NRuby

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/*
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 * Navigation allows movement using the arrow keys through the search results.
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 *
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 * When using this library you will need to set scrollIntoView to the
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 * appropriate function for your layout.  Use scrollInWindow if the container
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 * is not scrollable and scrollInElement if the container is a separate
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 * scrolling region.
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 */
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Navigation = new function() {
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  this.initNavigation = function() {
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    var _this = this;
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    document.addEventListener('keydown', function(e) {
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      _this.onkeydown(e);
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    });
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    this.navigationActive = true;
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  }
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  this.setNavigationActive = function(state) {
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    this.navigationActive = state;
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  }
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  this.onkeydown = function(e) {
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    if (!this.navigationActive) return;
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    switch(e.keyCode) {
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      case 37: //Event.KEY_LEFT:
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        if (this.moveLeft()) e.preventDefault();
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        break;
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      case 38: //Event.KEY_UP:
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        if (e.keyCode == 38 || e.ctrlKey) {
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          if (this.moveUp()) e.preventDefault();
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        }
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        break;
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      case 39: //Event.KEY_RIGHT:
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        if (this.moveRight()) e.preventDefault();
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        break;
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      case 40: //Event.KEY_DOWN:
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        if (e.keyCode == 40 || e.ctrlKey) {
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          if (this.moveDown()) e.preventDefault();
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        }
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        break;
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      case 13: //Event.KEY_RETURN:
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        if (this.current) e.preventDefault();
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        this.select(this.current);
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        break;
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    }
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    if (e.ctrlKey && e.shiftKey) this.select(this.current);
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  }
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  this.moveRight = function() {
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  }
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  this.moveLeft = function() {
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  }
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  this.move = function(isDown) {
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  }
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  this.moveUp = function() {
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    return this.move(false);
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  }
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  this.moveDown = function() {
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    return this.move(true);
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  }
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  /*
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   * Scrolls to the given element in the scrollable element view.
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   */
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  this.scrollInElement = function(element, view) {
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    var offset, viewHeight, viewScroll, height;
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    offset = element.offsetTop;
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    height = element.offsetHeight;
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    viewHeight = view.offsetHeight;
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    viewScroll = view.scrollTop;
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    if (offset - viewScroll + height > viewHeight) {
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      view.scrollTop = offset - viewHeight + height;
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    }
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    if (offset < viewScroll) {
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      view.scrollTop = offset;
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    }
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  }
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  /*
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   * Scrolls to the given element in the window.  The second argument is
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   * ignored
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   */
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  this.scrollInWindow = function(element, ignored) {
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    var offset, viewHeight, viewScroll, height;
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    offset = element.offsetTop;
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    height = element.offsetHeight;
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    viewHeight = window.innerHeight;
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    viewScroll = window.scrollY;
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    if (offset - viewScroll + height > viewHeight) {
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      window.scrollTo(window.scrollX, offset - viewHeight + height);
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    }
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    if (offset < viewScroll) {
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      window.scrollTo(window.scrollX, offset);
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    }
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  }
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}
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