WebRoot/js/canvas.js

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/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */

"use strict";

var JpegStreamProxyCounter = 0;
// WebWorker Proxy for JpegStream.
var JpegStreamProxy = (function() {
  function constructor(bytes, dict) {
    this.id = JpegStreamProxyCounter++;
    this.dict = dict;

    // Tell the main thread to create an image.
    postMessage({
      action: "jpeg_stream",
      data: {
        id: this.id,
        raw: bytesToString(bytes)
      }
    });
  }

  constructor.prototype = {
    getImage: function() {
      return this;
    },
    getChar: function() {
      error("internal error: getChar is not valid on JpegStream");
    }
  };

  return constructor;
})();

// Really simple GradientProxy. There is currently only one active gradient at
// the time, meaning you can't create a gradient, create a second one and then
// use the first one again. As this isn't used in pdf.js right now, it's okay.
function GradientProxy(cmdQueue, x0, y0, x1, y1) {
  cmdQueue.push(["$createLinearGradient", [x0, y0, x1, y1]]);
  this.addColorStop = function(i, rgba) {
    cmdQueue.push(["$addColorStop", [i, rgba]]);
  }
}

// Really simple PatternProxy.
var patternProxyCounter = 0;
function PatternProxy(cmdQueue, object, kind) {
  this.id = patternProxyCounter++;

  if (!(object instanceof CanvasProxy) ) {
    throw "unkown type to createPattern";
  }

  // Flush the object here to ensure it's available on the main thread.
  // TODO: Make some kind of dependency management, such that the object
  // gets flushed only if needed.
  object.flush();
  cmdQueue.push(["$createPatternFromCanvas", [this.id, object.id, kind]]);
}