# npe_gerber

![npm (scoped)](https://img.shields.io/npm/v/@nplayfair/npe_gerber)

**This is still being developed and isn't ready for production!**
Only tested with gerbers generated by EAGLE.

Requires node version 10 or higher.

## Usage
### Save a PNG file
```
const { ImageGenerator } = require('@nplayfair/npe_gerber');

const folderConfig = {
    tmpDir: path.join(__dirname, 'tmp'),
    imgDir: path.join(__dirname, 'img')
}

const imageConfig = {
    resizeWidth: 600,
    density: 1000,
    compLevel: 1
}

const gerberArchive = '/path/to/gerber.zip';

const fileProc = new ImageGenerator(folderConfig, imageConfig);

fileProc.gerberToImage(gerberArchive)
      .then(filename => {
        console.log(`Generated image ${filename}`);
      })
```
### Return a PNG stream
```
const { ImageGenerator } = require('@nplayfair/npe_gerber');

const folderConfig = {
    tmpDir: path.join(__dirname, 'tmp'),
    imgDir: path.join(__dirname, 'img')
}

const imageConfig = {
    resizeWidth: 600,
    density: 1000,
    compLevel: 1
}

const gerberArchive = '/path/to/gerber.zip';

const fileProc = new ImageGenerator(folderConfig, imageConfig);

fileProc.gerberToStream(gerberArchive)
      .then(stream => {
        // Do something with the stream
      })
```

## Image Processing Configuratation

Several values need to be set in the image configuration object. An SVG vector is first created as an intermediate step before being converted to a PNG. These correspond to the parameters passed to [sharp](https://sharp.pixelplumbing.com/) for
resizing the intermediary SVG and output PNG file. These settings are:

- `resizeWidth`: Width in pixels of the output image.
- `density`: DPI to create the SVG with. Low values will result in a poor quality output image.
- `compLevel`: PNG compression level.

More information about these settings can be found in the [sharp](https://sharp.pixelplumbing.com/) documentation.