "https://storage.googleapis.com/falserverless/example_outputs/coz_example_output_5"
}

Other types#

Image#

url string* required
width integer* required
height integer* required
content_type string

Default value: "image/jpeg"