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  • License MIT

node-chrome-canvas | a simple to use and performant HTML5 canvas for Node.js

Package Exports

  • ncc

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (ncc) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

logo

About

ncc (or node-chrome-canvas) utilizes Googles Chrome-Browser and its remote debugging protocol to give Node.js access to a full-blown HTML5 Canvas-Element and its 2d-Context.
In contrast to canvas (that may satisfy your needs as well) which uses Cairo to sham a canvas, ncc works with a real HTMLCanvasElement in a Browser-Context.

Behind the curtains of the familiar Canvas-API, ncc uses a single WebSocket-Connection and some command-bundeling-logic to gain its performance.

Quickstart

npm install ncc
var ncc = require('ncc')

var canvas = ncc();

canvas.width = canvas.height = 256;

var ctx = canvas.getContext('2d');

ctx.fillStyle = "slateGray";
ctx.fillRect(28, 28, 200, 200)();  // function call is intentional!

Examples

  1. draw ncc logo

    learn how to setup ncc and draw shapes to canvas

  2. early access

    learn how to start using ncc even before it is fully set up

  3. get return values

    learn how to get return values of non-void functions

  4. gardients/patterns

    learn how to use gradients and patterns

  5. images

    learn how to apply images from urls or the filesystem

  6. shadow canvas

    learn how work with more than one canvas

API

ncc follows the native Web API Interfaces... HTMLCanvasElement, HTMLImageElement, CanvasRenderingContext2D, CanvasGradient, CanvasPattern ... as close as possible.

Differences are a result of the asynchronous nature of ncc. All object creations, method calls and property manipulations don't get processed directly, but get serialized and stored until a return value is necessary and a request is therefore unavoidable.
Every 'Object' provided by ncc (and also every return value of a method) is actually a function to trigger a synchronization. You can pass a error-first-callback ( 'function(error, result){...}' ) to such a function to receive the return value of the last action (see examples).

flowchart

The **Canvas-** RenderingContext2D, -Gradient and -Pattern Proxys are fully implemented. The **HTML-** CanvasElement and -ImageElement Proxys only have properties and functions that are necessary. For example they both implement a 'width' and 'height' attribute but have no further DOM functionality.

Methods and properties beyond the native API are marked with a leading underscore and hidden from console by default (e.g. 'image._toFile(fileName, <callback>)' to write a image to the filesystem).

proxy - creators

  • ncc( <options> , <callback> ) >>> [canvas]
    ncc( <callback> ) >>> [canvas]

  • ncc.createCanvas() >>> [canvas] if one is not enough

  • ncc.createImage( <src> , <onloadFn> , <onerrorFn> ) >>> [image]

  • nccCanvas.getContext( nativeAPI ) >>> [context2d]

  • context2d.createLinearGradient( nativeAPI ) >>> [linearGradient]
    context2d.createRadialGradient( nativeAPI ) >>> [radialGradient]
    context2d.createPattern( nativeAPI ) >>> [pattern]

options (with defaults)

{ logLevel: 'info', //['log','info','warn','error']
  port: 9222,
  retry: 9,
  retryDelay: 500,
  headless: false
}