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