resources/src/mediawiki.page.gallery.slideshow.js

   1 /*!
   2  * mw.GallerySlideshow: Interface controls for the slideshow gallery
   3  */
   4 ( function () {
   5         /**
   6          * mw.GallerySlideshow encapsulates the user interface of the slideshow
   7          * galleries. An object is instantiated for each `.mw-gallery-slideshow`
   8          * element.
   9          *
  10          * @class mw.GallerySlideshow
  11          * @uses mw.Title
  12          * @uses mw.Api
  13          * @param {jQuery} gallery The `<ul>` element of the gallery.
  14          */
  15         mw.GallerySlideshow = function ( gallery ) {
  16                 // Properties
  17                 this.$gallery = $( gallery );
  18                 this.$galleryCaption = this.$gallery.find( '.gallerycaption' );
  19                 this.$galleryBox = this.$gallery.find( '.gallerybox' );
  20                 this.$currentImage = null;
  21                 this.imageInfoCache = {};
  22                 if ( this.$gallery.parent().attr( 'id' ) !== 'mw-content-text' ) {
  23                         this.$container = this.$gallery.parent();
  24                 }
  25
  26                 // Initialize
  27                 this.drawCarousel();
  28                 this.setSizeRequirement();
  29                 this.toggleThumbnails( !!this.$gallery.attr( 'data-showthumbnails' ) );
  30                 this.showCurrentImage();
  31
  32                 // Events
  33                 $( window ).on(
  34                         'resize',
  35                         OO.ui.debounce(
  36                                 this.setSizeRequirement.bind( this ),
  37                                 100
  38                         )
  39                 );
  40
  41                 // Disable thumbnails' link, instead show the image in the carousel
  42                 this.$galleryBox.on( 'click', function ( e ) {
  43                         this.$currentImage = $( e.currentTarget );
  44                         this.showCurrentImage();
  45                         return false;
  46                 }.bind( this ) );
  47         };
  48
  49         /* Properties */
  50         /**
  51          * @property {jQuery} $gallery The `<ul>` element of the gallery.
  52          */
  53
  54         /**
  55          * @property {jQuery} $galleryCaption The `<li>` that has the gallery caption.
  56          */
  57
  58         /**
  59          * @property {jQuery} $galleryBox Selection of `<li>` elements that have thumbnails.
  60          */
  61
  62         /**
  63          * @property {jQuery} $carousel The `<li>` elements that contains the carousel.
  64          */
  65
  66         /**
  67          * @property {jQuery} $interface The `<div>` elements that contains the interface buttons.
  68          */
  69
  70         /**
  71          * @property {jQuery} $img The `<img>` element that'll display the current image.
  72          */
  73
  74         /**
  75          * @property {jQuery} $imgLink The `<a>` element that links to the image's File page.
  76          */
  77
  78         /**
  79          * @property {jQuery} $imgCaption The `<p>` element that holds the image caption.
  80          */
  81
  82         /**
  83          * @property {jQuery} $imgContainer The `<div>` element that contains the image.
  84          */
  85
  86         /**
  87          * @property {jQuery} $currentImage The `<li>` element of the current image.
  88          */
  89
  90         /**
  91          * @property {jQuery} $container If the gallery contained in an element that is
  92          *   not the main content element, then it stores that element.
  93          */
  94
  95         /**
  96          * @property {Object} imageInfoCache A key value pair of thumbnail URLs and image info.
  97          */
  98
  99         /**
 100          * @property {number} imageWidth Width of the image based on viewport size
 101          */
 102
 103         /**
 104          * @property {number} imageHeight Height of the image based on viewport size
 105          *   the URLs in the required size.
 106          */
 107
 108         /* Setup */
 109         OO.initClass( mw.GallerySlideshow );
 110
 111         /* Methods */
 112         /**
 113          * Draws the carousel and the interface around it.
 114          */
 115         mw.GallerySlideshow.prototype.drawCarousel = function () {
 116                 var next, prev, toggle, interfaceElements, carouselStack;
 117
 118                 this.$carousel = $( '<li>' ).addClass( 'gallerycarousel' );
 119
 120                 // Buttons for the interface
 121                 prev = new OO.ui.ButtonWidget( {
 122                         framed: false,
 123                         icon: 'previous'
 124                 } ).on( 'click', this.prevImage.bind( this ) );
 125
 126                 next = new OO.ui.ButtonWidget( {
 127                         framed: false,
 128                         icon: 'next'
 129                 } ).on( 'click', this.nextImage.bind( this ) );
 130
 131                 toggle = new OO.ui.ButtonWidget( {
 132                         framed: false,
 133                         icon: 'imageGallery',
 134                         title: mw.msg( 'gallery-slideshow-toggle' )
 135                 } ).on( 'click', this.toggleThumbnails.bind( this ) );
 136
 137                 interfaceElements = new OO.ui.PanelLayout( {
 138                         expanded: false,
 139                         classes: [ 'mw-gallery-slideshow-buttons' ],
 140                         $content: $( '<div>' ).append(
 141                                 prev.$element,
 142                                 toggle.$element,
 143                                 next.$element
 144                         )
 145                 } );
 146                 this.$interface = interfaceElements.$element;
 147
 148                 // Containers for the current image, caption etc.
 149                 this.$img = $( '<img>' );
 150                 this.$imgLink = $( '<a>' ).append( this.$img );
 151                 this.$imgCaption = $( '<p>' ).attr( 'class', 'mw-gallery-slideshow-caption' );
 152                 this.$imgContainer = $( '<div>' )
 153                         .attr( 'class', 'mw-gallery-slideshow-img-container' )
 154                         .append( this.$imgLink );
 155
 156                 carouselStack = new OO.ui.StackLayout( {
 157                         continuous: true,
 158                         expanded: false,
 159                         items: [
 160                                 interfaceElements,
 161                                 new OO.ui.PanelLayout( {
 162                                         expanded: false,
 163                                         $content: this.$imgContainer
 164                                 } ),
 165                                 new OO.ui.PanelLayout( {
 166                                         expanded: false,
 167                                         $content: this.$imgCaption
 168                                 } )
 169                         ]
 170                 } );
 171                 this.$carousel.append( carouselStack.$element );
 172
 173                 // Append below the caption or as the first element in the gallery
 174                 if ( this.$galleryCaption.length !== 0 ) {
 175                         this.$galleryCaption.after( this.$carousel );
 176                 } else {
 177                         this.$gallery.prepend( this.$carousel );
 178                 }
 179         };
 180
 181         /**
 182          * Sets the {@link #imageWidth} and {@link #imageHeight} properties
 183          * based on the size of the window. Also flushes the
 184          * {@link #imageInfoCache} as we'll now need URLs for a different
 185          * size.
 186          */
 187         mw.GallerySlideshow.prototype.setSizeRequirement = function () {
 188                 var w, h;
 189
 190                 if ( this.$container !== undefined ) {
 191                         w = this.$container.width() * 0.9;
 192                         h = ( this.$container.height() - this.getChromeHeight() ) * 0.9;
 193                 } else {
 194                         w = this.$imgContainer.width();
 195                         h = Math.min( $( window ).height() * ( 3 / 4 ), this.$imgContainer.width() ) - this.getChromeHeight();
 196                 }
 197
 198                 // Only update and flush the cache if the size changed
 199                 if ( w !== this.imageWidth || h !== this.imageHeight ) {
 200                         this.imageWidth = w;
 201                         this.imageHeight = h;
 202                         this.imageInfoCache = {};
 203                         this.setImageSize();
 204                 }
 205         };
 206
 207         /**
 208          * Gets the height of the interface elements and the
 209          * gallery's caption.
 210          *
 211          * @return {number} Height
 212          */
 213         mw.GallerySlideshow.prototype.getChromeHeight = function () {
 214                 return this.$interface.outerHeight() + this.$galleryCaption.outerHeight();
 215         };
 216
 217         /**
 218          * Sets the height and width of {@link #$img} based on the
 219          * proportion of the image and the values generated by
 220          * {@link #setSizeRequirement}.
 221          *
 222          * @return {boolean} Whether or not the image was sized.
 223          */
 224         mw.GallerySlideshow.prototype.setImageSize = function () {
 225                 if ( this.$img === undefined || this.$thumbnail === undefined ) {
 226                         return false;
 227                 }
 228
 229                 // Reset height and width
 230                 this.$img
 231                         .removeAttr( 'width' )
 232                         .removeAttr( 'height' );
 233
 234                 // Stretch image to take up the required size
 235                 this.$img.attr( 'height', ( this.imageHeight - this.$imgCaption.outerHeight() ) + 'px' );
 236
 237                 // Make the image smaller in case the current image
 238                 // size is larger than the original file size.
 239                 this.getImageInfo( this.$thumbnail ).done( function ( info ) {
 240                         // NOTE: There will be a jump when resizing the window
 241                         // because the cache is cleared and this a new network request.
 242                         if (
 243                                 info.thumbwidth < this.$img.width() ||
 244                                 info.thumbheight < this.$img.height()
 245                         ) {
 246                                 this.$img.attr( 'width', info.thumbwidth + 'px' );
 247                                 this.$img.attr( 'height', info.thumbheight + 'px' );
 248                         }
 249                 }.bind( this ) );
 250
 251                 return true;
 252         };
 253
 254         /**
 255          * Displays the image set as {@link #$currentImage} in the carousel.
 256          */
 257         mw.GallerySlideshow.prototype.showCurrentImage = function () {
 258                 var imageLi = this.getCurrentImage(),
 259                         caption = imageLi.find( '.gallerytext' );
 260
 261                 // The order of the following is important for size calculations
 262                 // 1. Highlight current thumbnail
 263                 this.$gallery
 264                         .find( '.gallerybox.slideshow-current' )
 265                         .removeClass( 'slideshow-current' );
 266                 imageLi.addClass( 'slideshow-current' );
 267
 268                 // 2. Show thumbnail
 269                 this.$thumbnail = imageLi.find( 'img' );
 270                 this.$img.attr( 'src', this.$thumbnail.attr( 'src' ) );
 271                 this.$img.attr( 'alt', this.$thumbnail.attr( 'alt' ) );
 272                 this.$imgLink.attr( 'href', imageLi.find( 'a' ).eq( 0 ).attr( 'href' ) );
 273
 274                 // 3. Copy caption
 275                 this.$imgCaption
 276                         .empty()
 277                         .append( caption.clone() );
 278
 279                 // 4. Stretch thumbnail to correct size
 280                 this.setImageSize();
 281
 282                 // 5. Load image at the required size
 283                 this.loadImage( this.$thumbnail ).done( function ( info, $img ) {
 284                         // Show this image to the user only if its still the current one
 285                         if ( this.$thumbnail.attr( 'src' ) === $img.attr( 'src' ) ) {
 286                                 this.$img.attr( 'src', info.thumburl );
 287                                 this.setImageSize();
 288
 289                                 // Keep the next image ready
 290                                 this.loadImage( this.getNextImage().find( 'img' ) );
 291                         }
 292                 }.bind( this ) );
 293         };
 294
 295         /**
 296          * Loads the full image given the `<img>` element of the thumbnail.
 297          *
 298          * @param {Object} $img
 299          * @return {jQuery.Promise} Resolves with the images URL and original
 300          *      element once the image has loaded.
 301          */
 302         mw.GallerySlideshow.prototype.loadImage = function ( $img ) {
 303                 var img, d = $.Deferred();
 304
 305                 this.getImageInfo( $img ).done( function ( info ) {
 306                         img = new Image();
 307                         img.src = info.thumburl;
 308                         img.onload = function () {
 309                                 d.resolve( info, $img );
 310                         };
 311                         img.onerror = function () {
 312                                 d.reject();
 313                         };
 314                 } ).fail( function () {
 315                         d.reject();
 316                 } );
 317
 318                 return d.promise();
 319         };
 320
 321         /**
 322          * Gets the image's info given an `<img>` element.
 323          *
 324          * @param {Object} $img
 325          * @return {jQuery.Promise} Resolves with the image's info.
 326          */
 327         mw.GallerySlideshow.prototype.getImageInfo = function ( $img ) {
 328                 var api, title, params,
 329                         imageSrc = $img.attr( 'src' );
 330
 331                 // Reject promise if there is no thumbnail image
 332                 if ( $img[ 0 ] === undefined ) {
 333                         return $.Deferred().reject();
 334                 }
 335
 336                 if ( this.imageInfoCache[ imageSrc ] === undefined ) {
 337                         api = new mw.Api();
 338                         // TODO: This supports only gallery of images
 339                         title = mw.Title.newFromImg( $img );
 340                         params = {
 341                                 action: 'query',
 342                                 formatversion: 2,
 343                                 titles: title.toString(),
 344                                 prop: 'imageinfo',
 345                                 iiprop: 'url'
 346                         };
 347
 348                         // Check which dimension we need to request, based on
 349                         // image and container proportions.
 350                         if ( this.getDimensionToRequest( $img ) === 'height' ) {
 351                                 params.iiurlheight = this.imageHeight;
 352                         } else {
 353                                 params.iiurlwidth = this.imageWidth;
 354                         }
 355
 356                         this.imageInfoCache[ imageSrc ] = api.get( params ).then( function ( data ) {
 357                                 if ( OO.getProp( data, 'query', 'pages', 0, 'imageinfo', 0, 'thumburl' ) !== undefined ) {
 358                                         return data.query.pages[ 0 ].imageinfo[ 0 ];
 359                                 } else {
 360                                         return $.Deferred().reject();
 361                                 }
 362                         } );
 363                 }
 364
 365                 return this.imageInfoCache[ imageSrc ];
 366         };
 367
 368         /**
 369          * Given an image, the method checks whether to use the height
 370          * or the width to request the larger image.
 371          *
 372          * @param {jQuery} $img
 373          * @return {string}
 374          */
 375         mw.GallerySlideshow.prototype.getDimensionToRequest = function ( $img ) {
 376                 var ratio = $img.width() / $img.height();
 377
 378                 if ( this.imageHeight * ratio <= this.imageWidth ) {
 379                         return 'height';
 380                 } else {
 381                         return 'width';
 382                 }
 383         };
 384
 385         /**
 386          * Toggles visibility of the thumbnails.
 387          *
 388          * @param {boolean} show Optional argument to control the state
 389          */
 390         mw.GallerySlideshow.prototype.toggleThumbnails = function ( show ) {
 391                 this.$galleryBox.toggle( show );
 392                 this.$carousel.toggleClass( 'mw-gallery-slideshow-thumbnails-toggled', show );
 393         };
 394
 395         /**
 396          * Getter method for {@link #$currentImage}
 397          *
 398          * @return {jQuery}
 399          */
 400         mw.GallerySlideshow.prototype.getCurrentImage = function () {
 401                 this.$currentImage = this.$currentImage || this.$galleryBox.eq( 0 );
 402                 return this.$currentImage;
 403         };
 404
 405         /**
 406          * Gets the image after the current one. Returns the first image if
 407          * the current one is the last.
 408          *
 409          * @return {jQuery}
 410          */
 411         mw.GallerySlideshow.prototype.getNextImage = function () {
 412                 // Not the last image in the gallery
 413                 if ( this.$currentImage.next( '.gallerybox' )[ 0 ] !== undefined ) {
 414                         return this.$currentImage.next( '.gallerybox' );
 415                 } else {
 416                         return this.$galleryBox.eq( 0 );
 417                 }
 418         };
 419
 420         /**
 421          * Gets the image before the current one. Returns the last image if
 422          * the current one is the first.
 423          *
 424          * @return {jQuery}
 425          */
 426         mw.GallerySlideshow.prototype.getPrevImage = function () {
 427                 // Not the first image in the gallery
 428                 if ( this.$currentImage.prev( '.gallerybox' )[ 0 ] !== undefined ) {
 429                         return this.$currentImage.prev( '.gallerybox' );
 430                 } else {
 431                         return this.$galleryBox.last();
 432                 }
 433         };
 434
 435         /**
 436          * Sets the {@link #$currentImage} to the next one and shows
 437          * it in the carousel
 438          */
 439         mw.GallerySlideshow.prototype.nextImage = function () {
 440                 this.$currentImage = this.getNextImage();
 441                 this.showCurrentImage();
 442         };
 443
 444         /**
 445          * Sets the {@link #$currentImage} to the previous one and shows
 446          * it in the carousel
 447          */
 448         mw.GallerySlideshow.prototype.prevImage = function () {
 449                 this.$currentImage = this.getPrevImage();
 450                 this.showCurrentImage();
 451         };
 452
 453         // Bootstrap all slideshow galleries
 454         mw.hook( 'wikipage.content' ).add( function ( $content ) {
 455                 $content.find( '.mw-gallery-slideshow' ).each( function () {
 456                         // eslint-disable-next-line no-new
 457                         new mw.GallerySlideshow( this );
 458                 } );
 459         } );
 460 }() );