canvas/lib/image.js

Canvas graphics API backed by Cairo

'use strict';

/*!
 * Canvas - Image
 * Copyright (c) 2010 LearnBoost <tj@learnboost.com>
 * MIT Licensed
 */

/**
 * Module dependencies.
 */

const bindings = require('./bindings')
const Image = module.exports = bindings.Image
const http = require("http")
const https = require("https")

const proto = Image.prototype;
const _getSource = proto.getSource;
const _setSource = proto.setSource;

delete proto.getSource;
delete proto.setSource;

Object.defineProperty(Image.prototype, 'src', {
  /**
   * src setter. Valid values:
   *  * `data:` URI
   *  * Local file path
   *  * HTTP or HTTPS URL
   *  * Buffer containing image data (i.e. not a `data:` URI stored in a Buffer)
   *
   * @param {String|Buffer} val filename, buffer, data URI, URL
   * @api public
   */
  set(val) {
    if (typeof val === 'string') {
      if (/^\s*data:/.test(val)) { // data: URI
        const commaI = val.indexOf(',')
        // 'base64' must come before the comma
        const isBase64 = val.lastIndexOf('base64', commaI) !== -1
        const content = val.slice(commaI + 1)
        setSource(this, Buffer.from(content, isBase64 ? 'base64' : 'utf8'), val);
      } else if (/^\s*https?:\/\//.test(val)) { // remote URL
        const onerror = err => {
          if (typeof this.onerror === 'function') {
            this.onerror(err)
          } else {
            throw err
          }
        }

        const type = /^\s*https:\/\//.test(val) ? https : http
        type.get(val, res => {
          if (res.statusCode !== 200) {
            return onerror(new Error(`Server responded with ${res.statusCode}`))
          }
          const buffers = []
          res.on('data', buffer => buffers.push(buffer))
          res.on('end', () => {
            setSource(this, Buffer.concat(buffers));
          })
        }).on('error', onerror)
      } else { // local file path assumed
        setSource(this, val);
      }
    } else if (Buffer.isBuffer(val)) {
      setSource(this, val);
    }
  },

  get() {
    // TODO https://github.com/Automattic/node-canvas/issues/118
    return getSource(this);
  },

  configurable: true
});

/**
 * Inspect image.
 *
 * TODO: indicate that the .src was a buffer, data uri etc
 *
 * @return {String}
 * @api public
 */

Image.prototype.inspect = function(){
  return '[Image'
    + (this.complete ? ':' + this.width + 'x' + this.height : '')
    + (this.src ? ' ' + this.src : '')
    + (this.complete ? ' complete' : '')
    + ']';
};

function getSource(img){
  return img._originalSource || _getSource.call(img);
}

function setSource(img, src, origSrc){
  _setSource.call(img, src);
  img._originalSource = origSrc;
}