gerber-to-svg

gerber-to-svg

Gerber and NC drill file to SVG converter for Node and the browser.

Want to see this library in action right now? Go to svgerber and watch the magic.

usage

command line

1. $ npm install -g gerber-to-svg
2. $ gerber2svg [options] path/to/gerbers

options

switch	how it rolls
-o, --out	specify an output directory
-q, --quiet	do not print warnings and messages
-p, --pretty	prettily align SVG output
-d, --drill	process following file as an NC (Excellon) drill file
-a, --append-ext	append .svg rather than replace the old file extension
-v, --version	display version information
-h, --help	display help text

examples:

• gerber2svg path/to/gerber.gbr will write the SVG to stdout
• gerber2svg -o some/dir path/to/gerber.gbr will create some/dir/gerber.svg
• gerber2svg -d drill.drl -o out gerb/* will process drill.drl as a drill file, everything in gerb as a Gerber file, and output to out

api (node and browser)

For Node and Browserify:

$ npm install --save gerber-to-svg

With Bower:

$ bower install --save gerber-to-svg

If you'd rather not manage your packages:

1. Download the full or minified standalone library
2. Add <script src="path/to/gerber-to-svg.js"></script> to your HTML

Use in your app with:

// get an svg string
var svgString = gerberToSvg(gerberString, opts);
// get an svg object and then convert that object into a string
var svgObj = gerberToSvg(gerberString, { object: true } )
var svgString = gerberToSvg(svgObj)

Where gerberString is the gerber file (e.g. from fs.readFile encoded with UTF-8) or an SVG object previously outputted by the function.

options

key	default	how it be
drill	false	process the string as an NC drill file rather than a Gerber
pretty	false	output the SVG XML string with line-breaks and two-space tabs
object	false	return an XML object instead of a the default XML string

If an object is returned instead of a string, it will have the format:

  {
    svg: {
      xmlns: 'http://www.w3.org/2000/svg',
      version: '1.1',
      'xmlns:xlink': 'http://www.w3.org/1999/xlink',
      width: width + units,
      height: height + units,
      viewBox: [ xMin, yMin, width, height ],
      id: id,
      // array of child nodes
      _: [
        // if gerber had pad flashes or polarity changes, there will be a
        // defs child
        {
          defs: {
            // array of child nodes
            _: [ shapes ]
          }
        },
        // then there will be a group that holds all the shapes
        {
          g: {
            // flip horizontally because svg is y positive going down
            transform: 'translate(0,' + (yMin+yMax) + ') scale(1,-1)',
            // array of child nodes
            _: [ shapes ]
          }
        }
      ]
    }
  }

examples

Output an SVG to the console

// require gerber-to-svg library
var gerberToSvg = require('gerber-to-svg')
// read a gerber file in as a string and convert it
var gerberFile = require('fs').readFileSync('./path/to/file.gbr', 'utf-8')
var svgString = gerberToSvg(gerberFile, { pretty: true } )
// outputs pretty printed SVG
console.log(svgString)

Use the object output to align layers before getting the strings

# get the layer object
frontObj = gerberToSvg gerberFront, { object: true }
backObj  = gerberToSvg gerberBack, { object: true }
drillObj = gerberToSvg drillFile, { object: true, drill: true}
# pull the origins from the viewBox
offsetFront = frontObj.svg.viewBox[0..1]
offsetBack  = backObj.svg.viewBox[0..1]
offsetDrill = drillObj.svg.viewBox[0..1]
# pass the objets back in to get the svg strings
frontString = gerberToSvg frontObj
backString  = gerberToSvg backObj
drillString = gerberToSvg drillObj

what you get

Since Gerber is just an image format, this library does not attempt to identify nor infer anything about what the file represents (e.g. a copper layer, a silkscreen layer, etc.) It just takes in a Gerber and spits out an SVG. This converter uses RS-274X and strives to be true to the latest format specification. All the Gerber image features should be there.

Everywhere that is "dark" or "exposed" in the Gerber (think a copper trace or a line on the silkscreen) will be "currentColor" in the SVG. You can set this with the "color" CSS property or the "color" attribute in the svg node itself.

Everywhere that is "clear" (anywhere that was never drawn on or was drawn on but cleared later) will be transparent. This is accomplished though judicious use of SVG masks and groups.

The bounding box is carefully calculated as the Gerber's being converted, so the width and height of the resulting SVG should be nearly (if not exactly) the real world size of the Gerber image. The SVG's viewBox is in Gerber units, so its min-x and min-y values can be used to align SVGs generated from different board layers.

things to watch out for

The produced image should be correct, but if issues do occur, they'll most likely be with arcs or step / repeat blocks. It's possible a floating point rounding error or several could throw things off.

Certain exceptions to the spec have been made to allow some older and/or improperly written files to process, but if they're not technically to spec, they won't necessarily process without throwing an error. Try / catches are your friend.

If it messes up, open up an issue and attach your Gerber, if you can. I appreciate files to test on.

problems with drill files

If your drill file is a wildly different size than your Gerbers, or it's offset from your Gerbers, check for these things:

• The drill file processor assumes 2:4 precision for inches and 3:3 precision for millimeters
• Leading zero suppression (identical to no suppression and keep trailing zeros in Excellon speak) will be assumed if left unspecified
• Absolute coordinates will be assumed if left unspecified
• The CAD package that generated the drill file may have offset it to prevent negative coordinates
• The drill file may have been generated with a different origin than the Gerbers

building from source

1. $ git clone https://github.com/mcous/gerber-to-svg.git
2. $ npm install && gulp build
3. $ gulp build or $ gulp watch to rebuild or rebuild on source changes

Library files for Node live in lib/, standalone library files live in dist/, and the command line utility lives in bin/.

unit testing

This module uses mocha and shouldjs for unit testing. To run the tests once, run $ gulp test. To run the tests automatically when source or tests change, run $ gulp testwatch.

There's also a visual test suite. Run $ gulp testvisual and point your browser to http://localhost.com:4242 to take a look. This will also run the build watcher