chrome/browser/resources/print_preview/preview_generator.js

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 cr.define('print_preview', function() {
   6   'use strict';
   7
   8   /**
   9    * Interface to the Chromium print preview generator.
  10    * @param {!print_preview.DestinationStore} destinationStore Used to get the
  11    *     currently selected destination.
  12    * @param {!print_preview.PrintTicketStore} printTicketStore Used to read the
  13    *     state of the ticket and write document information.
  14    * @param {!print_preview.NativeLayer} nativeLayer Used to communicate to
  15    *     Chromium's preview rendering system.
  16    * @param {!print_preview.DocumentInfo} documentInfo Document data model.
  17    * @constructor
  18    * @extends {cr.EventTarget}
  19    */
  20   function PreviewGenerator(
  21        destinationStore, printTicketStore, nativeLayer, documentInfo) {
  22     cr.EventTarget.call(this);
  23
  24     /**
  25      * Used to get the currently selected destination.
  26      * @type {!print_preview.DestinationStore}
  27      * @private
  28      */
  29     this.destinationStore_ = destinationStore;
  30
  31     /**
  32      * Used to read the state of the ticket and write document information.
  33      * @type {!print_preview.PrintTicketStore}
  34      * @private
  35      */
  36     this.printTicketStore_ = printTicketStore;
  37
  38     /**
  39      * Interface to the Chromium native layer.
  40      * @type {!print_preview.NativeLayer}
  41      * @private
  42      */
  43     this.nativeLayer_ = nativeLayer;
  44
  45     /**
  46      * Document data model.
  47      * @type {!print_preview.DocumentInfo}
  48      * @private
  49      */
  50     this.documentInfo_ = documentInfo;
  51
  52     /**
  53      * ID of current in-flight request. Requests that do not share this ID will
  54      * be ignored.
  55      * @type {number}
  56      * @private
  57      */
  58     this.inFlightRequestId_ = -1;
  59
  60     /**
  61      * Media size to generate preview with. {@code null} indicates default size.
  62      * @type {cp.cdd.MediaSizeTicketItem}
  63      * @private
  64      */
  65     this.mediaSize_ = null;
  66
  67     /**
  68      * Whether the previews are being generated in landscape mode.
  69      * @type {boolean}
  70      * @private
  71      */
  72     this.isLandscapeEnabled_ = false;
  73
  74     /**
  75      * Whether the previews are being generated from a distilled page.
  76      * @type {boolean}
  77      * @private
  78      */
  79     this.isDistillPageEnabled_ = false;
  80
  81     /**
  82      * Whether the previews are being generated with a header and footer.
  83      * @type {boolean}
  84      * @private
  85      */
  86     this.isHeaderFooterEnabled_ = false;
  87
  88     /**
  89      * Whether the previews are being generated in color.
  90      * @type {boolean}
  91      * @private
  92      */
  93     this.colorValue_ = false;
  94
  95     /**
  96      * Whether the document should be fitted to the page.
  97      * @type {boolean}
  98      * @private
  99      */
 100     this.isFitToPageEnabled_ = false;
 101
 102     /**
 103      * Page ranges setting used used to generate the last preview.
 104      * @type {!Array<object<{from: number, to: number}>>}
 105      * @private
 106      */
 107     this.pageRanges_ = null;
 108
 109     /**
 110      * Margins type used to generate the last preview.
 111      * @type {!print_preview.ticket_items.MarginsType.Value}
 112      * @private
 113      */
 114     this.marginsType_ = print_preview.ticket_items.MarginsType.Value.DEFAULT;
 115
 116     /**
 117      * Whether the document should have element CSS backgrounds printed.
 118      * @type {boolean}
 119      * @private
 120      */
 121     this.isCssBackgroundEnabled_ = false;
 122
 123     /**
 124      * Destination that was selected for the last preview.
 125      * @type {print_preview.Destination}
 126      * @private
 127      */
 128     this.selectedDestination_ = null;
 129
 130     /**
 131      * Event tracker used to keep track of native layer events.
 132      * @type {!EventTracker}
 133      * @private
 134      */
 135     this.tracker_ = new EventTracker();
 136
 137     this.addEventListeners_();
 138   };
 139
 140   /**
 141    * Event types dispatched by the preview generator.
 142    * @enum {string}
 143    */
 144   PreviewGenerator.EventType = {
 145     // Dispatched when the document can be printed.
 146     DOCUMENT_READY: 'print_preview.PreviewGenerator.DOCUMENT_READY',
 147
 148     // Dispatched when a page preview is ready. The previewIndex field of the
 149     // event is the index of the page in the modified document, not the
 150     // original. So page 4 of the original document might be previewIndex = 0 of
 151     // the modified document.
 152     PAGE_READY: 'print_preview.PreviewGenerator.PAGE_READY',
 153
 154     // Dispatched when the document preview starts to be generated.
 155     PREVIEW_START: 'print_preview.PreviewGenerator.PREVIEW_START',
 156
 157     // Dispatched when the current print preview request fails.
 158     FAIL: 'print_preview.PreviewGenerator.FAIL'
 159   };
 160
 161   PreviewGenerator.prototype = {
 162     __proto__: cr.EventTarget.prototype,
 163
 164     /**
 165      * Request that new preview be generated. A preview request will not be
 166      * generated if the print ticket has not changed sufficiently.
 167      * @return {boolean} Whether a new preview was actually requested.
 168      */
 169     requestPreview: function() {
 170       if (!this.printTicketStore_.isTicketValidForPreview() ||
 171           !this.printTicketStore_.isInitialized ||
 172           !this.destinationStore_.selectedDestination) {
 173         return false;
 174       }
 175       if (!this.hasPreviewChanged_()) {
 176         // Changes to these ticket items might not trigger a new preview, but
 177         // they still need to be recorded.
 178         this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 179         return false;
 180       }
 181       this.mediaSize_ = this.printTicketStore_.mediaSize.getValue();
 182       this.isLandscapeEnabled_ = this.printTicketStore_.landscape.getValue();
 183       this.isHeaderFooterEnabled_ =
 184           this.printTicketStore_.headerFooter.getValue();
 185       this.isDistillPageEnabled_ =
 186           this.printTicketStore_.distillPage.getValue();
 187       this.colorValue_ = this.printTicketStore_.color.getValue();
 188       this.isFitToPageEnabled_ = this.printTicketStore_.fitToPage.getValue();
 189       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 190       this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 191       this.isCssBackgroundEnabled_ =
 192           this.printTicketStore_.cssBackground.getValue();
 193       this.isSelectionOnlyEnabled_ =
 194           this.printTicketStore_.selectionOnly.getValue();
 195       this.selectedDestination_ = this.destinationStore_.selectedDestination;
 196
 197       this.inFlightRequestId_++;
 198       this.nativeLayer_.startGetPreview(
 199           this.destinationStore_.selectedDestination,
 200           this.printTicketStore_,
 201           this.documentInfo_,
 202           this.inFlightRequestId_);
 203       return true;
 204     },
 205
 206     /** Removes all event listeners that the preview generator has attached. */
 207     removeEventListeners: function() {
 208       this.tracker_.removeAll();
 209     },
 210
 211     /**
 212      * Adds event listeners to the relevant native layer events.
 213      * @private
 214      */
 215     addEventListeners_: function() {
 216       this.tracker_.add(
 217           this.nativeLayer_,
 218           print_preview.NativeLayer.EventType.PAGE_LAYOUT_READY,
 219           this.onPageLayoutReady_.bind(this));
 220       this.tracker_.add(
 221           this.nativeLayer_,
 222           print_preview.NativeLayer.EventType.PAGE_COUNT_READY,
 223           this.onPageCountReady_.bind(this));
 224       this.tracker_.add(
 225           this.nativeLayer_,
 226           print_preview.NativeLayer.EventType.PAGE_PREVIEW_READY,
 227           this.onPagePreviewReady_.bind(this));
 228       this.tracker_.add(
 229           this.nativeLayer_,
 230           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_DONE,
 231           this.onPreviewGenerationDone_.bind(this));
 232       this.tracker_.add(
 233           this.nativeLayer_,
 234           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_FAIL,
 235           this.onPreviewGenerationFail_.bind(this));
 236     },
 237
 238     /**
 239      * Dispatches a PAGE_READY event to signal that a page preview is ready.
 240      * @param {number} previewIndex Index of the page with respect to the pages
 241      *     shown in the preview. E.g an index of 0 is the first displayed page,
 242      *     but not necessarily the first original document page.
 243      * @param {number} pageNumber Number of the page with respect to the
 244      *     document. A value of 3 means it's the third page of the original
 245      *     document.
 246      * @param {number} previewUid Unique identifier of the preview.
 247      * @private
 248      */
 249     dispatchPageReadyEvent_: function(previewIndex, pageNumber, previewUid) {
 250       var pageGenEvent = new Event(PreviewGenerator.EventType.PAGE_READY);
 251       pageGenEvent.previewIndex = previewIndex;
 252       pageGenEvent.previewUrl = 'chrome://print/' + previewUid.toString() +
 253           '/' + (pageNumber - 1) + '/print.pdf';
 254       this.dispatchEvent(pageGenEvent);
 255     },
 256
 257     /**
 258      * Dispatches a PREVIEW_START event. Signals that the preview should be
 259      * reloaded.
 260      * @param {number} previewUid Unique identifier of the preview.
 261      * @param {number} index Index of the first page of the preview.
 262      * @private
 263      */
 264     dispatchPreviewStartEvent_: function(previewUid, index) {
 265       var previewStartEvent = new Event(
 266           PreviewGenerator.EventType.PREVIEW_START);
 267       if (!this.documentInfo_.isModifiable) {
 268         index = -1;
 269       }
 270       previewStartEvent.previewUrl = 'chrome://print/' +
 271           previewUid.toString() + '/' + index + '/print.pdf';
 272       this.dispatchEvent(previewStartEvent);
 273     },
 274
 275     /**
 276      * @return {boolean} Whether the print ticket has changed sufficiently to
 277      *     determine whether a new preview request should be issued.
 278      * @private
 279      */
 280     hasPreviewChanged_: function() {
 281       var ticketStore = this.printTicketStore_;
 282       return this.inFlightRequestId_ == -1 ||
 283           !ticketStore.mediaSize.isValueEqual(this.mediaSize_) ||
 284           !ticketStore.landscape.isValueEqual(this.isLandscapeEnabled_) ||
 285           !ticketStore.headerFooter.isValueEqual(this.isHeaderFooterEnabled_) ||
 286           !ticketStore.distillPage.isValueEqual(
 287               this.isDistillPageEnabled_) ||
 288           !ticketStore.color.isValueEqual(this.colorValue_) ||
 289           !ticketStore.fitToPage.isValueEqual(this.isFitToPageEnabled_) ||
 290           this.pageRanges_ == null ||
 291           !areRangesEqual(ticketStore.pageRange.getPageRanges(),
 292                           this.pageRanges_) ||
 293           (!ticketStore.marginsType.isValueEqual(this.marginsType_) &&
 294               !ticketStore.marginsType.isValueEqual(
 295                   print_preview.ticket_items.MarginsType.Value.CUSTOM)) ||
 296           (ticketStore.marginsType.isValueEqual(
 297               print_preview.ticket_items.MarginsType.Value.CUSTOM) &&
 298               !ticketStore.customMargins.isValueEqual(
 299                   this.documentInfo_.margins)) ||
 300           !ticketStore.cssBackground.isValueEqual(
 301               this.isCssBackgroundEnabled_) ||
 302           !ticketStore.selectionOnly.isValueEqual(
 303               this.isSelectionOnlyEnabled_) ||
 304           (this.selectedDestination_ !=
 305               this.destinationStore_.selectedDestination);
 306     },
 307
 308     /**
 309      * Called when the page layout of the document is ready. Always occurs
 310      * as a result of a preview request.
 311      * @param {Event} event Contains layout info about the document.
 312      * @private
 313      */
 314     onPageLayoutReady_: function(event) {
 315       // NOTE: A request ID is not specified, so assuming its for the current
 316       // in-flight request.
 317
 318       var origin = new print_preview.Coordinate2d(
 319           event.pageLayout.printableAreaX,
 320           event.pageLayout.printableAreaY);
 321       var size = new print_preview.Size(
 322           event.pageLayout.printableAreaWidth,
 323           event.pageLayout.printableAreaHeight);
 324
 325       var margins = new print_preview.Margins(
 326           Math.round(event.pageLayout.marginTop),
 327           Math.round(event.pageLayout.marginRight),
 328           Math.round(event.pageLayout.marginBottom),
 329           Math.round(event.pageLayout.marginLeft));
 330
 331       var o = print_preview.ticket_items.CustomMargins.Orientation;
 332       var pageSize = new print_preview.Size(
 333           event.pageLayout.contentWidth +
 334               margins.get(o.LEFT) + margins.get(o.RIGHT),
 335           event.pageLayout.contentHeight +
 336               margins.get(o.TOP) + margins.get(o.BOTTOM));
 337
 338       this.documentInfo_.updatePageInfo(
 339           new print_preview.PrintableArea(origin, size),
 340           pageSize,
 341           event.hasCustomPageSizeStyle,
 342           margins);
 343     },
 344
 345     /**
 346      * Called when the document page count is received from the native layer.
 347      * Always occurs as a result of a preview request.
 348      * @param {Event} event Contains the document's page count.
 349      * @private
 350      */
 351     onPageCountReady_: function(event) {
 352       if (this.inFlightRequestId_ != event.previewResponseId) {
 353         return; // Ignore old response.
 354       }
 355       this.documentInfo_.updatePageCount(event.pageCount);
 356       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 357     },
 358
 359     /**
 360      * Called when a page's preview has been generated. Dispatches a
 361      * PAGE_READY event.
 362      * @param {Event} event Contains the page index and preview UID.
 363      * @private
 364      */
 365     onPagePreviewReady_: function(event) {
 366       if (this.inFlightRequestId_ != event.previewResponseId) {
 367         return; // Ignore old response.
 368       }
 369       var pageNumber = event.pageIndex + 1;
 370       var pageNumberSet = this.printTicketStore_.pageRange.getPageNumberSet();
 371       if (pageNumberSet.hasPageNumber(pageNumber)) {
 372         var previewIndex = pageNumberSet.getPageNumberIndex(pageNumber);
 373         if (previewIndex == 0) {
 374           this.dispatchPreviewStartEvent_(event.previewUid, event.pageIndex);
 375         }
 376         this.dispatchPageReadyEvent_(
 377             previewIndex, pageNumber, event.previewUid);
 378       }
 379     },
 380
 381     /**
 382      * Called when the preview generation is complete. Dispatches a
 383      * DOCUMENT_READY event.
 384      * @param {Event} event Contains the preview UID and response ID.
 385      * @private
 386      */
 387     onPreviewGenerationDone_: function(event) {
 388       if (this.inFlightRequestId_ != event.previewResponseId) {
 389         return; // Ignore old response.
 390       }
 391       // Dispatch a PREVIEW_START event since non-modifiable documents don't
 392       // trigger PAGE_READY events.
 393       if (!this.documentInfo_.isModifiable) {
 394         this.dispatchPreviewStartEvent_(event.previewUid, 0);
 395       }
 396       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.DOCUMENT_READY);
 397     },
 398
 399     /**
 400      * Called when the preview generation fails.
 401      * @private
 402      */
 403     onPreviewGenerationFail_: function() {
 404       // NOTE: No request ID is returned from Chromium so its assumed its the
 405       // current one.
 406       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.FAIL);
 407     }
 408   };
 409
 410   // Export
 411   return {
 412     PreviewGenerator: PreviewGenerator
 413   };
 414 });