text: /*
   * Copyright (C) 2003, 2009 Apple Inc.  All rights reserved.
   *
   * Portions are Copyright (C) 1998 Netscape Communications Corporation.
   *
   * Other contributors:
   *   Robert O'Callahan <roc+@cs.cmu.edu>
   *   David Baron <dbaron@fas.harvard.edu>
   *   Christian Biesinger <cbiesinger@web.de>
   *   Randall Jesup <rjesup@wgate.com>
   *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
   *   Josh Soref <timeless@mac.com>
   *   Boris Zbarsky <bzbarsky@mit.edu>
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
   *
   * Alternatively, the contents of this file may be used under the terms
   * of either the Mozilla Public License Version 1.1, found at
   * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
   * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
   * (the "GPL"), in which case the provisions of the MPL or the GPL are
   * applicable instead of those above.  If you wish to allow use of your
   * version of this file only under the terms of one of those two
   * licenses (the MPL or the GPL) and not to allow others to use your
   * version of this file under the LGPL, indicate your decision by
   * deletingthe provisions above and replace them with the notice and
   * other provisions required by the MPL or the GPL, as the case may be.
   * If you do not delete the provisions above, a recipient may use your
   * version of this file under any of the LGPL, the MPL or the GPL.
   */
  
  #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_SCROLL_SCROLL_ALIGNMENT_H_
  #define THIRD_PARTY_BLINK_RENDERER_CORE_SCROLL_SCROLL_ALIGNMENT_H_
  
  #include "third_party/blink/renderer/core/core_export.h"
  #include "third_party/blink/renderer/core/scroll/scroll_types.h"
  #include "third_party/blink/renderer/platform/wtf/allocator.h"
  
  namespace blink {
  
  enum ScrollAlignmentBehavior {
    kScrollAlignmentNoScroll,
    kScrollAlignmentCenter,
    kScrollAlignmentTop,
    kScrollAlignmentBottom,
    kScrollAlignmentLeft,
    kScrollAlignmentRight,
    kScrollAlignmentClosestEdge
  };
  
  class LayoutRect;
  
  struct CORE_EXPORT ScrollAlignment {
    STACK_ALLOCATED();
  
   public:
    static ScrollAlignmentBehavior GetVisibleBehavior(const ScrollAlignment& s) {
      return s.rect_visible_;
    }
    static ScrollAlignmentBehavior GetPartialBehavior(const ScrollAlignment& s) {
      return s.rect_partial_;
    }
    static ScrollAlignmentBehavior GetHiddenBehavior(const ScrollAlignment& s) {
      return s.rect_hidden_;
    }
  
    // Returns the scroll offset the scroller needs to scroll to in order to put
    // |expose_rect| into |visible_scroll_snapport_rect| aligned by |align_x| and
    // |align_y|.
    // The coordinates for |visible_scroll_snapport_rect|, |expose_rect| and
    // |current_scroll_position| are based on the scroller's scroll_origin
    // Note that the |current_scroll_offset| is not the location of
    // |visible_scroll_snapport_rect|, as |visible_scroll_snapport_rect| is the
    // visible rect contracted by its scroll-padding.
    // FIXME: This function should probably go somewhere else but where?
    static ScrollOffset GetScrollOffsetToExpose(
        const LayoutRect& visible_scroll_snapport_rect,
        const LayoutRect& expose_rect,
        const ScrollAlignment& align_x,
        const ScrollAlignment& align_y,
        const ScrollOffset& current_scroll_offset);
  
    static const ScrollAlignment kAlignCenterIfNeeded;
    static const ScrollAlignment kAlignToEdgeIfNeeded;
    static const ScrollAlignment kAlignCenterAlways;
    static const ScrollAlignment kAlignTopAlways;
    static const ScrollAlignment kAlignBottomAlways;
    static const ScrollAlignment kAlignLeftAlways;
    static const ScrollAlignment kAlignRightAlways;
  
    ScrollAlignmentBehavior rect_visible_;
    ScrollAlignmentBehavior rect_hidden_;
    ScrollAlignmentBehavior rect_partial_;
  };
  
  inline bool PLATFORM_EXPORT operator==(const ScrollAlignment& lhs,
                                         const ScrollAlignment& rhs) {
    return lhs.rect_visible_ == rhs.rect_visible_ &&
           lhs.rect_hidden_ == rhs.rect_hidden_ &&
           lhs.rect_partial_ == rhs.rect_partial_;
  }
  
  }  // namespace blink
  
  #endif  // THIRD_PARTY_BLINK_RENDERER_CORE_SCROLL_SCROLL_ALIGNMENT_H_
  