svgcanvas

I create this repo because I need a mock <canvas> element for my p5.js-svg. This lib is mainly based on gliffy's great work: canvas2svg.

You should use gliffy's canvas2svg if what you want is a clean and simple canvas context API.

The major difference is that: this lib also adds some mock API for element (such as width, height, style, className, getBoundingClientRect, toDataURL).

Note this lib also adds some dirty API (such as context API call history for debug, gc some invisible elements). These API are some how very dirty, so I did not pull request for these API. However, they are useful and necessary for my p5.js-svg, so I keep them in my lib.

Usage

var svgcanvas = new SVGCanvas();
svgcanvas.width = 100;
var height = svgcanvas.height;
var ctx = svgcanvas.getContext('2d');
svgcanvas.toDataURL('image/jpeg', function(err, jpeg) {
    console.log(jpeg);
});

Features

Element

• canvas.width

• canvas.height

• canvas.style

• canvas.className

• canvas.id

• canvas.getContext('2d')

• canvas.getBoundingClientRect()

• canvas.toDataURL()

  This method support image/jpeg | image/png | image/svg+xml. Note that sync api for jpeg and png is only available in chrome due to image load issue.

• canvas.toObjectURL();

  Note: you should always use URL.revokeObjectURL after your work done

Context

• ctx.save

• ctx.restore

• ctx.scale

• ctx.rotate

• ctx.translate

• ctx.transform

• ctx.beginPath

• ctx.moveTo

• ctx.closePath

• ctx.lineTo

• ctx.bezierCurveTo

• ctx.quadraticCurveTo

• ctx.arcTo

• ctx.stroke

• ctx.fill

• ctx.rect

• ctx.fillRect

• ctx.strokeRect

• ctx.clearRect (Buggy, see also: canvas2svg#19)

• ctx.createLinearGradient

• ctx.createRadialGradient

• ctx.fillText

• ctx.strokeText

• ctx.measureText

• ctx.arc

• ctx.clip

• ctx.drawImage

• ctx.createPattern

• ctx.imageSmoothingEnabled

  Note: this is implemented using properties["shape-rendering"] = "crispEdges", and may get different behavior in SVG and Canvas.

• Simple value check for fillStyle, strokeStyle

Other

• ctx.__history

  This array collect all (up to 1000) context call. Will only be available if debug on. (new SVGCanvas({debug: true}))

• It will gc some invisible elements to save resources

  This maybe aggressive and dirty, however it's necessary if you have to use it for animation. When fillRect or clearRect called, if its args matches 0, 0, canvas.width, canvas.height

Unit Test

See p5.js-svg's Unit Test:

http://zenozeng.github.io/p5.js-svg/test/

Contribute

You should always contribute to canvas2svg if it's context API issue. Together, we can make a better canvas2svg library.

License

The MIT License (MIT)

Copyright (c) 2015 Zeno Zeng

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This program incorporates work covered by the following copyright and permission notices:

• canvas2svg

  The MIT License (MIT)
  Copyright (c) 2014 Gliffy Inc.