resources/src/mediawiki.page.gallery.js

   1 /*!
   2  * Enhance MediaWiki galleries (from the `<gallery>` parser tag).
   3  *
   4  * - Toggle gallery captions when focused.
   5  * - Dynamically resize images to fill horizontal space.
   6  */
   7 ( function ( mw, $ ) {
   8         var $galleries,
   9                 bound = false,
  10                 lastWidth = window.innerWidth,
  11                 justifyNeeded = false,
  12                 // Is there a better way to detect a touchscreen? Current check taken from stack overflow.
  13                 isTouchScreen = !!( window.ontouchstart !== undefined ||
  14                         window.DocumentTouch !== undefined && document instanceof window.DocumentTouch
  15                 );
  16
  17         /**
  18          * Perform the layout justification.
  19          *
  20          * @ignore
  21          * @context {HTMLElement} A `ul.mw-gallery-*` element
  22          */
  23         function justify() {
  24                 var lastTop,
  25                         $img,
  26                         imgWidth,
  27                         imgHeight,
  28                         captionWidth,
  29                         rows = [],
  30                         $gallery = $( this );
  31
  32                 $gallery.children( 'li.gallerybox' ).each( function () {
  33                         // Math.floor to be paranoid if things are off by 0.00000000001
  34                         var top = Math.floor( $( this ).position().top ),
  35                                 $this = $( this );
  36
  37                         if ( top !== lastTop ) {
  38                                 rows[ rows.length ] = [];
  39                                 lastTop = top;
  40                         }
  41
  42                         $img = $this.find( 'div.thumb a.image img' );
  43                         if ( $img.length && $img[ 0 ].height ) {
  44                                 imgHeight = $img[ 0 ].height;
  45                                 imgWidth = $img[ 0 ].width;
  46                         } else {
  47                                 // If we don't have a real image, get the containing divs width/height.
  48                                 // Note that if we do have a real image, using this method will generally
  49                                 // give the same answer, but can be different in the case of a very
  50                                 // narrow image where extra padding is added.
  51                                 imgHeight = $this.children().children( 'div:first' ).height();
  52                                 imgWidth = $this.children().children( 'div:first' ).width();
  53                         }
  54
  55                         // Hack to make an edge case work ok
  56                         if ( imgHeight < 30 ) {
  57                                 // Don't try and resize this item.
  58                                 imgHeight = 0;
  59                         }
  60
  61                         captionWidth = $this.children().children( 'div.gallerytextwrapper' ).width();
  62                         rows[ rows.length - 1 ][ rows[ rows.length - 1 ].length ] = {
  63                                 $elm: $this,
  64                                 width: $this.outerWidth(),
  65                                 imgWidth: imgWidth,
  66                                 // XXX: can divide by 0 ever happen?
  67                                 aspect: imgWidth / imgHeight,
  68                                 captionWidth: captionWidth,
  69                                 height: imgHeight
  70                         };
  71
  72                         // Save all boundaries so we can restore them on window resize
  73                         $this.data( 'imgWidth', imgWidth );
  74                         $this.data( 'imgHeight', imgHeight );
  75                         $this.data( 'width', $this.outerWidth() );
  76                         $this.data( 'captionWidth', captionWidth );
  77                 } );
  78
  79                 ( function () {
  80                         var maxWidth,
  81                                 combinedAspect,
  82                                 combinedPadding,
  83                                 curRow,
  84                                 curRowHeight,
  85                                 wantedWidth,
  86                                 preferredHeight,
  87                                 newWidth,
  88                                 padding,
  89                                 $outerDiv,
  90                                 $innerDiv,
  91                                 $imageDiv,
  92                                 $imageElm,
  93                                 imageElm,
  94                                 $caption,
  95                                 i,
  96                                 j,
  97                                 avgZoom,
  98                                 totalZoom = 0;
  99
 100                         for ( i = 0; i < rows.length; i++ ) {
 101                                 maxWidth = $gallery.width();
 102                                 combinedAspect = 0;
 103                                 combinedPadding = 0;
 104                                 curRow = rows[ i ];
 105                                 curRowHeight = 0;
 106
 107                                 for ( j = 0; j < curRow.length; j++ ) {
 108                                         if ( curRowHeight === 0 ) {
 109                                                 if ( isFinite( curRow[ j ].height ) ) {
 110                                                         // Get the height of this row, by taking the first
 111                                                         // non-out of bounds height
 112                                                         curRowHeight = curRow[ j ].height;
 113                                                 }
 114                                         }
 115
 116                                         if ( curRow[ j ].aspect === 0 || !isFinite( curRow[ j ].aspect ) ) {
 117                                                 // One of the dimensions are 0. Probably should
 118                                                 // not try to resize.
 119                                                 combinedPadding += curRow[ j ].width;
 120                                         } else {
 121                                                 combinedAspect += curRow[ j ].aspect;
 122                                                 combinedPadding += curRow[ j ].width - curRow[ j ].imgWidth;
 123                                         }
 124                                 }
 125
 126                                 // Add some padding for inter-element spacing.
 127                                 combinedPadding += 5 * curRow.length;
 128                                 wantedWidth = maxWidth - combinedPadding;
 129                                 preferredHeight = wantedWidth / combinedAspect;
 130
 131                                 if ( preferredHeight > curRowHeight * 1.5 ) {
 132                                         // Only expand at most 1.5 times current size
 133                                         // As that's as high a resolution as we have.
 134                                         // Also on the off chance there is a bug in this
 135                                         // code, would prevent accidentally expanding to
 136                                         // be 10 billion pixels wide.
 137                                         if ( i === rows.length - 1 ) {
 138                                                 // If its the last row, and we can't fit it,
 139                                                 // don't make the entire row huge.
 140                                                 avgZoom = ( totalZoom / ( rows.length - 1 ) ) * curRowHeight;
 141                                                 if ( isFinite( avgZoom ) && avgZoom >= 1 && avgZoom <= 1.5 ) {
 142                                                         preferredHeight = avgZoom;
 143                                                 } else {
 144                                                         // Probably a single row gallery
 145                                                         preferredHeight = curRowHeight;
 146                                                 }
 147                                         } else {
 148                                                 preferredHeight = 1.5 * curRowHeight;
 149                                         }
 150                                 }
 151                                 if ( !isFinite( preferredHeight ) ) {
 152                                         // This *definitely* should not happen.
 153                                         // Skip this row.
 154                                         continue;
 155                                 }
 156                                 if ( preferredHeight < 5 ) {
 157                                         // Well something clearly went wrong...
 158                                         // Skip this row.
 159                                         continue;
 160                                 }
 161
 162                                 if ( preferredHeight / curRowHeight > 1 ) {
 163                                         totalZoom += preferredHeight / curRowHeight;
 164                                 } else {
 165                                         // If we shrink, still consider that a zoom of 1
 166                                         totalZoom += 1;
 167                                 }
 168
 169                                 for ( j = 0; j < curRow.length; j++ ) {
 170                                         newWidth = preferredHeight * curRow[ j ].aspect;
 171                                         padding = curRow[ j ].width - curRow[ j ].imgWidth;
 172                                         $outerDiv = curRow[ j ].$elm;
 173                                         $innerDiv = $outerDiv.children( 'div' ).first();
 174                                         $imageDiv = $innerDiv.children( 'div.thumb' );
 175                                         $imageElm = $imageDiv.find( 'img' ).first();
 176                                         imageElm = $imageElm.length ? $imageElm[ 0 ] : null;
 177                                         $caption = $outerDiv.find( 'div.gallerytextwrapper' );
 178
 179                                         // Since we are going to re-adjust the height, the vertical
 180                                         // centering margins need to be reset.
 181                                         $imageDiv.children( 'div' ).css( 'margin', '0px auto' );
 182
 183                                         if ( newWidth < 60 || !isFinite( newWidth ) ) {
 184                                                 // Making something skinnier than this will mess up captions,
 185                                                 if ( newWidth < 1 || !isFinite( newWidth ) ) {
 186                                                         $innerDiv.height( preferredHeight );
 187                                                         // Don't even try and touch the image size if it could mean
 188                                                         // making it disappear.
 189                                                         continue;
 190                                                 }
 191                                         } else {
 192                                                 $outerDiv.width( newWidth + padding );
 193                                                 $innerDiv.width( newWidth + padding );
 194                                                 $imageDiv.width( newWidth );
 195                                                 $caption.width( curRow[ j ].captionWidth + ( newWidth - curRow[ j ].imgWidth ) );
 196                                         }
 197
 198                                         if ( imageElm ) {
 199                                                 // We don't always have an img, e.g. in the case of an invalid file.
 200                                                 imageElm.width = newWidth;
 201                                                 imageElm.height = preferredHeight;
 202                                         } else {
 203                                                 // Not a file box.
 204                                                 $imageDiv.height( preferredHeight );
 205                                         }
 206                                 }
 207                         }
 208                 }() );
 209         }
 210
 211         function handleResizeStart() {
 212                 // Only do anything if window width changed. We don't care about the height.
 213                 if ( lastWidth === window.innerWidth ) {
 214                         return;
 215                 }
 216
 217                 justifyNeeded = true;
 218                 // Temporarily set min-height, so that content following the gallery is not reflowed twice
 219                 $galleries.css( 'min-height', function () {
 220                         return $( this ).height();
 221                 } );
 222                 $galleries.children( 'li.gallerybox' ).each( function () {
 223                         var imgWidth = $( this ).data( 'imgWidth' ),
 224                                 imgHeight = $( this ).data( 'imgHeight' ),
 225                                 width = $( this ).data( 'width' ),
 226                                 captionWidth = $( this ).data( 'captionWidth' ),
 227                                 $innerDiv = $( this ).children( 'div' ).first(),
 228                                 $imageDiv = $innerDiv.children( 'div.thumb' ),
 229                                 $imageElm, imageElm;
 230
 231                         // Restore original sizes so we can arrange the elements as on freshly loaded page
 232                         $( this ).width( width );
 233                         $innerDiv.width( width );
 234                         $imageDiv.width( imgWidth );
 235                         $( this ).find( 'div.gallerytextwrapper' ).width( captionWidth );
 236
 237                         $imageElm = $( this ).find( 'img' ).first();
 238                         imageElm = $imageElm.length ? $imageElm[ 0 ] : null;
 239                         if ( imageElm ) {
 240                                 imageElm.width = imgWidth;
 241                                 imageElm.height = imgHeight;
 242                         } else {
 243                                 $imageDiv.height( imgHeight );
 244                         }
 245                 } );
 246         }
 247
 248         function handleResizeEnd() {
 249                 // If window width never changed during the resize, don't do anything.
 250                 if ( justifyNeeded ) {
 251                         justifyNeeded = false;
 252                         lastWidth = window.innerWidth;
 253                         $galleries
 254                                 // Remove temporary min-height
 255                                 .css( 'min-height', '' )
 256                                 // Recalculate layout
 257                                 .each( justify );
 258                 }
 259         }
 260
 261         mw.hook( 'wikipage.content' ).add( function ( $content ) {
 262                 if ( isTouchScreen ) {
 263                         // Always show the caption for a touch screen.
 264                         $content.find( 'ul.mw-gallery-packed-hover' )
 265                                 .addClass( 'mw-gallery-packed-overlay' )
 266                                 .removeClass( 'mw-gallery-packed-hover' );
 267                 } else {
 268                         // Note use of just `a`, not `a.image`, since we also want this to trigger if a link
 269                         // within the caption text receives focus.
 270                         $content.find( 'ul.mw-gallery-packed-hover li.gallerybox' ).on( 'focus blur', 'a', function ( e ) {
 271                                 // Confusingly jQuery leaves e.type as focusout for delegated blur events
 272                                 var gettingFocus = e.type !== 'blur' && e.type !== 'focusout';
 273                                 $( this ).closest( 'li.gallerybox' ).toggleClass( 'mw-gallery-focused', gettingFocus );
 274                         } );
 275                 }
 276
 277                 $galleries = $content.find( 'ul.mw-gallery-packed-overlay, ul.mw-gallery-packed-hover, ul.mw-gallery-packed' );
 278                 // Call the justification asynchronous because live preview fires the hook with detached $content.
 279                 setTimeout( function () {
 280                         $galleries.each( justify );
 281
 282                         // Bind here instead of in the top scope as the callbacks use $galleries.
 283                         if ( !bound ) {
 284                                 bound = true;
 285                                 $( window )
 286                                         .resize( $.debounce( 300, true, handleResizeStart ) )
 287                                         .resize( $.debounce( 300, handleResizeEnd ) );
 288                         }
 289                 } );
 290         } );
 291 }( mediaWiki, jQuery ) );