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