README.md

gcode-context

A simple wrapper for canvas context to export a g-code file starting from your web sketch! Very useful to print your drawings with a penplot.

Installation

You can grab it as an npm package

npm i --save @gcode-context

Example

You can use gcode-context with canvas-sketch by Matt DesLauriers (@mattdesl).

Check https://github.com/lavolpecheprogramma/gcode-file to set correctly your gcode file.

const canvasSketch = require('canvas-sketch');
const GCodeContext = require('gcode-context');

const gcodeSettings = {
  feedRate: 4000,
  seekRate: 4000,
  flipX: true,
  paperSize: [210, 297],
  margin: 5,
  fileName: name + '.gcode',
}

const settings = {
  dimensions: [
    gcodeSettings.paperSize[0] - (gcodeSettings.margin*2),
    gcodeSettings.paperSize[1] - (gcodeSettings.margin*2)
  ],
  units: 'mm',
}

const sketch = ({context}) => {
  const ctx = new GCodeContext({context, gcodeSettings})
  return ({ width, height, data }) => {
    ctx.gCode.updateCoordsArea(width, height)
    ctx.clear()
    
    ctx.beginPath()
    ctx.rect(0, 0, width, height)
    ctx.stroke()

    // with CMD+S you can download your gcode file 
    // or
    ctx.saveFile()
  }
}

canvasSketch(sketch, settings);

or in plain javascript:

const GCodeContext = require('gcode-context');

// for more information on gcode file settings see https://github.com/lavolpecheprogramma/gcode-file
const gcodeSettings = {
  feedRate: 4000,
  seekRate: 4000,
  paperSize: [ 210, 297],
  margin: 10,
  fileName: 'sketch.gcode'
}

const canvas = document.getElementById("myCanvas");
const context = canvas.getContext("2d");
const ctx = new GCodeContext({context, gcodeSettings})
// ... your canvas setup ...
ctx.gCode.updateCoordsArea(canvas.width, canvas.height);

ctx.beginPath();
ctx.rect(20, 20, 150, 100);
ctx.stroke();

// with CMD+S you can download your gcode file 
// or
ctx.saveFile()

You can pass some options to costructor:

• context, the canvas context
• autoBind, if you want bind automatically CMD+S command to save the file (default is true)
• gcodeSettings, the options passed to gcode file class (see https://github.com/lavolpecheprogramma/gcode-file )

const ctx = new GCodeContext({
  context,
  autoBind: true,
  gcodeSettings
})

GCodeContext has the following drawing functions that match those in Canvas2D contexts. Under the hood, it use the original canvas context to render and createPath to store the paths for gcode file.

• beginPath()
• closePath()
• moveTo(x, y)
• lineTo(x, y)
• quadraticCurveTo(cpx, cpy, x, y)
• bezierCurveTo(cpx1, cpy1, cpx2, cpy2, x, y)
• arcTo(x1, y1, x2, y2, radius)
• arc(x, y, radius, startAngle, endAngle[, anticlockwise])
• rect(x, y, width, height)
• stroke()

Other methods are available:

clear()

Clear the canvas and remove all the saved paths

addLayer()

Add layer in gcode file instance

saveFile()

Download the gcode file