Initial commit

drupal7/web/misc/tableheader.js

@@ -0,0 +1,156 @@
+(function ($) {
+
+/**
+ * Attaches sticky table headers.
+ */
+Drupal.behaviors.tableHeader = {
+  attach: function (context, settings) {
+    if (!$.support.positionFixed) {
+      return;
+    }
+
+    $('table.sticky-enabled', context).once('tableheader', function () {
+      $(this).data("drupal-tableheader", new Drupal.tableHeader(this));
+    });
+  }
+};
+
+/**
+ * Constructor for the tableHeader object. Provides sticky table headers.
+ *
+ * @param table
+ *   DOM object for the table to add a sticky header to.
+ */
+Drupal.tableHeader = function (table) {
+  var self = this;
+
+  this.originalTable = $(table);
+  this.originalHeader = $(table).children('thead');
+  this.originalHeaderCells = this.originalHeader.find('> tr > th');
+  this.displayWeight = null;
+
+  // React to columns change to avoid making checks in the scroll callback.
+  this.originalTable.bind('columnschange', function (e, display) {
+    // This will force header size to be calculated on scroll.
+    self.widthCalculated = (self.displayWeight !== null && self.displayWeight === display);
+    self.displayWeight = display;
+  });
+
+  // Clone the table header so it inherits original jQuery properties. Hide
+  // the table to avoid a flash of the header clone upon page load.
+  this.stickyTable = $('<table class="sticky-header"/>')
+    .insertBefore(this.originalTable)
+    .css({ position: 'fixed', top: '0px' });
+  this.stickyHeader = this.originalHeader.clone(true)
+    .hide()
+    .appendTo(this.stickyTable);
+  this.stickyHeaderCells = this.stickyHeader.find('> tr > th');
+
+  this.originalTable.addClass('sticky-table');
+  $(window)
+    .bind('scroll.drupal-tableheader', $.proxy(this, 'eventhandlerRecalculateStickyHeader'))
+    .bind('resize.drupal-tableheader', { calculateWidth: true }, $.proxy(this, 'eventhandlerRecalculateStickyHeader'))
+    // Make sure the anchor being scrolled into view is not hidden beneath the
+    // sticky table header. Adjust the scrollTop if it does.
+    .bind('drupalDisplaceAnchor.drupal-tableheader', function () {
+      window.scrollBy(0, -self.stickyTable.outerHeight());
+    })
+    // Make sure the element being focused is not hidden beneath the sticky
+    // table header. Adjust the scrollTop if it does.
+    .bind('drupalDisplaceFocus.drupal-tableheader', function (event) {
+      if (self.stickyVisible && event.clientY < (self.stickyOffsetTop + self.stickyTable.outerHeight()) && event.$target.closest('sticky-header').length === 0) {
+        window.scrollBy(0, -self.stickyTable.outerHeight());
+      }
+    })
+    .triggerHandler('resize.drupal-tableheader');
+
+  // We hid the header to avoid it showing up erroneously on page load;
+  // we need to unhide it now so that it will show up when expected.
+  this.stickyHeader.show();
+};
+
+/**
+ * Call the header offset function to prevent use of eval().
+ *
+ * @param accessor
+ *   The callback function name.
+ * @return
+ *   The callback result.
+ */
+Drupal.tableHeader.callHeaderOffsetFunction = function(accessor) {
+  accessor = accessor.split('.');
+  var callback = window;
+  for (var i = 0, len = accessor.length - 1; i < len; i++) {
+    if (typeof callback[accessor[i]] !== 'function' && typeof callback[accessor[i]] != 'object') {
+      return 0;
+    }
+    callback = callback[accessor[i]];
+  }
+  if (typeof callback[accessor[accessor.length - 1]] === 'function') {
+    return callback[accessor[accessor.length - 1]]();
+  }
+  return 0;
+};
+
+/**
+ * Event handler: recalculates position of the sticky table header.
+ *
+ * @param event
+ *   Event being triggered.
+ */
+Drupal.tableHeader.prototype.eventhandlerRecalculateStickyHeader = function (event) {
+  var self = this;
+  var calculateWidth = event.data && event.data.calculateWidth;
+
+  // Reset top position of sticky table headers to the current top offset.
+  this.stickyOffsetTop = Drupal.settings.tableHeaderOffset ? Drupal.tableHeader.callHeaderOffsetFunction(Drupal.settings.tableHeaderOffset) : 0;
+  this.stickyTable.css('top', this.stickyOffsetTop + 'px');
+
+  // Save positioning data.
+  var viewHeight = document.documentElement.scrollHeight || document.body.scrollHeight;
+  if (calculateWidth || this.viewHeight !== viewHeight) {
+    this.viewHeight = viewHeight;
+    this.vPosition = this.originalTable.offset().top - 4 - this.stickyOffsetTop;
+    this.hPosition = this.originalTable.offset().left;
+    this.vLength = this.originalTable[0].clientHeight - 100;
+    calculateWidth = true;
+  }
+
+  // Track horizontal positioning relative to the viewport and set visibility.
+  var hScroll = document.documentElement.scrollLeft || document.body.scrollLeft;
+  var vOffset = (document.documentElement.scrollTop || document.body.scrollTop) - this.vPosition;
+  this.stickyVisible = vOffset > 0 && vOffset < this.vLength;
+  this.stickyTable.css({ left: (-hScroll + this.hPosition) + 'px', visibility: this.stickyVisible ? 'visible' : 'hidden' });
+
+  // Only perform expensive calculations if the sticky header is actually
+  // visible or when forced.
+  if (this.stickyVisible && (calculateWidth || !this.widthCalculated)) {
+    this.widthCalculated = true;
+    var $that = null;
+    var $stickyCell = null;
+    var display = null;
+    var cellWidth = null;
+    // Resize header and its cell widths.
+    // Only apply width to visible table cells. This prevents the header from
+    // displaying incorrectly when the sticky header is no longer visible.
+    for (var i = 0, il = this.originalHeaderCells.length; i < il; i += 1) {
+      $that = $(this.originalHeaderCells[i]);
+      $stickyCell = this.stickyHeaderCells.eq($that.index());
+      display = $that.css('display');
+      if (display !== 'none') {
+        cellWidth = $that.css('width');
+        // Exception for IE7.
+        if (cellWidth === 'auto') {
+          cellWidth = $that[0].clientWidth + 'px';
+        }
+        $stickyCell.css({'width': cellWidth, 'display': display});
+      }
+      else {
+        $stickyCell.css('display', 'none');
+      }
+    }
+    this.stickyTable.css('width', this.originalTable.outerWidth());
+  }
+};
+
+})(jQuery);