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           !this.destinationStore_.selectedDestination) {
 159         return false;
 160       }
 161       if (!this.hasPreviewChanged_()) {
 162         // Changes to these ticket items might not trigger a new preview, but
 163         // they still need to be recorded.
 164         this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 165         return false;
 166       }
 167       this.isLandscapeEnabled_ = this.printTicketStore_.landscape.getValue();
 168       this.isHeaderFooterEnabled_ =
 169           this.printTicketStore_.headerFooter.getValue();
 170       this.colorValue_ = this.printTicketStore_.color.getValue();
 171       this.isFitToPageEnabled_ = this.printTicketStore_.fitToPage.getValue();
 172       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 173       this.marginsType_ = this.printTicketStore_.marginsType.getValue();
 174       this.isCssBackgroundEnabled_ =
 175           this.printTicketStore_.cssBackground.getValue();
 176       this.isSelectionOnlyEnabled_ =
 177           this.printTicketStore_.selectionOnly.getValue();
 178       this.selectedDestination_ = this.destinationStore_.selectedDestination;
 179
 180       this.inFlightRequestId_++;
 181       this.nativeLayer_.startGetPreview(
 182           this.destinationStore_.selectedDestination,
 183           this.printTicketStore_,
 184           this.documentInfo_,
 185           this.inFlightRequestId_);
 186       return true;
 187     },
 188
 189     /** Removes all event listeners that the preview generator has attached. */
 190     removeEventListeners: function() {
 191       this.tracker_.removeAll();
 192     },
 193
 194     /**
 195      * Adds event listeners to the relevant native layer events.
 196      * @private
 197      */
 198     addEventListeners_: function() {
 199       this.tracker_.add(
 200           this.nativeLayer_,
 201           print_preview.NativeLayer.EventType.PAGE_LAYOUT_READY,
 202           this.onPageLayoutReady_.bind(this));
 203       this.tracker_.add(
 204           this.nativeLayer_,
 205           print_preview.NativeLayer.EventType.PAGE_COUNT_READY,
 206           this.onPageCountReady_.bind(this));
 207       this.tracker_.add(
 208           this.nativeLayer_,
 209           print_preview.NativeLayer.EventType.PAGE_PREVIEW_READY,
 210           this.onPagePreviewReady_.bind(this));
 211       this.tracker_.add(
 212           this.nativeLayer_,
 213           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_DONE,
 214           this.onPreviewGenerationDone_.bind(this));
 215       this.tracker_.add(
 216           this.nativeLayer_,
 217           print_preview.NativeLayer.EventType.PREVIEW_GENERATION_FAIL,
 218           this.onPreviewGenerationFail_.bind(this));
 219     },
 220
 221     /**
 222      * Dispatches a PAGE_READY event to signal that a page preview is ready.
 223      * @param {number} previewIndex Index of the page with respect to the pages
 224      *     shown in the preview. E.g an index of 0 is the first displayed page,
 225      *     but not necessarily the first original document page.
 226      * @param {number} pageNumber Number of the page with respect to the
 227      *     document. A value of 3 means it's the third page of the original
 228      *     document.
 229      * @param {number} previewUid Unique identifier of the preview.
 230      * @private
 231      */
 232     dispatchPageReadyEvent_: function(previewIndex, pageNumber, previewUid) {
 233       var pageGenEvent = new Event(PreviewGenerator.EventType.PAGE_READY);
 234       pageGenEvent.previewIndex = previewIndex;
 235       pageGenEvent.previewUrl = 'chrome://print/' + previewUid.toString() +
 236           '/' + (pageNumber - 1) + '/print.pdf';
 237       this.dispatchEvent(pageGenEvent);
 238     },
 239
 240     /**
 241      * Dispatches a PREVIEW_START event. Signals that the preview should be
 242      * reloaded.
 243      * @param {number} previewUid Unique identifier of the preview.
 244      * @param {number} index Index of the first page of the preview.
 245      * @private
 246      */
 247     dispatchPreviewStartEvent_: function(previewUid, index) {
 248       var previewStartEvent = new Event(
 249           PreviewGenerator.EventType.PREVIEW_START);
 250       if (!this.documentInfo_.isModifiable) {
 251         index = -1;
 252       }
 253       previewStartEvent.previewUrl = 'chrome://print/' +
 254           previewUid.toString() + '/' + index + '/print.pdf';
 255       this.dispatchEvent(previewStartEvent);
 256     },
 257
 258     /**
 259      * @return {boolean} Whether the print ticket has changed sufficiently to
 260      *     determine whether a new preview request should be issued.
 261      * @private
 262      */
 263     hasPreviewChanged_: function() {
 264       var ticketStore = this.printTicketStore_;
 265       return this.inFlightRequestId_ == -1 ||
 266           !ticketStore.landscape.isValueEqual(this.isLandscapeEnabled_) ||
 267           !ticketStore.headerFooter.isValueEqual(this.isHeaderFooterEnabled_) ||
 268           !ticketStore.color.isValueEqual(this.colorValue_) ||
 269           !ticketStore.fitToPage.isValueEqual(this.isFitToPageEnabled_) ||
 270           this.pageRanges_ == null ||
 271           !areRangesEqual(ticketStore.pageRange.getPageRanges(),
 272                           this.pageRanges_) ||
 273           (!ticketStore.marginsType.isValueEqual(this.marginsType_) &&
 274               !ticketStore.marginsType.isValueEqual(
 275                   print_preview.ticket_items.MarginsType.Value.CUSTOM)) ||
 276           (ticketStore.marginsType.isValueEqual(
 277               print_preview.ticket_items.MarginsType.Value.CUSTOM) &&
 278               !ticketStore.customMargins.isValueEqual(
 279                   this.documentInfo_.margins)) ||
 280           !ticketStore.cssBackground.isValueEqual(
 281               this.isCssBackgroundEnabled_) ||
 282           !ticketStore.selectionOnly.isValueEqual(
 283               this.isSelectionOnlyEnabled_) ||
 284           (this.selectedDestination_ !=
 285               this.destinationStore_.selectedDestination);
 286     },
 287
 288     /**
 289      * Called when the page layout of the document is ready. Always occurs
 290      * as a result of a preview request.
 291      * @param {Event} event Contains layout info about the document.
 292      * @private
 293      */
 294     onPageLayoutReady_: function(event) {
 295       // NOTE: A request ID is not specified, so assuming its for the current
 296       // in-flight request.
 297
 298       var origin = new print_preview.Coordinate2d(
 299           event.pageLayout.printableAreaX,
 300           event.pageLayout.printableAreaY);
 301       var size = new print_preview.Size(
 302           event.pageLayout.printableAreaWidth,
 303           event.pageLayout.printableAreaHeight);
 304
 305       var margins = new print_preview.Margins(
 306           Math.round(event.pageLayout.marginTop),
 307           Math.round(event.pageLayout.marginRight),
 308           Math.round(event.pageLayout.marginBottom),
 309           Math.round(event.pageLayout.marginLeft));
 310
 311       var o = print_preview.ticket_items.CustomMargins.Orientation;
 312       var pageSize = new print_preview.Size(
 313           event.pageLayout.contentWidth +
 314               margins.get(o.LEFT) + margins.get(o.RIGHT),
 315           event.pageLayout.contentHeight +
 316               margins.get(o.TOP) + margins.get(o.BOTTOM));
 317
 318       this.documentInfo_.updatePageInfo(
 319           new print_preview.PrintableArea(origin, size),
 320           pageSize,
 321           event.hasCustomPageSizeStyle,
 322           margins);
 323     },
 324
 325     /**
 326      * Called when the document page count is received from the native layer.
 327      * Always occurs as a result of a preview request.
 328      * @param {Event} event Contains the document's page count.
 329      * @private
 330      */
 331     onPageCountReady_: function(event) {
 332       if (this.inFlightRequestId_ != event.previewResponseId) {
 333         return; // Ignore old response.
 334       }
 335       this.documentInfo_.updatePageCount(event.pageCount);
 336       this.pageRanges_ = this.printTicketStore_.pageRange.getPageRanges();
 337     },
 338
 339     /**
 340      * Called when a page's preview has been generated. Dispatches a
 341      * PAGE_READY event.
 342      * @param {Event} event Contains the page index and preview UID.
 343      * @private
 344      */
 345     onPagePreviewReady_: function(event) {
 346       if (this.inFlightRequestId_ != event.previewResponseId) {
 347         return; // Ignore old response.
 348       }
 349       var pageNumber = event.pageIndex + 1;
 350       var pageNumberSet = this.printTicketStore_.pageRange.getPageNumberSet();
 351       if (pageNumberSet.hasPageNumber(pageNumber)) {
 352         var previewIndex = pageNumberSet.getPageNumberIndex(pageNumber);
 353         if (previewIndex == 0) {
 354           this.dispatchPreviewStartEvent_(event.previewUid, event.pageIndex);
 355         }
 356         this.dispatchPageReadyEvent_(
 357             previewIndex, pageNumber, event.previewUid);
 358       }
 359     },
 360
 361     /**
 362      * Called when the preview generation is complete. Dispatches a
 363      * DOCUMENT_READY event.
 364      * @param {Event} event Contains the preview UID and response ID.
 365      * @private
 366      */
 367     onPreviewGenerationDone_: function(event) {
 368       if (this.inFlightRequestId_ != event.previewResponseId) {
 369         return; // Ignore old response.
 370       }
 371       // Dispatch a PREVIEW_START event since non-modifiable documents don't
 372       // trigger PAGE_READY events.
 373       if (!this.documentInfo_.isModifiable) {
 374         this.dispatchPreviewStartEvent_(event.previewUid, 0);
 375       }
 376       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.DOCUMENT_READY);
 377     },
 378
 379     /**
 380      * Called when the preview generation fails.
 381      * @private
 382      */
 383     onPreviewGenerationFail_: function() {
 384       // NOTE: No request ID is returned from Chromium so its assumed its the
 385       // current one.
 386       cr.dispatchSimpleEvent(this, PreviewGenerator.EventType.FAIL);
 387     }
 388   };
 389
 390   // Export
 391   return {
 392     PreviewGenerator: PreviewGenerator
 393   };
 394 });