Add lib/screenshot.js

Based on:
http://hg.mozilla.org/qa/mozmill-tests/file/905bc0ba7a1e/firefox/lib/screenshot.js

mozmill-tests/lib/screenshot.js

+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Based on:
+// http://hg.mozilla.org/qa/mozmill-tests/file/905bc0ba7a1e/firefox/lib/screenshot.js
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+// Include the required modules
+var utils = require("utils");
+
+/**
+ * This function creates a screenshot of the window provided in the given
+ * controller and highlights elements from the coordinates provided in the
+ * given boxes-array.
+ *
+ * @param {array of array of int} boxes
+ * @param {MozmillController} controller
+ */
+function create(controller, boxes) {
+  var doc = controller.window.document;
+  var maxWidth = doc.documentElement.boxObject.width;
+  var maxHeight = doc.documentElement.boxObject.height;
+  var rect = [];
+  for (var i = 0, j = boxes.length; i < j; ++i) {
+    rect = boxes[i];
+    if (rect[0] + rect[2] > maxWidth) maxWidth = rect[0] + rect[2];
+    if (rect[1] + rect[3] > maxHeight) maxHeight = rect[1] + rect[3];
+  }
+  var canvas = doc.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
+  var width = doc.documentElement.boxObject.width;
+  var height = doc.documentElement.boxObject.height;
+  canvas.width = maxWidth;
+  canvas.height = maxHeight;
+  var ctx = canvas.getContext("2d");
+  ctx.clearRect(0,0, canvas.width, canvas.height);
+  ctx.save();
+  ctx.drawWindow(controller.window, 0, 0, width, height, "rgb(0,0,0)");
+  ctx.restore();
+  ctx.save();
+  ctx.fillStyle = "rgba(255,0,0,0.4)";
+  for (var i = 0, j = boxes.length; i < j; ++i) {
+    rect = boxes[i];
+    ctx.fillRect(rect[0], rect[1], rect[2], rect[3]);
+  }
+  ctx.restore();
+
+  _saveCanvas(canvas);
+}
+
+/**
+ * Saves a given Canvas object to a file.
+ * The path to save the file under should be given on the command line. If not,
+ * it will be saved in the temporary folder of the system.
+ *
+ * @param {canvas} canvas
+ */
+function _saveCanvas(canvas) {
+  // Use the path given on the command line and saved under
+  // persisted.screenshotPath, if available. If not, use the path to the
+  // temporary folder as a fallback.
+  var file = null;
+  if ("screenshotPath" in persisted) {
+    file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
+    file.initWithPath(persisted.screenshotPath);
+  }
+  else {
+    file = Services.dirsvc.get("TmpD", Ci.nsIFile);
+  }
+
+  var fileName = utils.appInfo.name + "-" +
+                 utils.appInfo.locale + "." +
+                 utils.appInfo.version + "." +
+                 utils.appInfo.buildID + "." +
+                 utils.appInfo.os + ".png";
+  file.append(fileName);
+
+  // if a file already exists, don't overwrite it and create a new name
+  file.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
+
+  // create a data url from the canvas and then create URIs of the source
+  // and targets
+  var source = Services.io.newURI(canvas.toDataURL("image/png", ""), "UTF8", null);
+  var target = Services.io.newFileURI(file)
+
+  // prepare to save the canvas data
+  var wbPersist = Cc["@mozilla.org/embedding/browser/nsWebBrowserPersist;1"].
+                  createInstance(Ci.nsIWebBrowserPersist);
+
+  wbPersist.persistFlags = Ci.nsIWebBrowserPersist.PERSIST_FLAGS_REPLACE_EXISTING_FILES;
+  wbPersist.persistFlags |= Ci.nsIWebBrowserPersist.PERSIST_FLAGS_AUTODETECT_APPLY_CONVERSION;
+
+  // save the canvas data to the file
+  wbPersist.saveURI(source, null, null, null, null, file, null);
+}
+
+// Export of functions
+exports.create = create;