third_party/WebKit/Source/web/ResizeViewportAnchor.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ResizeViewportAnchor_h
   6 #define ResizeViewportAnchor_h
   7
   8 #include "platform/geometry/DoublePoint.h"
   9 #include "platform/heap/Handle.h"
  10 #include "web/ViewportAnchor.h"
  11
  12 namespace blink {
  13
  14 class FrameView;
  15 class VisualViewport;
  16
  17 // The resize anchor saves the current scroll offset of the visual viewport and
  18 // restores to that scroll offset so that document location appears exactly
  19 // unchanged to the user.
  20 class ResizeViewportAnchor : public ViewportAnchor {
  21     STACK_ALLOCATED();
  22 public:
  23     ResizeViewportAnchor(FrameView& rootFrameView, VisualViewport&);
  24     ~ResizeViewportAnchor();
  25
  26 private:
  27     // Inner viewport origin in the reference frame of the root document, in CSS
  28     // pixels.
  29     DoublePoint m_visualViewportInDocument;
  30 };
  31
  32 } // namespace blink
  33
  34 #endif // ResizeViewportAnchor_h