More work on supporting hybrid contexts.

Relates to #1252

package.json

@@ -80,7 +80,7 @@
     "jsdom": false,
     "jsdom/lib/jsdom/living/generated/utils": false,
     "source-map-support": false,
-    "./dist/node/window.js": false,
+    "./dist/node/self.js": false,
     "./dist/node/extend.js": false
   },
   "keywords": [

src/init.js

@@ -17,14 +17,19 @@
 // their shared scope.
 
 /* global document:true, window:true */
-// Create a window variable valid in the paper.js scope, that points to the
-// native window in browsers and the emulated JSDom one in node.js
-// In workers, and on Node.js when no Canvas is present, `window` is null (but
-// `self` is defined), so we can use the validity of the local window object to
-// detect a worker-like context in the library.
-// Make sure `self` always points to a window object, also on Node.js.
-self = self || require('./node/window.js');
+// Set up a local `window` variable valid across the full the paper.js scope,
+// pointing to the native window in browsers and the one provided by JSDom in
+// Node.js
+// In workers and on Node.js, the global `window` variable is null. In workers,
+// `self` is defined as a `WorkerGlobalScope` object, while in Node.js, `self`
+// is null.
+// When `self` is null (Node.js only). './node/self.js' is required to provide
+// a window object through JSDom and assigned it to `self`.
+// When `self.window` and therefore the local `window` is still null after that,
+// we know that we are in a worker-like context. This check is used all across
+// the library, see for example `View.create()`.
 // NOTE: We're not modifying the global `self` here. We receive its value passed
 // to the paper.js function scope, and this is the one that is modified here.
+self = self || require('./node/self.js');
 var window = self.window,
     document = self.document;

src/load.js

@@ -43,7 +43,7 @@ if (typeof window === 'object') {
         include('../node_modules/stats.js/build/stats.min.js');
         include('paper.js');
     }
-} else {
+} else if (typeof require !== 'undefined') {
     // Node.js based loading through Prepro.js:
     var prepro = require('prepro/lib/node'),
         // Load the default browser-based options for further amendments.

src/node/canvas.js

@@ -15,7 +15,7 @@
 // - Various Node Canvas methods, routed through from HTMLCanvasElement:
 //   toBuffer, pngStream, createPNGStream, jpgStream, createJPGStream
 
-module.exports = function(window) {
+module.exports = function(self) {
     var Canvas;
     try {
         Canvas = require('canvas');
@@ -25,14 +25,14 @@ module.exports = function(window) {
         // - On the browser, this corresponds to a worker context.
         // - On Node.js, it basically means the canvas is missing or not working
         //   which can be treated the same way.
-        delete window.window;
+        delete self.window;
         console.info(
-                'Unable to load Canvas module. Running in a headless context.');
+                'Canvas module not found, running in a headless context.');
         return;
     }
 
     var idlUtils = require('jsdom/lib/jsdom/living/generated/utils'),
-        HTMLCanvasElement = window.HTMLCanvasElement;
+        HTMLCanvasElement = self.HTMLCanvasElement;
 
     // Add fake HTMLCanvasElement#type property:
     Object.defineProperty(HTMLCanvasElement.prototype, 'type', {

src/node/extend.js

@@ -57,8 +57,8 @@ module.exports = function(paper) {
     paper.PaperScope.inject({
         createCanvas: function(width, height, type) {
             // Do not use CanvasProvider.getCanvas(), since we may be changing
-            // the underlying node-canvas and don't want to release it after
-            // back into the pool.
+            // the underlying node-canvas when requesting PDF support, and don't
+            // want to release it after back into the pool.
             var canvas = paper.document.createElement('canvas');
             canvas.width = width;
             canvas.height = height;

src/node/self.js

@@ -0,0 +1,73 @@
+/*
+ * Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
+ * http://paperjs.org/
+ *
+ * Copyright (c) 2011 - 2016, Juerg Lehni & Jonathan Puckey
+ * http://scratchdisk.com/ & http://jonathanpuckey.com/
+ *
+ * Distributed under the MIT license. See LICENSE file for details.
+ *
+ * All rights reserved.
+ */
+
+// Node.js emulation layer of browser environment, based on jsdom with node-
+// canvas integration.
+
+var self;
+
+try {
+    var jsdom = require('jsdom');
+
+    // Create our document and window objects through jsdom.
+    /* global document:true, window:true */
+    var document = jsdom.jsdom('<html><body></body></html>', {
+        // Use the current working directory as the document's origin, so
+        // requests to local files work correctly with CORS.
+        url: 'file://' + process.cwd() + '/',
+        features: {
+            FetchExternalResources: ['img', 'script']
+        }
+    });
+    self = document.defaultView;
+
+    require('./canvas.js')(self);
+
+    // Define XMLSerializer shim, to emulate browser behavior.
+    // Effort to bring XMLSerializer to jsdom:
+    // https://github.com/tmpvar/jsdom/issues/1368
+    /*jshint -W082 */
+    function XMLSerializer() {
+    }
+
+    XMLSerializer.prototype.serializeToString = function(node) {
+        if (!node)
+            return '';
+        // Fix a jsdom issue where all SVG tagNames are lowercased:
+        // https://github.com/tmpvar/jsdom/issues/620
+        var text = node.outerHTML,
+            tagNames = ['linearGradient', 'radialGradient', 'clipPath',
+                'textPath'];
+        for (var i = 0, l = tagNames.length; i < l; i++) {
+            var tagName = tagNames[i];
+            text = text.replace(
+                new RegExp('(<|</)' + tagName.toLowerCase() + '\\b', 'g'),
+                function(match, start) {
+                    return start + tagName;
+                });
+        }
+        return text;
+    };
+
+    self.XMLSerializer = XMLSerializer;
+} catch(e) {
+    console.info(
+            'JSDom module not found, running in a headless context without DOM.');
+    self = {
+        navigator: {
+            userAgent: 'Node.js (' + process.platform + '; U; rv:' +
+                    process.version + ')'
+        }
+    };
+}
+
+module.exports = self;