Image to Image in Node.js

Overview

Convert images between formats and resize, crop, or rotate them with the PDFCrowd Node.js client. The client handles communication with the API, while conversions run on PDFCrowd's servers.

Installation

Install the Node.js client with npm, or see other installation options.

npm install pdfcrowd

Quick Start

You can run the examples below with the displayed API credentials. Update the input URLs and filenames as needed.

const pdfcrowd = require('pdfcrowd');

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

client.setOutputFormat("jpg");
client.convertUrlToFile(
    "https://your-server.com/logo.png", "logo.jpg",
    (error, filePath) => {
        if (error) {
            console.error(error.toString());
            return;
        }
        console.log("Saved:", filePath);
    }
);

const pdfcrowd = require('pdfcrowd');

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

client.setOutputFormat("jpg");
client.convertFileToFile("logo.png", "logo.jpg", (error, filePath) => {
    if (error) {
        console.error(error.toString());
        return;
    }
    console.log("Saved:", filePath);
});

Configure a Conversion

Authentication

Pass your PDFCrowd username and API key to ImageToImageClient. Find your credentials on the API Keys page.

Choose an Input

The source image format is detected automatically. Each conversion accepts one image.

For a local image or a URL on localhost, upload the file, bytes, or an open binary stream. Remote URLs must be reachable from PDFCrowd's servers.

Send Image Bytes

Read logo.png as bytes, convert it to JPEG, and save logo.jpg:

const fs = require("node:fs");
const pdfcrowd = require("pdfcrowd");

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

client.setOutputFormat("jpg");
const image = fs.readFileSync("logo.png");
client.convertRawDataToFile(image, "logo.jpg", (error) => {
    if (error) {
        console.error(error.toString());
        return;
    }
});

Add Conversion Settings

Set conversion options on the client before calling a conversion method. For example, client.setOutputFormat("jpg"); selects JPEG output.

Common settings are listed below. See the method reference for all available options or browse Node.js examples.

Image operations change the source image; canvas settings control the output area and image placement.

With an explicit canvas size, use setPrintCanvasMode() with "fit" to preserve the aspect ratio and fit the image inside the margins. The "stretch" mode fills the area and can distort the image. The default mode does not scale the image to fit and can crop it. Without an explicit size, margins add a border around the image.

Handle the Result

Choose an Output

The examples select JPEG. Use setOutputFormat() to choose PNG, WebP, or another supported format. The client defaults to PNG; match the filename extension to the selected format.

The methods below use URL input; local files, bytes, and input streams have corresponding methods.

For stream output, pass a callbacks object with these functions:

If you pipe the response to a file, writing may still be in progress when end runs. Use the pipeline callback, after checking for errors, for code that uses the saved file.

This example converts an image, collects the result in a Buffer, and saves it locally as logo.jpg:

const fs = require("node:fs");
const pdfcrowd = require("pdfcrowd");

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

client.setOutputFormat("jpg");
const chunks = [];
client.convertUrl("https://your-server.com/logo.png", {
    data: (stream) => stream.on("data", (chunk) => chunks.push(chunk)),
    error: (message, statusCode) => {
        console.error(new pdfcrowd.Pdfcrowd.Error(message, statusCode).toString());
    },
    end: () => {
        const result = Buffer.concat(chunks);
        fs.writeFileSync("logo.jpg", result);
    }
});

When serving the result from a web application, use Content-Type: image/jpeg for these examples, or the content type corresponding to your selected format.

Handle Errors

File-output methods pass a pdfcrowd.Pdfcrowd.Error to their callback on failure and null on success. Validation can also throw an exception. This example converts an image and handles both paths, logging the HTTP status and reason code when available:

const pdfcrowd = require("pdfcrowd");

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

function handleError(error) {
    if (error instanceof pdfcrowd.Pdfcrowd.Error) {
        console.error("PDFCrowd error:", error.getStatusCode(),
            error.getReasonCode(), error.getMessage());
    } else {
        console.error(error);
    }
}

try {
    client.setOutputFormat("jpg");
    client.convertUrlToFile(
        "https://your-server.com/logo.png", "logo.jpg",
        (error) => {
            if (error) {
                handleError(error);
                return;
            }
        }
    );
} catch (error) {
    handleError(error);
}

Stream-output methods call error(message, statusCode) on failure. Local file and stream errors may need separate handling.

pdfcrowd.Pdfcrowd.Error provides these methods:

error.toString() returns the complete error, including available status and reason codes.

Common Status Codes

See all status and reason codes for specific explanations and Limits and Retries for retry behavior.

Read Conversion Information

This information is available after a conversion and describes the client's last conversion. Read it in the completion or error callback.

Limits and Retries

Request rate and concurrency limits depend on your license. Control how quickly your application submits conversions and how many it runs at once. A 429 response concerns request rate; a 430 response concerns requests already in progress. The maximum upload size is 300 MB.

The Node.js client automatically retries a request once when it receives HTTP 502 or 503. Use setRetryCount() to change that count, or set it to 0 to disable automatic retries. Account for these retries when adding an application-level retry policy.

Troubleshooting

Inspect a Conversion

This example converts an image with debug logging enabled and logs the debug log URL when available. Use the input and settings from the conversion you are investigating.

const pdfcrowd = require("pdfcrowd");

const client = new pdfcrowd.ImageToImageClient("demo", "demo");

function finish(error) {
    if (error) {
        console.error(error.toString());
    }
    const debugLogUrl = client.getDebugLogUrl();
    if (debugLogUrl) console.info("Debug log:", debugLogUrl);
}

try {
    client.setOutputFormat("jpg");
    client.setDebugLog(true);
    client.convertUrlToFile(
        "https://your-server.com/logo.png", "logo.jpg", finish
    );
} catch (error) {
    finish(error);
}

The debug log contains conversion settings and processing details. You can also find logs in your conversion history. A local or connection failure may occur before a conversion log is available.

Common Problems

For help, contact support and include any available diagnostics, the client version, and enough detail to reproduce the problem.