Image for Node.js

This is a part of Node3D project.


``console
npm i -s image-raub
`

Using FreeImage, this addon loads images from:
* Local file.
* Data URI.
* Http(s) URL.
* Node.js Blob URL.
* Raw RGBA pixel data.

The Image class is similar to
HTMLImageElement,
and can be used as a replacement in non-DOM environments.

Additional features:
* save - saves the image to a local file.
* drawImage - is similar to
drawImage.

> Note: this addon uses N-API, and therefore is ABI-compatible across different
Node.js versions. Addon binaries are precompiled and there is no compilation
step during the npm i command.

Image

`js
import Image from 'image-raub';
const image = new Image('images/test.png'); // relative to CWD
icon.on('load', () => { console.log('data', image.width, image.height, image.data); });
`

For loaded images, image.data will contain a Buffer of 4 width height bytes.
You can directly interact with that buffer - read or write, and then save the image
to a file or use it any other way.

With Image.fromPixels() it is possible to generate new images from scratch by providing
your own data buffer.

See TS declarations for more details.

$3

Compatible with glfw-raub window.icon property.

`js
const icon = new Image();
icon.src = 'icons/logo.png';
icon.on('load', () => { window.icon = icon; });
`

$3

Here Image is used to load a texture. The constructed object receives src property,
then the file is read and 'load' event is emitted. After that, image.data is
available as a Buffer, containing the whole pixel data, and image.width/image.height
contain the dimensions.

`js
const Image = require('image-raub');
const image = new Image();
// Web-style onload
image.onload = () => {
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
gl.generateMipmap(gl.TEXTURE_2D);
gl.bindTexture(gl.TEXTURE_2D, null);
};

image.src = 'textures/grass.jpg';
`

$3

Image can save its current content to the filesystem. It can also load from raw
pixel values using static fromPixels() method.

`js
const memSize = screen.w screen.h 4; // estimated number of bytes
const storage = { data: Buffer.allocUnsafeSlow(memSize) };

gl.readPixels(
0, 0,
screen.w, screen.h,
gl.RGBA,
gl.UNSIGNED_BYTE,
storage
);

const img = Image.fromPixels(screen.w, screen.h, 32, storage.data);

img.save(${Date.now()}.jpg);
``