A simple wasm png encoder/decoder module for Cloudflare Workers, Next.js and Node. Powered by denosaurs/pngs.
Install the package by running the following command in terminal:
npm install @cf-wasm/png
- Cloudflare workers:
import * as png from "@cf-wasm/png";
- Next.js (Webpack):
import * as png from "@cf-wasm/png/next";
- CJS (file base):
import * as png from "@cf-wasm/png/node";
The png.encode
function encodes an input Uint8Array
representing an image into a PNG format.
const encode: (
image: Uint8Array,
width: number,
height: number,
options?: EncodeOptions
) => Uint8Array
The png.decode
function decodes an input Uint8Array
representing a PNG image.
const decode: (image: Uint8Array) => {
image: Uint8Array;
width: number;
height: number;
colorType: number;
bitDepth: number;
lineSize: number;
}
Here are some examples for using this library.
If you are using Cloudflare Workers, you can use it as shown below:
// src/index.ts
import * as photon from "@cf-wasm/photon";
import * as png from "@cf-wasm/png";
export type Env = Readonly<{}>;
const workers: ExportedHandler<Env> = {
async fetch() {
// url of image to fetch
const imageUrl = "https://avatars.githubusercontent.com/u/314135";
// fetch image and get the Uint8Array instance
const inputBytes = await fetch(imageUrl)
.then((res) => res.arrayBuffer())
.then((buffer) => new Uint8Array(buffer));
// create a photon instance
const inputImage = photon.PhotonImage.new_from_byteslice(inputBytes);
// resize image using photon
const outputImage = photon.resize(
inputImage,
inputImage.get_width() * 0.5,
inputImage.get_height() * 0.5,
1
);
// encode using png
const outputBytes = png.encode(
outputImage.get_raw_pixels(),
outputImage.get_width(),
outputImage.get_height()
);
// call free() method to free memory
inputImage.free();
outputImage.free();
// return the Response instance
return new Response(outputBytes, {
headers: {
"Content-Type": "image/png"
}
});
}
};
export default workers;
If you are using Next.js (App router) with edge runtime, you can use it as shown below:
// (src/)app/api/image/route.ts
import { type NextRequest } from "next/server";
import * as photon from "@cf-wasm/photon/next";
import * as png from "@cf-wasm/png/next";
export const runtime = "edge";
export async function GET(request: NextRequest) {
// url of image to fetch
const imageUrl = "https://avatars.githubusercontent.com/u/314135";
// fetch image and get the Uint8Array instance
const inputBytes = await fetch(imageUrl)
.then((res) => res.arrayBuffer())
.then((buffer) => new Uint8Array(buffer));
// create a photon instance
const inputImage = photon.PhotonImage.new_from_byteslice(inputBytes);
// resize image using photon
const outputImage = photon.resize(
inputImage,
inputImage.get_width() * 0.5,
inputImage.get_height() * 0.5,
1
);
// encode using png
const outputBytes = png.encode(
outputImage.get_raw_pixels(),
outputImage.get_width(),
outputImage.get_height()
);
// call free() method to free memory
inputImage.free();
outputImage.free();
// return the Response instance
return new Response(outputBytes, {
headers: {
"Content-Type": "image/png"
}
});
}
If you are using Next.js (Pages router) with edge runtime, you can use it as shown below:
// (src/)pages/api/image.ts
import { type NextRequest } from "next/server";
import * as photon from "@cf-wasm/photon/next";
import * as png from "@cf-wasm/png/next";
export const config = {
runtime: "edge",
// see https://nextjs.org/docs/messages/edge-dynamic-code-evaluation
unstable_allowDynamic: [
"**/node_modules/@cf-wasm/photon/**/*.js",
"**/node_modules/@cf-wasm/png/**/*.js"
]
};
export default async function handler(req: NextRequest) {
// url of image to fetch
const imageUrl = "https://avatars.githubusercontent.com/u/314135";
// fetch image and get the Uint8Array instance
const inputBytes = await fetch(imageUrl)
.then((res) => res.arrayBuffer())
.then((buffer) => new Uint8Array(buffer));
// create a photon instance
const inputImage = photon.PhotonImage.new_from_byteslice(inputBytes);
// resize image using photon
const outputImage = photon.resize(
inputImage,
inputImage.get_width() * 0.5,
inputImage.get_height() * 0.5,
1
);
// encode using png
const outputBytes = png.encode(
outputImage.get_raw_pixels(),
outputImage.get_width(),
outputImage.get_height()
);
// call free() method to free memory
inputImage.free();
outputImage.free();
// return the Response instance
return new Response(outputBytes, {
headers: {
"Content-Type": "image/png"
}
});
}