src/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      * Whether the previews are being generated in landscape mode.
  62      * @type {boolean}
  63      * @private
  64      */
  65     this.isLandscapeEnabled_ = false;
  66
  67     /**
  68      * Whether the previews are being generated with a header and footer.
  69      * @type {boolean}
  70      * @private
  71      */
  72     this.isHeaderFooterEnabled_ = false;
  73
  74     /**
  75      * Whether the previews are being generated in color.
  76      * @type {boolean}
  77      * @private
  78      */
  79     this.colorValue_ = false;
  80
  81     /**
  82      * Whether the document should be fitted to the page.
  83      * @type {boolean}
  84      * @private
  85      */
  86     this.isFitToPageEnabled_ = false;
  87
  88     /**
  89      * Page ranges setting used used to generate the last preview.
  90      * @type {!Array.<object.<{from: number, to: number}>>}
  91      * @private
  92      */
  93     this.pageRanges_ = null;
  94
  95     /**
  96      * Margins type used to generate the last preview.
  97      * @type {!print_preview.ticket_items.MarginsType.Value}
  98      * @private
  99      */
 100     this.marginsType_ = print_preview.ticket_items.MarginsType.Value.DEFAULT;
 101
 102     /**
 103      * Whether the document should have element CSS backgrounds printed.
 104      * @type {boolean}
 105      * @private
 106      */
 107     this.isCssBackgroundEnabled_ = false;
 108
 109     /**
 110      * Destination that was selected for the last preview.
 111      * @type {print_preview.Destination}
 112      * @private
 113      */
 114     this.selectedDestination_ = null;
 115
 116     /**
 117      * Event tracker used to keep track of native layer events.
 118      * @type {!EventTracker}
 119      * @private
 120      */
 121     this.tracker_ = new EventTracker();
 122
 123     this.addEventListeners_();
 124   };
 125
 126   /**
 127    * Event types dispatched by the preview generator.
 128    * @enum {string}
 129    */
 130   PreviewGenerator.EventType = {
 131     // Dispatched when the document can be printed.
 132     DOCUMENT_READY: 'print_preview.PreviewGenerator.DOCUMENT_READY',
 133
 134     // Dispatched when a page preview is ready. The previewIndex field of the
 135     // event is the index of the page in the modified document, not the
 136     // original. So page 4 of the original document might be previewIndex = 0 of
 137     // the modified document.
 138     PAGE_READY: 'print_preview.PreviewGenerator.PAGE_READY',
 139
 140     // Dispatched when the document preview starts to be generated.
 141     PREVIEW_START: 'print_preview.PreviewGenerator.PREVIEW_START',
 142
 143     // Dispatched when the current print preview request fails.
 144     FAIL: 'print_preview.PreviewGenerator.FAIL'
 145   };
 146
 147   PreviewGenerator.prototype = {
 148     __proto__: cr.EventTarget.prototype,
 149
 150     /**
 151      * Request that new preview be generated. A preview request will not be
 152      * generated if the print ticket has not changed sufficiently.
 153      * @return {boolean} Whether a new preview was actually requested.
 154      */
 155     requestPreview: function() {
 156       if (!this.printTicketStore_.isTicketValidForPreview() ||
 157           !this.printTicketStore_.isInitialized) {
 158         return false;
 159       }
 160       if (!this.hasPreviewChanged_()) {
 161         // Changes to these ticket items might not trigger a new preview, but
 162         // they still need to be recorded.
 163         this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 164         return false;
 165       }
 166       this.isLandscapeEnabled_ = this.printTicketStore_.landscape.getValue();
 167       this.isHeaderFooterEnabled_ =
 168           this.printTicketStore_.headerFooter.getValue();
 169       this.colorValue_ = this.printTicketStore_.color.getValue();
 170       this.isFitToPageEnabled_ = this.printTicketStore_.fitToPage.getValue();
 171       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 172       this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 173       this.isCssBackgroundEnabled_ =
 174           this.printTicketStore_.cssBackground.getValue();
 175       this.isSelectionOnlyEnabled_ =
 176           this.printTicketStore_.selectionOnly.getValue();
 177       this.selectedDestination_ = this.destinationStore_.selectedDestination;
 178
 179       this.inFlightRequestId_++;
 180       this.nativeLayer_.startGetPreview(
 181           this.destinationStore_.selectedDestination,
 182           this.printTicketStore_,
 183           this.documentInfo_,
 184           this.inFlightRequestId_);
 185       return true;
 186     },
 187
 188     /** Removes all event listeners that the preview generator has attached. */
 189     removeEventListeners: function() {
 190       this.tracker_.removeAll();
 191     },
 192
 193     /**
 194      * Adds event listeners to the relevant native layer events.
 195      * @private
 196      */
 197     addEventListeners_: function() {
 198       this.tracker_.add(
 199           this.nativeLayer_,
 200           print_preview.NativeLayer.EventType.PAGE_LAYOUT_READY,
 201           this.onPageLayoutReady_.bind(this));
 202       this.tracker_.add(
 203           this.nativeLayer_,
 204           print_preview.NativeLayer.EventType.PAGE_COUNT_READY,
 205           this.onPageCountReady_.bind(this));
 206       this.tracker_.add(
 207           this.nativeLayer_,
 208           print_preview.NativeLayer.EventType.PREVIEW_RELOAD,
 209           this.onPreviewReload_.bind(this));
 210       this.tracker_.add(
 211           this.nativeLayer_,
 212           print_preview.NativeLayer.EventType.PAGE_PREVIEW_READY,
 213           this.onPagePreviewReady_.bind(this));
 214       this.tracker_.add(
 215           this.nativeLayer_,
 216           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_DONE,
 217           this.onPreviewGenerationDone_.bind(this));
 218       this.tracker_.add(
 219           this.nativeLayer_,
 220           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_FAIL,
 221           this.onPreviewGenerationFail_.bind(this));
 222     },
 223
 224     /**
 225      * Dispatches a PAGE_READY event to signal that a page preview is ready.
 226      * @param {number} previewIndex Index of the page with respect to the pages
 227      *     shown in the preview. E.g an index of 0 is the first displayed page,
 228      *     but not necessarily the first original document page.
 229      * @param {number} pageNumber Number of the page with respect to the
 230      *     document. A value of 3 means it's the third page of the original
 231      *     document.
 232      * @param {number} previewUid Unique identifier of the preview.
 233      * @private
 234      */
 235     dispatchPageReadyEvent_: function(previewIndex, pageNumber, previewUid) {
 236       var pageGenEvent = new Event(PreviewGenerator.EventType.PAGE_READY);
 237       pageGenEvent.previewIndex = previewIndex;
 238       pageGenEvent.previewUrl = 'chrome://print/' + previewUid.toString() +
 239           '/' + (pageNumber - 1) + '/print.pdf';
 240       this.dispatchEvent(pageGenEvent);
 241     },
 242
 243     /**
 244      * Dispatches a PREVIEW_START event. Signals that the preview should be
 245      * reloaded.
 246      * @param {number} previewUid Unique identifier of the preview.
 247      * @param {number} index Index of the first page of the preview.
 248      * @private
 249      */
 250     dispatchPreviewStartEvent_: function(previewUid, index) {
 251       var previewStartEvent = new Event(
 252           PreviewGenerator.EventType.PREVIEW_START);
 253       if (!this.documentInfo_.isModifiable) {
 254         index = -1;
 255       }
 256       previewStartEvent.previewUrl = 'chrome://print/' +
 257           previewUid.toString() + '/' + index + '/print.pdf';
 258       this.dispatchEvent(previewStartEvent);
 259     },
 260
 261     /**
 262      * @return {boolean} Whether the print ticket has changed sufficiently to
 263      *     determine whether a new preview request should be issued.
 264      * @private
 265      */
 266     hasPreviewChanged_: function() {
 267       var ticketStore = this.printTicketStore_;
 268       return this.inFlightRequestId_ == -1 ||
 269           !ticketStore.landscape.isValueEqual(this.isLandscapeEnabled_) ||
 270           !ticketStore.headerFooter.isValueEqual(this.isHeaderFooterEnabled_) ||
 271           !ticketStore.color.isValueEqual(this.colorValue_) ||
 272           !ticketStore.fitToPage.isValueEqual(this.isFitToPageEnabled_) ||
 273           this.pageRanges_ == null ||
 274           !areRangesEqual(ticketStore.pageRange.getPageRanges(),
 275                           this.pageRanges_) ||
 276           (!ticketStore.marginsType.isValueEqual(this.marginsType_) &&
 277               !ticketStore.marginsType.isValueEqual(
 278                   print_preview.ticket_items.MarginsType.Value.CUSTOM)) ||
 279           (ticketStore.marginsType.isValueEqual(
 280               print_preview.ticket_items.MarginsType.Value.CUSTOM) &&
 281               !ticketStore.customMargins.isValueEqual(
 282                   this.documentInfo_.margins)) ||
 283           !ticketStore.cssBackground.isValueEqual(
 284               this.isCssBackgroundEnabled_) ||
 285           !ticketStore.selectionOnly.isValueEqual(
 286               this.isSelectionOnlyEnabled_) ||
 287           (this.selectedDestination_ !=
 288               this.destinationStore_.selectedDestination);
 289     },
 290
 291     /**
 292      * Called when the page layout of the document is ready. Always occurs
 293      * as a result of a preview request.
 294      * @param {Event} event Contains layout info about the document.
 295      * @private
 296      */
 297     onPageLayoutReady_: function(event) {
 298       // NOTE: A request ID is not specified, so assuming its for the current
 299       // in-flight request.
 300
 301       var origin = new print_preview.Coordinate2d(
 302           event.pageLayout.printableAreaX,
 303           event.pageLayout.printableAreaY);
 304       var size = new print_preview.Size(
 305           event.pageLayout.printableAreaWidth,
 306           event.pageLayout.printableAreaHeight);
 307
 308       var margins = new print_preview.Margins(
 309           Math.round(event.pageLayout.marginTop),
 310           Math.round(event.pageLayout.marginRight),
 311           Math.round(event.pageLayout.marginBottom),
 312           Math.round(event.pageLayout.marginLeft));
 313
 314       var o = print_preview.ticket_items.CustomMargins.Orientation;
 315       var pageSize = new print_preview.Size(
 316           event.pageLayout.contentWidth +
 317               margins.get(o.LEFT) + margins.get(o.RIGHT),
 318           event.pageLayout.contentHeight +
 319               margins.get(o.TOP) + margins.get(o.BOTTOM));
 320
 321       this.documentInfo_.updatePageInfo(
 322           new print_preview.PrintableArea(origin, size),
 323           pageSize,
 324           event.hasCustomPageSizeStyle,
 325           margins);
 326     },
 327
 328     /**
 329      * Called when the document page count is received from the native layer.
 330      * Always occurs as a result of a preview request.
 331      * @param {Event} event Contains the document's page count.
 332      * @private
 333      */
 334     onPageCountReady_: function(event) {
 335       if (this.inFlightRequestId_ != event.previewResponseId) {
 336         return; // Ignore old response.
 337       }
 338       this.documentInfo_.updatePageCount(event.pageCount);
 339       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 340     },
 341
 342     /**
 343      * Called when the print preview should be reloaded.
 344      * @param {Event} event Contains the preview UID and request ID.
 345      * @private
 346      */
 347     onPreviewReload_: function(event) {
 348       if (this.inFlightRequestId_ != event.previewResponseId) {
 349         return; // Ignore old response.
 350       }
 351       var pageNumberSet = this.printTicketStore_.pageRange.getPageNumberSet();
 352       this.dispatchPreviewStartEvent_(
 353           event.previewUid, pageNumberSet.getPageNumberAt(0) - 1);
 354       for (var i = 0; i < pageNumberSet.size; i++) {
 355         var pageNumber = pageNumberSet.getPageNumberAt(i);
 356         this.dispatchPageReadyEvent_(i, pageNumber, event.previewUid);
 357       }
 358       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.DOCUMENT_READY);
 359     },
 360
 361     /**
 362      * Called when a page's preview has been generated. Dispatches a
 363      * PAGE_READY event.
 364      * @param {Event} event Contains the page index and preview UID.
 365      * @private
 366      */
 367     onPagePreviewReady_: function(event) {
 368       if (this.inFlightRequestId_ != event.previewResponseId) {
 369         return; // Ignore old response.
 370       }
 371       var pageNumber = event.pageIndex + 1;
 372       var pageNumberSet = this.printTicketStore_.pageRange.getPageNumberSet();
 373       if (pageNumberSet.hasPageNumber(pageNumber)) {
 374         var previewIndex = pageNumberSet.getPageNumberIndex(pageNumber);
 375         if (previewIndex == 0) {
 376           this.dispatchPreviewStartEvent_(event.previewUid, event.pageIndex);
 377         }
 378         this.dispatchPageReadyEvent_(
 379             previewIndex, pageNumber, event.previewUid);
 380       }
 381     },
 382
 383     /**
 384      * Called when the preview generation is complete. Dispatches a
 385      * DOCUMENT_READY event.
 386      * @param {Event} event Contains the preview UID and response ID.
 387      * @private
 388      */
 389     onPreviewGenerationDone_: function(event) {
 390       if (this.inFlightRequestId_ != event.previewResponseId) {
 391         return; // Ignore old response.
 392       }
 393       // Dispatch a PREVIEW_START event since non-modifiable documents don't
 394       // trigger PAGE_READY events.
 395       if (!this.documentInfo_.isModifiable) {
 396         this.dispatchPreviewStartEvent_(event.previewUid, 0);
 397       }
 398       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.DOCUMENT_READY);
 399     },
 400
 401     /**
 402      * Called when the preview generation fails.
 403      * @private
 404      */
 405     onPreviewGenerationFail_: function() {
 406       // NOTE: No request ID is returned from Chromium so its assumed its the
 407       // current one.
 408       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.FAIL);
 409     }
 410   };
 411
 412   // Export
 413   return {
 414     PreviewGenerator: PreviewGenerator
 415   };
 416 });