wiki.techinc.nl/resources/src/mediawiki.page/mediawiki.page.gallery.js

/*!
 * Show gallery captions when focused. Copied directly from jquery.mw-jump.js.
 * Also Dynamically resize images to justify them.
 */
( function ( $ ) {
	$( function () {
		var isTouchScreen,
			gettingFocus,
			galleries = 'ul.mw-gallery-packed-overlay, ul.mw-gallery-packed-hover, ul.mw-gallery-packed';

		// Is there a better way to detect a touchscreen? Current check taken from stack overflow.
		isTouchScreen = !!( window.ontouchstart !== undefined || window.DocumentTouch !== undefined && document instanceof window.DocumentTouch );

		if ( isTouchScreen ) {
			// Always show the caption for a touch screen.
			$( 'ul.mw-gallery-packed-hover' )
				.addClass( 'mw-gallery-packed-overlay' )
				.removeClass( 'mw-gallery-packed-hover' );
		} else {
			// Note use of just "a", not a.image, since we want this to trigger if a link in
			// the caption receives focus
			$( 'ul.mw-gallery-packed-hover li.gallerybox' ).on( 'focus blur', 'a', function ( e ) {
				// Confusingly jQuery leaves e.type as focusout for delegated blur events
				gettingFocus = e.type !== 'blur' && e.type !== 'focusout';
				$( this ).closest( 'li.gallerybox' ).toggleClass( 'mw-gallery-focused', gettingFocus );
			} );
		}

		// Now on to justification.
		function justify() {
			var lastTop,
				$img,
				imgWidth,
				imgHeight,
				captionWidth,
				rows = [],
				$gallery = $( this );

			$gallery.children( 'li' ).each( function () {
				// Math.floor to be paranoid if things are off by 0.00000000001
				var top = Math.floor( $( this ).position().top ),
					$this = $( this );

				if ( top !== lastTop ) {
					rows[rows.length] = [];
					lastTop = top;
				}

				$img = $this.find( 'div.thumb a.image img' );
				if ( $img.length && $img[0].height ) {
					imgHeight = $img[0].height;
					imgWidth = $img[0].width;
				} else {
					// If we don't have a real image, get the containing divs width/height.
					// Note that if we do have a real image, using this method will generally
					// give the same answer, but can be different in the case of a very
					// narrow image where extra padding is added.
					imgHeight = $this.children().children( 'div:first' ).height();
					imgWidth = $this.children().children( 'div:first' ).width();
				}

				// Hack to make an edge case work ok
				if ( imgHeight < 30 ) {
					// Don't try and resize this item.
					imgHeight = 0;
				}

				captionWidth = $this.children().children( 'div.gallerytextwrapper' ).width();
				rows[rows.length - 1][rows[rows.length - 1].length] = {
					$elm: $this,
					width: $this.outerWidth(),
					imgWidth: imgWidth,
					// XXX: can divide by 0 ever happen?
					aspect: imgWidth / imgHeight,
					captionWidth: captionWidth,
					height: imgHeight
				};

				// Save all boundaries so we can restore them on window resize
				$this.data( 'imgWidth', imgWidth );
				$this.data( 'imgHeight', imgHeight );
				$this.data( 'width', $this.outerWidth() );
				$this.data( 'captionWidth', captionWidth );
			} );

			( function () {
				var maxWidth,
					combinedAspect,
					combinedPadding,
					curRow,
					curRowHeight,
					wantedWidth,
					preferredHeight,
					newWidth,
					padding,
					$outerDiv,
					$innerDiv,
					$imageDiv,
					$imageElm,
					imageElm,
					$caption,
					i,
					j,
					avgZoom,
					totalZoom = 0;

				for ( i = 0; i < rows.length; i++ ) {
					maxWidth = $gallery.width();
					combinedAspect = 0;
					combinedPadding = 0;
					curRow = rows[i];
					curRowHeight = 0;

					for ( j = 0; j < curRow.length; j++ ) {
						if ( curRowHeight === 0 ) {
							if ( isFinite( curRow[j].height ) ) {
								// Get the height of this row, by taking the first
								// non-out of bounds height
								curRowHeight = curRow[j].height;
							}
						}

						if ( curRow[j].aspect === 0 || !isFinite( curRow[j].aspect ) ) {
							// One of the dimensions are 0. Probably should
							// not try to resize.
							combinedPadding += curRow[j].width;
						} else {
							combinedAspect += curRow[j].aspect;
							combinedPadding += curRow[j].width - curRow[j].imgWidth;
						}
					}

					// Add some padding for inter-element spacing.
					combinedPadding += 5 * curRow.length;
					wantedWidth = maxWidth - combinedPadding;
					preferredHeight = wantedWidth / combinedAspect;

					if ( preferredHeight > curRowHeight * 1.5 ) {
						// Only expand at most 1.5 times current size
						// As that's as high a resolution as we have.
						// Also on the off chance there is a bug in this
						// code, would prevent accidentally expanding to
						// be 10 billion pixels wide.
						if ( i === rows.length - 1 ) {
							// If its the last row, and we can't fit it,
							// don't make the entire row huge.
							avgZoom = ( totalZoom / ( rows.length - 1 ) ) * curRowHeight;
							if ( isFinite( avgZoom ) && avgZoom >= 1 && avgZoom <= 1.5 ) {
								preferredHeight = avgZoom;
							} else {
								// Probably a single row gallery
								preferredHeight = curRowHeight;
							}
						} else {
							preferredHeight = 1.5 * curRowHeight;
						}
					}
					if ( !isFinite( preferredHeight ) ) {
						// This *definitely* should not happen.
						// Skip this row.
						continue;
					}
					if ( preferredHeight < 5 ) {
						// Well something clearly went wrong...
						// Skip this row.
						continue;
					}

					if ( preferredHeight / curRowHeight > 1 ) {
						totalZoom += preferredHeight / curRowHeight;
					} else {
						// If we shrink, still consider that a zoom of 1
						totalZoom += 1;
					}

					for ( j = 0; j < curRow.length; j++ ) {
						newWidth = preferredHeight * curRow[j].aspect;
						padding = curRow[j].width - curRow[j].imgWidth;
						$outerDiv = curRow[j].$elm;
						$innerDiv = $outerDiv.children( 'div' ).first();
						$imageDiv = $innerDiv.children( 'div.thumb' );
						$imageElm = $imageDiv.find( 'img' ).first();
						imageElm = $imageElm.length ? $imageElm[0] : null;
						$caption = $outerDiv.find( 'div.gallerytextwrapper' );

						// Since we are going to re-adjust the height, the vertical
						// centering margins need to be reset.
						$imageDiv.children( 'div' ).css( 'margin', '0px auto' );

						if ( newWidth < 60 || !isFinite( newWidth ) ) {
							// Making something skinnier than this will mess up captions,
							if ( newWidth < 1 || !isFinite( newWidth ) ) {
								$innerDiv.height( preferredHeight );
								// Don't even try and touch the image size if it could mean
								// making it disappear.
								continue;
							}
						} else {
							$outerDiv.width( newWidth + padding );
							$innerDiv.width( newWidth + padding );
							$imageDiv.width( newWidth );
							$caption.width( curRow[j].captionWidth + ( newWidth - curRow[j].imgWidth ) );
						}

						if ( imageElm ) {
							// We don't always have an img, e.g. in the case of an invalid file.
							imageElm.width = newWidth;
							imageElm.height = preferredHeight;
						} else {
							// Not a file box.
							$imageDiv.height( preferredHeight );
						}
					}
				}
			}() );
		}

		$( galleries ).each( justify );
		$( window ).resize( $.debounce( 300, true, function () {
			$( galleries ).children( 'li' ).each( function () {
				var imgWidth = $( this ).data( 'imgWidth' ),
					imgHeight = $( this ).data( 'imgHeight' ),
					width = $( this ).data( 'width' ),
					captionWidth = $( this ).data( 'captionWidth' ),
					$innerDiv = $( this ).children( 'div' ).first(),
					$imageDiv = $innerDiv.children( 'div.thumb' ),
					$imageElm, imageElm;

				// Restore original sizes so we can arrange the elements as on freshly loaded page
				$( this ).width( width );
				$innerDiv.width( width );
				$imageDiv.width( imgWidth );
				$( this ).find( 'div.gallerytextwrapper' ).width( captionWidth );

				$imageElm = $( this ).find( 'img' ).first();
				imageElm = $imageElm.length ? $imageElm[0] : null;
				if ( imageElm ) {
					imageElm.width = imgWidth;
					imageElm.height = imgHeight;
				} else {
					$imageDiv.height( imgHeight );
				}
			} );
		} ) );
		$( window ).resize( $.debounce( 300, function () {
			$( galleries ).each( justify );
		} ) );
	} );
}( jQuery ) );